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Garibaldi C, Beddar S, Bizzocchi N, Tobias Böhlen T, Iliaskou C, Moeckli R, Psoroulas S, Subiel A, Taylor PA, Van den Heuvel F, Vanreusel V, Verellen D. Minimum and optimal requirements for a safe clinical implementation of ultra-high dose rate radiotherapy: A focus on patient's safety and radiation protection. Radiother Oncol 2024; 196:110291. [PMID: 38648991 DOI: 10.1016/j.radonc.2024.110291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/28/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Affiliation(s)
- Cristina Garibaldi
- IEO, Unit of Radiation Research, European Institute of Oncology IRCCS, 20141 Milan, Italy.
| | - Sam Beddar
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Nicola Bizzocchi
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Charoula Iliaskou
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center Freiburg, 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Serena Psoroulas
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - Anna Subiel
- National Physical Laboratory, Medical Radiation Science, Teddington, UK
| | - Paige A Taylor
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Frank Van den Heuvel
- Zuidwest Radiotherapeutisch Institute, Vlissingen, the Netherlands; Dept of Oncology, University of Oxford, Oxford, UK
| | - Verdi Vanreusel
- Iridium Netwerk, Antwerp University (Centre for Oncological Research, CORE), Antwerpen, Belgium; SCK CEN (Research in Dosimetric Applications), Mol, Belgium
| | - Dirk Verellen
- Iridium Netwerk, Antwerp University (Centre for Oncological Research, CORE), Antwerpen, Belgium
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2
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van Marlen P, van de Water S, Slotman BJ, Dahele M, Verbakel W. Technical note: Dosimetry and FLASH potential of UHDR proton PBS for small lung tumors: Bragg-peak-based delivery versus transmission beam and IMPT. Med Phys 2024. [PMID: 38795376 DOI: 10.1002/mp.17185] [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: 11/22/2023] [Revised: 04/19/2024] [Accepted: 05/04/2024] [Indexed: 05/27/2024] Open
Abstract
BACKGROUND High-energy transmission beams (TBs) are currently the main delivery method for proton pencil beam scanning ultrahigh dose-rate (UHDR) FLASH radiotherapy. TBs place the Bragg-peaks behind the target, outside the patient, making delivery practical and achievement of high dose-rates more likely. However, they lead to higher integral dose compared to conventional intensity-modulated proton therapy (IMPT), in which Bragg-peaks are placed within the tumor. It is hypothesized that, when energy changes are not required and high beam currents are possible, Bragg-peak-based beams can not only achieve more conformal dose distributions than TBs, but also have more FLASH-potential. PURPOSE This works aims to verify this hypothesis by taking three different Bragg-peak-based delivery techniques and comparing them with TB and IMPT-plans in terms of dosimetry and FLASH-potential for single-fraction lung stereotactic body radiotherapy (SBRT). METHODS For a peripherally located lung target of various sizes, five different proton plans were made using "matRad" and inhouse-developed algorithms for spot/energy-layer/beam reduction and minimum monitor unit maximization: (1) IMPT-plan, reference for dosimetry, (2) TB-plan, reference for FLASH-amount, (3) pristine Bragg-peak plan (non-depth-modulated Bragg-peaks), (4) Bragg-peak plan using generic ridge filter, and (5) Bragg-peak plan using 3D range-modulated ridge filter. RESULTS Bragg-peak-based plans are able to achieve sufficient plan quality and high dose-rates. IMPT-plans resulted in lowest OAR-dose and integral dose (also after a FLASH sparing-effect of 30%) compared to both TB-plans and Bragg-peak-based plans. Bragg-peak-based plans vary only slightly between themselves and generally achieve lower integral dose than TB-plans. However, TB-plans nearly always resulted in lower mean lung dose than Bragg-peak-based plans and due to a higher amount of FLASH-dose for TB-plans, this difference increased after including a FLASH sparing-effect. CONCLUSION This work indicates that there is no benefit in using Bragg-peak-based beams instead of TBs for peripherally located, UHDR stereotactic lung radiotherapy, if lung dose is the priority.
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Affiliation(s)
- Patricia van Marlen
- Department of Radiation Oncology, Amsterdam UMC, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Steven van de Water
- Department of Radiation Oncology, Amsterdam UMC, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Ben J Slotman
- Department of Radiation Oncology, Amsterdam UMC, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Max Dahele
- Department of Radiation Oncology, Amsterdam UMC, Cancer Center Amsterdam, Amsterdam, the Netherlands
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3
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Yagi M, Shimizu S, Hamatani N, Miyoshi T, Nomura T, Toyoda T, Nakatani M, Tsubouchi T, Shimizu M, Kuwana Y, Umezawa M, Takashina M, Nishio T, Koizumi M, Ogawa K, Kanai T. Development and characterization of a dedicated dose monitor for ultrahigh-dose-rate scanned carbon-ion beams. Sci Rep 2024; 14:11574. [PMID: 38773165 PMCID: PMC11109334 DOI: 10.1038/s41598-024-62148-2] [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: 05/29/2023] [Accepted: 05/14/2024] [Indexed: 05/23/2024] Open
Abstract
The current monochromatic beam mode (i.e., uHDR irradiation mode) of the scanned carbon-ion beam lacks a dedicated dose monitor, making the beam control challenging. We developed and characterized a dedicated dose monitor for uHDR-scanned carbon-ion beams. Furthermore, a simple measurable dose rate (dose rate per spot (DRspot)) was suggested by using the developed dose monitor and experimentally validating quantities relevant to the uHDR scanned carbon-ion beam. A large plane-parallel ionization chamber (IC) with a smaller electrode spacing was used to reduce uHDR recombination effects, and a dedicated operational amplifier was manufactured for the uHDR-scanned carbon-ion beam. The dose linearity of the IC was within ± 1% in the range of 1.8-12.3 Gy. The spatial inhomogeneity of the dose response of the IC was ± 0.38% inside the ± 40-mm detector area, and a systematic deviation of approximately 2% was measured at the edge of the detector. uHDR irradiation with beam scanning was tested and verified for different doses at the corresponding dose rates (in terms of both the average dose rate and DRspot). We confirmed that the dose monitor can highlight the characteristics (i.e., dose, dose rate, and dose profile) of uHDR-scanned carbon-ion beams at several dose levels in the monochromatic beam mode.
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Affiliation(s)
- Masashi Yagi
- Department of Carbon Ion Radiotherapy, Osaka University Graduate School of Medicine, Osaka, Japan.
| | - Shinichi Shimizu
- Department of Carbon Ion Radiotherapy, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Noriaki Hamatani
- Department of Medical Physics, Osaka Heavy Ion Therapy Center, Osaka, Japan
| | - Takuto Miyoshi
- Hitachi, Ltd. Research & Development Group, Ibaraki, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Takuya Nomura
- Healthcare Business Division, Hitachi, Ltd, Chiba, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Takashi Toyoda
- Healthcare Business Division, Hitachi, Ltd, Chiba, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Mahoro Nakatani
- Medical Physics Laboratory, Division of Health Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Toshiro Tsubouchi
- Department of Medical Physics, Osaka Heavy Ion Therapy Center, Osaka, Japan
| | - Masaki Shimizu
- Healthcare Business Division, Hitachi, Ltd, Chiba, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Yoshiaki Kuwana
- Healthcare Business Division, Hitachi, Ltd, Chiba, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Masumi Umezawa
- Healthcare Business Division, Hitachi, Ltd, Chiba, Japan
- Healthcare Business Groupe, Hitachi High-Tech Corporation, Chiba, Japan
| | - Masaaki Takashina
- Department of Medical Physics, Osaka Heavy Ion Therapy Center, Osaka, Japan
| | - Teiji Nishio
- Medical Physics Laboratory, Division of Health Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka, Japan
- Department of Radiation Oncology, Nozaki Tokushukai Hospital, Osaka, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tatsuaki Kanai
- Department of Medical Physics, Osaka Heavy Ion Therapy Center, Osaka, Japan
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4
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Whitmore L, Mackay RI, van Herk M, Korysko P, Farabolini W, Malyzhenkov A, Corsini R, Jones RM. CERN-based experiments and Monte-Carlo studies on focused dose delivery with very high energy electron (VHEE) beams for radiotherapy applications. Sci Rep 2024; 14:11120. [PMID: 38750131 PMCID: PMC11096185 DOI: 10.1038/s41598-024-60997-5] [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: 06/14/2023] [Accepted: 04/30/2024] [Indexed: 05/18/2024] Open
Abstract
Very High Energy Electron (VHEE) beams are a promising alternative to conventional radiotherapy due to their highly penetrating nature and their applicability as a modality for FLASH (ultra-high dose-rate) radiotherapy. The dose distributions due to VHEE need to be optimised; one option is through the use of quadrupole magnets to focus the beam, reducing the dose to healthy tissue and allowing for targeted dose delivery at conventional or FLASH dose-rates. This paper presents an in depth exploration of the focusing achievable at the current CLEAR (CERN Linear Electron Accelerator for Research) facility, for beam energies >200 MeV. A shorter, more optimal quadrupole setup was also investigated using the TOPAS code in Monte Carlo simulations, with dimensions and beam parameters more appropriate to a clinical situation. This work provides insight into how a focused VHEE radiotherapy beam delivery system might be achieved.
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Affiliation(s)
- L Whitmore
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
- The Cockcroft Institute of Science and Technology, Daresbury, UK
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, USA
| | - R I Mackay
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - M van Herk
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - P Korysko
- Department of Physics, University of Oxford, Oxford, UK
- CERN, 1211, Geneva 23, Switzerland
| | | | | | | | - R M Jones
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK.
- The Cockcroft Institute of Science and Technology, Daresbury, UK.
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Böhlen TT, Germond JF, Desorgher L, Veres I, Bratel A, Landström E, Engwall E, Herrera FG, Ozsahin EM, Bourhis J, Bochud F, Moeckli R. Very high-energy electron therapy as light-particle alternative to transmission proton FLASH therapy - An evaluation of dosimetric performances. Radiother Oncol 2024; 194:110177. [PMID: 38378075 DOI: 10.1016/j.radonc.2024.110177] [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: 11/23/2023] [Revised: 01/29/2024] [Accepted: 02/16/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE Clinical translation of FLASH-radiotherapy (RT) to deep-seated tumours is still a technological challenge. One proposed solution consists of using ultra-high dose rate transmission proton (TP) beams of about 200-250 MeV to irradiate the tumour with the flat entrance of the proton depth-dose profile. This work evaluates the dosimetric performance of very high-energy electron (VHEE)-based RT (50-250 MeV) as a potential alternative to TP-based RT for the clinical transfer of the FLASH effect. METHODS Basic physics characteristics of VHEE and TP beams were compared utilizing Monte Carlo simulations in water. A VHEE-enabled research treatment planning system was used to evaluate the plan quality achievable with VHEE beams of different energies, compared to 250 MeV TP beams for a glioblastoma, an oesophagus, and a prostate cancer case. RESULTS Like TP, VHEE above 100 MeV can treat targets with roughly flat (within ± 20 %) depth-dose distributions. The achievable dosimetric target conformity and adjacent organs-at-risk (OAR) sparing is consequently driven for both modalities by their lateral beam penumbrae. Electron beams of 400[500] MeV match the penumbra of 200[250] MeV TP beams and penumbra is increased for lower electron energies. For the investigated patient cases, VHEE plans with energies of 150 MeV and above achieved a dosimetric plan quality comparable to that of 250 MeV TP plans. For the glioblastoma and the oesophagus case, although having a decreased conformity, even 100 MeV VHEE plans provided a similar target coverage and OAR sparing compared to TP. CONCLUSIONS VHEE-based FLASH-RT using sufficiently high beam energies may provide a lighter-particle alternative to TP-based FLASH-RT with comparable dosimetric plan quality.
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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
| | - Laurent Desorgher
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Izabella Veres
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | | | | | | | - Fernanda G Herrera
- 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
| | - Jean Bourhis
- 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
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland.
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6
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Ma C, Zhou J, Chang CW, Wang Y, Patel PR, Yu DS, Tian S, Yang X. Streamlined pin-ridge-filter design for single-energy proton FLASH planning. Med Phys 2024; 51:2955-2966. [PMID: 38214381 DOI: 10.1002/mp.16939] [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: 06/28/2023] [Revised: 11/24/2023] [Accepted: 12/21/2023] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND FLASH radiotherapy (FLASH-RT) with ultra-high dose rate has yielded promising results in reducing normal tissue toxicity while maintaining tumor control. Planning with single-energy proton beams modulated by ridge filters (RFs) has been demonstrated feasible for FLASH-RT. PURPOSE This study explored the feasibility of a streamlined pin-shaped RF (pin-RF) design, characterized by coarse resolution and sparsely distributed ridge pins, for single-energy proton FLASH planning. METHODS An inverse planning framework integrated within a treatment planning system was established to design streamlined pin RFs for single-energy FLASH planning. The framework involves generating a multi-energy proton beam plan using intensity-modulated proton therapy (IMPT) planning based on downstream energy modulation strategy (IMPT-DS), followed by a nested pencil-beam-direction-based (PBD-based) spot reduction process to iteratively reduce the total number of PBDs and energy layers along each PBD for the IMPT-DS plan. The IMPT-DS plan is then translated into the pin-RFs and the single-energy beam configurations for IMPT planning with pin-RFs (IMPT-RF). This framework was validated on three lung cases, quantifying the FLASH dose of the IMPT-RF plan using the FLASH effectiveness model. The FLASH dose was then compared to the reference dose of a conventional IMPT plan to measure the clinical benefit of the FLASH planning technique. RESULTS The IMPT-RF plans closely matched the corresponding IMPT-DS plans in high dose conformity (conformity index of <1.2), with minimal changes in V7Gy and V7.4 Gy for the lung (<3%) and small increases in maximum doses (Dmax) for other normal structures (<3.4 Gy). Comparing the FLASH doses to the doses of corresponding IMPT-RF plans, drastic reductions of up to nearly 33% were observed in Dmax for the normal structures situated in the high-to-moderate-dose regions, while negligible changes were found in Dmax for normal structures in low-dose regions. Positive clinical benefits were seen in comparing the FLASH doses to the reference doses, with notable reductions of 21.4%-33.0% in Dmax for healthy tissues in the high-dose regions. However, in the moderate-to-low-dose regions, only marginal positive or even negative clinical benefit for normal tissues were observed, such as increased lung V7Gy and V7.4 Gy (up to 17.6%). CONCLUSIONS A streamlined pin-RF design was developed and its effectiveness for single-energy proton FLASH planning was validated, revealing positive clinical benefits for the normal tissues in the high dose regions. The coarsened design of the pin-RF demonstrates potential advantages, including cost efficiency and ease of adjustability, making it a promising option for efficient production.
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Affiliation(s)
- Chaoqiong Ma
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Jun Zhou
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Chih-Wei Chang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Yinan Wang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Pretesh R Patel
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - David S Yu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Sibo Tian
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
| | - Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
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7
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Rank L, Dogan O, Kopp B, Mein S, Verona-Rinati G, Kranzer R, Marinelli M, Mairani A, Tessonnier T. Development and benchmarking of a dose rate engine for raster-scanned FLASH helium ions. Med Phys 2024; 51:2251-2262. [PMID: 37847027 PMCID: PMC10939952 DOI: 10.1002/mp.16793] [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: 12/19/2022] [Revised: 09/14/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Radiotherapy with charged particles at high dose and ultra-high dose rate (uHDR) is a promising technique to further increase the therapeutic index of patient treatments. Dose rate is a key quantity to predict the so-called FLASH effect at uHDR settings. However, recent works introduced varying calculation models to report dose rate, which is susceptible to the delivery method, scanning path (in active beam delivery) and beam intensity. PURPOSE This work introduces an analytical dose rate calculation engine for raster scanned charged particle beams that is able to predict dose rate from the irradiation plan and recorded beam intensity. The importance of standardized dose rate calculation methods is explored here. METHODS Dose is obtained with an analytical pencil beam algorithm, using pre-calculated databases for integrated depth dose distributions and lateral penumbra. Dose rate is then calculated by combining dose information with the respective particle fluence (i.e., time information) using three dose-rate-calculation models (mean, instantaneous, and threshold-based). Dose rate predictions for all three models are compared to uHDR helium ion beam (145.7 MeV/u, range in water of approximatively 14.6 cm) measurements performed at the Heidelberg Ion Beam Therapy Center (HIT) with a diamond-detector prototype. Three scanning patterns (scanned or snake-like) and four field sizes are used to investigate the dose rate differences. RESULTS Dose rate measurements were in good agreement with in-silico generated distributions using the here introduced engine. Relative differences in dose rate were below 10% for varying depths in water, from 2.3 to 14.8 cm, as well as laterally in a near Bragg peak area. In the entrance channel of the helium ion beam, dose rates were predicted within 7% on average for varying irradiated field sizes and scanning patterns. Large differences in absolute dose rate values were observed for varying calculation methods. For raster-scanned irradiations, the deviation between mean and threshold-based dose rate at the investigated point was found to increase with the field size up to 63% for a 10 mm × 10 mm field, while no significant differences were observed for snake-like scanning paths. CONCLUSIONS This work introduces the first dose rate calculation engine benchmarked to instantaneous dose rate, enabling dose rate predictions for physical and biophysical experiments. Dose rate is greatly affected by varying particle fluence, scanning path, and calculation method, highlighting the need for a consensus among the FLASH community on how to calculate and report dose rate in the future. The here introduced engine could help provide the necessary details for the analysis of the sparing effect and uHDR conditions.
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Affiliation(s)
- Luisa Rank
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Karlsruhe Institute of Technology (KIT), Faculty of Physics, Karlsruhe, Germany
| | - Ozan Dogan
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Heidelberg University, Faculty of Physics and Astronomy, Heidelberg, Germany
| | - Benedikt Kopp
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stewart Mein
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- 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), Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital (UKHD), Heidelberg Faculty of Medicine (MFHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Rafael Kranzer
- PTW-Freiburg, Freiburg, Germany
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, Germany
| | - Marco Marinelli
- Industrial Engineering Department, University of Rome “Tor Vergata”, Rome, Italy
| | - Andrea Mairani
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- 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), Heidelberg, Germany
- Division of Molecular and Translational Radiation Oncology, Heidelberg Faculty of Medicine (MFHD) and Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital (UKHD), Heidelberg Faculty of Medicine (MFHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Medical Physics, National Centre of Oncological Hadrontherapy (CNAO), Pavia, Italy
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- 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), Heidelberg, Germany
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg University Hospital (UKHD), Heidelberg Faculty of Medicine (MFHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany
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8
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Liu G, Zhao L, Li X, Zhang S, Dai S, Lu X, Ding X. A Novel Ultrahigh-Dose-Rate Proton Therapy Technology: Spot-Scanning Proton Arc Therapy + FLASH (SPLASH). Int J Radiat Oncol Biol Phys 2023; 117:730-737. [PMID: 37196836 DOI: 10.1016/j.ijrobp.2023.05.012] [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: 12/05/2022] [Revised: 04/10/2023] [Accepted: 05/08/2023] [Indexed: 05/19/2023]
Abstract
PURPOSE To take full advantage of FLASH dose rate (40 Gy/s) and high-dose conformity, we introduce a novel optimization and delivery technique, the spot-scanning proton arc therapy (SPArc) + FLASH (SPLASH). METHODS AND MATERIALS SPLASH framework was implemented in an open-source proton planning platform (MatRad, Department of Medical Physics in Radiation Oncology, German Cancer Research Center). It optimizes with the clinical dose-volume constraint based on dose distribution and the dose-average dose rate by minimizing the monitor unit constraint on spot weight and accelerator beam current sequentially, enabling the first dynamic arc therapy with voxel-based FLASH dose rate. This new optimization framework minimizes the overall cost function value combined with plan quality and voxel-based dose-rate constraints. Three representative cases (brain, liver, and prostate cancer) were used for testing purposes. Dose-volume histogram, dose-rate-volume histogram, and dose-rate map were compared among intensity modulated proton radiation therapy (IMPT), SPArc, and SPLASH. RESULTS SPLASH/SPArc could offer superior plan quality over IMPT in terms of dose conformity. The dose-rate-volume histogram results indicated SPLASH could significantly improve V40 Gy/s in the target and region of interest for all tested cases compared with SPArc and IMPT. The optimal beam current per spot is simultaneously generated, which is within the existing proton machine specifications in the research version (<200 nA). CONCLUSIONS SPLASH offers the first voxel-based ultradose-rate and high-dose conformity treatment using proton beam therapy. Such a technique has the potential to fit the needs of a broad range of disease sites and simplify clinical workflow without applying a patient-specific ridge filter, which has never before been demonstrated.
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Affiliation(s)
- Gang Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430023 China.
| | - Lewei Zhao
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan
| | - Xiaoqiang Li
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan
| | - Sheng Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430023 China.
| | - Shuyang Dai
- School of Mathematics and Statistics, Wuhan University, Wuhan 430072 China
| | - Xiliang Lu
- School of Mathematics and Statistics, Wuhan University, Wuhan 430072 China
| | - Xuanfeng Ding
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan.
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9
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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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10
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Zou W, Zhang R, Schüler E, Taylor PA, Mascia AE, Diffenderfer ES, Zhao T, Ayan AS, Sharma M, Yu SJ, Lu W, Bosch WR, Tsien C, Surucu M, Pollard-Larkin JM, Schuemann J, Moros EG, Bazalova-Carter M, Gladstone DJ, Li H, Simone CB, Petersson K, Kry SF, Maity A, Loo BW, Dong L, Maxim PG, Xiao Y, Buchsbaum JC. Framework for Quality Assurance of Ultrahigh Dose Rate Clinical Trials Investigating FLASH Effects and Current Technology Gaps. Int J Radiat Oncol Biol Phys 2023; 116:1202-1217. [PMID: 37121362 PMCID: PMC10526970 DOI: 10.1016/j.ijrobp.2023.04.018] [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: 03/08/2023] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/02/2023]
Abstract
FLASH radiation therapy (FLASH-RT), delivered with ultrahigh dose rate (UHDR), may allow patients to be treated with less normal tissue toxicity for a given tumor dose compared with currently used conventional dose rate. Clinical trials are being carried out and are needed to test whether this improved therapeutic ratio can be achieved clinically. During the clinical trials, quality assurance and credentialing of equipment and participating sites, particularly pertaining to UHDR-specific aspects, will be crucial for the validity of the outcomes of such trials. This report represents an initial framework proposed by the NRG Oncology Center for Innovation in Radiation Oncology FLASH working group on quality assurance of potential UHDR clinical trials and reviews current technology gaps to overcome. An important but separate consideration is the appropriate design of trials to most effectively answer clinical and scientific questions about FLASH. This paper begins with an overview of UHDR RT delivery methods. UHDR beam delivery parameters are then covered, with a focus on electron and proton modalities. The definition and control of safe UHDR beam delivery and current and needed dosimetry technologies are reviewed and discussed. System and site credentialing for large, multi-institution trials are reviewed. Quality assurance is then discussed, and new requirements are presented for treatment system standard analysis, patient positioning, and treatment planning. The tables and figures in this paper are meant to serve as reference points as we move toward FLASH-RT clinical trial performance. Some major questions regarding FLASH-RT are discussed, and next steps in this field are proposed. FLASH-RT has potential but is associated with significant risks and complexities. We need to redefine optimization to focus not only on the dose but also on the dose rate in a manner that is robust and understandable and that can be prescribed, validated, and confirmed in real time. Robust patient safety systems and access to treatment data will be critical as FLASH-RT moves into the clinical trials.
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Affiliation(s)
- Wei Zou
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
| | - Rongxiao Zhang
- Department of Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Emil Schüler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Paige A Taylor
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Eric S Diffenderfer
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University, St. Louis, MO, USA
| | - Ahmet S Ayan
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
| | - Manju Sharma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - Shu-Jung Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Weiguo Lu
- Department of Radiation Oncology, University of Texas Southwestern, Dallas, TX, USA
| | - Walter R Bosch
- Department of Radiation Oncology, Washington University, St. Louis, MO, USA
| | - Christina Tsien
- Department of Radiation Oncology, McGill University Health Center, Montreal, QC, Canada
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Julianne M Pollard-Larkin
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Eduardo G Moros
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA
| | | | - David J Gladstone
- Department of Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Heng Li
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA
| | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, NY, USA
| | - Kristoffer Petersson
- Department of Radiation Oncology, MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Stephen F Kry
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Amit Maity
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter G Maxim
- Department of Radiation Oncology, University of California Irvine, Irvine, CA, USA
| | - Ying Xiao
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey C Buchsbaum
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
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11
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Graeff C, Volz L, Durante M. Emerging technologies for cancer therapy using accelerated particles. PROGRESS IN PARTICLE AND NUCLEAR PHYSICS 2023; 131:104046. [PMID: 37207092 PMCID: PMC7614547 DOI: 10.1016/j.ppnp.2023.104046] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Cancer therapy with accelerated charged particles is one of the most valuable biomedical applications of nuclear physics. The technology has vastly evolved in the past 50 years, the number of clinical centers is exponentially growing, and recent clinical results support the physics and radiobiology rationale that particles should be less toxic and more effective than conventional X-rays for many cancer patients. Charged particles are also the most mature technology for clinical translation of ultra-high dose rate (FLASH) radiotherapy. However, the fraction of patients treated with accelerated particles is still very small and the therapy is only applied to a few solid cancer indications. The growth of particle therapy strongly depends on technological innovations aiming to make the therapy cheaper, more conformal and faster. The most promising solutions to reach these goals are superconductive magnets to build compact accelerators; gantryless beam delivery; online image-guidance and adaptive therapy with the support of machine learning algorithms; and high-intensity accelerators coupled to online imaging. Large international collaborations are needed to hasten the clinical translation of the research results.
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Affiliation(s)
- Christian Graeff
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
| | - Lennart Volz
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
| | - Marco Durante
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
- Dipartimento di Fisica “Ettore Pancini”, University Federico II, Naples, Italy
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12
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Ma C, Yang X, Chang CW, Liu R, Bohannon D, Lin L, Liu T, Tian S, Zhou J. Feasibility study of hybrid inverse planning with transmission beams and single-energy spread-out Bragg peaks for proton FLASH radiotherapy. Med Phys 2023; 50:3687-3700. [PMID: 36932635 DOI: 10.1002/mp.16370] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/30/2023] [Accepted: 03/02/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND Ultra-high dose rate (FLASH) proton planning with only transmission beams (TBs) has limitations in normal tissue sparing. The single-energy spread-out Bragg peaks (SESOBPs) of the FLASH dose rate have been demonstrated feasible for proton FLASH planning. PURPOSE To investigate the feasibility of combining TBs and SESOBPs for proton FLASH treatment. METHODS A hybrid inverse optimization method was developed to combine the TBs and SESOBPs (TB-SESOBP) for FLASH planning. The SESOBPs were generated field-by-field from spreading out the BPs by pre-designed general bar ridge filters (RFs) and placed at the central target by range shifters (RSs) to obtain a uniform dose within the target. The SESOBPs and TBs were fully placed field-by-field allowing automatic spot selection and weighting in the optimization process. A spot reduction strategy was conducted in the optimization process to push up the minimum MU/spot assuring the plan deliverability at beam current of 165 nA. The TB-SESOBP plans were validated in comparison with the TB only (TB-only) plans and the plans with the combination of TBs and BPs (TB-BP plans) regarding 3D dose and dose rate (dose-averaged dose rate) distributions for five lung cases. The FLASH dose rate coverage (V40Gy/s ) was evaluated in the structure volume receiving > 10% of the prescription dose. RESULTS Compared to the TB-only plans, the mean spinal cord D1.2cc drastically reduced by 41% (P < 0.05), the mean lung V7Gy and V7.4 Gy moderately reduced by up to 17% (P < 0.05), and the target dose homogeneity slightly increased in the TB-SESOBP plans. Comparable dose homogeneity was achieved in both TB-SESOBP and TB-BP plans. Besides, prominent improvements were achieved in lung sparing for the cases of relatively large targets by the TB-SESOBP plans compared to the TB-BP plans. The targets and the skin were fully covered with the FLASH dose rate in all three plans. For the OARs, V40Gy/s = 100% was achieved by the TB-only plans while V40Gy/s > 85% was obtained by the other two plans. CONCLUSION We have demonstrated that the hybrid TB-SESOBP planning was feasible to achieve FLASH dose rate for proton therapy. With pre-designed general bar RFs, the hybrid TB-SESOBP planning could be implemented for proton adaptive FLASH radiotherapy. As an alternative FLASH planning approach to TB-only planning, the hybrid TB-SESOBP planning has great potential in dosimetrically improving OAR sparing while maintaining high target dose homogeneity.
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Affiliation(s)
- Chaoqiong Ma
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Xiaofeng Yang
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Chih-Wei Chang
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Ruirui Liu
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Duncan Bohannon
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Liyong Lin
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Tian Liu
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Sibo Tian
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Jun Zhou
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
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13
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van Marlen P, van de Water S, Dahele M, Slotman BJ, Verbakel WFAR. Single Ultra-High Dose Rate Proton Transmission Beam for Whole Breast FLASH-Irradiation: Quantification of FLASH-Dose and Relation with Beam Parameters. Cancers (Basel) 2023; 15:cancers15092579. [PMID: 37174045 PMCID: PMC10177419 DOI: 10.3390/cancers15092579] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Healthy tissue-sparing effects of FLASH (≥40 Gy/s, ≥4-8 Gy/fraction) radiotherapy (RT) make it potentially useful for whole breast irradiation (WBI), since there is often a lot of normal tissue within the planning target volume (PTV). We investigated WBI plan quality and determined FLASH-dose for various machine settings using ultra-high dose rate (UHDR) proton transmission beams (TBs). While five-fraction WBI is commonplace, a potential FLASH-effect might facilitate shorter treatments, so hypothetical 2- and 1-fraction schedules were also analyzed. Using one tangential 250 MeV TB delivering 5 × 5.7 Gy, 2 × 9.74 Gy or 1 × 14.32 Gy, we evaluated: (1) spots with equal monitor units (MUs) in a uniform square grid with variable spacing; (2) spot MUs optimized with a minimum MU-threshold; and (3) splitting the optimized TB into two sub-beams: one delivering spots above an MU-threshold, i.e., at UHDRs; the other delivering the remaining spots necessary to improve plan quality. Scenarios 1-3 were planned for a test case, and scenario 3 was also planned for three other patients. Dose rates were calculated using the pencil beam scanning dose rate and the sliding-window dose rate. Various machine parameters were considered: minimum spot irradiation time (minST): 2 ms/1 ms/0.5 ms; maximum nozzle current (maxN): 200 nA/400 nA/800 nA; two gantry-current (GC) techniques: energy-layer and spot-based. For the test case (PTV = 819 cc) we found: (1) a 7 mm grid achieved the best balance between plan quality and FLASH-dose for equal-MU spots; (2) near the target boundary, lower-MU spots are necessary for homogeneity but decrease FLASH-dose; (3) the non-split beam achieved >95% FLASH for favorable (not clinically available) machine parameters (SB GC, low minST, high maxN), but <5% for clinically available settings (EB GC, minST = 2 ms, maxN = 200 nA); and (4) splitting gave better plan quality and higher FLASH-dose (~50%) for available settings. The clinical cases achieved ~50% (PTV = 1047 cc) or >95% (PTV = 477/677 cc) FLASH after splitting. A single UHDR-TB for WBI can achieve acceptable plan quality. Current machine parameters limit FLASH-dose, which can be partially overcome using beam-splitting. WBI FLASH-RT is technically feasible.
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Affiliation(s)
- Patricia van Marlen
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Steven van de Water
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Max Dahele
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Berend J Slotman
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
| | - Wilko F A R Verbakel
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, De Boelelaan 1117, 1118, 1081 HV Amsterdam, The Netherlands
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14
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Zhang G, Zhang Z, Gao W, Quan H. Treatment planning consideration for very high-energy electron FLASH radiotherapy. Phys Med 2023; 107:102539. [PMID: 36804694 DOI: 10.1016/j.ejmp.2023.102539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/18/2023] Open
Abstract
PURPOSE Very high-energy electron (VHEE) can make up the insufficient treatment depth of the low-energy electron while offering an intermediate dosimetric advantage between photon and proton. Combining FLASH with VHEE, a quantitative comparison between different energies was made, with regard to plan quality, dose rate distribution (both in PTV and OAR), and total duration of treatment (beam-on time). METHODS In two patient cases (head and lung), we created the treatment plans utilizing the scanning pencil beam via the Monte Carlo simulation and a PTV-based optimization algorithm. Geant4 was used to simulate VHEE pencil beams and sizes of 0.3-5 mm defined by the full width at half maximum (FWHM). Monoenergetic beams with Gaussian distribution in x and y directions (ISOURC = 19) were used as the source of electrons. A large-scale non-linear solver (IPOPT) was used to calculate the optimal spot weights. After optimization, a quantitative comparison between different energies was made regarding treatment plan quality, dose rate distribution (both in PTV and OAR), and total beam duration. RESULTS For head (80 MeV, 100 MeV, and 120 MeV) and lung cases (100 MeV, 120 MeV, and 140 MeV), the minimum beam intensity needs to be ∼2.5 × 1011 electrons/s and ∼9.375 × 1011 electrons/s to allow > 90 % volume of PTV reaching the average dose rate (DADR) higher than 40 Gy/s. At this beam intensity (fraction dose: 10 Gy), the overall irradiation time for the head case is 5258.75 ms (80 MeV), 5149.75 ms (100 MeV), and 4976.75 ms (120 MeV), including scanning time 872.75 ms. For lung cases, this number is 1034.25 ms (100 MeV), 981.55 ms (120 MeV), and 928.15 ms (140 MeV), including scanning time 298.75 ms. The plan of higher energy always performs with a higher dose rate (both in PTV and OAR) and thereby costs less delivery time (beam-on time). CONCLUSION The study systematically investigated the currently known FLASH parameters for VHEE radiotherapy and successfully established a benchmark reference for its FLASH dose rate performance.
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Affiliation(s)
- Guoliang Zhang
- School of Physics and Technology, Wuhan University, 430072, China
| | - Zhengzhao Zhang
- Cancer Radiation Therapy Center, Fifth Medical Center of Chinese PLA General Hospital, 100039, China
| | - Wenchao Gao
- Cancer Radiation Therapy Center, Fifth Medical Center of Chinese PLA General Hospital, 100039, China
| | - Hong Quan
- School of Physics and Technology, Wuhan University, 430072, China.
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15
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Ramesh P, Gu W, Ruan D, Sheng K. Dose and dose rate objectives in Bragg peak and shoot-through beam orientation optimization for FLASH proton therapy. Med Phys 2022; 49:7826-7837. [PMID: 36222217 PMCID: PMC9829523 DOI: 10.1002/mp.16009] [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: 05/11/2021] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 01/12/2023] Open
Abstract
PURPOSE The combined use of Bragg peak (BP) and shoot-through (ST) beams has previously been shown to increase the normal tissue volume receiving FLASH dose rates while maintaining dose conformality compared to conventional intensity-modulated proton therapy (IMPT) methods. However, the fixed beam optimization method has not considered the effects of beam orientation on the dose and dose rates. To maximize the proton FLASH effect, here, we incorporate dose rate objectives into our beam orientation optimization framework. METHODS From our previously developed group-sparsity dose objectives, we add upper and lower dose rate terms using a surrogate dose-averaged dose rate definition and solve using the fast-iterative shrinking threshold algorithm. We compare the dosimetry for three head-and-neck cases between four techniques: (1) spread-out BP IMPT (BP), (2) dose rate optimization using BP beams only (BP-DR), (3) dose rate optimization using ST beams only (ST-DR), and (4) dose rate optimization using combined BP and ST (BPST-DR), with the goal of sparing organs at risk without loss of tumor coverage and maintaining high dose rate within a 10 mm region of interest (ROI) surrounding the clinical target volume (CTV). RESULTS For BP, BP-DR, ST-DR, and BPST-DR, CTV homogeneity index and Dmax were found to be on average 0.886, 0.867, 0.687, and 0.936 and 107%, 109%, 135%, and 101% of prescription, respectively. Although ST-DR plans were not able to meet dosimetric standards, BPST-DR was able to match or improve either maximum or mean dose in the right submandibular gland, left and right parotids, constrictors, larynx, and spinal cord compared to BP plans. Volume of ROIs receiving greater than 40 Gy/s ( V γ 0 ) ${V_{\gamma 0}})$ was 51.0%, 91.4%, 95.5%, and 92.1% on average. CONCLUSIONS The dose rate techniques, particularly BPST-DR, were able to significantly increase dose rate without compromising physical dose compared with BP. Our algorithm efficiently selects beams that are optimal for both dose and dose rate.
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Affiliation(s)
- Pavitra Ramesh
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Wenbo Gu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dan Ruan
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ke Sheng
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA 90095, USA
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16
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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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17
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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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