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Diepeveen MH, Lathouwers D, José Santo R, Hoogeman MS, Habraken SJM. Two-dimensional oxygen-diffusion modelling for FLASH proton therapy with pencil beam scanning-Impact of diffusive tissue properties, dose, dose rate and scan patterns. Phys Med Biol 2024; 69:155020. [PMID: 38959905 DOI: 10.1088/1361-6560/ad5eee] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 07/03/2024] [Indexed: 07/05/2024]
Abstract
Objective.Oxygen depletion is generally believed to play an important role in the FLASH effect-a differential reduction of the radiosensitivity of healthy tissues, relative to that of the tumour under ultra-high dose-rate (UHDR) irradiation conditions. In proton therapy (PT) with pencil-beam scanning (PBS), the deposition of dose, and, hence, the degree of (radiolytic) oxygen depletion varies both spatially and temporally. Therefore, the resulting oxygen concentration and the healthy-tissue sparing effect through radiation-induced hypoxia varies both spatially and temporally as well.Approach.We propose and numerically solve a physical oxygen diffusion model to study these effects and their dependence on tissue parameters and the scan pattern in pencil-beam delivery. Since current clinical FLASH PT (FLASH-PT) is based on 250 MeV shoot-through (transmission) beams, for which dose and dose rate (DR) hardly vary with depth compared to the variation transverse to the beam axis, we focus on the two-dimensional case. We numerically integrate the model to obtain the oxygen concentration in each voxel as a function of time and extract voxel-based and spatially and temporarily integrated metrics for oxygen (FLASH) enhanced dose. Furthermore, we evaluate the impact on oxygen enhancement of standard pencil-beam delivery patterns and patterns that were optimised on dose-rate. Our model can contribute to the identification of tissue properties and pencil-beam delivery parameters that are critical for FLASH-PT and it may be used for the optimisation of FLASH-PT treatment plans and their delivery.Main results.(i) the diffusive properties of oxygen are critical for the steady state concentration and therefore the FLASH effect, even more so in two dimensions when compared to one dimension. (ii) The FLASH effect through oxygen depletion depends primarily on dose and less on other parameters. (iii) At a fixed fraction dose there is a slight dependence on DR. (iv) Scan patterns optimised on DR slightly increase the oxygen induced FLASH effect.Significance.To our best knowledge, this is the first study assessing the impact of scan-pattern optimization (SPO) in FLASH-PT with PBS on a biological FLASH model. While the observed impact of SPO is relatively small, a larger effect is expected for larger target volumes. A better understanding of the FLASH effect and the role of oxygen (depletion) therein is essential for the further development of FLASH-PT with PBS, and SPO.
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Affiliation(s)
- Maarten H Diepeveen
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, The Netherlands
- Delft University of Technology, Department of Radiation Science and Technology, Delft, The Netherlands
| | - Danny Lathouwers
- Delft University of Technology, Department of Radiation Science and Technology, Delft, The Netherlands
- Holland Proton Therapy Center, Department of Medical Physics and Informatics, Delft, The Netherlands
| | - Rodrigo José Santo
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, The Netherlands
- Holland Proton Therapy Center, Department of Medical Physics and Informatics, Delft, The Netherlands
| | - Mischa S Hoogeman
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, The Netherlands
- Delft University of Technology, Department of Radiation Science and Technology, Delft, The Netherlands
- Holland Proton Therapy Center, Department of Medical Physics and Informatics, Delft, The Netherlands
| | - Steven J M Habraken
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, The Netherlands
- Holland Proton Therapy Center, Department of Medical Physics and Informatics, Delft, The Netherlands
- Leiden University Medical Center, Department of Radiotherapy,Leiden, The Netherlands
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Kyle AH, Karan T, Baker JHE, Püspöky Banáth J, Wang T, Liu A, Mendez C, Peter Petric M, Duzenli C, Minchinton AI. Detection of FLASH-radiotherapy tissue sparing in a 3D-spheroid model using DNA damage response markers. Radiother Oncol 2024; 196:110326. [PMID: 38735536 DOI: 10.1016/j.radonc.2024.110326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 04/07/2024] [Accepted: 04/28/2024] [Indexed: 05/14/2024]
Abstract
PURPOSE The oxygen depletion hypothesis has been proposed as a rationale to explain the observed phenomenon of FLASH-radiotherapy (FLASH-RT) sparing normal tissues while simultaneously maintaining tumor control. In this study we examined the distribution of DNA Damage Response (DDR) markers in irradiated 3D multicellular spheroids to explore the relationship between FLASH-RT protection and radiolytic-oxygen-consumption (ROC) in tissues. METHODS Studies were performed using a Varian Truebeam linear accelerator delivering 10 MeV electrons with an average dose rate above 50 Gy/s. Irradiations were carried out on 3D spheroids maintained under a range of O2 and temperature conditions to control O2 consumption and create gradients representative of in vivo tissues. RESULTS Staining for pDNA-PK (Ser2056) produced a linear radiation dose response whereas γH2AX (Ser139) showed saturation with increasing dose. Using the pDNA-PK staining, radiation response was then characterised for FLASH compared to standard-dose-rates as a function of depth into the spheroids. At 4 °C, chosen to minimize the development of metabolic oxygen gradients within the tissues, FLASH protection could be observed at all distances under oxygen conditions of 0.3-1 % O2. Whereas at 37 °C a FLASH-protective effect was limited to the outer cell layers of tissues, an effect only observed at 3 % O2. Modelling of changes in the pDNA-PK-based oxygen enhancement ratio (OER) yielded a tissue ROC g0-value estimate of 0.73 ± 0.25 µM/Gy with a km of 5.4 µM at FLASH dose rates. CONCLUSIONS DNA damage response markers are sensitive to the effects of transient oxygen depletion during FLASH radiotherapy. Findings support the rationale that well-oxygenated tissues would benefit more from FLASH-dose-rate protection relative to poorly-oxygenated tissues.
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Affiliation(s)
| | | | | | | | | | - Anam Liu
- BC Cancer Research Institute, Vancouver, Canada
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Ma J, Lin Y, Tang M, Zhu YN, Gan GN, Rotondo RL, Chen RC, Gao H. Simultaneous dose and dose rate optimization via dose modifying factor modeling for FLASH effective dose. Med Phys 2024. [PMID: 38873848 DOI: 10.1002/mp.17251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/28/2024] [Accepted: 05/31/2024] [Indexed: 06/15/2024] Open
Abstract
BACKGROUND Although the FLASH radiotherapy (FLASH) can improve the sparing of organs-at-risk (OAR) via the FLASH effect, it is generally a tradeoff between the physical dose coverage and the biological FLASH coverage, for which the concept of FLASH effective dose (FED) is needed to quantify the net improvement of FLASH, compared to the conventional radiotherapy (CONV). PURPOSE This work will develop the first-of-its-kind treatment planning method called simultaneous dose and dose rate optimization via dose modifying factor modeling (SDDRO-DMF) for proton FLASH that directly optimizes FED. METHODS SDDRO-DMF models and optimizes FED using FLASH dose modifying factor (DMF) models, which can be classified into two categories: (1) the phenomenological model of the FLASH effect, such as the FLASH effectiveness model (FEM); (2) the mechanistic model of the FLASH radiobiology, such as the radiolytic oxygen depletion (ROD) model. The general framework of SDDRO-DMF will be developed, with specific DMF models using FEM and ROD, as a demonstration of general applicability of SDDRO-DMF for proton FLASH via transmission beams (TB) or Bragg peaks (BP) with single-field or multi-field irradiation. The FLASH dose rate is modeled as pencil beam scanning dose rate. The solution algorithm for solving the inverse optimization problem of SDDRO-DMF is based on iterative convex relaxation method. RESULTS SDDRO-DMF is validated in comparison with IMPT and a state-of-the-art method called SDDRO, with demonstrated efficacy and improvement for reducing the high dose and the high-dose volume for OAR in terms of FED. For example, in a SBRT lung case of the dose-limiting factor that the max dose of brachial plexus should be no more than 26 Gy, only SDDRO-DMF met this max dose constraint; moreover, SDDRO-DMF completely eliminated the high-dose (V70%) volume to zero for CTV10mm (a high-dose region as a 10 mm ring expansion of CTV). CONCLUSION We have proposed a new proton FLASH optimization method called SDDRO-DMF that directly optimizes FED using phenomenological or mechanistic models of DMF, and have demonstrated the efficacy of SDDO-DMF in reducing the high-dose volume or/and the high-dose value for OAR, compared to IMPT and a state-of-the-art method SDDRO.
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Affiliation(s)
- Jiangjun Ma
- Institute of Natural Sciences and School of Mathematics, Shanghai Jiao Tong University, Shanghai, China
| | - Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
| | - Min Tang
- Institute of Natural Sciences and School of Mathematics, Shanghai Jiao Tong University, Shanghai, China
| | - Ya-Nan Zhu
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
| | - Gregory N Gan
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
| | - Ronny L Rotondo
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
| | - Ronald C Chen
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas city, Kansas, USA
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Zhao X, Huang S, Lin H, Choi JI, Zhu K, Simone CB, Yan X, Kang M. A Novel Dose Rate Optimization Method to Maximize Ultrahigh-Dose-Rate Coverage of Critical Organs at Risk Without Compromising Dosimetry Metrics in Proton Pencil Beam Scanning FLASH Radiation Therapy. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00735-1. [PMID: 38879087 DOI: 10.1016/j.ijrobp.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/12/2024] [Accepted: 06/09/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE This study aimed to investigate a dose rate optimization framework based on the spot-scanning patterns to improve ultrahigh-dose-rate coverage of critical organs at risk (OARs) for proton pencil beam scanning (PBS) FLASH radiation therapy (ultrahigh dose-rate (often referred to as >40 Gy per second) delivery) and present implementation of a genetic algorithm (GA) method for spot sequence optimization to achieve PBS FLASH dose rate optimization under relatively low nozzle beam currents. METHODS AND MATERIALS First, a multifield FLASH plan was developed to meet all the dosimetric goals and optimal FLASH dose rate coverage by considering the deliverable minimum monitor unit constraint. Then, a GA method was implemented into the in-house treatment platform to maximize the dose rate by exploring the best spot delivery sequence. A phantom study was performed to evaluate the effectiveness of the dose rate optimization. Then, 10 consecutive plans for patients with lung cancer previously treated using PBS intensity-modulated proton therapy were optimized using 45 GyRBE in 3 fractions for both transmission and Bragg peak FLASH radiation therapy for further validation. The spot delivery sequence of each treatment field was optimized using this GA. The ultrahigh-dose-rate-volume histogram and dose rate coverage V40GyRBE/s were investigated to assess the efficacy of dose rate optimization quantitatively. RESULTS Using a relatively low monitor unit/spot of 150, corresponding to a nozzle beam current of 65 nA, the FLASH dose rate ratio V40GyRBE/s of the OAR contour of the core was increased from 0% to ∼60% in the phantom study. In the patients with lung cancer, the ultrahigh-dose-rate coverage V40GyRBE/s was improved from 15.2%, 15.5%, 17.6%, and 16.0% before the delivery sequence optimization to 31.8%, 43.5%, 47.6%, and 30.5% after delivery sequence optimization in the lungs-GTV (gross tumor volume), spinal cord, esophagus, and heart (for all, P < .001). When the beam current increased to 130 nA, V40GyRBE/s was improved from 45.1%, 47.1%, 51.2%, and 51.4% to 65.3%, 83.5%, 88.1%, and 69.4% (P < .05). The averaged V40GyRBE/s for the target and OARs increased from 12.9% to 41.6% and 46.3% to 77.5% for 65 and 130 nA, respectively, showing significant improvements based on a clinical proton system. After optimizing the dose rate for the Bragg peak FLASH technique with a beam current of 340 nA, the V40GyRBE/s values for the lung GTV, spinal cord, esophagus, and heart were increased by 8.9%, 15.8%, 22%, and 20.8%, respectively. CONCLUSIONS An optimal plan quality can be maintained as the spot delivery sequence optimization is a separate independent process after the plan optimization. Both the phantom and patient results demonstrated that novel spot delivery sequence optimization can effectively improve the ultrahigh-dose-rate coverage for critical OARs, which can potentially be applied in clinical practice for better OARs-sparing efficacy.
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Affiliation(s)
- Xingyi Zhao
- State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, Center for Applied Physics and Technology, Peking University, Beijing, China; New York Proton Center, New York, New York
| | - Sheng Huang
- Radiation Oncology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Haibo Lin
- New York Proton Center, New York, New York; Departments of Radiation Oncology and Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - J Isabelle Choi
- New York Proton Center, New York, New York; Departments of Radiation Oncology and Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Kun Zhu
- State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, Center for Applied Physics and Technology, Peking University, Beijing, China
| | - Charles B Simone
- New York Proton Center, New York, New York; Departments of Radiation Oncology and Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Xueqing Yan
- State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, Center for Applied Physics and Technology, Peking University, Beijing, China.
| | - Minglei Kang
- New York Proton Center, New York, New York; Departments of Radiation Oncology and Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
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Taylor E, Létourneau D. How quickly does FLASH need to be delivered? A theoretical study of radiolytic oxygen depletion kinetics in tissues. Phys Med Biol 2024; 69:115008. [PMID: 38608644 DOI: 10.1088/1361-6560/ad3e5e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 04/12/2024] [Indexed: 04/14/2024]
Abstract
Purpose. Radiation delivered over ultra-short timescales ('FLASH' radiotherapy) leads to a reduction in normal tissue toxicities for a range of tissues in the preclinical setting. Experiments have shown this reduction occurs for total delivery times less than a 'critical' time that varies by two orders of magnitude between brain (∼0.3 s) and skin (⪆10 s), and three orders of magnitude across different bowel experiments, from ∼0.01 to ⪆(1-10) s. Understanding the factors responsible for this broad variation may be important for translation of FLASH into the clinic and understanding the mechanisms behind FLASH.Methods.Assuming radiolytic oxygen depletion (ROD) to be the primary driver of FLASH effects, oxygen diffusion, consumption, and ROD were evaluated numerically for simulated tissues with pseudorandom vasculatures for a range of radiation delivery times, capillary densities, and oxygen consumption rates (OCR's). The resulting time-dependent oxygen partial pressure distribution histograms were used to estimate cell survival in these tissues using the linear quadratic model, modified to incorporate oxygen-enhancement ratio effects.Results. Independent of the capillary density, there was a substantial increase in predicted cell survival when the total delivery time was less than the capillary oxygen tension (mmHg) divided by the OCR (expressed in units of mmHg/s), setting the critical delivery time for FLASH in simulated tissues. Using literature OCR values for different normal tissues, the predicted range of critical delivery times agreed well with experimental values for skin and brain and, modifying our model to allow for fluctuating perfusion, bowel.Conclusions. The broad three-orders-of-magnitude variation in critical irradiation delivery times observed inin vivopreclinical experiments can be accounted for by the ROD hypothesis and differences in the OCR amongst simulated normal tissues. Characterization of these may help guide future experiments and open the door to optimized tissue-specific clinical protocols.
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Affiliation(s)
- Edward Taylor
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Daniel Létourneau
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
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Tang R, Yin J, Liu Y, Xue J. FLASH radiotherapy: A new milestone in the field of cancer radiotherapy. Cancer Lett 2024; 587:216651. [PMID: 38342233 DOI: 10.1016/j.canlet.2024.216651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/03/2023] [Accepted: 01/13/2024] [Indexed: 02/13/2024]
Abstract
Radiotherapy plays a pivotal role in the control and eradication of tumors, but it can also induce radiation injury to surrounding normal tissues while targeting tumor cells. In recent years, FLASH-Radiotherapy (FLASH-RT) has emerged as a cutting-edge research focus in the field of radiation therapy. By delivering high radiation doses to the treatment target in an ultra-short time, FLASH-RT produces the FLASH effect, which reduces the toxicity to normal tissues while achieving comparable tumor control efficacy to conventional radiotherapy. This review provides a brief overview of the development history of FLASH-RT and its impact on tumor control. Additionally, it focuses on introducing the protective effects and molecular mechanisms of this technology on various normal tissues, as well as exploring its synergistic effects when combined with other tumor therapies. Importantly, this review discusses the challenges faced in translating FLASH-RT into clinical practice and outlines its promising future applications.
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Affiliation(s)
- Rui Tang
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China; Division of Thoracic Tumor Multimodality Treatment, Cancer Center, The National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jianqiong Yin
- Division of Thoracic Tumor Multimodality Treatment, Cancer Center, The National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yuanxin Liu
- Division of Thoracic Tumor Multimodality Treatment, Cancer Center, The National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jianxin Xue
- Division of Thoracic Tumor Multimodality Treatment, Cancer Center, The National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China; Department of Radiation Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China; Laboratory of Clinical Cell Therapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China; Disaster Medical Center, Sichuan University, Chengdu, 610041, Sichuan, China.
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Zeng Y, Li H, Wang W, Liu X, Qin B, Dai S, Pang B, Liu M, Quan H, Yang K, Chang Y, Yang Z. Feasibility study of multiple-energy Bragg peak proton FLASH on a superconducting gantry with large momentum acceptance. Med Phys 2024; 51:2164-2174. [PMID: 38169535 DOI: 10.1002/mp.16932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/30/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND While the Bragg peak proton beam (BP) is capable of superior target conformity and organs-at-risk sparing than the transmission proton beam (TB), its efficacy in FLASH-RT is hindered by both a slow energy switching process and the beam current. A universal range shifter (URS) can pull back the high-energy proton beam while preserving the beam current. Meanwhile, a superconducting gantry with large momentum acceptance (LMA-SC gantry) enables fast energy switching. PURPOSE This study explores the feasibility of multiple-energy BP FLASH-RT on the LMA-SC gantry. METHOD AND MATERIALS A simultaneous dose and spot map optimization algorithm was developed for BP FLASH-RT treatment planning to improve the dose delivery efficiency. The URS was designed to be 0-27 cm thick, with 1 cm per step. BP plans using the URS were optimized using single-field optimization (SFO) and multiple-field optimization (MFO) for ten prostate cancer patients and ten lung cancer patients. The plan delivery parameters, dose, and dose rate metrics of BP plans were compared to those of TB plans using the parameters of the LMA-SC gantry. RESULTS Compared to TB plans, BP plans significantly reduced MUs by 42.7% (P < 0.001) with SFO and 33.3% (P < 0.001) with MFO for prostate cases. For lung cases, the reduction in MUs was 56.8% (P < 0.001) with SFO and 36.4% (P < 0.001) with MFO. BP plans also outperformed TB plans by reducing mean normal tissue doses. BP-SFO plans achieved a reduction of 56.7% (P < 0.001) for prostate cases and 57.7% (P < 0.001) for lung cases, while BP-MFO plans achieved a reduction of 54.2% (P < 0.001) for the prostate case and 40.0% (P < 0.001) for lung cases. For both TB and BP plans, normal tissues in prostate and lung cases received 100.0% FLASH dose rate coverage (>40 Gy/s). CONCLUSIONS By utilizing the URS and the LMA-SC gantry, it is possible to perform multiple-energy BP FLASH-RT, resulting in better normal tissue sparing, as compared to TB plans.
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Affiliation(s)
- Yiling Zeng
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, China
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
| | - Heng Li
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Wei Wang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Xu Liu
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Qin
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Shuyang Dai
- School of Mathematics and Statistics, Wuhan University, Wuhan, P. R. China
| | - Bo Pang
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Muyu Liu
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Hong Quan
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, China
| | - Kunyu Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
| | - Yu Chang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
| | - Zhiyong Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
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Zhu H, Schuemann J, Zhang Q, Gerweck LE. Modeling the impact of tissue oxygen profiles and oxygen depletion parameter uncertainties on biological response and therapeutic benefit of FLASH. Med Phys 2024; 51:670-681. [PMID: 36939370 PMCID: PMC10509320 DOI: 10.1002/mp.16366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/22/2023] [Accepted: 03/06/2023] [Indexed: 03/21/2023] Open
Abstract
BACKGROUND Ultra-high dose rate (FLASH) radiation has been reported to efficiently suppress tumor growth while sparing normal tissue; however, the mechanism of the differential tissue sparing effect is still not known. Oxygen has long been known to profoundly impact radiobiological responses, and radiolytic oxygen depletion has been considered to be a possible cause or contributor to the FLASH phenomenon. PURPOSE This work investigates the impact of tissue pO2 profiles, oxygen depletion per unit dose (g), and the oxygen concentration yielding half-maximum radiosensitization (the average of its maximum value and one) (k) in tumor and normal tissue. METHODS We developed a model that considers the dependent relationship between oxygen depletion and change of radiosensitivity by FLASH irradiation. The model assumed that FLASH irradiation depletes intracellular oxygen more rapidly than it diffuses into the cell from the extracellular environment. Cell survival was calculated based on the linear quadratic-linear model and the radiosensitivity related parameters were adjusted in 1 Gy increments of the administered dose. The model reproduced published experimental data that were obtained with different cell lines and oxygen concentrations, and was used to analyze the impact of parameter uncertainties on the radiobiological responses. This study expands the oxygen depletion analysis of FLASH to normal human tissue and tumor based on clinically determined aggregate and individual patient pO2 profiles. RESULTS The results show that the pO2 profile is the most essential factor that affects biological response and analyses based on the median pO2 rather than the full pO2 profile can be unreliable and misleading. Additionally, the presence of a small fraction of cells on the threshold of radiobiologic hypoxia substantially alters biological response due to FLASH oxygen depletion. We found that an increment in the k value is generally more protective of tumor than normal tissue due to a higher frequency of lower pO2 values in tumors. Variation in the g value affects the dose at which oxygen depletion impacts response, but does not alter the dose-dependent response trends, if the g value is identical in both tumor and normal tissue. CONCLUSIONS The therapeutic efficacy of FLASH oxygen depletion is likely patient and tissue-dependent. For breast cancer, FLASH is beneficial in a minority of cases; however, in a subset of well oxygenated tumors, a therapeutic gain may be realized due to induced normal tissue hypoxia.
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Affiliation(s)
- Hongyu Zhu
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Qixian Zhang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Leo E Gerweck
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, United States of America
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Beckers C, Pruschy M, Vetrugno I. Tumor hypoxia and radiotherapy: A major driver of resistance even for novel radiotherapy modalities. Semin Cancer Biol 2024; 98:19-30. [PMID: 38040401 DOI: 10.1016/j.semcancer.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023]
Abstract
Hypoxia in solid tumors is an important predictor of poor clinical outcome to radiotherapy. Both physicochemical and biological processes contribute to a reduced sensitivity of hypoxic tumor cells to ionizing radiation and hypoxia-related treatment resistances. A conventional low-dose fractionated radiotherapy regimen exploits iterative reoxygenation in between the individual fractions, nevertheless tumor hypoxia still remains a major hurdle for successful treatment outcome. The technological advances achieved in image guidance and highly conformal dose delivery make it nowadays possible to prescribe larger doses to the tumor as part of single high-dose or hypofractionated radiotherapy, while keeping an acceptable level of normal tissue complication in the co-irradiated organs at risk. However, we insufficiently understand the impact of tumor hypoxia to single high-doses of RT and hypofractionated RT. So-called FLASH radiotherapy, which delivers ionizing radiation at ultrahigh dose rates (> 40 Gy/sec), has recently emerged as an important breakthrough in the radiotherapy field to reduce normal tissue toxicity compared to irradiation at conventional dose rates (few Gy/min). Not surprisingly, oxygen consumption and tumor hypoxia also seem to play an intriguing role for FLASH radiotherapy. Here we will discuss the role of tumor hypoxia for radiotherapy in general and in the context of novel radiotherapy treatment approaches.
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Affiliation(s)
- Claire Beckers
- Laboratory for Applied Radiobiology, Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Martin Pruschy
- Laboratory for Applied Radiobiology, Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
| | - Irene Vetrugno
- Laboratory for Applied Radiobiology, Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Gupta S, Inman JL, De Chant J, Obst-Huebl L, Nakamura K, Costello SM, Marqusee S, Mao JH, Kunz L, Paisley R, Vozenin MC, Snijders AM, Ralston CY. A Novel Platform for Evaluating Dose Rate Effects on Oxidative Damage to Peptides: Toward a High-Throughput Method to Characterize the Mechanisms Underlying the FLASH Effect. Radiat Res 2023; 200:523-530. [PMID: 38014573 PMCID: PMC10754258 DOI: 10.1667/rade-23-00131.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/05/2023] [Indexed: 11/29/2023]
Abstract
High dose rate radiation has gained considerable interest recently as a possible avenue for increasing the therapeutic window in cancer radiation treatment. The sparing of healthy tissue at high dose rates relative to conventional dose rates, while maintaining tumor control, has been termed the FLASH effect. Although the effect has been validated in animal models using multiple radiation sources, it is not yet well understood. Here, we demonstrate a new experimental platform for quantifying oxidative damage to protein sidechains in solution as a function of radiation dose rate and oxygen availability using liquid chromatography mass spectrometry. Using this reductionist approach, we show that for both X-ray and electron sources, isolated peptides in solution are oxidatively modified to different extents as a function of both dose rate and oxygen availability. Our method provides an experimental platform for exploring the parameter space of the dose rate effect on oxidative changes to proteins in solution.
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Affiliation(s)
- Sayan Gupta
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Jamie L. Inman
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Jared De Chant
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Lieselotte Obst-Huebl
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Kei Nakamura
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Shawn M. Costello
- Biophysics Graduate Program, Department of Chemistry; California Institute for Quantitative Biosciences, University of California, Berkeley, Califormia; Chan Zuckerberg Biohub, San Francisco, California
| | - Susan Marqusee
- Department of Molecular and Cell Biology, Department of Chemistry; California Institute for Quantitative Biosciences, University of California, Berkeley, Califormia; Chan Zuckerberg Biohub, San Francisco, California
| | - Jian-Hua Mao
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Louis Kunz
- University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Ryan Paisley
- University Hospital and University of Lausanne, Lausanne, Switzerland
| | | | - Antoine M. Snijders
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Corie Y. Ralston
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
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11
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Ma J, Gao H, Shen X, Bai X, Tang M. A FLASH model of radiolytic oxygen depletion and reactive oxygen species for differential tumor and normal-tissue response. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.10.20.23297337. [PMID: 37961572 PMCID: PMC10635166 DOI: 10.1101/2023.10.20.23297337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Objective FLASH-RT can potentially improve the sparing of normal tissues while preserving the tumoricidal efficiency, owing to the radiation with ultra-high dose rate. However, the FLASH mechanism remains to be solved. A popular FLASH model is based on radiolytic oxygen depletion (ROD), which explains for radiation protection of normal tissues under FLASH-RT. However, ROD does not explain the preservation of tumoricidal efficiency for tumors. This work will develop a ROS+ROD FLASH model that can explain the differential tumor and normal-tissue response. Approach The new FLASH model utilizes reactive oxygen species (ROS) in addition to ROD, and takes into account that ROS level decreases during FLASH-RT. Specifically, the differential-equation model takes into account that the basic ROS level is lower during FLASH-RT and the degeneration rates of ROS are different in tumor cells and healthy cells. Based on this ROS+ROD FLASH model, the surviving fractions of tumor and normal cells are respectively compared between conventional radiotherapy (CONV-RT) and FLASH-RT. Main results While ROD alone does not distinguish the response of tumors and normal tissues to FLASH-RT, the proposed new FLASH model based on ROD and ROS successfully explained the differential response of tumors and normal tissues to FLASH-RT, i.e., the preserved tumoricidal capability, which cannot be explained by ROD alone, and the extra normal-tissue protection owing to the ultra-high dose rate. Significance Since the ROS level decreases slower in tumors than in normal tissues, during FLASH-RT, ROS decreases more in normal tissue, thus can get more protection. By incorporating ROS in addition to ROD, the new FLASH model can not only recover all results by previous FLASH model with ROD alone, but also explain the differential response: preserved lethality of FLASH-RT to tumors and improved protection to normal tissues.
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Affiliation(s)
- Jiangjun Ma
- Institute of Natural Sciences and School of Mathematics, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, USA
| | - Xing Shen
- Ruijin hospital proton therapy center Shanghai Jiaotong University School of Medicine
| | - Xuemin Bai
- Mevion Medical Systems, Inc., Kunshan, Jiangsu, China
| | - Min Tang
- Institute of Natural Sciences and School of Mathematics, Shanghai Jiao Tong University, Shanghai, China
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12
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Polevoy GG, Kumar DS, Daripelli S, Prasanna M. Flash Therapy for Cancer: A Potentially New Radiotherapy Methodology. Cureus 2023; 15:e46928. [PMID: 38021805 PMCID: PMC10640654 DOI: 10.7759/cureus.46928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
In traditional treatment modalities and standard clinical practices, FLASH radiotherapy (FL-RT) administers radiation therapy at an exceptionally high dosage rate. When compared to standard dose rate radiation therapy, numerous preclinical investigations have demonstrated that FL-RT provides similar benefits in conserving normal tissue while maintaining equal antitumor efficacy, a phenomenon possible due to the 'FLASH effect' (FE) of FL-RT. The methodologies involve proton radiotherapy, intensity-modulated radiation treatment, and managing high-throughput damage by radiation to solid tissues. Recent results from animal studies indicate that FL-RT can reduce radiation-induced tissue damage, significantly enhancing anticancer potency. Focusing on the potential benefits of FL proton beam treatment in the years to come, this review details the FL-RT research that has been done so far and the existing theories illuminating the FL effects. This subject remains of interest, with many issues still needing to be answered. We offer a brief review to emphasize a few of the key efforts and difficulties in moving FL radiation research forward. The existing research state of FL-RT, its affecting variables, and its different specific impacts are presented in this current review. Key topics discussed include the biochemical mechanism during FL therapy, beam sources for FL therapy, the FL effect on immunity, clinical and preclinical studies on the protective effect of FL therapy, and parameters for effective FL therapy.
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Affiliation(s)
| | - Devika S Kumar
- Department of Research and Development, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, IND
| | - Sushma Daripelli
- Department of Anatomy, Government Medical College (GMC) Jangaon, Jangaon, IND
| | - Muthu Prasanna
- Department of Pharmaceutical Biotechnology, Surya Group of Institutions, Tamil Nadu, IND
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13
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Hu S, Lan X, Zheng J, Bi Y, Ye Y, Si M, Fang Y, Wang J, Liu J, Chen Y, Chen Y, Xiang P, Niu T, Huang Y. The dose-related plateau effect of surviving fraction in normal tissue during the ultra-high-dose-rate radiotherapy. Phys Med Biol 2023; 68:185004. [PMID: 37586385 DOI: 10.1088/1361-6560/acf112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/16/2023] [Indexed: 08/18/2023]
Abstract
Objective.Ultra-high-dose-rate radiotherapy, referred to as FLASH therapy, has been demonstrated to reduce the damage of normal tissue as well as inhibiting tumor growth compared with conventional dose-rate radiotherapy. The transient hypoxia may be a vital explanation for sparing the normal tissue. The heterogeneity of oxygen distribution for different doses and dose rates in the different radiotherapy schemes are analyzed. With these results, the influence of doses and dose rates on cell survival are evaluated in this work.Approach.The two-dimensional reaction-diffusion equations are used to describe the heterogeneity of the oxygen distribution in capillaries and tissue. A modified linear quadratic model is employed to characterize the surviving fraction at different doses and dose rates.Main results.The reduction of the damage to the normal tissue can be observed if the doses exceeds a minimum dose threshold under the ultra-high-dose-rate radiation. Also, the surviving fraction exhibits the 'plateau effect' under the ultra-high dose rates radiation, which signifies that within a specific range of doses, the surviving fraction either exhibits minimal variation or increases with the dose. For a given dose, the surviving fraction increases with the dose rate until tending to a stable value, which means that the protection in normal tissue reaches saturation.Significance.The emergence of the 'plateau effect' allows delivering the higher doses while minimizing damage to normal tissue. It is necessary to develop appropriate program of doses and dose rates for different irradiated tissue to achieve more efficient protection.
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Affiliation(s)
- Shuai Hu
- School of Physics and Astronomy, China West Normal University, Nanchong 637009, People's Republic of China
- School of Science, Sun Yat-Sen University, Shenzhen 518107, People's Republic of China
| | - Xiaofei Lan
- School of Physics and Astronomy, China West Normal University, Nanchong 637009, People's Republic of China
| | - Jinfen Zheng
- Dermatology, Center for Chronic Disease Prevention of Shenzhen, Guangdong Shenzhen 518020, People's Republic of China
| | - Yuanjie Bi
- School of Science, Sun Yat-Sen University, Shenzhen 518107, People's Republic of China
| | - Yuanchun Ye
- Department of Hematology, Oncology and Cancer Immunology Campus Benjamin Franklin Charité-Universitätsmedizin Berlin Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin Hindenburgdamm, 30,12203, Berlin Germany
| | - Meiyu Si
- School of Science, Sun Yat-Sen University, Shenzhen 518107, People's Republic of China
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuhong Fang
- School of Science, Sun Yat-Sen University, Shenzhen 518107, People's Republic of China
| | - Jinghui Wang
- Varian Medical Systems, Palo Alto, CA 94304, United States of America
| | - Junyan Liu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94304, United States of America
| | - Yuan Chen
- The Institute for Advanced Studies of Wuhan University, 299, Bayi Road, Wuhan, 430072, People's Republic of China
| | - Yuling Chen
- Department of Rheumatology and Immunology, The Seventh Affiliated Hospital Sun Yat-sen University, Shenzhen 518107, People's Republic of China
| | - Pai Xiang
- The Institute for Advanced Studies of Wuhan University, 299, Bayi Road, Wuhan, 430072, People's Republic of China
| | - Tianye Niu
- Shenzhen Bay Laboratory, Shenzhen 518107, People's Republic of China
| | - Yongsheng Huang
- School of Science, Sun Yat-Sen University, Shenzhen 518107, People's Republic of China
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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14
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Koch CJ, Kim MM, Wiersma RD. Radiation-Chemical Oxygen Depletion Depends on Chemical Environment and Dose Rate: Implications for the FLASH Effect. Int J Radiat Oncol Biol Phys 2023; 117:214-222. [PMID: 37059234 DOI: 10.1016/j.ijrobp.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/27/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
PURPOSE FLASH (dose rates >40 Gy/s) radiation therapy protects normal tissues from radiation damage, compared with conventional radiation therapy (∼Gy/m). Radiation-chemical oxygen depletion (ROD) occurs when oxygen reacts with radiation-induced free radicals, so a possible mechanism for FLASH involves radioprotection by the decreased oxygen as ROD occurs. High ROD rates would favor this mechanism, but prior studies have reported low ROD values (∼0.35 µM/Gy) in chemical environments such as water and protein/nutrient solutions. We proposed that intracellular ROD might be much larger, possibly promoted by its strongly reducing chemical environment. METHODS AND MATERIALS ROD was measured, using precision polarographic sensors, from ∼100 µM to zero in solutions containing intracellular reducing agents ± glycerol (1M), to simulate intracellular reducing and hydroxyl-radical-scavenging capacity. Cs irradiators and a research proton beamline allowed dose rates from 0.0085 to 100 Gy/s. RESULTS Reducing agents significantly altered ROD values. Most greatly increased ROD but some (eg, ascorbate) actually decreased ROD and additionally imposed an oxygen dependence of ROD at low oxygen concentrations. The highest values of ROD were found at low dose rates, but these montonically decreased with increasing dose rate. CONCLUSIONS ROD was greatly augmented by some intracellular reducing agents but others (eg, ascorbate) effectively reversed this effect. Ascorbate had its greatest effect at low oxygen concentrations. ROD decreased with increasing dose rate in most cases.
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Affiliation(s)
- Cameron J Koch
- Radiation Oncology Department, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Michele M Kim
- Radiation Oncology Department, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rodney D Wiersma
- Radiation Oncology Department, University of Pennsylvania, Philadelphia, Pennsylvania
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15
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Deffet S, Hamaide V, Sterpin E. Definition of dose rate for FLASH pencil-beam scanning proton therapy: A comparative study. Med Phys 2023; 50:5784-5792. [PMID: 37439504 DOI: 10.1002/mp.16607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/28/2023] [Accepted: 06/20/2023] [Indexed: 07/14/2023] Open
Abstract
BACKGROUND FLASH proton therapy has the potential to reduce side effects of conventional proton therapy by delivering a high dose of radiation in a very short period of time. However, significant progress is needed in the development of FLASH proton therapy. Increasing the dose rate while maintaining dose conformality may involve the use of advanced beam-shaping technologies and specialized equipment such as 3D patient-specific range modulators, to take advantage of the higher transmission efficiency at the highest energy available. The dose rate is an important factor in FLASH proton therapy, but its definition can vary because of the uneven distribution of the dose over time in pencil-beam scanning (PBS). PURPOSE Highlight the distinctions, both in terms of concept and numerical values, of the various definitions that can be established for the dose rate in PBS proton therapy. METHODS In an in silico study, five definitions of the dose rate, namely the PBS dose rate, the percentile dose rate, the maximum percentile dose rate, the average dose rate, and the dose averaged dose rate (DADR) were analyzed first through theoretical comparison, and then applied to a head and neck case. To carry out this study, a treatment plan utilizing a single energy level and requiring the use of a patient-specific range modulator was employed. The dose rate values were compared both locally and by means of dose rate volume histograms (DRVHs). RESULTS The PBS dose rate, the percentile dose rate, and the maximum percentile dose are definitions that are specifically designed to take into account the time structure of the delivery of a PBS treatment plan. Although they may appear similar, our study shows that they can vary locally by up to 10%. On the other hand, the DADR values were approximately twice as high as those of the PBS, percentile, and maximum percentile dose rates, since the DADR disregards the periods when a voxel does not receive any dose. Finally, the average dose rate can be defined in various ways, as discussed in this paper. The average dose rate is found to be lower by a factor of approximately 1/2 than the PBS, percentile, and maximum percentile dose rates. CONCLUSIONS We have shown that using different definitions for the dose rate in FLASH proton therapy can lead to variations in calculated values ranging from a few percent to a factor of two. Since the dose rate is a critical parameter in FLASH radiation therapy, it is essential to carefully consider the choice of definition. However, to make an informed decision, additional biological data and models are needed.
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Affiliation(s)
- Sylvain Deffet
- Center of Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Louvain-La-Neuve, Belgium
| | | | - Edmond Sterpin
- Center of Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Louvain-La-Neuve, Belgium
- Laboratory of Experimental Radiotherapy, Department of Oncology, KU Leuven, Leuven, Belgium
- Particle Therapy Interuniversity Center Leuven-PARTICLE, Leuven, Belgium
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16
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Pennock M, Wei S, Cheng C, Lin H, Hasan S, Chhabra AM, Choi JI, Bakst RL, Kabarriti R, Simone II CB, Lee NY, Kang M, Press RH. Proton Bragg Peak FLASH Enables Organ Sparing and Ultra-High Dose-Rate Delivery: Proof of Principle in Recurrent Head and Neck Cancer. Cancers (Basel) 2023; 15:3828. [PMID: 37568644 PMCID: PMC10417542 DOI: 10.3390/cancers15153828] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Proton pencil-beam scanning (PBS) Bragg peak FLASH combines ultra-high dose rate delivery and organ-at-risk (OAR) sparing. This proof-of-principle study compared dosimetry and dose rate coverage between PBS Bragg peak FLASH and PBS transmission FLASH in head and neck reirradiation. PBS Bragg peak FLASH plans were created via the highest beam single energy, range shifter, and range compensator, and were compared to PBS transmission FLASH plans for 6 GyE/fraction and 10 GyE/fraction in eight recurrent head and neck patients originally treated with quad shot reirradiation (14.8/3.7 CGE). The 6 GyE/fraction and 10 GyE/fraction plans were also created using conventional-rate intensity-modulated proton therapy techniques. PBS Bragg peak FLASH, PBS transmission FLASH, and conventional plans were compared for OAR sparing, FLASH dose rate coverage, and target coverage. All FLASH OAR V40 Gy/s dose rate coverage was 90-100% at 6 GyE and 10 GyE for both FLASH modalities. PBS Bragg peak FLASH generated dose volume histograms (DVHs) like those of conventional therapy and demonstrated improved OAR dose sparing over PBS transmission FLASH. All the modalities had similar CTV coverage. PBS Bragg peak FLASH can deliver conformal, ultra-high dose rate FLASH with a two-millisecond delivery of the minimum MU per spot. PBS Bragg peak FLASH demonstrated similar dose rate coverage to PBS transmission FLASH with improved OAR dose-sparing, which was more pronounced in the 10 GyE/fraction than in the 6 GyE/fraction. This feasibility study generates hypotheses for the benefits of FLASH in head and neck reirradiation and developing biological models.
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Affiliation(s)
- Michael Pennock
- Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY 10461, USA;
| | - Shouyi Wei
- Department of Physics, New York Proton Center, New York, NY 10035, USA; (S.W.); (H.L.); (S.H.); (M.K.)
| | - Chingyun Cheng
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA;
| | - Haibo Lin
- Department of Physics, New York Proton Center, New York, NY 10035, USA; (S.W.); (H.L.); (S.H.); (M.K.)
| | - Shaakir Hasan
- Department of Physics, New York Proton Center, New York, NY 10035, USA; (S.W.); (H.L.); (S.H.); (M.K.)
| | - Arpit M. Chhabra
- Department of Radiation Oncology, New York Proton Center, New York, NY 10035, USA; (A.M.C.); (J.I.C.); (C.B.S.II)
| | - J. Isabelle Choi
- Department of Radiation Oncology, New York Proton Center, New York, NY 10035, USA; (A.M.C.); (J.I.C.); (C.B.S.II)
| | - Richard L. Bakst
- Department of Radiation Oncology—Radiation Oncology Associates, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Rafi Kabarriti
- Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY 10461, USA;
| | - Charles B. Simone II
- Department of Radiation Oncology, New York Proton Center, New York, NY 10035, USA; (A.M.C.); (J.I.C.); (C.B.S.II)
| | - Nancy Y. Lee
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Minglei Kang
- Department of Physics, New York Proton Center, New York, NY 10035, USA; (S.W.); (H.L.); (S.H.); (M.K.)
| | - Robert H. Press
- Department of Radiation Oncology, Baptist Health South Florida, Miami Cancer Institute, Miami, FL 33176, USA;
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17
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Tan HS, Teo KBK, Dong L, Friberg A, Koumenis C, Diffenderfer E, Zou JW. Modeling ultra-high dose rate electron and proton FLASH effect with the physicochemical approach. Phys Med Biol 2023; 68:10.1088/1361-6560/ace14d. [PMID: 37352867 PMCID: PMC10472835 DOI: 10.1088/1361-6560/ace14d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/23/2023] [Indexed: 06/25/2023]
Abstract
Objective. A physicochemical model built on the radiochemical kinetic theory was recently proposed in (Labarbeet al2020) to explain the FLASH effect. We performed extensive simulations to scrutinize its applicability for oxygen depletion studies and FLASH-related experiments involving both proton and electron beams.Approach. Using the dose and beam delivery parameters for each FLASH experiment, we numerically solved the radiochemical rate equations comprised of a set of coupled nonlinear ordinary differential equations to obtain the area under the curve (AUC) of radical concentrations.Main results. The modeled differences in AUC induced by ultra-high dose rates appeared to correlate well with the FLASH effect. (i) For the whole brain irradiation of mice performed in (Montay-Gruelet al2017), the threshold dose rate values for memory preservation coincided with those at which AUC started to decrease much less rapidly. (ii) For the proton pencil beam scanning FLASH of (Cunninghamet al2021), we found linear correlations between radicals' AUC and the biological endpoints: TGF-β1, leg contracture and plasma level of cytokine IL-6. (iii) Compatible with the findings of the proton FLASH experiment in (Kimet al2021), we found that radicals' AUC at the entrance and mid-Spread-Out Bragg peak regions were highly similar. In addition, our model also predicted ratios of oxygen depletionG-values between normal and UHDR irradiation similar to those observed in (Caoet al2021) and (El Khatibet al2022).Significance. Collectively, our results suggest that the normal tissue sparing conferred by UHDR irradiation may be due to the lower degree of exposure to peroxyl and superoxide radicals. We also found that the differential effect of dose rate on the radicals' AUC was less pronounced at lower initial oxygen levels, a trait that appears to align with the FLASH differential effect on normal versus tumor tissues.
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Affiliation(s)
- Hai Siong Tan
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Kevin Boon Keng Teo
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Lei Dong
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Andrew Friberg
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Constantinos Koumenis
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Eric Diffenderfer
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
| | - Jennifer Wei Zou
- University of Pennsylvania, Perelman School of Medicine, Department of Radiation Oncology, Philadelphia, United States of America
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18
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Atkinson J, Bezak E, Le H, Kempson I. The current status of FLASH particle therapy: a systematic review. Phys Eng Sci Med 2023; 46:529-560. [PMID: 37160539 DOI: 10.1007/s13246-023-01266-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/20/2023] [Indexed: 05/11/2023]
Abstract
Particle therapies are becoming increasingly available clinically due to their beneficial energy deposition profile, sparing healthy tissues. This may be further promoted with ultra-high dose rates, termed FLASH. This review comprehensively summarises current knowledge based on studies relevant to proton- and carbon-FLASH therapy. As electron-FLASH literature presents important radiobiological findings that form the basis of proton and carbon-based FLASH studies, a summary of key electron-FLASH papers is also included. Preclinical data suggest three key mechanisms by which proton and carbon-FLASH are able to reduce normal tissue toxicities compared to conventional dose rates, with equipotent, or enhanced, tumour kill efficacy. However, a degree of caution is needed in clinically translating these findings as: most studies use transmission and do not conform the Bragg peak to tumour volume; mechanistic understanding is still in its infancy; stringent verification of dosimetry is rarely provided; biological assays are prone to limitations which need greater acknowledgement.
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Affiliation(s)
- Jake Atkinson
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, 5095, Australia
| | - Eva Bezak
- Cancer Research Institute, University of South Australia, Adelaide, South Australia, 5000, Australia
- Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia, 5000, Australia
| | - Hien Le
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, 5000, Australia
| | - Ivan Kempson
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, 5095, Australia.
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19
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Klett KC, Martin-Villa BC, Villarreal VS, Melemenidis S, Viswanathan V, Manjappa R, Ashraf MR, Soto L, Lau B, Dutt S, Rankin EB, Loo BW, Heilshorn SC. Human enteroids as a tool to study conventional and ultra-high dose rate radiation. Integr Biol (Camb) 2023; 15:zyad013. [PMID: 37874173 PMCID: PMC10594601 DOI: 10.1093/intbio/zyad013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/25/2023]
Abstract
Radiation therapy, one of the most effective therapies to treat cancer, is highly toxic to healthy tissue. The delivery of radiation at ultra-high dose rates, FLASH radiation therapy (FLASH), has been shown to maintain therapeutic anti-tumor efficacy while sparing normal tissues compared to conventional dose rate irradiation (CONV). Though promising, these studies have been limited mainly to murine models. Here, we leveraged enteroids, three-dimensional cell clusters that mimic the intestine, to study human-specific tissue response to radiation. We observed enteroids have a greater colony growth potential following FLASH compared with CONV. In addition, the enteroids that reformed following FLASH more frequently exhibited proper intestinal polarity. While we did not observe differences in enteroid damage across groups, we did see distinct transcriptomic changes. Specifically, the FLASH enteroids upregulated the expression of genes associated with the WNT-family, cell-cell adhesion, and hypoxia response. These studies validate human enteroids as a model to investigate FLASH and provide further evidence supporting clinical study of this therapy. Insight Box Promising work has been done to demonstrate the potential of ultra-high dose rate radiation (FLASH) to ablate cancerous tissue, while preserving healthy tissue. While encouraging, these findings have been primarily observed using pre-clinical murine and traditional two-dimensional cell culture. This study validates the use of human enteroids as a tool to investigate human-specific tissue response to FLASH. Specifically, the work described demonstrates the ability of enteroids to recapitulate previous in vivo findings, while also providing a lens through which to probe cellular and molecular-level responses to FLASH. The human enteroids described herein offer a powerful model that can be used to probe the underlying mechanisms of FLASH in future studies.
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Affiliation(s)
- Katarina C Klett
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Victoria S Villarreal
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - M Ramish Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Luis Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Suparna Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Erinn B Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Sarah C Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
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20
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Dai Y, Liang R, Wang J, Zhang J, Wu D, Zhao R, Liu Z, Chen F. Fractionated FLASH radiation in xenografted lung tumors induced FLASH effect at a split dose of 2 Gy. Int J Radiat Biol 2023; 99:1542-1549. [PMID: 36952604 DOI: 10.1080/09553002.2023.2194403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 03/16/2023] [Indexed: 03/25/2023]
Abstract
PURPOSE To explore the minimum split dose of FLASH radiotherapy (FLASH). MATERIAL AND METHODS Lungs of nude mice were used to verify the capacity of normal tissue sparing of FLASH, while tumor-bearing nude mice were used to evaluate the curative power. Xenografted tumor models were established in Balb/c-nu mice using A549 cells at a concentration of 5 × 10 6 / 100 μ L . With the same total dose (20 Gy), the dose rate of FLASH was 200 Gy/s when conventional radiotherapy(CONV) was 0.033 Gy/s. Two schemes of FLASH irradiations were applied: single pulse (FLASH1) and ten pulses (FLASH10). Then, according to the different tissue types and irradiation schemes, mice were divided into eight groups: Control-T, CONV-T, FLASH1-T, FLASH10-T (T for tumor) and Control-L, CONV-L, FLASH1-L, FLASH10-L (L for lung). Evaluation of FLASH effect was based on the changes in tumor volume and pathological analysis of tumor and lung tissues before and after irradiation. RESULTS Compared to control group, the mean volume of tumors in nude mice increased slowly or decreased after irradiation with both FLASH and CONV (Control-T: 233.6± 55.19 mm3, CONV-T: 146.1± 50.62 mm3, FLASH1-T: 148± 18.83 mm3, FLASH10-T: 119.1± 50.62 mm3, p ≤ . 05) . Tumor cells of irradiated groups had similar degrees of dissolution damage and inflammation, while the acute radiation pneumonia induced by FLASH was less severe. The pulmonary pathology of FLASH1-L and FLASH10-L were similar, and only a few neutrophils were observed. In addition to inflammatory cells, slight thickening of alveolar septum and obvious interstitial hemorrhage were also observed in the CONV-L group. CONCLUSION The FLASH effect was successfully reproduced in both single and fractionated irradiation, with 2 Gy being the minimum split dose to achieve the FLASH effect in existing experiments. It is suggested that the transient oxygen depletion might not be the only mechanism behind the FLASH effect.
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Affiliation(s)
- Yuling Dai
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
| | - Runcheng Liang
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
| | - Jianxin Wang
- Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, China
| | - Jing Zhang
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
| | - Dai Wu
- Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, China
| | - Ri Zhao
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
| | - Zhaoxing Liu
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
| | - Faguo Chen
- Nuclear and Radiation Frontier Technology Research Center, China Institute for Radiation Protection, Taiyuan, China
- Shanxi Provincial Key Laboratory for Translational Nuclear Medicine and Precision Protection, Taiyuan, China
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21
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Liew H, Mein S, Tessonnier T, Abdollahi A, Debus J, Dokic I, Mairani A. Do We Preserve Tumor Control Probability (TCP) in FLASH Radiotherapy? A Model-Based Analysis. Int J Mol Sci 2023; 24:5118. [PMID: 36982185 PMCID: PMC10049554 DOI: 10.3390/ijms24065118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
Reports of concurrent sparing of normal tissue and iso-effective treatment of tumors at ultra-high dose-rates (uHDR) have fueled the growing field of FLASH radiotherapy. However, iso-effectiveness in tumors is often deduced from the absence of a significant difference in their growth kinetics. In a model-based analysis, we investigate the meaningfulness of these indications for the clinical treatment outcome. The predictions of a previously benchmarked model of uHDR sparing in the "UNIfied and VERSatile bio response Engine" (UNIVERSE) are combined with existing models of tumor volume kinetics as well as tumor control probability (TCP) and compared to experimental data. The potential TCP of FLASH radiotherapy is investigated by varying the assumed dose-rate, fractionation schemes and oxygen concentration in the target. The developed framework describes the reported tumor growth kinetics appropriately, indicating that sparing effects could be present in the tumor but might be too small to be detected with the number of animals used. The TCP predictions show the possibility of substantial loss of treatment efficacy for FLASH radiotherapy depending on several variables, including the fractionation scheme, oxygen level, and DNA repair kinetics. The possible loss of TCP should be seriously considered when assessing the clinical viability of FLASH treatments.
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Affiliation(s)
- Hans Liew
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Stewart Mein
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104-6303, USA
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Amir Abdollahi
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Jürgen Debus
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg Institute of Radiation Oncology (HIRO), University Hospital Heidelberg, National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany
- Clinical Cooperation Unit Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Ivana Dokic
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Andrea Mairani
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Medical Physics Unit, National Centre of Oncological Hadrontherapy (CNAO), 27100 Pavia, Italy
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Mali SB, Dahivelkar S. Flash radiotherapy-gateway to promised land or another mirage. Oral Oncol 2023; 139:106342. [PMID: 36821983 DOI: 10.1016/j.oraloncology.2023.106342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 02/23/2023]
Abstract
Radiation therapy damages cancer cells with ionizing radiation, leading to their death. However, radiation‑induced toxicity limits the dose delivered to the tumor, thereby constraining the control effect of radiotherapy n tumor growth. In addition, the delayed toxicity caused by radiotherapy significantly harms the physical and mental health of patients. FLASH‑RT, an emerging class of radiotherapy, causes a phenomenon known as the 'FLASH effect', which delivers radiotherapy at an ultra‑high dose rate with lower toxicity to normal tissue than conventional radiotherapy to achieve local tumor control.
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Affiliation(s)
- Shrikant B Mali
- MDS Oral and Maxillofacial Surgery Mahatma Gandhi Vidya Mandir's Dental College and Hospital Nashik, India.
| | - Sachinkumar Dahivelkar
- MDS Oral and Maxillofacial Surgery Mahatma Gandhi Vidya Mandir's Dental College and Hospital Nashik, India.
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23
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Royba E, Repin M, Balajee AS, Shuryak I, Pampou S, Karan C, Wang YF, Lemus OD, Obaid R, Deoli N, Wuu CS, Brenner DJ, Garty G. Validation of a High-Throughput Dicentric Chromosome Assay Using Complex Radiation Exposures. Radiat Res 2023; 199:1-16. [PMID: 35994701 PMCID: PMC9947868 DOI: 10.1667/rade-22-00007.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 10/24/2022] [Indexed: 01/12/2023]
Abstract
Validation of biodosimetry assays is routinely performed using primarily orthovoltage irradiators at a conventional dose rate of approximately 1 Gy/min. However, incidental/ accidental exposures caused by nuclear weapons can be more complex. The aim of this work was to simulate the DNA damage effects mimicking those caused by the detonation of a several kilotons improvised nuclear device (IND). For this, we modeled complex exposures to: 1. a mixed (photons + IND-neutrons) field and 2. different dose rates that may come from the blast, nuclear fallout, or ground deposition of radionuclides (ground shine). Additionally, we assessed whether myeloid cytokines affect the precision of radiation dose estimation by modulating the frequency of dicentric chromosomes. To mimic different exposure scenarios, several irradiation systems were used. In a mixed field study, human blood samples were exposed to a photon field enriched with neutrons (ranging from 10% to 37%) from a source that mimics Hiroshima's A-bomb's energy spectrum (0.2-9 MeV). Using statistical analysis, we assessed whether photons and neutrons act in an additive or synergistic way to form dicentrics. For the dose rates study, human blood was exposed to photons or electrons at dose rates ranging from low (where the dose was spread over 32 h) to extremely high (where the dose was delivered in a fraction of a microsecond). Potential effects of cytokine treatment on biodosimetry dose predictions were analyzed in irradiated blood subjected to Neupogen or Neulasta for 24 or 48 h at the concentration recommended to forestall manifestation of an acute radiation syndrome in bomb survivors. All measurements were performed using a robotic station, the Rapid Automated Biodosimetry Tool II, programmed to culture lymphocytes and score dicentrics in multiwell plates (the RABiT-II DCA). In agreement with classical concepts of radiation biology, the RABiT-II DCA calibration curves suggested that the frequency of dicentrics depends on the type of radiation and is modulated by changes in the dose rate. The resulting dose-response curves suggested an intermediate dicentric yields and additive effects of photons and IND-neutrons in the mixed field. At ultra-high dose rate (600 Gy/s), affected lymphocytes exhibited significantly fewer dicentrics (P < 0.004, t test). In contrast, we did not find the dose-response modification effects of radiomitigators on the yields of dicentrics (Bonferroni corrected P > 0.006, ANOVA test). This result suggests no bias in the dose predictions should be expected after emergency cytokine treatment initiated up to 48 h prior to blood collection for dicentric analysis.
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Affiliation(s)
- Ekaterina Royba
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York
| | - Mikhail Repin
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York
| | - Adayabalam S. Balajee
- Radiation Emergency Assistance Center/Training Site (REAC/TS), Cytogenetic Biodosimetry Laboratory (CBL), Oak Ridge Institute for Science and Education, Oak Ridge Associated Universities, Oak Ridge, Tennessee
| | - Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York
| | - Sergey Pampou
- Columbia Genome Center High-Throughput Screening facility, Columbia University Irving Medical Center, New York, New York
| | - Charles Karan
- Columbia Genome Center High-Throughput Screening facility, Columbia University Irving Medical Center, New York, New York
| | - Yi-Fang Wang
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, New York
| | - Olga Dona Lemus
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, New York
| | - Razib Obaid
- Radiological Research Accelerator facility, Columbia University Irving Medical Center, Irvington, New York
- Currently at Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, California
| | - Naresh Deoli
- Radiological Research Accelerator facility, Columbia University Irving Medical Center, Irvington, New York
| | - Cheng-Shie Wuu
- Department of Radiation Oncology, Columbia University Irving Medical Center, New York, New York
| | - David J. Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York
| | - Guy Garty
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York
- Radiological Research Accelerator facility, Columbia University Irving Medical Center, Irvington, New York
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Vilaplana-Lopera N, Abu-Halawa A, Walker E, Kim J, Moon EJ. Ferroptosis, a key to unravel the enigma of the FLASH effect? Br J Radiol 2022; 95:20220825. [PMID: 36314903 PMCID: PMC9733624 DOI: 10.1259/bjr.20220825] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Ferroptosis is a non-apoptotic form of cell death dependent on iron and lipid peroxides. It has been recently described to have a role on cell death after radiation (RT) through a DNA damage independent mechanism. While the modification of ferroptosis pathways is suggested to enhance radiosensitisation, normal tissue toxicity may limit the combined treatment of RT and ferroptosis inducers. FLASH RT is given at ultra-high dose rates to reduce normal tissue toxicities, which contributes to the RT effect on the tumour. Although several hypotheses including oxygen depletion, reduced ROS, and immune responses are suggested to explain the FLASH effect, the underlying mechanisms of normal tissue sparing effects are still not well understood. Previous studies highlighting the inverse effect of RT dose rates and lipid peroxidation, along with the hypothesis by Spitz et al, suggest that oxygen depletion from the chain reaction of lipid peroxidation and differences in labile pool between normal and tumour tissues may be related to the normal tissue sparing effect of FLASH. Therefore, the role of ferroptosis in ultra-high dose rate FLASH RT needs to be investigated further as it might be the key to increase the therapeutic window of FLASH RT.
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Affiliation(s)
- Nuria Vilaplana-Lopera
- Department of Oncology, MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | | | - Ellie Walker
- Somerville College, University of Oxford, Oxford, United Kingdom
| | | | - Eui Jung Moon
- Department of Oncology, MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
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25
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Zou W, Kim H, Diffenderfer ES, Carlson DJ, Koch CJ, Xiao Y, Teo BK, Kim MM, Metz JM, Fan Y, Maity A, Koumenis C, Busch TM, Wiersma R, Cengel KA, Dong L. A phenomenological model of proton FLASH oxygen depletion effects depending on tissue vasculature and oxygen supply. Front Oncol 2022; 12:1004121. [PMID: 36518319 PMCID: PMC9742361 DOI: 10.3389/fonc.2022.1004121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/11/2022] [Indexed: 11/29/2022] Open
Abstract
Introduction Radiation-induced oxygen depletion in tissue is assumed as a contributor to the FLASH sparing effects. In this study, we simulated the heterogeneous oxygen depletion in the tissue surrounding the vessels and calculated the proton FLASH effective-dose-modifying factor (FEDMF), which could be used for biology-based treatment planning. Methods The dose and dose-weighted linear energy transfer (LET) of a small animal proton irradiator was simulated with Monte Carlo simulation. We deployed a parabolic partial differential equation to account for the generalized radiation oxygen depletion, tissue oxygen diffusion, and metabolic processes to investigate oxygen distribution in 1D, 2D, and 3D solution space. Dose and dose rates, particle LET, vasculature spacing, and blood oxygen supplies were considered. Using a similar framework for the hypoxic reduction factor (HRF) developed previously, the FEDMF was derived as the ratio of the cumulative normoxic-equivalent dose (CNED) between CONV and UHDR deliveries. Results Dynamic equilibrium between oxygen diffusion and tissue metabolism can result in tissue hypoxia. The hypoxic region displayed enhanced radio-resistance and resulted in lower CNED under UHDR deliveries. In 1D solution, comparing 15 Gy proton dose delivered at CONV 0.5 and UHDR 125 Gy/s, 61.5% of the tissue exhibited ≥20% FEDMF at 175 μm vasculature spacing and 18.9 μM boundary condition. This percentage reduced to 34.5% and 0% for 8 and 2 Gy deliveries, respectively. Similar trends were observed in the 3D solution space. The FLASH versus CONV differential effect remained at larger vasculature spacings. A higher FLASH dose rate showed an increased region with ≥20% FEDMF. A higher LET near the proton Bragg peak region did not appear to alter the FLASH effect. Conclusion We developed 1D, 2D, and 3D oxygen depletion simulation process to obtain the dynamic HRF and derive the proton FEDMF related to the dose delivery parameters and the local tissue vasculature information. The phenomenological model can be used to simulate or predict FLASH effects based on tissue vasculature and oxygen concentration data obtained from other experiments.
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26
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Ha B, Liang K, Liu C, Melemenidis S, Manjappa R, Viswanathan V, Das N, Ashraf R, Lau B, Soto L, Graves EE, Rao J, Loo BW, Pratx G. Real-time optical oximetry during FLASH radiotherapy using a phosphorescent nanoprobe. Radiother Oncol 2022; 176:239-243. [PMID: 35964762 DOI: 10.1016/j.radonc.2022.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/04/2022] [Accepted: 08/07/2022] [Indexed: 12/14/2022]
Abstract
The rapid depletion of oxygen during irradiation at ultra-high dose rate calls for tissue oximeters capable of high temporal resolution. This study demonstrates a water-soluble phosphorescent nanoprobe and fiber-coupled instrument, which together are used to measure the kinetics of oxygen depletion at 200 Hz during irradiation of in vitro solutions.
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Affiliation(s)
- Byunghang Ha
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Kaitlyn Liang
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Cheng Liu
- Molecular Imaging Program at Stanford, Departments of Radiology and Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Neeladrisingha Das
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Ramish Ashraf
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Luis Soto
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Jianghong Rao
- Molecular Imaging Program at Stanford, Departments of Radiology and Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA.
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27
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Vozenin MC, Bourhis J, Durante M. Towards clinical translation of FLASH radiotherapy. Nat Rev Clin Oncol 2022; 19:791-803. [DOI: 10.1038/s41571-022-00697-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2022] [Indexed: 11/09/2022]
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Potential Molecular Mechanisms behind the Ultra-High Dose Rate "FLASH" Effect. Int J Mol Sci 2022; 23:ijms232012109. [PMID: 36292961 PMCID: PMC9602825 DOI: 10.3390/ijms232012109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/26/2022] [Accepted: 10/08/2022] [Indexed: 11/17/2022] Open
Abstract
FLASH radiotherapy, or the delivery of a dose at an ultra-high dose rate (>40 Gy/s), has recently emerged as a promising tool to enhance the therapeutic index in cancer treatment. The remarkable sparing of normal tissues and equivalent tumor control by FLASH irradiation compared to conventional dose rate irradiation—the FLASH effect—has already been demonstrated in several preclinical models and even in a first patient with T-cell cutaneous lymphoma. However, the biological mechanisms responsible for the differential effect produced by FLASH irradiation in normal and cancer cells remain to be elucidated. This is of great importance because a good understanding of the underlying radiobiological mechanisms and characterization of the specific beam parameters is required for a successful clinical translation of FLASH radiotherapy. In this review, we summarize the FLASH investigations performed so far and critically evaluate the current hypotheses explaining the FLASH effect, including oxygen depletion, the production of reactive oxygen species, and an altered immune response. We also propose a new theory that assumes an important role of mitochondria in mediating the normal tissue and tumor response to FLASH dose rates.
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29
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Gao Y, Liu R, Chang C, Charyyev S, Zhou J, Bradley JD, Liu T, Yang X. A potential revolution in cancer treatment: A topical review of FLASH radiotherapy. J Appl Clin Med Phys 2022; 23:e13790. [PMID: 36168677 PMCID: PMC9588273 DOI: 10.1002/acm2.13790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 07/08/2022] [Accepted: 09/01/2022] [Indexed: 11/26/2022] Open
Abstract
FLASH radiotherapy (RT) is a novel technique in which the ultrahigh dose rate (UHDR) (≥40 Gy/s) is delivered to the entire treatment volume. Recent outcomes of in vivo studies show that the UHDR RT has the potential to spare normal tissue without sacrificing tumor control. There is a growing interest in the application of FLASH RT, and the ultrahigh dose irradiation delivery has been achieved by a few experimental and modified linear accelerators. The underlying mechanism of FLASH effect is yet to be fully understood, but the oxygen depletion in normal tissue providing extra protection during FLASH irradiation is a hypothesis that attracts most attention currently. Monte Carlo simulation is playing an important role in FLASH, enabling the understanding of its dosimetry calculations and hardware design. More advanced Monte Carlo simulation tools are under development to fulfill the challenge of reproducing the radiolysis and radiobiology processes in FLASH irradiation. FLASH RT may become one of standard treatment modalities for tumor treatment in the future. This paper presents the history and status of FLASH RT studies with a focus on FLASH irradiation delivery modalities, underlying mechanism of FLASH effect, in vivo and vitro experiments, and simulation studies. Existing challenges and prospects of this novel technique are discussed in this manuscript.
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Affiliation(s)
- Yuan Gao
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Ruirui Liu
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Chih‐Wei Chang
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Serdar Charyyev
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Jun Zhou
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Jeffrey D. Bradley
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Tian Liu
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
| | - Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGeorgiaUSA
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30
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Hageman E, Che PP, Dahele M, Slotman BJ, Sminia P. Radiobiological Aspects of FLASH Radiotherapy. Biomolecules 2022; 12:biom12101376. [PMID: 36291585 PMCID: PMC9599153 DOI: 10.3390/biom12101376] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Radiotherapy (RT) is one of the primary treatment modalities for cancer patients. The clinical use of RT requires a balance to be struck between tumor effect and the risk of toxicity. Sparing normal tissue is the cornerstone of reducing toxicity. Advances in physical targeting and dose-shaping technology have helped to achieve this. FLASH RT is a promising, novel treatment technique that seeks to exploit a potential normal tissue-sparing effect of ultra-high dose rate irradiation. A significant body of in vitro and in vivo data has highlighted a decrease in acute and late radiation toxicities, while preserving the radiation effect in tumor cells. The underlying biological mechanisms of FLASH RT, however, remain unclear. Three main mechanisms have been hypothesized to account for this differential FLASH RT effect between the tumor and healthy tissue: the oxygen depletion, the DNA damage, and the immune-mediated hypothesis. These hypotheses and molecular mechanisms have been evaluated both in vitro and in vivo. Furthermore, the effect of ultra-high dose rate radiation with extremely short delivery times on the dynamic tumor microenvironment involving circulating blood cells and immune cells in humans is essentially unknown. Therefore, while there is great interest in FLASH RT as a means of targeting tumors with the promise of an increased therapeutic ratio, evidence of a generalized FLASH effect in humans and data to show that FLASH in humans is safe and at least effective against tumors as standard photon RT is currently lacking. FLASH RT needs further preclinical investigation and well-designed in-human studies before it can be introduced into clinical practice.
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Affiliation(s)
- Eline Hageman
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Radiation Oncology, Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Cancer Center Amsterdam, Cancer Biology and Immunology, 1081 HV Amsterdam, The Netherlands
| | - Pei-Pei Che
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Radiation Oncology, Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Cancer Center Amsterdam, Cancer Biology and Immunology, 1081 HV Amsterdam, The Netherlands
| | - Max Dahele
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Radiation Oncology, Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Ben J. Slotman
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Radiation Oncology, Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Peter Sminia
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Radiation Oncology, Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Cancer Center Amsterdam, Cancer Biology and Immunology, 1081 HV Amsterdam, The Netherlands
- Correspondence:
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Lai Y, Chi Y, Jia X. Mechanistic modelling of oxygen enhancement ratio of radiation via Monte Carlo simulation-based DNA damage calculation. Phys Med Biol 2022; 67:10.1088/1361-6560/ac8853. [PMID: 35944522 PMCID: PMC10152552 DOI: 10.1088/1361-6560/ac8853] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/09/2022] [Indexed: 11/12/2022]
Abstract
Objective.Oxygen plays an important role in affecting the cellular radio-sensitivity to ionizing radiation. The objective of this study is to build a mechanistic model to compute oxygen enhancement ratio (OER) using a GPU-based Monte Carlo (MC) simulation package gMicroMC for microscopic radiation transport simulation and DNA damage calculation.Approach.We first simulated the water radiolysis process in the presence of DNA and oxygen for 1 ns and recorded the produced DNA damages. In this process, chemical reactions among oxygen, water radiolysis free radicals and DNA molecules were considered. We then applied a probabilistic approach to model the reactions between oxygen and indirect DNA damages for a maximal reaction time oft0. Finally, we defined two parametersP0andP1, representing probabilities for DNA damages without and with oxygen fixation effect not being restored in the repair process, to compute the final DNA double strand breaks (DSBs). As cell survival fraction is mainly determined by the number of DSBs, we assumed that the same numbers of DSBs resulted in the same cell survival rates, which enabled us to compute the OER as the ratio of doses producing the same number of DSBs without and with oxygen. We determined the three parameters (t0,P0andP1) by fitting the OERs obtained in our computation to a set of published experimental data under x-ray irradiation. We then validated the model by performing OER studies under proton irradiation and studied model sensitivity to parameter values.Main results.We obtained the model parameters ast0= 3.8 ms,P0= 0.08, andP1= 0.28 with a mean difference of 3.8% between the OERs computed by our model and that obtained from experimental measurements under x-ray irradiation. Applying the established model to proton irradiation, we obtained OERs as functions of oxygen concentration, LET, and dose values, which generally agreed with published experimental data. The parameter sensitivity analysis revealed that the absolute magnitude of the OER curve relied on the values ofP0andP1, while the curve was subject to a horizontal shift when adjustingt0.Significance.This study developed a mechanistic model that fully relies on microscopic MC simulations to compute OER.
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Affiliation(s)
- Youfang Lai
- Innovative Technology of Radiotherapy Computations and Hardware (iTORCH) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75287, United States of America
- Department of Physics, University of Texas at Arlington, Arlington, TX 76019, United States of America
| | - Yujie Chi
- Department of Physics, University of Texas at Arlington, Arlington, TX 76019, United States of America
| | - Xun Jia
- Innovative Technology of Radiotherapy Computations and Hardware (iTORCH) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75287, United States of America
- Now at Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, MD, United States of America
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Wei S, Lin H, Isabelle Choi J, Shi C, Simone CB, Kang M. Advanced pencil beam scanning Bragg peak FLASH-RT delivery technique can enhance lung cancer planning treatment outcomes compared to conventional multiple-energy proton PBS techniques. Radiother Oncol 2022; 175:238-247. [PMID: 35961583 DOI: 10.1016/j.radonc.2022.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE To investigate the dosimetric characteristics between an advanced proton pencil beam scanning (PBS) Bragg peak FLASH technique and conventional PBS planning technique in lung tumors. To evaluate the "FLASHness" of single-field in a multiple-field delivery scheme for a hypofractionation regimen and move a step forward to clinical application. METHODS Single-energy PBS Bragg peak FLASH treatment plans were optimized based on a novel Bragg peak tracking technique to enable Bragg peaks to stop at the distal edge of the target. Inverse treatment planning using multiple-field optimization (MFO) can achieve sufficient FLASH dose rate and intensity-modulated proton therapy (IMPT)-equivalent dosimetric quality. The dose rate of organs-at-risk (OARs) and the target were calculated under FLASH machine parameters. A group of 10 consecutive lung SBRT patients was optimized to 34 Gy/fraction using a standard treatment of PBS technique with multiple energy layers as references to the Bragg peak plans. The dosimetric quality was compared between Bragg peak FLASH and conventional plans based on RTOG0915 dose metrics. FLASH dose rate ratios (V40Gy/s) were calculated as a metric of the FLASH-sparing effect. RESULTS For higher dose thresholds, the Bragg peak plans achieved greater V40Gy/s FLASH coverage for all major OARs. The V40Gy/s was close to 100% for all OARs when the dose thresholds were > 5 Gy for full plan and single beam evaluations. The less "FLASHness" region was associated with a low dose distribution, mainly occurring in the PBS field penumbra region. The conventional IMPT treatment plans yielded slightly superior target dose uniformity with a D2%(%) of 108.02% versus that of Bragg peak 300 MU plans of 111.81% (p < 0.01) and that of Bragg peak 1200 MU plans of 115.95% (p < 0.01). No significant difference in dose metrics was found between Bragg peak and IMPT treatment plans for the spinal cord, esophagus, heart, or lung-GTV (all p > 0.05). CONCLUSION Hypofractionated lung Bragg peak plans can maintain comparable plan quality to conventional PBS while achieving sufficient FLASH dose rate coverage for major OARs for each field under the multiple-field delivery scheme. The novel Bragg peak FLASH technique has the potential to enhance lung cancer planning treatment outcomes compared to standard PBS treatment techniques.
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Affiliation(s)
- Shouyi Wei
- New York Proton Center, New York, NY 10035, USA
| | - Haibo Lin
- New York Proton Center, New York, NY 10035, USA.
| | | | - Chengyu Shi
- City of Hope, Orange County, Irvine, CA 92618, USA
| | | | - Minglei Kang
- New York Proton Center, New York, NY 10035, USA.
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Rothwell B, Lowe M, Traneus E, Krieger M, Schuemann J. Treatment planning considerations for the development of FLASH proton therapy. Radiother Oncol 2022; 175:222-230. [PMID: 35963397 DOI: 10.1016/j.radonc.2022.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/21/2022] [Accepted: 08/01/2022] [Indexed: 10/15/2022]
Abstract
With increasing focus on the translation of the observed FLASH effect into clinical practice, this paper presents treatment planning considerations for its development using proton therapy. Potential requirements to induce a FLASH effect are discussed along with the properties of existing proton therapy delivery systems and the changes in planning and delivery approaches required to satisfy these prerequisites. For the exploration of treatment planning approaches for FLASH, developments in treatment planning systems are needed. Flexibility in adapting to new information will be important in such an evolving area. Variations in definitions, threshold values and assumptions can make it difficult to compare different published studies and to interpret previous studies in the context of new information. Together with the fact that much is left to be understood about the underlying mechanism behind the FLASH effect, a systematic and comprehensive approach to information storage is encouraged. Collecting and retaining more detailed information on planned and realised dose delivery as well as reporting the assumptions made in planning studies creates the potential for research to be revisited and re-evaluated in the light of future improvements in understanding. Forward thinking at the time of study development can help facilitate retrospective analysis. This, we hope, will increase the available evidence and accelerate the translation of the FLASH effect into clinical benefit.
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Affiliation(s)
- Bethany Rothwell
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom.
| | - Matthew Lowe
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom; Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | | | - Miriam Krieger
- Varian Medical Systems Particle Therapy GmbH & Co. KG, Troisdorf, Germany
| | - Jan Schuemann
- Division of Physics, Dept. of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Wei S, Lin H, Shi C, Xiong W, Chen CC, Huang S, Press RH, Hasan S, Chhabra AM, Choi JI, Simone CB, Kang M. Use of single-energy proton pencil beam scanning Bragg peak for intensity-modulated proton therapy FLASH treatment planning in liver hypofractionated radiation therapy. Med Phys 2022; 49:6560-6574. [PMID: 35929404 DOI: 10.1002/mp.15894] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 06/09/2022] [Accepted: 07/20/2022] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The transmission proton FLASH technique delivers high doses to the normal tissue distal to the target, which is less conformal compared to the Bragg peak technique. To investigate FLASH RT planning using single-energy Bragg peak beams with a similar beam arrangement as clinical intensity-modulated proton therapy (IMPT) in liver stereotactic body radiation therapy (SBRT) and to characterize the plan quality, dose sparing of organs-at-risk (OARs), and FLASH dose rate percentage. MATERIALS AND METHODS An in-house platform was developed to enable inverse IMPT-FLASH planning using single-energy Bragg peaks. A universal range shifter and range compensators were utilized to effectively align the Bragg peak to the distal edge of the target. Two different minimum MU settings of 400 and 800 MU/spot (Bragg-400MU and Bragg-800MU) plans were investigated on 10 consecutive hepatocellular carcinoma patients previously treated by IMPT-SBRT to evaluate the FLASH dose and dose rate coverage for OARs. The IMPT-FLASH using single-energy Bragg peaks delivered 50 Gy in 5 fractions with similar or identical beam arrangement to the clinical IMPT-SBRT plans. NRG GI003 dose constraint metrics were used. Three dose rate calculation methods, including average dose rate (ADR), dose threshold dose rate (DTDR), and dose-averaged dose rate (DADR), were all studied. RESULTS The novel spot map optimization can fulfill the inverse planning using single-energy Bragg peaks. All the Bragg peak FLASH plans achieved similar results for the liver-GTV Dmean and heart D0.5cc , compared to SBRT-IMPT. The Bragg-800MU plans resulted in 18.3% higher CTV D2cc compared with SBRT (p < 0.05), and no significant difference was found between Bragg-400MU and SBRT plans. For the CTV Dmax , SBRT plans resulted in 10.3% (p<0.01) less than Bragg-400MU plans and 16.6% (p<0.01) less than Bragg-800MU plans. The Bragg-800MU plans generally achieved higher ADR, DADR, and DTDR dose rates than Bragg-400MU plans, and DADR mostly led to the highest V40Gy/s compared to other dose rate calculation methods, whereas ADR led to the lowest. The lower dose rate portions in certain OARs are related to the lower dose deposited due to the farther distances from targets, especially in the penumbra of the beams. CONCLUSION Single-energy Bragg peak IMPT-FLASH plans eliminate the exit dose in normal tissues, maintaining comparable dose metrics to the conventional IMPT-SBRT plans while achieving a sufficient FLASH dose rate for liver cancers. This study demonstrates the feasibility of and sufficiently high dose rate when applying Bragg peak FLASH treatment for liver cancer hypofractionated FLASH therapy. The advancement of this novel method has the potential to optimize treatment for liver cancer patients. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shouyi Wei
- New York Proton Center, New York, NY, USA
| | - Haibo Lin
- New York Proton Center, New York, NY, USA
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Böhlen TT, Germond JF, Bourhis J, Vozenin MC, Ozsahin EM, Bochud F, Bailat C, Moeckli R. Normal tissue sparing by FLASH as a function of single fraction dose: A quantitative analysis. Int J Radiat Oncol Biol Phys 2022; 114:1032-1044. [PMID: 35810988 DOI: 10.1016/j.ijrobp.2022.05.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/26/2022] [Accepted: 05/24/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE The FLASH effect designates normal tissue sparing by ultra-high dose rate (UHDR) compared to conventional dose rate (CONV) irradiation without compromising tumor control. Understanding the magnitude of this effect and its dependency on dose are essential requirements for an optimized clinical translation of FLASH radiation therapy. In this context, we evaluated available experimental data on the magnitudes of normal tissue sparing provided by the FLASH effect as a function of dose, and followed a phenomenological data-driven approach for its parameterization. METHODS We gathered available in vivo data of the normal tissue sparing of CONV compared to UHDR single fraction doses and converted it to a common scale using isoeffect dose ratios, hereafter referred to as FLASH modifying factors (FMF). We then evaluated the suitability of a piecewise linear function with two pieces to parametrize FMF × D as a function of dose D. RESULTS We found that the magnitude of FMF generally decreases (i.e., sparing increases) as function of single fraction dose and that individual data series can be described by the piecewise linear function. The sparing magnitude appears organ specific. Pooled skin reaction data followed a consistent trend as a function of dose. Average FMF values and their standard deviations were 0.95±0.11 for all data below 10 Gy, 0.92±0.06 for mouse gut data between 10-25 Gy, and 0.96±0.07 and 0.71±0.06 for mammalian skin reaction data between 10-25 Gy and >25 Gy, respectively. CONCLUSIONS The magnitude of normal tissue sparing by FLASH is increasing with dose and is dependent on the irradiated tissue. A piecewise linear function can parameterize currently available individual data series.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Esat Mahmut Ozsahin
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland..
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Kusumoto T, Inaniwa T, Mizushima K, Sato S, Hojo S, Kitamura H, Konishi T, Kodaira S. Radiation Chemical Yields of 7-Hydroxy-Coumarin-3-Carboxylic Acid for Proton- and Carbon-Ion Beams at Ultra-High Dose Rates: Potential Roles in FLASH Effects. Radiat Res 2022; 198:255-262. [PMID: 35738014 DOI: 10.1667/rade-21-00.230.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 06/06/2022] [Indexed: 11/03/2022]
Abstract
It has been observed that healthy tissues are spared at ultra-high dose rate (UHDR: >40 Gy/s), so called FLASH effect. To elucidate the mechanism of FLASH effect, we evaluate changes in radiation chemical yield (G value) of 7-hydroxy-coumarin-3-carboxylic acid (7OH-C3CA), which is formed by the reaction of hydroxyl radicals with coumarin-3-carboxylic acid (C3CA), under carbon ions (140 MeV/u) and protons (27.5 and 55 MeV) in a wide-dose-rate range up to 100 Gy/s. The relative G value, which is the G value at each dose rate normalized by that at the conventional dose (CONV: 0.1 Gy/s >), 140 MeV/u carbon-ion beam is almost equivalent to 27.5 and 55 MeV proton beams. This finding implies that UHDR irradiations using carbon-ion beams have a potential to spare healthy tissues. Furthermore, we evaluate the G value of 7OH-C3CA under the de-oxygenated condition to investigate roles of oxygen to the generation of 7OH-C3CA effect. The G value of 7OH-C3CA under the de-oxygenated condition is lower than that under the oxygenated condition. The G value of 7OH-C3CA under the de-oxygenated condition is higher than those under UHDR irradiations. By direct measurements of the oxygen concentration during 55 MeV proton irradiations, the oxygen concentration drops by 0.1%/Gy, which is independent of the dose rate. When the oxygen concentration directly affects to yields of 7OH-C3CA, the rate of decrease in the oxygen concentration may be correlated with that of decrease in the G value of 7OH-C3CA. However, the reduction rate of G value under UHDR is significantly higher than the oxygen consumption. This finding implied that the influence of the reaction between water radiolysis species formed by neighborhood tracks could be strongly related to the mechanisms of UHDR effect.
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Affiliation(s)
- Tamon Kusumoto
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Taku Inaniwa
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Kota Mizushima
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Shinji Sato
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Satoru Hojo
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Hisashi Kitamura
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Teruaki Konishi
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
| | - Satoshi Kodaira
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, 263-8555 Chiba, Japan
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Blain G, Vandenborre J, Villoing D, Fiegel V, Fois GR, Haddad F, Koumeir C, Maigne L, Métivier V, Poirier F, Potiron V, Supiot S, Servagent N, Delpon G, Chiavassa S. Proton Irradiations at Ultra-High Dose Rate vs. Conventional Dose Rate: Strong Impact on Hydrogen Peroxide Yield. Radiat Res 2022; 198:318-324. [PMID: 35675499 DOI: 10.1667/rade-22-00021.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 05/25/2022] [Indexed: 11/03/2022]
Abstract
During ultra-high dose rate (UHDR) external radiation therapy, healthy tissues appear to be spared while tumor control remains the same compared to conventional dose rate. However, the understanding of radiochemical and biological mechanisms involved are still to be discussed. This study shows how the hydrogen peroxide (H2O2) production, one of the reactive oxygen species (ROS), could be controlled by early heterogenous radiolysis processes in water during UHDR proton-beam irradiations. Pure water was irradiated in the plateau region (track-segment) with 68 MeV protons under conventional (0.2 Gy/s) and several UHDR conditions (40 Gy/s to 60 kGy/s) at the ARRONAX cyclotron. Production of H2O2 was then monitored using the Ghormley triiodide method. New values of GTS(H2O2) were added in conventional dose rate. A substantial decrease in H2O2 production was observed from 0.2 to 1.5 kGy/s with a more dramatic decrease below 100 Gy/s. At higher dose rate, up to 60 kGy/s, the H2O2 production stayed stable with a mean decrease of 38% ± 4%. This finding, associated to the decrease in the production of hydroxyl radical (•OH) already observed in other studies in similar conditions can be explained by the well-known spur theory in radiation chemistry. Thus, a two-step FLASH-RT mechanism can be envisioned: an early step at the microsecond scale mainly controlled by heterogenous radiolysis, and a second, slower, dominated by O2 depletion and biochemical processes. To validate this hypothesis, more measurements of radiolytic species will soon be performed, including radicals and associated lifetimes.
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Affiliation(s)
- Guillaume Blain
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | - Johan Vandenborre
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | | | - Vincent Fiegel
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France
| | - Giovanna Rosa Fois
- Université Clermont Auvergne, CNRS/IN2P3, LPC, 63000 Clermont-Ferrand, France
| | - Ferid Haddad
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France.,GIP ARRONAX, Saint-Herblain, France
| | | | - Lydia Maigne
- Université Clermont Auvergne, CNRS/IN2P3, LPC, 63000 Clermont-Ferrand, France
| | - Vincent Métivier
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | | | | | | | - Noël Servagent
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | - Grégory Delpon
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France
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Taylor E, Hill RP, Létourneau D. Modeling the impact of spatial oxygen heterogeneity on radiolytic oxygen depletion during FLASH radiotherapy. Phys Med Biol 2022; 67. [PMID: 35576920 DOI: 10.1088/1361-6560/ac702c] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/16/2022] [Indexed: 12/12/2022]
Abstract
Purpose.It has been postulated that the delivery of radiotherapy at ultra-high dose rates ('FLASH') reduces normal tissue toxicities by depleting them of oxygen. The fraction of normal tissue and cancer cells surviving radiotherapy depends on dose and oxygen levels in an exponential manner and even a very small fraction of tissue at low oxygen levels can determine radiotherapy response. To quantify the differential impact of FLASH radiotherapy on normal and tumour tissues, the spatial heterogeneity of oxygenation in tissue should thus be accounted for.Methods.The effect of FLASH on radiation-induced normal and tumour tissue cell killing was studied by simulating oxygen diffusion, metabolism, and radiolytic oxygen depletion (ROD) over domains with simulated capillary architectures. To study the impact of heterogeneity, two architectural models were used: (1) randomly distributed capillaries and (2) capillaries forming a regular square lattice array. The resulting oxygen partial pressure distribution histograms were used to simulate normal and tumour tissue cell survival using the linear quadratic model of cell survival, modified to incorporate oxygen-enhancement ratio effects. The ratio ('dose modifying factors') of conventional low-dose-rate dose and FLASH dose at iso-cell survival was computed and compared with empirical iso-toxicity dose ratios.Results.Tumour cell survival was found to be increased by FLASH as compared to conventional radiotherapy, with a 0-1 order of magnitude increase for expected levels of tumour hypoxia, depending on the relative magnitudes of ROD and tissue oxygen metabolism. Interestingly, for the random capillary model, the impact of FLASH on well-oxygenated (normal) tissues was found to be much greater, with an estimated increase in cell survival by up to 10 orders of magnitude, even though reductions in mean tissue partial pressure were modest, less than ∼7 mmHg for the parameter values studied. The dose modifying factor for normal tissues was found to lie in the range 1.2-1.7 for a representative value of normal tissue oxygen metabolic rate, consistent with preclinical iso-toxicity results.Conclusions.The presence of very small nearly hypoxic regions in otherwise well-perfused normal tissues with high mean oxygen levels resulted in a greater proportional sparing of normal tissue than tumour cells during FLASH irradiation, possibly explaining empirical normal tissue sparing and iso-tumour control results.
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Affiliation(s)
- Edward Taylor
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Richard P Hill
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Létourneau
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
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Jin JY. Prospect of radiotherapy technology development in the era of immunotherapy. JOURNAL OF THE NATIONAL CANCER CENTER 2022; 2:106-112. [PMID: 39034954 PMCID: PMC11256706 DOI: 10.1016/j.jncc.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 10/18/2022] Open
Abstract
Radiotherapy (RT) is one of the important modalities for cancer treatments. Mounting evidence suggests that the host immune system is involved in the tumor cell killing during RT, and future RT technology development should aim to minimize radiation dose to the immune system while maintaining a sufficient dose to the tumor. A brief history of RT technology development is first summarized. Three RT technologies, namely FLASH RT, proton therapy, and spatially fractionated RT (SFRT), are singled out for the era of immunotherapy. Besides the technical aspects, the mechanism of FLASH effect is discussed, which is likely the combined results of the recombination effect, oxygen depletion effect and immune sparing effect. The proton therapy should have the advantage of causing much less immune damage in comparison to X-ray based RT due to the Bragg peak. However, the relative biological effectiveness (RBE) uncertainty and range uncertainty may hinder the translation of this advantage into clinical benefit. Research approaches to overcome these two technical hurdles are discussed. Various SFRT approaches and their application are reviewed. These approaches are categorized as single-field 1D/2D SFRT, multi-field 3D SFRT and quasi-3D SFRT techniques. A 3D SFRT approach, which is achieved by placing the Bragg peak of a proton 2D SFRT field in discrete depths, may have special potential because all 3 technologies (FLASH RT, proton therapy and SFRT) may be used in this approach.
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Affiliation(s)
- Jian-Yue Jin
- Radiation Oncology, Seidman Cancer Center, University Hospitals, Case Western Reserve University, Cleveland, United States
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40
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Compact and very high dose-rate plasma focus radiation sources for medical applications. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Van Slyke AL, El Khatib M, Velalopoulou A, Diffenderfer E, Shoniyozov K, Kim MM, Karagounis IV, Busch TM, Vinogradov SA, Koch CJ, Wiersma RD. Oxygen Monitoring in Model Solutions and In Vivo in Mice During Proton Irradiation at conventional and FLASH Dose Rates. Radiat Res 2022; 198:181-189. [PMID: 35640166 PMCID: PMC10176203 DOI: 10.1667/rade-21-00232.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/06/2022] [Indexed: 11/03/2022]
Abstract
FLASH is a high-dose-rate form of radiation therapy that has the reported ability, compared with conventional dose rates, to spare normal tissues while being equipotent in tumor control, thereby increasing the therapeutic ratio. The mechanism underlying this normal tissue sparing effect is currently unknown, however one possibility is radiochemical oxygen depletion (ROD) during dose delivery in tissue at FLASH dose rates. In order to investigate this possibility, we used the phosphorescence quenching method to measure oxygen partial pressure before, during and after proton radiation delivery in model solutions and in normal muscle and sarcoma tumors in mice, at both conventional (Conv) (∼0.5 Gy/s) and FLASH (∼100 Gy/s) dose rates. Radiation dosimetry was determined by Advanced Markus Chamber and EBT-XL film. For solutions contained in sealed glass vials, phosphorescent probe Oxyphor PtG4 (1 μM) was dissolved in a buffer (10 mM HEPES) containing glycerol (1 M), glucose (5 mM) and glutathione (5 mM), designed to mimic the reducing and free radical-scavenging nature of the intracellular environment. In vivo oxygen measurements were performed 24 h after injection of PtG4 into the interstitial space of either normal thigh muscle or intra-muscular sarcoma tumors in mice. The "g-value" for ROD is reported in mmHg/Gy, which represents a slight modification of the more standard chemical definition (μM/Gy). In solutions, proton irradiation at conventional dose rates resulted in a g-value for ROD of up to 0.55 mmHg/Gy, consistent with earlier studies using X or gamma rays. At FLASH dose rates, the g-value for ROD was ∼25% lower, 0.37 mmHg/Gy. pO2 levels were stable after each dose delivery. For normal muscle in vivo, oxygen depletion during irradiation was counterbalanced by resupply from the vasculature. This process was fast enough to maintain tissue pO2 virtually unchanged at Conv dose rates. However, during FLASH irradiation there was a stepwise decrease in pO2 (g-value ∼0.28 mmHg/Gy), followed by a rebound to the initial level after ∼8 s. The g-values were smaller and recovery times longer in tumor tissue when compared to muscle and may be related to the lower initial endogenous pO2 levels in the former. Considering that the FLASH effect is seen in vivo even at doses as low as 10 Gy, it is difficult to reconcile the amount of protection seen by oxygen depletion alone. However, the phosphorescence probe in our experiments was confined to the extracellular space, and it remains possible that intracellular oxygen depletion was greater than observed herein. In cell-mimicking solutions the oxygen depletion g-vales were indeed significantly higher than observed in vivo.
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Affiliation(s)
| | - Mirna El Khatib
- Department of Biochemistry and Biophysics, Perelman School of Medicine, and Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Eric Diffenderfer
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
| | | | - Michele M Kim
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
| | - Ilias V Karagounis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
| | - Theresa M Busch
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, and Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cameron J Koch
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
| | - Rodney D Wiersma
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia
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Cui S, Pratx G. 3D computational model of oxygen depletion kinetics in brain vasculature during FLASH RT, and its implications for in vivo oximetry experiments. Med Phys 2022; 49:3914-3925. [PMID: 35393643 DOI: 10.1002/mp.15642] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/19/2022] [Accepted: 03/23/2022] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Ultra-high dose rate irradiation, also known as FLASH, has been shown to improve the therapeutic ratio of radiation therapy (RT). The mechanism behind this effect has been partially explained by the radiochemical oxygen depletion (ROD) hypothesis, which attributes the protection of the normal tissue to the induction of transient hypoxia by ROD. To better understand the contribution of oxygen to the FLASH effect, it is necessary to measure oxygen (O2 ) in vivo during FLASH irradiation. This study's goal is to determine the temporal resolution required to accurately measure the rapidly changing oxygen concentration immediately after FLASH irradiation. METHODS We conducted a computational simulation of oxygen dynamics using a real vascular model that was constructed from a public fluorescence microscopy dataset. The dynamic distribution of oxygen tension (po2 ) during and after FLASH RT was modeled by a partial differential equation (PDE) considering oxygen diffusion, metabolism, and ROD. The underestimation of ROD due to oxygen recovery was evaluated assuming either complete or partial depletion, and a range of possible values for parameters such as oxygen diffusion, consumption, vascular po2 and vessel density. RESULT The O2 concentration recovers rapidly after FLASH RT. Assuming a temporal resolution of 0.5 s, the estimated ROD is only 50.7% and 36.7% of its actual value in cases of partial and complete depletion, respectively. Additionally, the underestimation of ROD is highly dependent on the vascular density. To estimate ROD rate with 90% accuracy, temporal resolution on the order of milliseconds is required considering the uncertainty in parameters involved, especially, the diverse vascular density of the tissue. CONCLUSION The rapid recovery of O2 poses a great challenge for in vivo ROD measurements during FLASH RT. Temporal resolution on the order of milliseconds is recommended for ROD measurements in the normal tissue. Further work is warranted to investigate whether the same requirements apply to tumors, given their irregular vasculature. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Sunan Cui
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA
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Liew H, Mein S, Tessonnier T, Abdollahi A, Debus J, Dokic I, Mairani A. The Impact of Sub-Millisecond Damage Fixation Kinetics on the In Vitro Sparing Effect at Ultra-High Dose Rate in UNIVERSE. Int J Mol Sci 2022; 23:ijms23062954. [PMID: 35328377 PMCID: PMC8954991 DOI: 10.3390/ijms23062954] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/28/2022] [Accepted: 03/07/2022] [Indexed: 02/04/2023] Open
Abstract
The impact of the exact temporal pulse structure on the potential cell and tissue sparing of ultra-high dose-rate irradiation applied in FLASH studies has gained increasing attention. A previous version of our biophysical mechanistic model (UNIVERSE: UNIfied and VERSatile bio response Engine), based on the oxygen depletion hypothesis, has been extended in this work by considering oxygen-dependent damage fixation dynamics on the sub-milliseconds scale and introducing an explicit implementation of the temporal pulse structure. The model successfully reproduces in vitro experimental data on the fast kinetics of the oxygen effect in irradiated mammalian cells. The implemented changes result in a reduction in the assumed amount of oxygen depletion. Furthermore, its increase towards conventional dose-rates is parameterized based on experimental data from the literature. A recalculation of previous benchmarks shows that the model retains its predictive power, while the assumed amount of depleted oxygen approaches measured values. The updated UNIVERSE could be used to investigate the impact of different combinations of pulse structure parameters (e.g., dose per pulse, pulse frequency, number of pulses, etc.), thereby aiding the optimization of potential clinical application and the development of suitable accelerators.
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Affiliation(s)
- Hans Liew
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; (H.L.); (J.D.)
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Stewart Mein
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Amir Abdollahi
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Jürgen Debus
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; (H.L.); (J.D.)
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Ivana Dokic
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Andrea Mairani
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Correspondence: ; Tel.: +49-0-6221-56-37535
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Gao H, Liu J, Lin Y, Gan GN, Pratx G, Wang F, Langen K, Bradley JD, Rotondo RL, Li HH, Chen RC. Simultaneous dose and dose rate optimization (SDDRO) of the FLASH effect for pencil-beam-scanning proton therapy. Med Phys 2022; 49:2014-2025. [PMID: 34800301 PMCID: PMC8917068 DOI: 10.1002/mp.15356] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/29/2021] [Accepted: 10/25/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Compared to CONV-RT (with conventional dose rate), FLASH-RT (with ultra-high dose rate) can provide biological dose sparing for organs-at-risk (OARs) via the so-called FLASH effect, in addition to physical dose sparing. However, the FLASH effect only occurs, when both dose and dose rate meet certain minimum thresholds. This work will develop a simultaneous dose and dose rate optimization (SDDRO) method accounting for both FLASH dose and dose rate constraints during treatment planning for pencil-beam-scanning proton therapy. METHODS SDDRO optimizes the FLASH effect (specific to FLASH-RT) as well as the dose distribution (similar to CONV-RT). The nonlinear dose rate constraint is linearized, and the reformulated optimization problem is efficiently solved via iterative convex relaxation powered by alternating direction method of multipliers. To resolve and quantify the generic tradeoff of FLASH-RT between FLASH and dose optimization, we propose the use of FLASH effective dose based on dose modifying factor (DMF) owing to the FLASH effect. RESULTS FLASH-RT via transmission beams (TB) (IMPT-TB or SDDRO) and CONV-RT via Bragg peaks (BP) (IMPT-BP) were evaluated for clinical prostate, lung, head-and-neck (HN), and brain cases. Despite the use of TB, which is generally suboptimal to BP for normal tissue sparing, FLASH-RT via SDDRO considerably reduced FLASH effective dose for high-dose OAR adjacent to the target. For example, in the lung SBRT case, the max esophageal dose constraint 27 Gy was only met by SDDRO (24.8 Gy), compared to IMPT-BP (35.3 Gy) or IMPT-TB (36.6 Gy); in the brain SRS case, the brain constraint V12Gy≤15cc was also only met by SDDRO (13.7cc), compared to IMPT-BP (43.9cc) or IMPT-TB (18.4cc). In addition, SDDRO substantially improved the FLASH coverage from IMPT-TB, e.g., an increase from 37.2% to 67.1% for lung, from 39.1% to 58.3% for prostate, from 65.4% to 82.1% for HN, from 50.8% to 73.3% for the brain. CONCLUSIONS Both FLASH dose and dose rate constraints are incorporated into SDDRO for FLASH-RT that jointly optimizes the FLASH effect and physical dose distribution. FLASH effective dose via FLASH DMF is introduced to reconcile the tradeoff between physical dose sparing and FLASH sparing, and quantify the net effective gain from CONV-RT to FLASH-RT.
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Affiliation(s)
- Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Jiulong Liu
- LSEC, Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
| | - Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Gregory N Gan
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University, USA
| | - Fen Wang
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Katja Langen
- Department of Radiation Oncology, Emory University, USA
| | | | - Ronny L Rotondo
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Harold H Li
- Department of Radiation Oncology, University of Kansas Medical Center, USA
| | - Ronald C Chen
- Department of Radiation Oncology, University of Kansas Medical Center, USA
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Khatib ME, Van Slyke AL, Velalopoulou A, Kim MM, Shoniyozov K, Allu SR, Diffenderfer EE, Busch TM, Wiersma RD, Koch CJ, Vinogradov SA. Ultrafast Tracking of Oxygen Dynamics during Proton FLASH. Int J Radiat Oncol Biol Phys 2022; 113:624-634. [DOI: 10.1016/j.ijrobp.2022.03.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/01/2022] [Accepted: 03/12/2022] [Indexed: 10/18/2022]
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Favaudon V, Labarbe R, Limoli CL. Model studies of the role of oxygen in the FLASH effect. Med Phys 2022; 49:2068-2081. [PMID: 34407219 PMCID: PMC8854455 DOI: 10.1002/mp.15129] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 06/02/2021] [Accepted: 06/10/2021] [Indexed: 12/13/2022] Open
Abstract
Current radiotherapy facilities are standardized to deliver dose rates around 0.1-0.4 Gy/s in 2 Gy daily fractions, designed to deliver total accumulated doses to reach the tolerance limit of normal tissues undergoing irradiation. FLASH radiotherapy (FLASH-RT), on the other hand, relies on facilities capable of delivering ultrahigh dose rates in large doses in a single microsecond pulse, or in a few pulses given over a very short time sequence. For example, most studies to date have implemented 4-6 MeV electrons with intra-pulse dose rates in the range 106 -107 Gy/s. The proposed dependence of the FLASH effect on oxygen tension has stimulated several theoretical models based on three different hypotheses: (i) Radiation-induced transient oxygen depletion; (ii) cell-specific differences in the ability to detoxify and/or recover from injury caused by reactive oxygen species; (iii) self-annihilation of radicals by bimolecular recombination. This article focuses on the observations supporting or refuting these models in the frame of the chemical-biological bases of the impact of oxygen on the radiation response of cell free, in vitro and in vivo model systems.
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Affiliation(s)
- Vincent Favaudon
- Institut Curie, Inserm U 1021- CNRS UMR 3347, University Paris-Saclay, PSL Research University, Centre Universitaire, 91405 Orsay Cedex, France
- Corresponding author:
| | - Rudi Labarbe
- Ion Beam Applications S.A. (IBA), Louvain-la-Neuve, Belgium
| | - Charles L. Limoli
- Dept. of Radiation Oncology, Medical Sciences I, B146B, Irvine, California 92697-2695, USA
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Kim MM, Darafsheh A, Schuemann J, Dokic I, Lundh O, Zhao T, Ramos-Méndez J, Dong L, Petersson K. Development of Ultra-High Dose-Rate (FLASH) Particle Therapy. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022; 6:252-262. [PMID: 36092270 PMCID: PMC9457346 DOI: 10.1109/trpms.2021.3091406] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Research efforts in FLASH radiotherapy have increased at an accelerated pace recently. FLASH radiotherapy involves ultra-high dose rates and has shown to reduce toxicity to normal tissue while maintaining tumor response in pre-clinical studies when compared to conventional dose rate radiotherapy. The goal of this review is to summarize the studies performed to-date with proton, electron, and heavy ion FLASH radiotherapy, with particular emphasis on the physical aspects of each study and the advantages and disadvantages of each modality. Beam delivery parameters, experimental set-up, and the dosimetry tools used are described for each FLASH modality. In addition, modeling efforts and treatment planning for FLASH radiotherapy is discussed along with potential drawbacks when translated into the clinical setting. The final section concludes with further questions that have yet to be answered before safe clinical implementation of FLASH radiotherapy.
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Affiliation(s)
- Michele M Kim
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ivana Dokic
- Clinical Cooperation Unit Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 460, Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Department of Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Heidelberg University Hospital (UKHD), Heidelberg Ion-Beam Therapy Center (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK) Core-Center Heidelberg, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 222, Heidelberg, Germany
| | - Olle Lundh
- Department of Physics, Lund University, Lund, Sweden
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - José Ramos-Méndez
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California, USA
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kristoffer Petersson
- Department of Oncology, The Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
- Radiation Physics, Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
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Okoro CM, Schüler E, Taniguchi CM. The Therapeutic Potential of FLASH-RT for Pancreatic Cancer. Cancers (Basel) 2022; 14:cancers14051167. [PMID: 35267474 PMCID: PMC8909276 DOI: 10.3390/cancers14051167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/21/2022] Open
Abstract
Simple Summary Ultra-high dose rate radiation, widely nicknamed FLASH-RT, kills tumors without significantly damaging nearby normal tissues. This selective sparing of normal tissue by FLASH-RT tissue is called the FLASH effect. This review explores some of the proposed mechanisms of the FLASH effect and the current data that might support its use in pancreatic cancer. Since radiation for pancreatic cancer treatment is limited by GI toxicity issues and is a disease with one of the lowest five-year survival rates, FLASH-RT could have a large impact in the treatment of this disease with further study. Abstract Recent preclinical evidence has shown that ionizing radiation given at an ultra-high dose rate (UHDR), also known as FLASH radiation therapy (FLASH-RT), can selectively reduce radiation injury to normal tissue while remaining isoeffective to conventional radiation therapy (CONV-RT) with respect to tumor killing. Unresectable pancreatic cancer is challenging to control without ablative doses of radiation, but this is difficult to achieve without significant gastrointestinal toxicity. In this review article, we explore the propsed mechanisms of FLASH-RT and its tissue-sparing effect, as well as its relevance and suitability for the treatment of pancreatic cancer. We also briefly discuss the challenges with regard to dosimetry, dose rate, and fractionation for using FLASH-RT to treat this disease.
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Affiliation(s)
- Chidi M. Okoro
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Emil Schüler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Correspondence: (E.S.); (C.M.T.)
| | - Cullen M. Taniguchi
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Correspondence: (E.S.); (C.M.T.)
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Sultana A, Alanazi A, Meesungnoen J, Jay-Gerin JP. On the Transient Radiolytic Oxygen Depletion in the Ultra-High (FLASH) Dose-Rate Radiolysis of Water in a Cell-Like Environment: Effect of e−aq and •OH Competing Scavengers. Radiat Res 2022; 197:566-567. [DOI: 10.1667/rade-21-00229.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/24/2022] [Indexed: 11/03/2022]
Affiliation(s)
- Abida Sultana
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke (Québec), Canada
| | - Ahmed Alanazi
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke (Québec), Canada
| | - Jintana Meesungnoen
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke (Québec), Canada
| | - Jean-Paul Jay-Gerin
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke (Québec), Canada
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Perstin A, Poirier Y, Sawant A, Tambasco M. Quantifying the DNA-damaging effects of FLASH irradiation with plasmid DNA. Int J Radiat Oncol Biol Phys 2022; 113:437-447. [PMID: 35124135 DOI: 10.1016/j.ijrobp.2022.01.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 11/15/2022]
Abstract
PURPOSE To investigate a plasmid DNA nicking assay approach for isolating and quantifying the DNA damaging effects of ultra-high dose rate (i.e., FLASH) irradiation relative to conventional dose rate irradiation. METHODS We constructed and irradiated phantoms containing plasmid DNA to nominal doses of 20 Gy and 30 Gy using 16 MeV electrons at conventional (0.167 Gy/s) and FLASH (46.6 Gy/s and 93.2 Gy/s) dose rates. We delivered conventional dose rates using a standard clinical Varian iX linac and FLASH dose rates (FDR) using a modified Varian 21EX C-series linac. We ran the irradiated DNA and controls (0 Gy) through an agarose gel electrophoresis procedure that sorted and localized the DNA into bands associated with single strand breaks (SSBs), double strand breaks (DSBs), and undamaged DNA. We quantitatively analyzed the gel images to compute the relative yields of SSBs and DSBs, and applied a mathematical model of plasmid DNA damage as a function of dose to compute relative biological effectiveness (RBE) of SSB and DSB (RBESSBandRBEDSB) damage for a given endpoint and FDR. RESULTS Both RBESSBandRBEDSB were less than unity with the FDR irradiations, indicating FLASH sparing. With regard to the more deleterious DNA DSB damage, RBEDSBs of FLASH beams at dose rates of 46.6 Gy/s and 93.2 Gy/s relative to the conventional 16 MeV beam dose rate were 0.54 ± 0.15 and 0.55 ± 0.17, respectively. CONCLUSION We have demonstrated the feasibility of using a DNA-based phantom to isolate and assess the FLASH sparing effect on DNA. We also found that FLASH irradiation causes less damage to DNA compared to a conventional dose rate. This result supports the notion that the protective effect of FLASH irradiation occurs at least partially via fundamental biochemical processes.
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Affiliation(s)
- Alan Perstin
- Physics Graduate Student, San Diego State University
| | - Yannick Poirier
- Assistant Professor, Oncology, Department of Radiation Oncology, University of Maryland
| | - Amit Sawant
- Professor and Vice Chair, Department of Radiation Oncology, University of Maryland
| | - Mauro Tambasco
- Associate Professor/Medical Physicist, Associate Program Director, Medical Physics Residency, Associate Director, Medical Physics , Department of Physics, San Diego State University.
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