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Potiron S, Iturri L, Juchaux M, Espenon J, Gilbert C, McGarrigle J, Ortiz Catalan R, Fernandez-Rodriguez A, Sebrié C, Jourdain L, De Marzi L, Créhange G, Prezado Y. The significance of dose heterogeneity on the anti-tumor response of minibeam radiation therapy. Radiother Oncol 2024; 201:110577. [PMID: 39393469 DOI: 10.1016/j.radonc.2024.110577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 09/24/2024] [Accepted: 10/03/2024] [Indexed: 10/13/2024]
Abstract
BACKGROUND AND PURPOSE Proton Minibeam Radiation Therapy (pMBRT) is an unconventional radiation technique based on a strong modulation of the dose deposition. Due to its specific pattern, pMBRT involves several dosimetry (peak and valley doses, peak-to-valley dose ratio (PVDR)) and geometrical parameters (beam width, spacing) that can influence the biological response. This study aims at contributing to the efforts to deepen the comprehension of how the various parameters relate to central biological mechanisms, particularly anti-tumor immunity, and how these correlations affect treatment outcomes with the goal to fully unleash the potential of pMBRT. We also evaluated the effects of X-ray MBRT to further elucidate the influence of peak dose and dose heterogeneity. METHODS AND MATERIALS An orthotopic rat model of glioblastoma underwent several pMBRT configurations. The impact of different dosimetric parameters on survival and on the modulation of crucial mechanisms for pMBRT, such as immune response, was investigated. The latter was assessed by immunohistochemistry and flow cytometry at 7 days post-irradiation. RESULTS Survival was improved across the various pMBRT regimens via maintaining a minimum valley dose as well as a higher dose heterogeneity, which is driven by peak dose. While the mean dose did not impact immune infiltration, a higher PVDR promoted a less immunosuppressive microenvironment. CONCLUSIONS Our results suggest that both tumor eradication, and immune infiltration are associated with higher dose heterogeneity. Higher dose heterogeneity was achieved by optimizing the peak dose, as well as maintaining a minimum valley dose. These parameters contributed to direct tumor eradication as well as reduction of immunosuppression, which is a departure from the more immunosuppressive tumor environment found in conventional proton therapy that delivers uniform dose distributions.
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Affiliation(s)
- Sarah Potiron
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France.
| | - Lorea Iturri
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France.
| | - Marjorie Juchaux
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Julie Espenon
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Cristèle Gilbert
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Josie McGarrigle
- Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Ramon Ortiz Catalan
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Alfredo Fernandez-Rodriguez
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Catherine Sebrié
- Service Hospitalier Frederic Joliot, CEA, CNRS, Inserm, BIOMAPS Universite Paris-Saclay, Orsay, France
| | - Laurène Jourdain
- Service Hospitalier Frederic Joliot, CEA, CNRS, Inserm, BIOMAPS Universite Paris-Saclay, Orsay, France
| | - Ludovic De Marzi
- Institut Curie, Université PSL, Université Paris-Saclay, Inserm U1288, Laboratoire d'Imagerie Translationnelle en Oncologie (LITO), 91898 Orsay, France; Institut Curie, Radiation Oncology Department, PSL Research University, 25 rue d'Ulm 75005, Paris/Orsay, France
| | - Gilles Créhange
- Institut Curie, Université PSL, Université Paris-Saclay, Inserm U1288, Laboratoire d'Imagerie Translationnelle en Oncologie (LITO), 91898 Orsay, France; Institut Curie, Radiation Oncology Department, PSL Research University, 25 rue d'Ulm 75005, Paris/Orsay, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France.
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Bertho A, Ortiz R, Maurin M, Juchaux M, Gilbert C, Espenon J, Ramasamy G, Patriarca A, De Marzi L, Pouzoulet F, Prezado Y. Thoracic Proton Minibeam Radiation Therapy: Tissue Preservation and Survival Advantage Over Conventional Proton Therapy. Int J Radiat Oncol Biol Phys 2024; 120:579-592. [PMID: 38621606 DOI: 10.1016/j.ijrobp.2024.04.011] [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: 01/10/2024] [Revised: 03/25/2024] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
PURPOSE Proton minibeam radiation therapy (pMBRT) is an innovative radiation therapy approach that highly modulates the spatial dimension of the dose delivery using narrow, parallel, and submillimetric proton beamlets. pMBRT has proven its remarkable healthy tissue preservation in the brain and skin. This study assesses the potential advantages of pMBRT for thoracic irradiations compared with conventional radiation therapy in terms of normal tissue toxicity. The challenge here was the influence of respiratory motion on the typical peak and valley dose patterns of pMBRT and its potential biologic effect. METHODS AND MATERIALS The whole thorax of naïve C57BL/6 mice received one fraction of high dose (18 Gy) pMBRT or conventional proton therapy (CPT) without any respiratory control. The development of radiation-induced pulmonary fibrosis was longitudinally monitored using cone beam computed tomography. Anatomopathologic analysis was carried out at 9 months postirradiation and focused on the reaction of the lungs' parenchyma and the response of cell types involved in the development of radiation-induced fibrosis and lung regeneration as alveolar type II epithelial cells, club cells, and macrophages. RESULTS pMBRT has milder effects on survival, skin reactions, and lung fibrosis compared with CPT. The pMBRT-induced lung changes were more regional and less severe, with evidence of potential reactive proliferation of alveolar type II epithelial cells and less extensive depletion of club cells and macrophage invasion than the more damaging effects observed in CPT. CONCLUSIONS pMBRT appears suitable to treat moving targets, holding a significant ability to preserve healthy lung tissue, even without respiratory control or precise targeting.
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Affiliation(s)
- Annaïg Bertho
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France
| | - Ramon Ortiz
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France
| | - Mathieu Maurin
- Institut Curie, PSL Research University, INSERM U932, Paris, France
| | - Marjorie Juchaux
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France
| | - Cristèle Gilbert
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France
| | - Julie Espenon
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France
| | - Gabriel Ramasamy
- Institut Curie, PSL Research University, Département de Recherche Translationnelle, CurieCoreTech-Experimental Radiation therapy (RadeXp), Paris, France
| | - Annalisa Patriarca
- Centre de Protonthérapie d'Orsay, Radiation Oncology Department, Campus Universitaire, Institut Curie, PSL University, Orsay, France
| | - Ludovic De Marzi
- Centre de Protonthérapie d'Orsay, Radiation Oncology Department, Campus Universitaire, Institut Curie, PSL University, Orsay, France; Institut Curie, Campus Universitaire, PSL University, University Paris Saclay, INSERM, Orsay
| | - Frédéric Pouzoulet
- Institut Curie, PSL Research University, Département de Recherche Translationnelle, CurieCoreTech-Experimental Radiation therapy (RadeXp), Paris, France; Institut Curie, PSL University, Université Paris-Saclay, Inserm, Laboratoire de Recherche Translationnelle en Oncologie, Orsay, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France; Université Paris-Saclay, CNRS UMR3347, INSERM U1021, Signalisation Radiobiologie et Cancer, Orsay, France.
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Lin Y, Li W, Wang A, Johnson D, Gan GN, Gao H. Comprehensive dosimetric commissioning of proton minibeam radiotherapy on a single gantry proton system. Front Oncol 2024; 14:1421869. [PMID: 39099699 PMCID: PMC11294745 DOI: 10.3389/fonc.2024.1421869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 07/01/2024] [Indexed: 08/06/2024] Open
Abstract
Background Proton minibeam radiation therapy (pMBRT) can deliver spatially fractionated dose distributions with submillimeter resolution. These dose distributions exhibit significant heterogeneity in both depth and lateral directions. Accurate characterization of pMBRT doses requires dosimetry devices with high spatial resolution and a wide dynamic range. Furthermore, the dependency of dosimetric measurements on Linear Energy Transfer (LET), as observed in conventional proton therapy, is also present in pMBRT depth dose measurements. Purpose This work demonstrates the process of performing comprehensive dosimetric measurements to characterize the pMBRT collimator on a clinical single-gantry proton machine, utilizing commercially available dosimetry devices. Methods The minibeam collimator is designed to be mounted on the clinical nozzle as a beam-modifying accessory. Three collimators, each with a slit opening of 0.4 mm, are thoroughly evaluated. The center-to-center (c-t-c) distances of the slits for these collimators are 2.8 mm, 3.2 mm, and 4.0 mm, respectively. High spatial resolution dosimetry devices are essential for PMBRT dose characterizations. To meet this requirement, two-dimensional (2D) dose measurement devices, Gafchromic films, are used to measure lateral profiles at various depths. Films are also used for depth dose profile measurements in solid water. Additionally, high-resolution point dose detectors, microDiamond, and Razor diode detectors are employed for lateral profile measurements at various depths. Percent depth dose (PDD) measurements of pMBRT in solid water, with various proton energies, collimators, and air gaps, are performed using Gafchromic films. The film's LET dependency for proton beams is corrected to ensure accurate pMBRT PDD measurements. The Monte Carlo simulation tool TOPAS is utilized to compare and validate all experimental measurements. Results At depths where LET is not a concern, film dose measurements were consistent with microDiamond and Razor diode point measurements. The point detectors need to be orientated with the thin side aligned to the incoming beam. Comparison of the lateral dose profiles extracted from TOPAS simulations, films, microDiamond, and Razor diode detectors shows a passing rate exceeding 98% in 1D gamma analysis at 3% 0.1 mm criteria.However, when the microDiamond detector is orientated to face the pMBRT beam, its spatial resolution may not be sufficient to capture the peak and valley dose accurately. Nevertheless, an accuracy within 2% can still be achieved when comparing the average dose. The PDD measurements show that the peak valley dose ratio (PVDR) of pMBRT can be altered at different depths with different air gaps using the same collimator or different collimators of different c-t-c distances. Conclusion Our study demonstrates that comprehensive dose measurements for pMBRT can be conducted using standard clinical dose measurement devices. These measurements are indispensable for guiding and ensuring accurate dose reporting in pre-clinical studies using the pMBRT technique.
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Affiliation(s)
- Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Aoxiang Wang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Daniel Johnson
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Gregory N. Gan
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, United States
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Mossahebi S, Byrne K, Jiang K, Gerry A, Deng W, Repetto C, Jackson IL, Sawant A, Poirier Y. A high-throughput focused collimator for OAR-sparing preclinical proton FLASH studies: commissioning and validation. Phys Med Biol 2024; 69:14NT01. [PMID: 38876112 DOI: 10.1088/1361-6560/ad589f] [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: 03/23/2024] [Accepted: 06/14/2024] [Indexed: 06/16/2024]
Abstract
Objective. To fabricate and validate a novel focused collimator designed to spare normal tissue in a murine hemithoracic irradiation model using 250 MeV protons delivered at ultra-high dose rates (UHDRs) for preclinical FLASH radiation therapy (FLASH-RT) studies.Approach. A brass collimator was developed to shape 250 MeV UHDR protons from our Varian ProBeam. Six 13 mm apertures, of equivalent size to kV x-ray fields historically used to perform hemithorax irradiations, were precisely machined to match beam divergence, allowing concurrent hemithoracic irradiation of six mice while sparing the contralateral lung and abdominal organs. The collimated field profiles were characterized by film dosimetry, and a radiation survey of neutron activation was performed to ensure the safety of staff positioning animals.Main results. The brass collimator produced 1.2 mm penumbrae radiation fields comparable to kV x-rays used in preclinical studies. The penumbrae in the six apertures are similar, with full-width half-maxima of 13.3 mm and 13.5 mm for the central and peripheral apertures, respectively. The collimator delivered a similar dose at an average rate of 52 Gy s-1for all apertures. While neutron activation produces a high (0.2 mSv h-1) initial ambient equivalent dose rate, a parallel work-flow in which imaging and setup are performed without the collimator ensures safety to staff.Significance. Scanned protons have the greatest potential for future translation of FLASH-RT in clinical treatments due to their ability to treat deep-seated tumors with high conformality. However, the Gaussian distribution of dose in proton spots produces wider lateral penumbrae compared to other modalities. This presents a challenge in small animal pre-clinical studies, where millimeter-scale penumbrae are required to precisely target the intended volume. Offering high-throughput irradiation of mice with sharp penumbrae, our novel collimator-based platform serves as an important benchmark for enabling large-scale, cost-effective radiobiological studies of the FLASH effect in murine models.
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Affiliation(s)
- Sina Mossahebi
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Kevin Byrne
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Kai Jiang
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Andrew Gerry
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Wei Deng
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Carlo Repetto
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Isabel L Jackson
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
- True North Biopharm, LLC, Rockville, MD, United States of America
| | - Amit Sawant
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Yannick Poirier
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States of America
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Lin Y, Li W, Johnson D, Prezado Y, Gan GN, Gao H. Development and characterization of the first proton minibeam system for single-gantry proton facility. Med Phys 2024; 51:3995-4006. [PMID: 38642468 DOI: 10.1002/mp.17074] [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: 11/27/2023] [Revised: 03/28/2024] [Accepted: 03/28/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Minibeam represents a preclinical spatially fractionated radiotherapy modality with great translational potential. The advantage lies in its high therapeutic index (compared to GRID and LATTICE) and ability to treat at greater depth (compared to microbeam). Proton minibeam radiotherapy (pMBRT) is a synergy of proton and minibeam. While the single-gantry proton facility has gained popularity due to its affordability and compact design, it often has limited beam time available for research purposes. Conversely, given the current requirement of pMBRT on specific minibeam hardware collimators, necessitates a reproducible and fast setup to minimize pMBRT treatment time and streamline the switching time between pMBRT and conventional treatment for clinically translation. PURPOSE The contribution of this work is the development and characterization of the first pMBRT system tailored for single-gantry proton facility. The system allows for efficient and reproducible plug-and-play setup, achievable within minutes. METHODS The single room pMBRT system is constructed based on IBA ProteusONE proton machine. The end of nozzle is attached with beam modifying accessories though an accessory drawer. A small snout is attached to the accessory drawer and used to hold apertures and range shifters. The minibeam aperture consists of two components: a fitting ring and an aperture body. Three minibeam apertures were manufactured. The first-generation apertures underwent qualitatively analysis with film, and the second generation aperture underwent more comprehensive quantitative measurement. The reproducibility of the setup is accessed, and the film measurements are performed to characterize the pMBRT system in cross validation with Monte Carlo (MC) simulations. RESULTS We presented initial results of large field pMBRT aperture and the film measurements indicates the effect of source-to-isocenter distance = 930 cm in Y proton scanning direction. Consistent with TOPAS MC simulation, the dose uniformity of pMBRT field <2 cm is demonstrated to be better than 2%, rendering its suitability for pre-clinical studies. Subsequently, we developed the second generation of aperture with five slits and characterized the aperture with film dosimetry studies and compared the results to the benchmark MC. Comprehensive film measurements were also performed to evaluate the effect of divergence, air gap and gantry-angle dependency and repeatability and revealing a consistent performance within 5%. Furthermore, the 2D gamma analysis indicated a passing rate exceeding 99% using 3% dose difference and 0.2 mm distance agreement criteria. We also establish the peak valley dose ratio and the depth dose profile measurements, and the results are within 10% from MC simulation. CONCLUSIONS We have developed the first pMBRT system tailored for a single-gantry proton facility, which has demonstrated accuracy in benchmark with MC simulations, and allows for efficient plug-and-play setup, emphasizing efficiency.
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Affiliation(s)
- Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Daniel Johnson
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Yolanda Prezado
- Institut Curie, University PSL, CNRS UMR3347, INSERM U1021, Orsay, France
| | - Gregory N Gan
- 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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Prezado Y, Grams M, Jouglar E, Martínez-Rovira I, Ortiz R, Seco J, Chang S. Spatially fractionated radiation therapy: a critical review on current status of clinical and preclinical studies and knowledge gaps. Phys Med Biol 2024; 69:10TR02. [PMID: 38648789 DOI: 10.1088/1361-6560/ad4192] [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: 11/27/2023] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
Spatially fractionated radiation therapy (SFRT) is a therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT activates distinct radiobiological mechanisms which lead to a remarkable increase in normal tissue tolerances. Several decades of clinical use and numerous preclinical experiments suggest that SFRT has the potential to increase the therapeutic index, especially in bulky and radioresistant tumors. To unleash the full potential of SFRT a deeper understanding of the underlying biology and its relationship with the complex dosimetry of SFRT is needed. This review provides a critical analysis of the field, discussing not only the main clinical and preclinical findings but also analyzing the main knowledge gaps in a holistic way.
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Affiliation(s)
- Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, F-91400, Orsay, France
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, F-91400, Orsay, France
- New Approaches in Radiotherapy Lab, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de investigación Sanitaria de Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, A Coruña, E-15706, Spain
- Oportunius Program, Galician Agency of Innovation (GAIN), Xunta de Galicia, Santiago de Compostela, A Coruña, Spain
| | - Michael Grams
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, United States of America
| | - Emmanuel Jouglar
- Institut Curie, PSL Research University, Department of Radiation Oncology, F-75005, Paris and Orsay Protontherapy Center, F-91400, Orsay, France
| | - Immaculada Martínez-Rovira
- Physics Department, Universitat Auto`noma de Barcelona, E-08193, Cerdanyola del Valle`s (Barcelona), Spain
| | - Ramon Ortiz
- University of California San Francisco, Department of Radiation Oncology, 1600 Divisadero Street, San Francisco, CA 94143, United States of America
| | - Joao Seco
- Division of Biomedical physics in Radiation Oncology, DKFZ-German Cancer Research Center, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Sha Chang
- Dept of Radiation Oncology and Department of Biomedical Engineering, University of North Carolina School of Medicine, United States of America
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolin State University, United States of America
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Reaz F, Traneus E, Bassler N. Tuning spatially fractionated radiotherapy dose profiles using the moiré effect. Sci Rep 2024; 14:8468. [PMID: 38605022 PMCID: PMC11009409 DOI: 10.1038/s41598-024-55104-7] [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: 11/03/2023] [Accepted: 02/20/2024] [Indexed: 04/13/2024] Open
Abstract
Spatially Fractionated Radiotherapy (SFRT) has demonstrated promising potential in cancer treatment, combining the advantages of reduced post-radiation effects and enhanced local control rates. Within this paradigm, proton minibeam radiotherapy (pMBRT) was suggested as a new treatment modality, possibly producing superior normal tissue sparing to conventional proton therapy, leading to improvements in patient outcomes. However, an effective and convenient beam generation method for pMBRT, capable of implementing various optimum dose profiles, is essential for its real-world application. Our study investigates the potential of utilizing the moiré effect in a dual collimator system (DCS) to generate pMBRT dose profiles with the flexibility to modify the center-to-center distance (CTC) of the dose distribution in a technically simple way.We employ the Geant4 Monte Carlo simulations tool to demonstrate that the angle between the two collimators of a DCS can significantly impact the dose profile. Varying the DCS angle from 10∘ to 50∘ we could cover CTC ranging from 11.8 mm to 2.4 mm, respectively. Further investigations reveal the substantial influence of the multi-slit collimator's (MSC) physical parameters on the spatially fractionated dose profile, such as period (CTC), throughput, and spacing between MSCs. These findings highlight opportunities for precision dose profile adjustments tailored to specific clinical scenarios.The DCS capacity for rapid angle adjustments during the energy transition stages of a spot scanning system can facilitate dynamic alterations in the irradiation profile, enhancing dose contrast in normal tissues. Furthermore, its unique attribute of spatially fractionated doses in both lateral directions could potentially improve normal tissue sparing by minimizing irradiated volume. Beyond the realm of pMBRT, the dual MSC system exhibits remarkable versatility, showing compatibility with different types of beams (X-rays and electrons) and applicability across various SFRT modalities.Our study illuminates the dual MSC system's potential as an efficient and adaptable tool in the refinement of pMBRT techniques. By enabling meticulous control over irradiation profiles, this system may expedite advancements in clinical and experimental applications, thereby contributing to the evolution of SFRT strategies.
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Affiliation(s)
- Fardous Reaz
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.
| | | | - Niels Bassler
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
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Loap P, Giorgi M, Vu-Bezin J, Kirov K, Sampai JM, Prezado Y, Kirova Y. Dosimetric feasibility study ("proof of concept") of refractory ventricular tachycardia radioablation using proton minibeams. Cancer Radiother 2024; 28:195-201. [PMID: 38599941 DOI: 10.1016/j.canrad.2024.02.002] [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: 12/20/2023] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 04/12/2024]
Abstract
PURPOSE Preclinical data demonstrated that the use of proton minibeam radiotherapy reduces the risk of toxicity in healthy tissue. Ventricular tachycardia radioablation is an area under clinical investigation in proton beam therapy. We sought to simulate a ventricular tachycardia radioablation with proton minibeams and to demonstrate that it was possible to obtain a homogeneous coverage of an arrhythmogenic cardiac zone with this technique. MATERIAL AND METHODS An arrhythmogenic target volume was defined on the simulation CT scan of a patient, localized in the lateral wall of the left ventricle. A dose of 25Gy was planned to be delivered by proton minibeam radiotherapy, simulated using a Monte Carlo code (TOPAS v.3.7) with a collimator of 19 0.4 mm-wide slits spaced 3mm apart. The main objective of the study was to obtain a plan ensuring at least 93% of the prescription dose in 93% of the planning target volume without exceeding 110% of the prescribed dose in the planning target volume. RESULTS The average dose in the planning treatment volume in proton minibeam radiotherapy was 25.12Gy. The percentage of the planning target volume receiving 93% (V93%), 110% (V110%), and 95% (V95%) of the prescribed dose was 94.25%, 0%, and 92.6% respectively. The lateral penumbra was 6.6mm. The mean value of the peak-to-valley-dose ratio in the planning target volume was 1.06. The mean heart dose was 2.54Gy versus 5.95Gy with stereotactic photon beam irradiation. CONCLUSION This proof-of-concept study shows that proton minibeam radiotherapy can achieve a homogeneous coverage of an arrhythmogenic cardiac zone, reducing the dose at the normal tissues. This technique, ensuring could theoretically reduce the risk of late pulmonary and breast fibrosis, as well as cardiac toxicity as seen in previous biological studies in proton minibeam radiotherapy.
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Affiliation(s)
- P Loap
- Department of Radiation Oncology, institut Curie, Paris, France
| | - M Giorgi
- Signalisation radiobiologie et cancer, Inserm U1021, CNRS UMR3347, Institut Curie, université PSL, 91400 Orsay, France; Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisboa, Portugal; Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - J Vu-Bezin
- Department of Radiation Oncology, institut Curie, Paris, France
| | - K Kirov
- Department of Anesthesia and Reanimation, institut Curie, Paris, France
| | - J M Sampai
- Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisboa, Portugal; Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Y Prezado
- Signalisation radiobiologie et cancer, Inserm U1021, CNRS UMR3347, Institut Curie, université PSL, 91400 Orsay, France
| | - Y Kirova
- Department of Radiation Oncology, institut Curie, Paris, France; Université Versailles, Saint-Quentin, France.
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9
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Reaz F, Sitarz MK, Traneus E, Bassler N. Parameters for proton minibeam radiotherapy using a clinical scanning beam system. Acta Oncol 2023; 62:1561-1565. [PMID: 37837215 DOI: 10.1080/0284186x.2023.2266125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023]
Affiliation(s)
- Fardous Reaz
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Niels Bassler
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
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10
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Zhang W, Li W, Lin Y, Wang F, Chen RC, Gao H. TVL1-IMPT: Optimization of Peak-to-Valley Dose Ratio Via Joint Total-Variation and L1 Dose Regularization for Spatially Fractionated Pencil-Beam-Scanning Proton Therapy. Int J Radiat Oncol Biol Phys 2023; 115:768-778. [PMID: 36155212 PMCID: PMC10155885 DOI: 10.1016/j.ijrobp.2022.09.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 07/18/2022] [Accepted: 09/08/2022] [Indexed: 02/04/2023]
Abstract
PURPOSE Proton minibeam radiation therapy (pMBRT) is a novel proton modality of spatially fractionated RT. pMBRT can reduce the radiation damage to normal tissues via biological dose sparing of high peak-to-valley dose ratio (PVDR). This work will develop a new spatially fractionated IMPT treatment planning method for pMBRT that jointly optimizes the plan quality and maximizes the PVDR. METHODS The new optimization method simultaneously maximizes the normal-tissue PVDR and optimizes the dose distribution at tumor targets and organs at risk. The PVDR maximization is through the joint total variation (TV) and L1 regularization with respect to the normal-tissue dose. That is, the beam-eye view projects dose slices of several depths for each beam angle; the TV of dose is maximized, corresponding to the PVDR maximization; and the L1 of dose is minimized, corresponding to the minimization of the organs-at-risk dose and maximization of survival fraction (SF). RESULTS The new IMPT method with TV and L1 regularization was validated in comparison with the conventional IMPT method for pMBRT in several clinical cases. The results show that TVL1 provided larger PVDR and SF than the conventional IMPT method for biological sparing of normal tissues, with preserved plan quality in terms of physical dose distribution. CONCLUSIONS A new spatially fractionated IMPT treatment planning method was developed for pMBRT that can optimize and improve normal-tissue PVDR and SF by incorporating TV and L1 dose regularization with properly chosen regularization parameters into IMPT.
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Affiliation(s)
- Weijie Zhang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Fen Wang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Ronald C Chen
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas.
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11
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Sotiropoulos M, Prezado Y. Radiation quality correction factors for improved dosimetry in preclinical minibeam radiotherapy. Med Phys 2022; 49:6716-6727. [PMID: 35904962 DOI: 10.1002/mp.15838] [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: 12/24/2021] [Revised: 06/03/2022] [Accepted: 06/19/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND In reference dosimetry, radiation quality correction factors are used in order to account for changes in the detector's response among different radiation qualities, improving dosimetric accuracy. PURPOSE Reference dosimetry radiation quality corrections factors for the PTW microDiamond were calculated for preclinical X-ray and proton minibeams, and their impact in dosimetric accuracy was evaluated. METHODS A formalism for the calculation of radiation quality correction factors for absolute dosimetry in minibeam fields was developed. Following our formalism, radiation quality correction factors were calculated for the PTW microDiamond detector, using the Monte Carlo method. Models of the detector, and X-ray and proton irradiation platform, were imported into the TOPAS Monte Carlo simulation toolkit. The radiation quality correction factors were calculated in the following scenarios: (i) reference dosimetry open field to minibeam center of the central peak, (ii) different positions at the minibeam profile (along the peaks and valleys direction) to the center of the central minibeam, and (iii) some representative depth positions. In addition, the radiation quality correction factors needed for the calculation of the peak-to-valley dose ratio at different depths were calculated. RESULTS An important overestimation of the dose (about 10%) was found in the case of the open to minibeam field for both X-rays and proton beams, when the correction factors were used. Smaller differences were observed in the other cases. CONCLUSIONS The usage of the PTW microDiamond detector requires radiation quality correction factors in order to be used in minibeam reference dosimetry.
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Affiliation(s)
- Marios Sotiropoulos
- Signalisation Radiobiologie et Cancer, CNRS UMR3347, Inserm U1021, Institut Curie, Université PSL, Orsay, France
| | - Yolanda Prezado
- Signalisation Radiobiologie et Cancer, CNRS UMR3347, Inserm U1021, Institut Curie, Université PSL, Orsay, France
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12
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Schneider T, Fernandez-Palomo C, Bertho A, Fazzari J, Iturri L, Martin OA, Trappetti V, Djonov V, Prezado Y. Combining FLASH and spatially fractionated radiation therapy: The best of both worlds. Radiother Oncol 2022; 175:169-177. [PMID: 35952978 DOI: 10.1016/j.radonc.2022.08.004] [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: 04/14/2022] [Revised: 07/23/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
Abstract
FLASH radiotherapy (FLASH-RT) and spatially fractionated radiation therapy (SFRT) are two new therapeutical strategies that use non-standard dose delivery methods to reduce normal tissue toxicity and increase the therapeutic index. Although likely based on different mechanisms, both FLASH-RT and SFRT have shown to elicit radiobiological effects that significantly differ from those induced by conventional radiotherapy. With the therapeutic potential having been established separately for each technique, the combination of FLASH-RT and SFRT could therefore represent a winning alliance. In this review, we discuss the state of the art, advantages and current limitations, potential synergies, and where a combination of these two techniques could be implemented today or in the near future.
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Affiliation(s)
- Tim Schneider
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | | | - Annaïg Bertho
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Jennifer Fazzari
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Lorea Iturri
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Olga A Martin
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; Division of Radiation Oncology, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia; University of Melbourne, Parkville, VIC 3010, Australia
| | - Verdiana Trappetti
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Valentin Djonov
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France.
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13
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Technical aspects of proton minibeam radiation therapy: Minibeam generation and delivery. Phys Med 2022; 100:64-71. [PMID: 35750002 DOI: 10.1016/j.ejmp.2022.06.010] [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: 02/02/2022] [Revised: 06/02/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022] Open
Abstract
Proton minibeam radiation therapy (pMBRT) is a novel therapeutic strategy that combines the normal tissue sparing of sub-millimetric, spatially fractionated beams with the improved ballistics of protons. This may allow a safe dose escalation in the tumour and has already proven to provide a remarkable increase of the therapeutic index for high-grade gliomas in animal experiments. One of the main challenges in pMBRT concerns the generation of minibeams and the implementation in a clinical environment. This article reviews the different approaches for generating minibeams, using mechanical collimators and focussing magnets, and discusses the technical aspects of the implementation and delivery of pMBRT.
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14
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Dose Profile Modulation of Proton Minibeam for Clinical Application. Cancers (Basel) 2022; 14:cancers14122888. [PMID: 35740553 PMCID: PMC9221247 DOI: 10.3390/cancers14122888] [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: 03/25/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 01/25/2023] Open
Abstract
Simple Summary Proton minibeam radiation therapy (pMBRT) using multislit collimator (MSC) and scatterers has been proposed to spare healthy tissues and organs on the beam path and beyond the Bragg peak. An MSC that was much thicker than the maximum range of the proton beam could provide a sufficiently high peak-to-valley dose ratio at the patient’s skin, and the scatterers could actively convert the spatially fractionated proton beam to a uniform and broad beam in tumors by changing their thickness. The combination of the MSC and the scatterers can be a good solution for implementing pMBRT in clinical proton therapy facilities. Abstract The feasibility of proton minibeam radiation therapy (pMBRT) using a multislit collimator (MSC) and a scattering device was evaluated for clinical use at a clinical proton therapy facility. We fabricated, through Monte Carlo (MC) simulations, not only an MSC with a high peak-to-valley dose ratio (PVDR) at the entrance of the proton beam, to prevent radiation toxicity, but also a scattering device to modulate the PVDR in depth. The slit width and center-to-center distance of the diverging MSC were 2.5 mm and 5.0 mm at the large end, respectively, and its thickness and available field size were 100 mm and 76 × 77.5 mm2, respectively. Spatially fractionated dose distributions were measured at various depths using radiochromic EBT3 films and also tested on bacterial cells. MC simulation showed that the thicker the MSC, the higher the PVDR at the phantom surface. Dosimetric evaluations showed that lateral dose profiles varied according to the scatterer’s thickness, and the depths satisfying PVDR = 1.1 moved toward the surface as their thickness increased. The response of the bacterial cells to the proton minibeams’ depth was also established, in a manner similar to the dosimetric pattern. Conclusively, these results strongly suggest that pMBRT can be implemented in clinical centers by using MSC and scatterers.
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15
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Ortiz R, De Marzi L, Prezado Y. Preclinical dosimetry in proton minibeam radiation therapy: robustness analysis and guidelines. Med Phys 2022; 49:5551-5561. [PMID: 35621386 PMCID: PMC9544651 DOI: 10.1002/mp.15780] [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: 02/24/2022] [Revised: 05/03/2022] [Accepted: 05/22/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose Proton minibeam radiation therapy (pMBRT) is a new radiotherapy approach that has shown a significant increase in the therapeutic window in glioma‐bearing rats compared to conventional proton therapy. The dosimetry of pMBRT is challenging and error prone due to the submillimetric beamlet sizes used. The aim of this study was to perform a robustness analysis on the setup parameters utilized in current preclinical trials and provide guidelines for reproducible dosimetry. The results of this work are intended to guide upcoming implementations of pMBRT worldwide, as well as pave the way for future clinical implementations. Methods Monte Carlo simulations and experimental data were used to evaluate the impact of variations in setup parameters and uncertainties in collimator specifications on lateral pMBRT dose distributions. The value of each parameter was modified individually to evaluate their effect on dose distributions. Experimental dosimetry was performed by means of high‐resolution detectors, that is, radiochromic films, the IBA Razor and the Microdiamond detector. New guidelines were proposed to optimize the experimental setup in pMBRT studies and perform reproducible dosimetry. Results The sensitivity of dose distributions to uncertainties and variations in setup parameters was quantified. Quantities that define pMBRT lateral profiles (i.e., the peak‐to‐valley dose ratio [PVDR], peak and valley doses, and peak width) are significantly influenced by small‐scale fluctuations in several of those parameters. The setup implemented at the Orsay proton therapy center for pMBRT irradiation was optimized to increase PVDRs and peak symmetry. In addition, we proposed guidelines to perform accurate and reproducible dosimetry in preclinical studies. Conclusions This study revealed the importance of adopting guidelines and protocols tailored to the distinct dose delivery method and dose distributions in pMBRT. This new methodology leads to reproducible dosimetry, which is imperative in preclinical trials. The results and guidelines presented in this manuscript can ease the initiation of pMBRT investigations in other centers.
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Affiliation(s)
- Ramon Ortiz
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France.,Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France
| | - Ludovic De Marzi
- Centre de Protonthérapie d'Orsay, Radiation Oncology Department, Campus Universitaire, Institut Curie, PSL Research University, Orsay, 91898, France.,Institut Curie, Campus Universitaire, PSL Research University, University Paris Saclay, INSERM LITO, Orsay, 91898, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France.,Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France
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16
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McAuley GA, Lim CJ, Teran AV, Slater JD, Wroe AJ. Monte Carlo evaluation of high-gradient magnetically focused planar proton minibeams in a passive nozzle. Phys Med Biol 2022; 67. [PMID: 35421853 DOI: 10.1088/1361-6560/ac678b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/14/2022] [Indexed: 11/12/2022]
Abstract
Objective. To investigate the potential of using a single quadrupole magnet with a high magnetic field gradient to create planar minibeams suitable for clinical applications of proton minibeam radiation therapy.Approach. We performed Monte Carlo simulations involving single quadrupole Halbach cylinders in a passively scattered nozzle in clinical use for proton therapy. Pencil beams produced by the nozzle of 10-15 mm initial diameters and particle range of ∼10-20 cm in water were focused by magnets with field gradients of 225-350 T m-1and cylinder lengths of 80-110 mm to produce very narrow elongated (planar) beamlets. The corresponding dose distributions were scored in a water phantom. Composite minibeam dose distributions composed from three beamlets were created by laterally shifting copies of the single beamlet distribution to either side of a central beamlet. Modulated beamlets (with 18-30 mm nominal central SOBP) and corresponding composite dose distributions were created in a similar manner. Collimated minibeams were also compared with beams focused using one magnet/particle range combination.Main results. The focusing magnets produced planar beamlets with minimum lateral FWHM of ∼1.1-1.6 mm. Dose distributions composed from three unmodulated beamlets showed a high degree of proximal spatial fractionation and a homogeneous target dose. Maximal peak-to-valley dose ratios (PVDR) for the unmodulated beams ranged from 32 to 324, and composite modulated beam showed maximal PVDR ranging from 32 to 102 and SOBPs with good target dose coverage.Significance.Advantages of the high-gradient magnets include the ability to focus beams with phase space parameters that reflect beams in operation today, and post-waist particle divergence allowing larger beamlet separations and thus larger PVDR. Our results suggest that high gradient quadrupole magnets could be useful to focus beams of moderate emittance in clinical proton therapy.
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Affiliation(s)
- Grant A McAuley
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America
| | - Crystal J Lim
- School of Medicine, Loma Linda University, Loma Linda, CA United States of America
| | - Anthony V Teran
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America.,Orange County CyberKnife and Radiation Oncology Center, Fountain Valley, CA, United States of America
| | - Jerry D Slater
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America
| | - Andrew J Wroe
- School of Medicine, Loma Linda University, Loma Linda, CA United States of America.,Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, United States of America.,Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
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17
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Proton Minibeam Radiation Therapy and Arc Therapy: Proof of Concept of a Winning Alliance. Cancers (Basel) 2021; 14:cancers14010116. [PMID: 35008280 PMCID: PMC8749801 DOI: 10.3390/cancers14010116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/03/2022] Open
Abstract
Simple Summary Normal tissue’s morbidity continues to limit the increase in the therapeutic index in radiation therapy. This study explores the potential advantages of combining proton arc therapy and proton minibeam radiation therapy, which have already individually shown a significant normal tissue’s sparing. This alliance aims to integrate the benefits of those techniques in a single approach. Abstract (1) Background: Proton Arc Therapy and Proton Minibeam Radiation Therapy are two novel therapeutic approaches with the potential to lower the normal tissue complication probability, widening the therapeutic window for radioresistant tumors. While the benefits of both modalities have been individually evaluated, their combination and its potential advantages are being assessed in this proof-of-concept study for the first time. (2) Methods: Monte Carlo simulations were employed to evaluate the dose and LET distributions in brain tumor irradiations. (3) Results: a net reduction in the dose to normal tissues (up to 90%), and the preservation of the spatial fractionation of the dose were achieved for all configurations evaluated. Additionally, Proton Minibeam Arc Therapy (pMBAT) reduces the volumes exposed to high-dose and high-LET values at expense of increased low-dose and intermediate-LET values. (4) Conclusions: pMBAT enhances the individual benefits of proton minibeams while keeping those of conventional proton arc therapy. These results might facilitate the path towards patients’ treatments since lower peak doses in normal tissues would be needed than in the case of a single array of proton minibeams.
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Cavallone M, Prezado Y, De Marzi L. Converging Proton Minibeams with Magnetic Fields for Optimized Radiation Therapy: A Proof of Concept. Cancers (Basel) 2021; 14:cancers14010026. [PMID: 35008189 PMCID: PMC8750079 DOI: 10.3390/cancers14010026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 12/14/2022] Open
Abstract
Proton MiniBeam Radiation Therapy (pMBRT) is a novel strategy that combines the benefits of minibeam radiation therapy with the more precise ballistics of protons to further optimize the dose distribution and reduce radiation side effects. The aim of this study is to investigate possible strategies to couple pMBRT with dipole magnetic fields to generate a converging minibeam pattern and increase the center-to-center distance between minibeams. Magnetic field optimization was performed so as to obtain the same transverse dose profile at the Bragg peak position as in a reference configuration with no magnetic field. Monte Carlo simulations reproducing realistic pencil beam scanning settings were used to compute the dose in a water phantom. We analyzed different minibeam generation techniques, such as the use of a static multislit collimator or a dynamic aperture, and different magnetic field positions, i.e., before or within the water phantom. The best results were obtained using a dynamic aperture coupled with a magnetic field within the water phantom. For a center-to-center distance increase from 4 mm to 6 mm, we obtained an increase of peak-to-valley dose ratio and decrease of valley dose above 50%. The results indicate that magnetic fields can be effectively used to improve the spatial modulation at shallow depth for enhanced healthy tissue sparing.
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Affiliation(s)
- Marco Cavallone
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Institut Curie, Campus Universitaire, PSL Research University, 91898 Orsay, France
- Correspondence: (M.C.); (L.D.M.)
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France;
| | - Ludovic De Marzi
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Institut Curie, Campus Universitaire, PSL Research University, 91898 Orsay, France
- Institut Curie, Campus Universitaire, PSL Research University, University Paris Saclay, INSERM LITO, 91898 Orsay, France
- Correspondence: (M.C.); (L.D.M.)
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19
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Prezado Y. Proton minibeam radiation therapy: a promising therapeutic approach for radioresistant tumors. C R Biol 2021; 344:409-420. [DOI: 10.5802/crbiol.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 11/24/2022]
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20
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Leite AMM, Ronga MG, Giorgi M, Ristic Y, Perrot Y, Trompier F, Prezado Y, Créhange G, De Marzi L. Secondary neutron dose contribution from pencil beam scanning, scattered and spatially fractionated proton therapy. Phys Med Biol 2021; 66. [PMID: 34673555 DOI: 10.1088/1361-6560/ac3209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/21/2021] [Indexed: 11/11/2022]
Abstract
The Orsay Proton therapy Center (ICPO) has a long history of intracranial radiotherapy using both double scattering (DS) and pencil beam scanning (PBS) techniques, and is actively investigating a promising modality of spatially fractionated radiotherapy using proton minibeams (pMBRT). This work provides a comprehensive comparison of the organ-specific secondary neutron dose due to each of these treatment modalities, assessed using Monte Carlo (MC) algorithms and measurements. A MC model of a universal nozzle was benchmarked by comparing the neutron ambient dose equivalent,H*(10), in the gantry room with measurements obtained using a WENDI-II counter. The secondary neutron dose was evaluated for clinically relevant intracranial treatments of patients of different ages, in which secondary neutron doses were scored in anthropomorphic phantoms merged with the patients' images. The MC calculatedH*(10) values showed a reasonable agreement with the measurements and followed the expected tendency, in which PBS yields the lowest dose, followed by pMBRT and DS. Our results for intracranial treatments show that pMBRT yielded a higher secondary neutron dose for organs closer to the target volume, while organs situated furthest from the target volume received a greater quantity of neutrons from the passive scattering beam line. To the best of our knowledge, this is the first study to compare MC secondary neutron dose estimates in clinical treatments between these various proton therapy modalities and to realistically quantify the secondary neutron dose contribution of clinical pMBRT treatments. The method established in this study will enable epidemiological studies of the long-term effects of intracranial treatments at ICPO, notably radiation-induced second malignancies.
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Affiliation(s)
- A M M Leite
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, F-91898 Orsay, France.,Institut Curie, PSL Research University, University Paris Saclay, Inserm U 1021- CNRS UMR 3347, F-91898 Orsay, France
| | - M G Ronga
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, F-91898 Orsay, France
| | - M Giorgi
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, F-91898 Orsay, France
| | - Y Ristic
- Institut de Radioprotection et de Sûreté Nucléaire, Service de Dosimétrie, Laboratoire de Dosimétrie des Rayonnements Ionisants, F-92262 Fontenay-aux-Roses Cedex, France
| | - Y Perrot
- Institut de Radioprotection et de Sûreté Nucléaire, Service de Dosimétrie, Laboratoire de Dosimétrie des Rayonnements Ionisants, F-92262 Fontenay-aux-Roses Cedex, France
| | - F Trompier
- Institut de Radioprotection et de Sûreté Nucléaire, Service de Dosimétrie, Laboratoire de Dosimétrie des Rayonnements Ionisants, F-92262 Fontenay-aux-Roses Cedex, France
| | - Y Prezado
- Institut Curie, PSL Research University, University Paris Saclay, Inserm U 1021- CNRS UMR 3347, F-91898 Orsay, France
| | - G Créhange
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, F-91898 Orsay, France
| | - L De Marzi
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, F-91898 Orsay, France.,Institut Curie, PSL Research University, University Paris Saclay, Inserm LITO, F-91898 Orsay, France
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21
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Bertho A, Ortiz R, Juchaux M, Gilbert C, Lamirault C, Pouzoulet F, Polledo L, Liens A, Warfving N, Sebrie C, Jourdain L, Patriarca A, de Marzi L, Prezado Y. First Evaluation of Temporal and Spatial Fractionation in Proton Minibeam Radiation Therapy of Glioma-Bearing Rats. Cancers (Basel) 2021; 13:cancers13194865. [PMID: 34638352 PMCID: PMC8507607 DOI: 10.3390/cancers13194865] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 01/11/2023] Open
Abstract
Simple Summary Proton minibeam radiation therapy (pMBRT) is a novel therapeutic approach based on a distinct dose delivery method: the dose distributions follow a pattern with regions of peaks (high doses) and valleys (low doses). pMBRT was shown to be able to widen the therapeutic window in glioma-bearing rats. In previous studies the irradiation was performed in one single fraction. The work reported in this manuscript is the first evaluation detailing the response of glioma-bearing rats to a temporal fractionation in proton minibeam radiation therapy, delivered under a crossfire geometry. A significant increase of the median survival time was obtained when the dose was delivered over two sessions as opposed to in a single fraction. This result could facilitate the path towards pMBRT treatments. Abstract (1) Background: Proton minibeam radiation therapy (pMBRT) is a new radiotherapy technique using spatially modulated narrow proton beams. pMBRT results in a significantly reduced local tissue toxicity while maintaining or even increasing the tumor control efficacy as compared to conventional radiotherapy in small animal experiments. In all the experiments performed up to date in tumor bearing animals, the dose was delivered in one single fraction. This is the first assessment on the impact of a temporal fractionation scheme on the response of glioma-bearing animals to pMBRT. (2) Methods: glioma-bearing rats were irradiated with pMBRT using a crossfire geometry. The response of the irradiated animals in one and two fractions was compared. An additional group of animals was also treated with conventional broad beam irradiations. (3) Results: pMBRT delivered in two fractions at the biological equivalent dose corresponding to one fraction resulted in the highest median survival time, with 80% long-term survivors free of tumors. No increase in local toxicity was noted in this group with respect to the other pMBRT irradiated groups. Conventional broad beam irradiations resulted in the most severe local toxicity. (4) Conclusion: Temporal fractionation increases the therapeutic index in pMBRT and could ease the path towards clinical trials.
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Affiliation(s)
- Annaïg Bertho
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; (A.B.); (R.O.); (M.J.); (C.G.)
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Ramon Ortiz
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; (A.B.); (R.O.); (M.J.); (C.G.)
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Marjorie Juchaux
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; (A.B.); (R.O.); (M.J.); (C.G.)
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Cristèle Gilbert
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; (A.B.); (R.O.); (M.J.); (C.G.)
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Charlotte Lamirault
- Translational Research Department, Institut Curie, Experimental Radiotherapy Platform, Université Paris Saclay, 91400 Orsay, France; (C.L.); (F.P.)
| | - Frederic Pouzoulet
- Translational Research Department, Institut Curie, Experimental Radiotherapy Platform, Université Paris Saclay, 91400 Orsay, France; (C.L.); (F.P.)
| | - Laura Polledo
- AnaPath GmbH, AnaPath Services, Hammerstrasse 49, 4410 Liestal, Switzerland; (L.P.); (A.L.); (N.W.)
| | - Alethea Liens
- AnaPath GmbH, AnaPath Services, Hammerstrasse 49, 4410 Liestal, Switzerland; (L.P.); (A.L.); (N.W.)
| | - Nils Warfving
- AnaPath GmbH, AnaPath Services, Hammerstrasse 49, 4410 Liestal, Switzerland; (L.P.); (A.L.); (N.W.)
| | - Catherine Sebrie
- CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, BIOMAPS Université Paris-Saclay, 91401 Orsay, France; (C.S.); (L.J.)
| | - Laurène Jourdain
- CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, BIOMAPS Université Paris-Saclay, 91401 Orsay, France; (C.S.); (L.J.)
| | - Annalisa Patriarca
- Centre de Protonthérapie d’Orsay, Radiation Oncology Department, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (A.P.); (L.d.M.)
| | - Ludovic de Marzi
- Centre de Protonthérapie d’Orsay, Radiation Oncology Department, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (A.P.); (L.d.M.)
- Institut Curie, Campus Universitaire, PSL Research University, University Paris Saclay, INSERM LITO, 91898 Orsay, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; (A.B.); (R.O.); (M.J.); (C.G.)
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
- Correspondence:
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22
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Conceptual Design of a Novel Nozzle Combined with a Clinical Proton Linac for Magnetically Focussed Minibeams. Cancers (Basel) 2021; 13:cancers13184657. [PMID: 34572884 PMCID: PMC8467416 DOI: 10.3390/cancers13184657] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 11/23/2022] Open
Abstract
Simple Summary Proton minibeam radiation therapy (pMBRT) is a novel therapeutic strategy that combines the tissue sparing potential of submillimetric, spatially fractionated beams (minibeams) with the improved ballistics of protons to enhance the tolerance of normal tissue and allow a dose escalation in the tumour. This approach could allow a more effective treatment of radioresistant tumours and has already shown excellent results for rat gliomas. To exploit the full potential of pMBRT, it should be delivered using magnetically focussed and scanned minibeams. However, such an implementation has not yet been demonstrated at clinically relevant beam energies. In this work, we therefore present a new design combining our recently developed minibeam nozzle with the first clinical proton linear accelerator. We show the suitability of this combination for the generation of magnetically focussed and scanned minibeams with clinically relevant parameters as well as for the delivery of conventional pencil beam scanning techniques. Abstract (1) Background: Proton minibeam radiation therapy (pMBRT) is a novel therapeutic approach with the potential to significantly increase normal tissue sparing while providing tumour control equivalent or superior to standard proton therapy. For reasons of efficiency, flexibility and minibeam quality, the optimal implementation of pMBRT should use magnetically focussed minibeams which, however, could not yet be generated in a clinical environment. In this study, we evaluated our recently proposed minibeam nozzle together with a new clinical proton linac as a potential implementation. (2) Methods: Monte Carlo simulations were performed to determine under which conditions minibeams can be generated and to evaluate the robustness against focussing magnet errors. Moreover, an example of conventional pencil beam scanning irradiation was simulated. (3) Results: Excellent minibeam sizes between 0.6 and 0.9 mm full width at half maximum could be obtained and a good tolerance to errors was observed. Furthermore, the delivery of a 10 cm × 10 cm field with pencil beams was demonstrated. (4) Conclusion: The combination of the new proton linac and minibeam nozzle could represent an optimal implementation of pMBRT by allowing the generation of magnetically focussed minibeams with clinically relevant parameters. It could furthermore be used for conventional pencil beam scanning.
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23
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Sotiropoulos M, Prezado Y. A scanning dynamic collimator for spot-scanning proton minibeam production. Sci Rep 2021; 11:18321. [PMID: 34526628 PMCID: PMC8443660 DOI: 10.1038/s41598-021-97941-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/01/2021] [Indexed: 11/23/2022] Open
Abstract
In proton minibeam radiation therapy, proton minibeams are typically produced by modulating a uniform field using a multislit collimator. Multislit collimators produce minibeams of fixed length and width, and a new collimator has to be manufactured each time a new minibeam array is required, limiting its flexibility. In this work, we propose a scanning dynamic collimator for the generation of proton minibeams arrays. The new collimator system proposed is able to produce any minibeam required on an on-line basis by modulating the pencil beam spots of modern proton therapy machines, rather than a uniform field. The new collimator is evaluated through Monte Carlo simulations and the produced proton minibeams are compared with that of a multislit collimator. Furthermore, a proof of concept experiment is conducted to demonstrate the feasibility of producing a minibeam array by repositioning (i.e. scanning) a collimator. It is concluded that besides the technical challenges, the new collimator design is producing equivalent minibeam arrays to the multislit collimator, whilst is flexible to produce any minibeam array desired.
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Affiliation(s)
- Marios Sotiropoulos
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400, Orsay, France.
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400, Orsay, France
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24
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Yamamoto S, Yabe T, Akagi T. Possibility evaluation of the optical imaging of proton mini-beams. Phys Med Biol 2021; 66. [PMID: 34010817 DOI: 10.1088/1361-6560/ac02d7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 05/19/2021] [Indexed: 11/11/2022]
Abstract
Proton therapy using mini-beams is a promising method to reduce radiation damage to normal tissue. However, distribution measurements of mini-beams are difficult due to their small structures. Since optical imaging is a possible method to measure high-resolution two-dimensional dose distribution, we conducted optical imaging of an acrylic block during the irradiation of mini-beams of protons. Mini-beams were made from a proton pencil beam irradiated to 1 mm slits made of tungsten plate. During irradiation of the mini-beams to the acrylic block, we measured the luminescence of the acrylic block using a charge-coupled device camera. With the measurements, we could obtain slit beam images that have slit shapes in the shallow area while they were uniform in their Bragg peaks, which was similar to the case of simulated optical images by Monte Carlo simulations. We confirmed that high-resolution optical imaging of mini-beams is possible and provides a promising method for efficient quality assessment of mini-beams as well as research on mini-beam therapy.
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Affiliation(s)
- Seiichi Yamamoto
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Japan
| | - Takuya Yabe
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Japan.,Department of Medical Technology, Nagoya University Hospital, Japan
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25
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Mazal A, Vera Sanchez JA, Sanchez-Parcerisa D, Udias JM, España S, Sanchez-Tembleque V, Fraile LM, Bragado P, Gutierrez-Uzquiza A, Gordillo N, Garcia G, Castro Novais J, Perez Moreno JM, Mayorga Ortiz L, Ilundain Idoate A, Cremades Sendino M, Ares C, Miralbell R, Schreuder N. Biological and Mechanical Synergies to Deal With Proton Therapy Pitfalls: Minibeams, FLASH, Arcs, and Gantryless Rooms. Front Oncol 2021; 10:613669. [PMID: 33585238 PMCID: PMC7874206 DOI: 10.3389/fonc.2020.613669] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 12/02/2020] [Indexed: 12/28/2022] Open
Abstract
Proton therapy has advantages and pitfalls comparing with photon therapy in radiation therapy. Among the limitations of protons in clinical practice we can selectively mention: uncertainties in range, lateral penumbra, deposition of higher LET outside the target, entrance dose, dose in the beam path, dose constraints in critical organs close to the target volume, organ movements and cost. In this review, we combine proposals under study to mitigate those pitfalls by using individually or in combination: (a) biological approaches of beam management in time (very high dose rate “FLASH” irradiations in the order of 100 Gy/s) and (b) modulation in space (a combination of mini-beams of millimetric extent), together with mechanical approaches such as (c) rotational techniques (optimized in partial arcs) and, in an effort to reduce cost, (d) gantry-less delivery systems. In some cases, these proposals are synergic (e.g., FLASH and minibeams), in others they are hardly compatible (mini-beam and rotation). Fixed lines have been used in pioneer centers, or for specific indications (ophthalmic, radiosurgery,…), they logically evolved to isocentric gantries. The present proposals to produce fixed lines are somewhat controversial. Rotational techniques, minibeams and FLASH in proton therapy are making their way, with an increasing degree of complexity in these three approaches, but with a high interest in the basic science and clinical communities. All of them must be proven in clinical applications.
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Affiliation(s)
| | | | - Daniel Sanchez-Parcerisa
- Grupo de Física Nuclear and IPARCOS, U. Complutense Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain.,Sedecal Molecular Imaging, Madrid, Spain
| | - Jose Manuel Udias
- Grupo de Física Nuclear and IPARCOS, U. Complutense Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Samuel España
- Grupo de Física Nuclear and IPARCOS, U. Complutense Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Victor Sanchez-Tembleque
- Grupo de Física Nuclear and IPARCOS, U. Complutense Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Luis Mario Fraile
- Grupo de Física Nuclear and IPARCOS, U. Complutense Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Paloma Bragado
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain.,Department of Biochemistry and Molecular Biology. U. Complutense, Madrid, Spain
| | - Alvaro Gutierrez-Uzquiza
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain.,Department of Biochemistry and Molecular Biology. U. Complutense, Madrid, Spain
| | - Nuria Gordillo
- Department of Applied Physics, U. Autonoma de Madrid, Madrid, Spain.,Center for Materials Microanalysis, (CMAM), U. Autonoma de Madrid, Madrid, Spain
| | - Gaston Garcia
- Center for Materials Microanalysis, (CMAM), U. Autonoma de Madrid, Madrid, Spain
| | | | | | | | | | | | - Carme Ares
- Centro de Protonterapia Quironsalud, Madrid, Spain
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26
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Charyyev S, Wang CKC. ASSESSMENT OF AMBIENT NEUTRON DOSE EQUIVALENT IN SPATIALLY FRACTIONATED RADIOTHERAPY WITH PROTONS USING PHYSICAL COLLIMATORS. RADIATION PROTECTION DOSIMETRY 2020; 189:190-197. [PMID: 32144416 DOI: 10.1093/rpd/ncaa030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/21/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
New technique is trending in spatially fractionated radiotherapy with protons to utilize the spot scanning together with a physical collimator to obtain minibeams. The primary goal of this study is to quantify ambient neutron dose equivalent (${H}^{\ast }(10)$) due to the secondary neutrons when physical collimator is used to achieve desired minibeams. The ${H}^{\ast }(10)$ per treatment proton dose (D) was assessed using Monte Carlo code TOPAS and measured using WENDI-II detector at different angles (135, 180, 225 and 270 degrees) and distances (11 cm, 58 and 105 cm) from the phantom for two cases: with and without physical collimation. Without collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.0013 to 0.242 mSv/Gy. With collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.017 to 3.23 mSv/Gy. Results show that the secondary neutron dose will increase tenfold when the physical collimator is used. Regardless, it will be low and comparable to the neutron dose produced by conventional passive-scattered proton beams.
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Affiliation(s)
- Serdar Charyyev
- Radiation Oncology and Winship Cancer Institute, Emory University, 1365 Clifton Rd NE, Atlanta, GA 30322, USA
| | - C-K Chris Wang
- Nuclear and Radiological Engineering, Georgia Institute of Technology, 770 State St NW, Atlanta, GA 30332, USA
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27
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Charyyev S, Artz M, Szalkowski G, Chang C, Stanforth A, Lin L, Zhang R, Wang CC. Optimization of hexagonal‐pattern minibeams for spatially fractionated radiotherapy using proton beam scanning. Med Phys 2020; 47:3485-3495. [DOI: 10.1002/mp.14192] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Serdar Charyyev
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | - Mark Artz
- UF Health Proton Therapy Institute Jacksonville FL 32206 USA
| | - Gregory Szalkowski
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
- Department of Radiation Oncology University of North Carolina Chapel Hill NC 27514 USA
| | - Chih‐Wei Chang
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | | | - Liyong Lin
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | - Rongxiao Zhang
- Department of Radiation Oncology Dartmouth College Hanover NH 03755 USA
| | - C.‐K. Chris Wang
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
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28
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Lansonneur P, Mammar H, Nauraye C, Patriarca A, Hierso E, Dendale R, Prezado Y, De Marzi L. First proton minibeam radiation therapy treatment plan evaluation. Sci Rep 2020; 10:7025. [PMID: 32341427 PMCID: PMC7184593 DOI: 10.1038/s41598-020-63975-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 04/08/2020] [Indexed: 11/09/2022] Open
Abstract
Proton minibeam radiation therapy (pMBRT) is a novel dose delivery method based on spatial dose fractionation. pMBRT has been shown to be promising in terms of reduced side effects and superior tumour control in high-grade glioma-bearing rats compared to standard irradiation. These findings, together with the recent optimized implementation of pMBRT in a clinical pencil beam scanning system, have triggered reflection on the possible application to patient treatments. In this context, the present study was designed to conduct a first theoretical investigation of the clinical potential of this technique. For this purpose, a dedicated dose engine was developed and used to evaluate two clinically relevant patient treatment plans (high-grade glioma and meningioma). Treatment plans were compared with standard proton therapy plans assessed by means of a commercial treatment planning system (ECLIPSE-Varian Medical systems) and Monte Carlo simulations. A multislit brass collimator consisting of 0.4 mm wide slits separated by a centre-to-centre distance of 4 or 6 mm was placed between the nozzle and the patient to shape the planar minibeams. For each plan, spread-out Bragg peaks and homogeneous dose distributions (±7% dose variations) can be obtained in target volumes. The Peak-to-Valley Dose Ratios (PVDR) were evaluated between 9.2 and 12.8 at a depth of 20 mm for meningioma and glioma, respectively. Dose volume histograms (DVHs) for target volumes and organs at risk were quantitatively compared, resulting in a slightly better target homogeneity with standard PT than with pMBRT plans, but similar DVHs for deep-seated organs-at-risk and lower average dose for shallow organs. The proposed delivery method evaluated in this work opens the way to an effective treatment for radioresistant tumours and will support the design of future clinical research.
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Affiliation(s)
- P Lansonneur
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - H Mammar
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - C Nauraye
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - A Patriarca
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - E Hierso
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - R Dendale
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France
| | - Y Prezado
- Institut Curie, PSL Research University, University Paris Saclay, Inserm U 1021-CNRS UMR 3347, 91898, Orsay, France
| | - L De Marzi
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, 91898, Orsay, France. .,Institut Curie, PSL Research University, University Paris Saclay, Inserm U 1021-CNRS UMR 3347, 91898, Orsay, France.
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29
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Mazal A, Prezado Y, Ares C, de Marzi L, Patriarca A, Miralbell R, Favaudon V. FLASH and minibeams in radiation therapy: the effect of microstructures on time and space and their potential application to protontherapy. Br J Radiol 2020; 93:20190807. [PMID: 32003574 PMCID: PMC7066940 DOI: 10.1259/bjr.20190807] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
After years of lethargy, studies on two non-conventional microstructures in time and space of the beams used in radiation therapy are enjoying a huge revival. The first effect called “FLASH” is based on very high dose-rate irradiation (pulse amplitude ≥106 Gy/s), short beam-on times (≤100 ms) and large single doses (≥10 Gy) as experimental parameters established so far to give biological and potential clinical effects. The second effect relies on the use of arrays of minibeams (e.g., 0.5–1 mm, spaced 1–3.5 mm). Both approaches have been shown to protect healthy tissues as an endpoint that must be clearly specified and could be combined with each other (e.g., minibeams under FLASH conditions). FLASH depends on the presence of oxygen and could proceed from the chemistry of peroxyradicals and a reduced incidence on DNA and membrane damage. Minibeams action could be based on abscopal effects, cell signalling and/or migration of cells between “valleys and hills” present in the non-uniform irradiation field as well as faster repair of vascular damage. Both effects are expected to maintain intact the tumour control probability and might even preserve antitumoural immunological reactions. FLASH in vivo experiments involving Zebrafish, mice, pig and cats have been done with electron beams, while minibeams are an intermediate approach between X-GRID and synchrotron X-ray microbeams radiation. Both have an excellent rationale to converge and be applied with proton beams, combining focusing properties and high dose rates in the beam path of pencil beams, and the inherent advantage of a controlled limited range. A first treatment with electron FLASH (cutaneous lymphoma) has recently been achieved, but clinical trials have neither been presented for FLASH with protons, nor under the minibeam conditions. Better understanding of physical, chemical and biological mechanisms of both effects is essential to optimize the technical developments and devise clinical trials.
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Affiliation(s)
| | - Yolanda Prezado
- IMNC, University Paris-Sud and Paris-Saclay, CNRS/IN2P3, Orsay, France
| | - Carme Ares
- Centro de Protonterapia Quironsalud, Madrid, Spain
| | - Ludovic de Marzi
- Institut Curie, Institut Curie, PSL Research University, Centre de protonthérapie d'Orsay, Campus universitaire, bâtiment 101, Orsay 91898, France.,Institut Curie, Inserm U 1021-CNRS UMR 3347, Paris-Saclay and PSL Research Universities, Orsay, France
| | - Annalisa Patriarca
- Institut Curie, Institut Curie, PSL Research University, Centre de protonthérapie d'Orsay, Campus universitaire, bâtiment 101, Orsay 91898, France
| | | | - Vincent Favaudon
- Institut Curie, Inserm U 1021-CNRS UMR 3347, Paris-Saclay and PSL Research Universities, Orsay, France
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30
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Schneider T, De Marzi L, Patriarca A, Prezado Y. Advancing proton minibeam radiation therapy: magnetically focussed proton minibeams at a clinical centre. Sci Rep 2020; 10:1384. [PMID: 31992757 PMCID: PMC6987213 DOI: 10.1038/s41598-020-58052-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
Proton minibeam radiation therapy (pMBRT) is a novel therapeutic strategy that has proven to significantly increase dose tolerances and sparing of normal tissue. It uses very narrow proton beams (diameter ≤1 mm), roughly one order of magnitude smaller than state-of-the-art pencil beams. The current implementation of pMBRT with mechanical collimators is suboptimal as it is inflexible, decreases efficiency and produces additional secondary neutrons. As a potential solution, we explore in this article minibeam generation through magnetic focussing and investigate possibilities for the integration of such a technique at existing clinical centres. For this, a model of the pencil beam scanning (PBS) nozzle and beam at the Orsay Proton Therapy Centre was established and Monte Carlo simulations were performed to determine its focussing capabilities. Moreover, various modifications of the nozzle geometry were considered. It was found that the PBS nozzle in its current state is not suitable for magnetic minibeam generation. Instead, a new, optimised nozzle design has been proposed and conditions necessary for minibeam generation were benchmarked. In addition, dose simulations in a water phantom were performed which showed improved dose distributions compared to those obtained with mechanical collimators.
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Affiliation(s)
- Tim Schneider
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France. .,Université de Paris, IJCLab, 91405, Orsay, France.
| | - Ludovic De Marzi
- Institut Curie, University Paris Saclay, Radiation Oncology Department, Centre de protonthérapie d'Orsay, Orsay, France.,Institut Curie, University Paris Saclay, PSL Research University, Inserm U 1021-CNRS UMR 3347, Orsay, France
| | - Annalisa Patriarca
- Institut Curie, University Paris Saclay, Radiation Oncology Department, Centre de protonthérapie d'Orsay, Orsay, France
| | - Yolanda Prezado
- Institut Curie, University Paris Saclay, PSL Research University, Inserm U 1021-CNRS UMR 3347, Orsay, France
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Dos Santos M, Delorme R, Salmon R, Prezado Y. Minibeam radiation therapy: A micro- and nano-dosimetry Monte Carlo study. Med Phys 2020; 47:1379-1390. [PMID: 31900944 DOI: 10.1002/mp.14009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 12/12/2019] [Accepted: 12/22/2019] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Minibeam radiation therapy (MBRT) is an innovative strategy based on a distinct dose delivery method that is administered using a series of narrow (submillimetric) parallel beams. To shed light on the biological effects of MBRT irradiation, we explored the micro- and nanodosimetric characteristics of three promising MBRT modalities (photon, electron, and proton) using Monte Carlo (MC) calculations. METHODS Irradiation with proton (100 MeV), electron (300 MeV), and photon (effective energy of 69 keV) minibeams were simulated using Geant4 MC code and the Geant4-DNA extension, which allows the simulation of energy transfer points with nanometric accuracy. As the target of the simulations, cells containing spherical nuclei with or without a detailed description of the DNA (deoxyribonucleic acid) geometry were placed at different depths in peak and valley regions in a water phantom. The energy deposition and number of events in the cell nuclei were recorded in the microdosimetry study, and the number of DNA breaks and their complexity were determined in the nanodosimetric study, where a multi-scale simulation approach was used for the latter. For DNA damage assessment, an adapted DBSCAN clustering algorithm was used. To compare the photon MBRT (xMBRT), electron MBRT (eMBRT), and proton MBRT (pMBRT) approaches, we considered the treatment of a brain tumor located at a depth of 75 mm. RESULTS Both mean energy deposition at micrometric scale and DNA damage in the "valley" cell nuclei were very low as compared with these parameters in the peak region at all depths for xMBRT and at depths of 0 to 30 mm and 0 to 50 mm for eMBRT and pMBRT, respectively. Only the charged minibeams were favorable for tumor control by producing similar effects in peak and valley cells after 70 mm. At the micrometer scale, the energy deposited per event pointed to a potential advantage of proton beams for tumor control, as more aggressive events could be expected at the end of their tracks. At the nanometer scale, all three MBRT modalities produced direct clustered DNA breaks, although the majority of damage (>93%) was composed of isolated single strand breaks. The pMBRT led to a significant increase in the proportion of clustered single strand breaks and double-strand breaks at the end of its range as compared to the entrance (7% at 75 mm vs 3% at 10 mm) in contrast to eMBRT and xMBRT. In the latter cases, the proportions of complex breaks remained constant, irrespective of the depth and region (peak or valley). CONCLUSIONS Enhanced normal tissue sparing can be expected with these three MBRT techniques. Among the three modalities, pMBRT offers an additional gain for radioresistant tumors, as it resulted in a higher number of complex DNA damage clusters in the tumor region. These results can aid understanding of the biological mechanisms of MBRT.
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Affiliation(s)
- M Dos Santos
- Department of Radiobiology and regenerative medicine (SERAMED), Laboratory of Radiobiology of Accidental exposures (LRAcc), IRSN, F-92260, Fontenay-aux-Roses, France
| | - R Delorme
- Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91400, Orsay, France.,Université de Paris, IMNC, F-91400, Orsay, France
| | - R Salmon
- Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91400, Orsay, France.,Université de Paris, IMNC, F-91400, Orsay, France
| | - Y Prezado
- Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91400, Orsay, France.,Université de Paris, IMNC, F-91400, Orsay, France
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Guardiola C, De Marzi L, Prezado Y. Verification of a Monte Carlo dose calculation engine in proton minibeam radiotherapy in a passive scattering beamline for preclinical trials. Br J Radiol 2019; 93:20190578. [PMID: 31868523 DOI: 10.1259/bjr.20190578] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Proton minibeam radiation therapy (pMBRT) is a novel therapeutic strategy that combines the benefits of proton therapy with the remarkable normal tissue preservation observed with the use of submillimetric spatially fractionated beams. This promising technique has been implemented at the Institut Curie-Proton therapy centre (ICPO) using a first prototype of a multislit collimator. The purpose of this work was to develop a Monte Carlo-based dose calculation engine to reliably guide preclinical studies at ICPO. METHODS The whole "Y1"-passive beamline at the ICPO, including pMBRT implementation, was modelled using the Monte Carlo GATE v. 7.0 code. A clinically relevant proton energy (100 MeV) was used as starting point. Minibeam generation by means of the brass collimator used in the first experiments was modelled. A virtual source was modelled at the exit of the beamline nozzle and outcomes were compared with dosimetric measurements performed with EBT3 gafchromic films and a diamond detector in water. Dose distributions were recorded in a water phantom and in rat CT images (7-week-old male Fischer rats). RESULTS The dose calculation engine was benchmarked against experimental data and was then used to assess dose distributions in CT images of a rat, resulting from different irradiation configurations used in several experiments. It reduced computational time by an order of magnitude. This allows us to speed up simulations for in vivo trials, where we obtained peak-to-valley dose ratios of 1.20 ± 0.05 and 6.1 ± 0.2 for proton minibeam irradiations targeting the tumour and crossing the rat head. Tumour eradication was observed in the 67 and 22% of the animals treated respectively. CONCLUSION A Monte Carlo dose calculation engine for pMBRT implementation with mechanical collimation has been developed. This tool can be used to guide and interpret the results of in vivo trials. ADVANCES IN KNOWLEDGE This is the first Monte Carlo dose engine for pMBRT that is being used to guide preclinical trials in a clinical proton therapy centre.
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Affiliation(s)
- Consuelo Guardiola
- Centre National de la Recherche Scientifique (CNRS); Universités Paris 11 and Paris 7, Laboratoire d'Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), Orsay Cedex, 91405, France
| | - Ludovic De Marzi
- Institut Curie, PSL Research University, Centre de protonthérapie d'Orsay, Campus universitaire, bâtiment 101, Orsay 91898, France.,Institut Curie, University Paris Saclay, PSL Research University, Inserm U 1021-CNRS UMR 3347, Orsay, France
| | - Yolanda Prezado
- Centre National de la Recherche Scientifique (CNRS); Universités Paris 11 and Paris 7, Laboratoire d'Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), Orsay Cedex, 91405, France
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De Marzi L, Nauraye C, Lansonneur P, Pouzoulet F, Patriarca A, Schneider T, Guardiola C, Mammar H, Dendale R, Prezado Y. Spatial fractionation of the dose in proton therapy: Proton minibeam radiation therapy. Cancer Radiother 2019; 23:677-681. [DOI: 10.1016/j.canrad.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/01/2019] [Indexed: 10/26/2022]
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Meyer J, Eley J, Schmid TE, Combs SE, Dendale R, Prezado Y. Spatially fractionated proton minibeams. Br J Radiol 2019; 92:20180466. [PMID: 30359081 PMCID: PMC6541186 DOI: 10.1259/bjr.20180466] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/11/2018] [Accepted: 10/15/2018] [Indexed: 12/26/2022] Open
Abstract
Extraordinary normal tissue response to highly spatially fractionated X-ray beams has been explored for over 25 years. More recently, alternative radiation sources have been developed and utilized with the aim to evoke comparable effects. These include protons, which lend themselves well for this endeavour due to their physical depth dose characteristics as well as corresponding variable biological effectiveness. This paper addresses the motivation for using protons to generate spatially fractionated beams and reviews the technological implementations and experimental results to date. This includes simulation and feasibility studies, collimation and beam characteristics, dosimetry and biological considerations as well as the results of in vivo and in vitro studies. Experimental results are emerging indicating an extraordinary normal tissue sparing effect analogous to what has been observed for synchrotron generated X-ray microbeams. The potential for translational research and feasibility of spatially modulated proton beams in clinical settings is discussed.
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Affiliation(s)
- Juergen Meyer
- Department of Radiation Oncology, University of Washington, Seattle, WA, USA
| | - John Eley
- Department of Radiation Oncology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | | | | | - Remi Dendale
- Institut Curie, Centre de Protonthérapie d’Orsay, Orsay, France
| | - Yolanda Prezado
- Laboratoire d'Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), Centre National de la Recherche Scientifique, Universités Paris 11 and Paris 7, Campus d'Orsay, Orsay, France
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