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Gogineni E, Chen H, Cruickshank IK, Koempel A, Gogineni A, Li H, Deville C. In Silico Comparison of Three Different Beam Arrangements for Intensity-Modulated Proton Therapy for Postoperative Whole Pelvic Irradiation of Prostate Cancer. Cancers (Basel) 2024; 16:2702. [PMID: 39123430 PMCID: PMC11311848 DOI: 10.3390/cancers16152702] [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: 04/15/2024] [Revised: 07/17/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024] Open
Abstract
Background and purpose: Proton therapy has been shown to provide dosimetric benefits in comparison with IMRT when treating prostate cancer with whole pelvis radiation; however, the optimal proton beam arrangement has yet to be established. The aim of this study was to evaluate three different intensity-modulated proton therapy (IMPT) beam arrangements when treating the prostate bed and pelvis in the postoperative setting. Materials and Methods: Twenty-three post-prostatectomy patients were planned using three different beam arrangements: two-field (IMPT2B) (opposed laterals), three-field (IMPT3B) (opposed laterals inferiorly matched to a posterior-anterior beam superiorly), and four-field (IMPT4B) (opposed laterals inferiorly matched to two posterior oblique beams superiorly) arrangements. The prescription was 50 Gy radiobiological equivalent (GyE) to the pelvis and 70 GyE to the prostate bed. Comparisons were made using paired two-sided Wilcoxon signed-rank tests. Results: CTV coverages were met for all IMPT plans, with 99% of CTVs receiving ≥ 100% of prescription doses. All organ at risk (OAR) objectives were met with IMPT3B and IMPT4B plans, while several rectum objectives were exceeded by IMPT2B plans. IMPT4B provided the lowest doses to OARs for the majority of analyzed outcomes, with significantly lower doses than IMPT2B +/- IMPT3B for bladder V30-V50 and mean dose; bowel V15-V45 and mean dose; sigmoid maximum dose; rectum V40-V72.1, maximum dose, and mean dose; femoral head V37-40 and maximum dose; bone V40 and mean dose; penile bulb mean dose; and skin maximum dose. Conclusion: This study is the first to compare proton beam arrangements when treating the prostate bed and pelvis. four-field plans provided better sparing of the bladder, bowel, and rectum than 2- and three-field plans. The data presented herein may help inform the future delivery of whole pelvis IMPT for prostate cancer.
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Affiliation(s)
- Emile Gogineni
- Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (A.K.); (A.G.)
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (H.C.); (I.K.C.J.); (H.L.); (C.D.J.)
| | - Hao Chen
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (H.C.); (I.K.C.J.); (H.L.); (C.D.J.)
| | - Ian K. Cruickshank
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (H.C.); (I.K.C.J.); (H.L.); (C.D.J.)
| | - Andrew Koempel
- Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (A.K.); (A.G.)
| | - Aarush Gogineni
- Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (A.K.); (A.G.)
| | - Heng Li
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (H.C.); (I.K.C.J.); (H.L.); (C.D.J.)
| | - Curtiland Deville
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (H.C.); (I.K.C.J.); (H.L.); (C.D.J.)
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2
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Gao RW, Ma J, Pisansky TM, Kruse JJ, Stish BJ, Kowalchuk RO, McMenomy BP, Waddle MR, Phillips RM, Choo R, Davis BJ. Dosimetric Features of Ultra-Hypofractionated Intensity Modulated Proton Therapy for Prostate Cancer. Int J Part Ther 2024; 12:100015. [PMID: 38827121 PMCID: PMC11137510 DOI: 10.1016/j.ijpt.2024.100015] [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: 12/05/2023] [Revised: 02/08/2024] [Accepted: 03/06/2024] [Indexed: 06/04/2024] Open
Abstract
Purpose To report clinical and dosimetric characteristics of 5-fraction stereotactic ablative radiotherapy (SABR) using intensity modulated proton therapy (IMPT) for localized prostate cancer. Materials and Methods All patients receiving IMPT SABR from 2017 to 2021 for localized prostate cancer at our institution were included. Five fractions were delivered every other day to the prostate +/- seminal vesicles [clinical target volume (CTV)] with 3 mm/3% robustness. A 4-field arrangement with 2 anterior oblique and 2 opposed lateral beams was used in most patients (97%), and most (99%) had a retroprostatic hydrogel spacer. Results A total of 534 patients with low (14%), favorable intermediate (45%), unfavorable intermediate (36%), high (4.0%), or very high-risk (0.6%) disease are evaluated. Prescription dose was 36.25 Gy (31%), 38 Gy (38%), or 40 Gy (31%) was prescribed. Median volume percentage of CTV receiving at least 100% of prescription dose [V100% (%)] was 100% [interquartile range: 99.99-100]. Rectum V50% (%), V80% (%), and V90% (%) were significantly lower in patients who had spacer, with a mean difference of -9.70%, -6.59%, and -4.42%, respectively, compared to those who did not have spacer. Femoral head dose was lower with a 4-field arrangement. Mean differences in left and right femoral head V40% (%) were -6.99% and -10.74%, respectively. Conclusion We provide a large, novel report of patients treated with IMPT SABR for localized prostate cancer. Four-field IMPT with hydrogel spacer provides significant sparing of rectum and femoral heads without compromising target coverage.
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Affiliation(s)
- Robert W. Gao
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Jiasen Ma
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Thomas M. Pisansky
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Jon J. Kruse
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Bradley J. Stish
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Roman O. Kowalchuk
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Mark R. Waddle
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Ryan M. Phillips
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Richard Choo
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Brian J. Davis
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
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3
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Gardner LL, O'Connor JD, McMahon SJ. Benchmarking proton RBE models. Phys Med Biol 2024; 69:085022. [PMID: 38471187 DOI: 10.1088/1361-6560/ad3329] [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: 10/03/2023] [Accepted: 03/12/2024] [Indexed: 03/14/2024]
Abstract
Objective.To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current phenomenological models show large disagreements in RBE predictions, due to different model assumptions and differences in the data to which they were fit. In this work, thirteen RBE models were benchmarked against a comprehensive proton RBE dataset to evaluate predictions when all models are fit using the same data and fitting techniques, and to assess the statistical robustness of the models.Approach.Model performance was initially evaluated by fitting to the full dataset, and then a cross-validation approach was applied to assess model generalisability and robustness. The impact of weighting the fit and the choice of biological endpoint (either single or multiple survival levels) was also evaluated.Main results.Fitting the models to a common dataset reduced differences between their predictions, however significant disagreements remained due to different underlying assumptions. All models performed poorly under cross-validation in the weighted fits, suggesting that some uncertainties on the experimental data were significantly underestimated, resulting in over-fitting and poor performance on unseen data. The simplest model, which depends linearly on the LET but has no tissue or dose dependence, performed best for a single survival level. However, when fitting to multiple survival levels simultaneously, more complex models with tissue dependence performed better. All models had significant residual uncertainty in their predictions compared to experimental data.Significance.This analysis highlights that poor quality of error estimation on the dose response parameters introduces substantial uncertainty in model fitting. The significant residual error present in all approaches illustrates the challenges inherent in fitting to large, heterogeneous datasets and the importance of robust statistical validation of RBE models.
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Affiliation(s)
- Lydia L Gardner
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
| | - John D O'Connor
- School of Engineering, Ulster University, Belfast, United Kingdom
| | - Stephen J McMahon
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
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4
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Kato T, Kato M, Takemasa K, Murakami M. Dosimetric Effects of the Supine and Prone Positions in Proton Therapy for Prostate Cancer. J Med Phys 2022; 47:331-335. [PMID: 36908499 PMCID: PMC9997540 DOI: 10.4103/jmp.jmp_85_22] [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: 09/18/2022] [Revised: 11/06/2022] [Accepted: 11/07/2022] [Indexed: 01/12/2023] Open
Abstract
Purpose To quantitatively evaluate how much the doses to organs at risk are affected in the prone position compared to the supine position in the proton therapy (PT) for prostate cancer. Materials and Methods Fifteen consecutive patients with clinically localized prostate cancer underwent treatment planning computed tomography scans in both the supine and prone positions. The clinical target volume (CTV) consisted of the prostate gland plus the seminal vesicles. The PT plans were designed using the standard lateral opposed fields with passively scattered proton beams for both treatment positions. The prescribed dose for each plan was set to 78 Gy (Relative biological effectiveness)/39 fractions to 50% of the planning target volume. Dose-volume metrics of the rectum and bladder in the two treatment positions were analyzed. Results It was confirmed that all the parameters of D05, D10, D20, D30, Dmean, and V90 examined in the rectum were significantly reduced in the prone position. There was no significant difference between the two positions in the bladder dose except for Dmean. The distance between the CTV and the rectum tended to increase with the patient in the prone position; at the prostate level, however, the maximum change was approximately 5 mm, and there was significant variation between cases. Conclusions We confirmed that the rectal doses were significantly lower in the prone compared with the supine position in PT. Although uncertain, the prone position could be an effective method to reduce the rectal dose in PT.
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Affiliation(s)
- Takahiro Kato
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Masato Kato
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Kimihiro Takemasa
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Masao Murakami
- Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
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5
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Tamura H, Kobashi K, Nishioka K, Yoshimura T, Hashimoto T, Shimizu S, Ito YM, Maeda Y, Sasaki M, Yamamoto K, Tamamura H, Aoyama H, Shirato H. Dosimetric advantages of daily adaptive strategy in IMPT for high-risk prostate cancer. J Appl Clin Med Phys 2022; 23:e13531. [PMID: 35045211 PMCID: PMC8992948 DOI: 10.1002/acm2.13531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/10/2021] [Accepted: 12/28/2021] [Indexed: 11/05/2022] Open
Abstract
Purpose To evaluate the dosimetric advantages of daily adaptive radiotherapy (DART) in intensity‐modulated proton therapy (IMPT) for high‐risk prostate cancer by comparing estimated doses of the conventional non‐adaptive radiotherapy (NART) that irradiates according to an original treatment plan through the entire treatment and the DART that uses an adaptive treatment plan generated by using daily CT images acquired before each treatment. Methods Twenty‐three patients with prostate cancer were included. A treatment plan with 63 Gy (relative biological effectiveness (RBE)) in 21 fractions was generated using treatment planning computed tomography (CT) images assuming that all patients had high‐risk prostate cancer for which the clinical target volume (CTV) needs to include prostate and the seminal vesicle (SV) in our treatment protocol. Twenty‐one adaptive treatment plans for each patient (total 483 data sets) were generated using daily CT images, and dose distributions were calculated. Using a 3 mm set‐up uncertainty in the robust optimization, the doses to the CTV, prostate, SV, rectum, and bladder were compared. Results Estimated accumulated doses of NART and DART in the 23 patients were 60.81 ± 3.47 Gy (RBE) and 63.24 ± 1.04 Gy (RBE) for CTV D99 (p < 0.01), 62.99 ± 1.28 Gy (RBE) and 63.43 ± 1.33 Gy (RBE) for the prostate D99 (p = 0.2529), and 59.07 ± 5.19 Gy (RBE) and 63.17 ± 1.04 Gy (RBE) for SV D99 (p < 0.001). No significant differences were observed between NART and DART in the estimated accumulated dose for the rectum and bladder. Conclusion Compared with the NART, DART was shown to be a useful approach that can maintain the dose coverage to the target without increasing the dose to the organs at risk (OAR) using the 3 mm set‐up uncertainty in the robust optimization in patients with high‐risk prostate cancer.
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Affiliation(s)
- Hiroshi Tamura
- Department of Radiation Oncology, Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Japan.,Department of Radiological Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Keiji Kobashi
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan.,Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Kentaro Nishioka
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Takaaki Yoshimura
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Department of Health Sciences and Technology, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan
| | - Takayuki Hashimoto
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichi Shimizu
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan.,Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Yoichi M Ito
- Data Science Center, Promotion Unit, Institute of Health Science Innovation for Medical Care, Hokkaido University Hospital, Sapporo, Japan
| | - Yoshikazu Maeda
- Proton Therapy Center, Fukui Prefectural Hospital, Fukui, Japan
| | - Makoto Sasaki
- Proton Therapy Center, Fukui Prefectural Hospital, Fukui, Japan
| | | | | | - Hidefumi Aoyama
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroki Shirato
- Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
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6
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Moteabbed M, Harisinghani M, Paganetti H, Trofimov A, Lu HM, Efstathiou JA. Proton vs. photon radiotherapy for MR-guided dose escalation of intraprostatic lesions. Acta Oncol 2021; 60:1283-1290. [PMID: 34282708 DOI: 10.1080/0284186x.2021.1947523] [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] [Indexed: 12/11/2022]
Abstract
BACKGROUND Dose escalation has been associated with improved biochemical control for prostate cancer. Focusing the high dose on the MRI-defined intraprostatic lesions (IL) could spare the surrounding organs at risk and hence allow further escalation. We compare treatment efficacy between state-of-the-art focally-boosted proton and photon-based radiotherapy, and investigate possible predictive guidelines regarding individualized treatment prescriptions. MATERIAL AND METHODS Ten prostate cancer patients with well-defined ILs were selected. Multiparametric MRI was used to delineate ILs, which were transferred to the planning CT via image registration. Pencil beam scanning proton therapy and volumetric modulated arc therapy treatment plans, were created for each patient. Each modality featured 6 plans: (1) moderately hypofractionated dose: 70 Gy to the prostate in 28 fractions, (2)-(6) plan 1 plus additional simultaneous-integrated-boost to ILs to 75.6, 81.2, 86.6, 98 and 112 Gy in 28 fractions. Equivalent dose to 2 Gy-per-fraction (EqD2) was used to calculate tumor control (TCP) and normal tissue complication probabilities (NTCP) for ILs and organs-at-risk. RESULTS For both modalities, the maximum necessary dose to achieve TCP > 99% was 98 Gy for very high-risk ILs. For lower risk ILs lower doses were sufficient. NTCP was <25% and 35% for protons and photons at the maximum dose escalation, respectively. For the cases and beam characteristics considered, proton therapy was dosimetrically superior when IL was >4 cc or located <2.5 mm from the rectum. CONCLUSION This work demonstrated the potential role for proton therapy in the setting of prostate focal dose escalation. We propose that anatomical characteristic could be used as criteria to identify patients who would benefit from proton treatment.
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Affiliation(s)
- Maryam Moteabbed
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mukesh Harisinghani
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Harald Paganetti
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexei Trofimov
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | | | - Jason A. Efstathiou
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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7
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Deng W, Yang Y, Liu C, Bues M, Mohan R, Wong WW, Foote RH, Patel SH, Liu W. A Critical Review of LET-Based Intensity-Modulated Proton Therapy Plan Evaluation and Optimization for Head and Neck Cancer Management. Int J Part Ther 2021; 8:36-49. [PMID: 34285934 PMCID: PMC8270082 DOI: 10.14338/ijpt-20-00049.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/14/2020] [Indexed: 12/15/2022] Open
Abstract
In this review article, we review the 3 important aspects of linear-energy-transfer (LET) in intensity-modulated proton therapy (IMPT) for head and neck (H&N) cancer management. Accurate LET calculation methods are essential for LET-guided plan evaluation and optimization, which can be calculated either by analytical methods or by Monte Carlo (MC) simulations. Recently, some new 3D analytical approaches to calculate LET accurately and efficiently have been proposed. On the other hand, several fast MC codes have also been developed to speed up the MC simulation by simplifying nonessential physics models and/or using the graphics processor unit (GPU)–acceleration approach. Some concepts related to LET are also briefly summarized including (1) dose-weighted versus fluence-weighted LET; (2) restricted versus unrestricted LET; and (3) microdosimetry versus macrodosimetry. LET-guided plan evaluation has been clinically done in some proton centers. Recently, more and more studies using patient outcomes as the biological endpoint have shown a positive correlation between high LET and adverse events sites, indicating the importance of LET-guided plan evaluation in proton clinics. Various LET-guided plan optimization methods have been proposed to generate proton plans to achieve biologically optimized IMPT plans. Different optimization frameworks were used, including 2-step optimization, 1-step optimization, and worst-case robust optimization. They either indirectly or directly optimize the LET distribution in patients while trying to maintain the same dose distribution and plan robustness. It is important to consider the impact of uncertainties in LET-guided optimization (ie, LET-guided robust optimization) in IMPT, since IMPT is sensitive to uncertainties including both the dose and LET distributions. We believe that the advancement of the LET-guided plan evaluation and optimization will help us exploit the unique biological characteristics of proton beams to improve the therapeutic ratio of IMPT to treat H&N and other cancers.
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Affiliation(s)
- Wei Deng
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Yunze Yang
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Chenbin Liu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong, China
| | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - William W Wong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Robert H Foote
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Samir H Patel
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| | - Wei Liu
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
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8
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Kalholm F, Grzanka L, Traneus E, Bassler N. A systematic review on the usage of averaged LET in radiation biology for particle therapy. Radiother Oncol 2021; 161:211-221. [PMID: 33894298 DOI: 10.1016/j.radonc.2021.04.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 12/20/2022]
Abstract
Linear Energy Transfer (LET) is widely used to express the radiation quality of ion beams, when characterizing the biological effectiveness. However, averaged LET may be defined in multiple ways, and the chosen definition may impact the resulting reported value. We review averaged LET definitions found in the literature, and quantify which impact using these various definitions have for different reference setups. We recorded the averaged LET definitions used in 354 publications quantifying the relative biological effectiveness (RBE) of hadronic beams, and investigated how these various definitions impact the reported averaged LET using a Monte Carlo particle transport code. We find that the kind of averaged LET being applied is, generally, poorly defined. Some definitions of averaged LET may influence the reported averaged LET values up to an order of magnitude. For publications involving protons, most applied dose averaged LET when reporting RBE. The absence of what target medium is used and what secondary particles are included further contributes to an ill-defined averaged LET. We also found evidence of inconsistent usage of averaged LET definitions when deriving LET-based RBE models. To conclude, due to commonly ill-defined averaged LET and to the inherent problems of LET-based RBE models, averaged LET may only be used as a coarse indicator of radiation quality. We propose a more rigorous way of reporting LET values, and suggest that ideally the entire particle fluence spectra should be recorded and provided for future RBE studies, from which any type of averaged LET (or other quantities) may be inferred.
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Affiliation(s)
- Fredrik Kalholm
- Medical Radiation Physics, Dept. of Physics, Stockholm University, Stockholm, Sweden; Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, Sweden
| | - Leszek Grzanka
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
| | | | - Niels Bassler
- Medical Radiation Physics, Dept. of Physics, Stockholm University, Stockholm, Sweden; Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, Sweden; Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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9
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Bryant CM, Henderson RH, Nichols RC, Mendenhall WM, Hoppe BS, Vargas CE, Daniels TB, Choo CR, Parikh RR, Giap H, Slater JD, Vapiwala N, Barrett W, Nanda A, Mishra MV, Choi S, Liao JJ, Mendenhall NP. Consensus Statement on Proton Therapy for Prostate Cancer. Int J Part Ther 2021; 8:1-16. [PMID: 34722807 PMCID: PMC8489490 DOI: 10.14338/ijpt-20-00031.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 02/02/2021] [Indexed: 11/21/2022] Open
Abstract
Proton therapy is a promising but controversial treatment in the management of prostate cancer. Despite its dosimetric advantages when compared with photon radiation therapy, its increased cost to patients and insurers has raised questions regarding its value. Multiple prospective and retrospective studies have been published documenting the efficacy and safety of proton therapy for patients with localized prostate cancer and for patients requiring adjuvant or salvage pelvic radiation after surgery. The Particle Therapy Co-Operative Group (PTCOG) Genitourinary Subcommittee intends to address current proton therapy indications, advantages, disadvantages, and cost effectiveness. We will also discuss the current landscape of clinical trials. This consensus report can be used to guide clinical practice and research directions.
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Affiliation(s)
- Curtis M. Bryant
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Randal H. Henderson
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA
| | - R. Charles Nichols
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA
| | - William M. Mendenhall
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Bradford S. Hoppe
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA
| | | | | | - C. Richard Choo
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, USA
| | - Rahul R. Parikh
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Huan Giap
- Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL, USA
| | - Jerry D. Slater
- Department of Radiation Oncology, Loma Linda University, Loma Linda, CA, USA
| | - Neha Vapiwala
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - William Barrett
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, USA
| | - Akash Nanda
- Department of Radiation Oncology, Orlando Health, Orlando, FL, USA
| | - Mark V. Mishra
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Seungtaek Choi
- Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Jay J. Liao
- Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA, USA
| | - Nancy P. Mendenhall
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA
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10
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Ytre-Hauge KS, Fjæra LF, Rørvik E, Dahle TJ, Dale JE, Pilskog S, Stokkevåg CH. Inter-patient variations in relative biological effectiveness for cranio-spinal irradiation with protons. Sci Rep 2020; 10:6212. [PMID: 32277106 PMCID: PMC7148381 DOI: 10.1038/s41598-020-63164-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/23/2020] [Indexed: 12/30/2022] Open
Abstract
Cranio-spinal irradiation (CSI) using protons has dosimetric advantages compared to photons and is expected to reduce risk of adverse effects. The proton relative biological effectiveness (RBE) varies with linear energy transfer (LET), tissue type and dose, but a variable RBE has not replaced the constant RBE of 1.1 in clinical treatment planning. We examined inter-patient variations in RBE for ten proton CSI patients. Variable RBE models were used to obtain RBE and RBE-weighted doses. RBE was quantified in terms of dose weighted organ-mean RBE ([Formula: see text] = mean RBE-weighted dose/mean physical dose) and effective RBE of the near maximum dose (D2%), i.e. RBED2% = [Formula: see text], where subscripts RBE and phys indicate that the D2% is calculated based on an RBE model and the physical dose, respectively. Compared to the median [Formula: see text] of the patient population, differences up to 15% were observed for the individual [Formula: see text] values found for the thyroid, while more modest variations were seen for the heart (6%), lungs (2%) and brainstem (<1%). Large inter-patient variation in RBE could be correlated to large spread in LET and dose for these organs at risk (OARs). For OARs with small inter-patient variations, the results show that applying a population based RBE in treatment planning may be a step forward compared to using RBE of 1.1. OARs with large inter-patient RBE variations should ideally be selected for patient-specific biological or RBE robustness analysis if the physical doses are close to known dose thresholds.
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Affiliation(s)
| | - Lars Fredrik Fjæra
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Eivind Rørvik
- Department of Medical Physics, Oslo University Hospital, The Radium Hospital, Oslo, Norway
| | - Tordis J Dahle
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Jon Espen Dale
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | - Sara Pilskog
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | - Camilla H Stokkevåg
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
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11
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Faddegon B, Ramos-Méndez J, Schuemann J, McNamara A, Shin J, Perl J, Paganetti H. The TOPAS tool for particle simulation, a Monte Carlo simulation tool for physics, biology and clinical research. Phys Med 2020; 72:114-121. [PMID: 32247964 DOI: 10.1016/j.ejmp.2020.03.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/06/2020] [Accepted: 03/19/2020] [Indexed: 01/02/2023] Open
Abstract
PURPOSE This paper covers recent developments and applications of the TOPAS TOol for PArticle Simulation and presents the approaches used to disseminate TOPAS. MATERIALS AND METHODS Fundamental understanding of radiotherapy and imaging is greatly facilitated through accurate and detailed simulation of the passage of ionizing radiation through apparatus and into a patient using Monte Carlo (MC). TOPAS brings Geant4, a reliable, experimentally validated MC tool mainly developed for high energy physics, within easy reach of medical physicists, radiobiologists and clinicians. Requiring no programming knowledge, TOPAS provides all of the flexibility of Geant4. RESULTS After 5 years of development followed by its initial release, TOPAS was subsequently expanded from its focus on proton therapy physics to incorporate radiobiology modeling. Next, in 2018, the developers expanded their user support and code maintenance as well as the scope of TOPAS towards supporting X-ray and electron therapy and medical imaging. Improvements have been achieved in user enhancement through software engineering and a graphical user interface, calculational efficiency, validation through experimental benchmarks and QA measurements, and either newly available or recently published applications. A large and rapidly increasing user base demonstrates success in our approach to dissemination of this uniquely accessible and flexible MC research tool. CONCLUSIONS The TOPAS developers continue to make strides in addressing the needs of the medical community in applications of ionizing radiation to medicine, creating the only fully integrated platform for four-dimensional simulation of all forms of radiotherapy and imaging with ionizing radiation, with a design that promotes inter-institutional collaboration.
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Affiliation(s)
- Bruce Faddegon
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA.
| | - José Ramos-Méndez
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - Jan Schuemann
- Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Aimee McNamara
- Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Jungwook Shin
- Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Joseph Perl
- SLAC National Accelerator Laboratory, Menlo Park, USA
| | - Harald Paganetti
- Massachusetts General Hospital and Harvard Medical School, Boston, USA
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Gutierrez A, Rompokos V, Li K, Gillies C, D’Souza D, Solda F, Fersht N, Chang YC, Royle G, Amos RA, Underwood T. The impact of proton LET/RBE modeling and robustness analysis on base-of-skull and pediatric craniopharyngioma proton plans relative to VMAT. Acta Oncol 2019; 58:1765-1774. [PMID: 31429359 PMCID: PMC6882303 DOI: 10.1080/0284186x.2019.1653496] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/04/2019] [Indexed: 11/04/2022]
Abstract
Purpose: Pediatric craniopharyngioma, adult base-of-skull sarcoma and chordoma cases are all regarded as priority candidates for proton therapy. In this study, a dosimetric comparison between volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) was first performed. We then investigated the impact of physical and biological uncertainties. We assessed whether IMPT plans remained dosimetrically superior when such uncertainty estimates were considered, especially with regards to sparing organs at risk (OARs).Methodology: We studied 10 cases: four chondrosarcoma, two chordoma and four pediatric craniopharyngioma. VMAT and IMPT plans were created according to modality-specific protocols. For IMPT, we considered (i) variable RBE modeling using the McNamara model for different values of (α/β)x, and (ii) robustness analysis with ±3 mm set-up and 3.5% range uncertainties.Results: When comparing the VMAT and IMPT plans, the dosimetric advantages of IMPT were clear: IMPT led to reduced integral dose and, typically, improved CTV coverage given our OAR constraints. When physical robustness analysis was performed for IMPT, some uncertainty scenarios worsened the CTV coverage but not usually beyond that achieved by VMAT. Certain scenarios caused OAR constraints to be exceeded, particularly for the brainstem and optical chiasm. However, variable RBE modeling predicted even more substantial hotspots, especially for low values of (α/β)x. Variable RBE modeling often prompted dose constraints to be exceeded for critical structures.Conclusion: For base-of-skull and pediatric craniopharyngioma cases, both physical and biological robustness analyses should be considered for IMPT: these analyses can substantially affect the sparing of OARs and comparisons against VMAT. All proton RBE modeling is subject to high levels of uncertainty, but the clinical community should remain cognizant possible RBE effects. Careful clinical and imaging follow-up, plus further research on end-of-range RBE mitigation strategies such as LET optimization, should be prioritized for these cohorts of proton patients.
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Affiliation(s)
- A. Gutierrez
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - V. Rompokos
- Department of Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - K. Li
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - C. Gillies
- Department of Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - D. D’Souza
- Department of Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - F. Solda
- Department of Clinical Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - N. Fersht
- Department of Clinical Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Y.-C. Chang
- Department of Clinical Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - G. Royle
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - R. A. Amos
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - T. Underwood
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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13
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Draulans C, De Roover R, van der Heide UA, Haustermans K, Pos F, Smeenk RJ, De Boer H, Depuydt T, Kunze-Busch M, Isebaert S, Kerkmeijer L. Stereotactic body radiation therapy with optional focal lesion ablative microboost in prostate cancer: Topical review and multicenter consensus. Radiother Oncol 2019; 140:131-142. [PMID: 31276989 DOI: 10.1016/j.radonc.2019.06.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/25/2022]
Abstract
Stereotactic body radiotherapy (SBRT) for prostate cancer (PCa) is gaining interest by the recent publication of the first phase III trials on prostate SBRT and the promising results of many other phase II trials. Before long term results became available, the major concern for implementing SBRT in PCa in daily clinical practice was the potential risk of late genitourinary (GU) and gastrointestinal (GI) toxicity. A number of recently published trials, including late outcome and toxicity data, contributed to the growing evidence for implementation of SBRT for PCa in daily clinical practice. However, there exists substantial variability in delivering SBRT for PCa. The aim of this topical review is to present a number of prospective trials and retrospective analyses of SBRT in the treatment of PCa. We focus on the treatment strategies and techniques used in these trials. In addition, recent literature on a simultaneous integrated boost to the tumor lesion, which could create an additional value in the SBRT treatment of PCa, was described. Furthermore, we discuss the multicenter consensus of the FLAME consortium on SBRT for PCa with a focal boost to the macroscopic intraprostatic tumor nodule(s).
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Affiliation(s)
- Cédric Draulans
- Department of Radiation Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU Leuven, Belgium.
| | - Robin De Roover
- Department of Radiation Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU Leuven, Belgium.
| | - Uulke A van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| | - Karin Haustermans
- Department of Radiation Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU Leuven, Belgium.
| | - Floris Pos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| | - Robert Jan Smeenk
- Department of Radiation Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Hans De Boer
- Department of Radiation Oncology, University Medical Center, Utrecht, The Netherlands.
| | - Tom Depuydt
- Department of Radiation Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU Leuven, Belgium.
| | - Martina Kunze-Busch
- Department of Radiation Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Sofie Isebaert
- Department of Radiation Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU Leuven, Belgium.
| | - Linda Kerkmeijer
- Department of Radiation Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Radiation Oncology, University Medical Center, Utrecht, The Netherlands.
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14
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Marteinsdottir M, Schuemann J, Paganetti H. Impact of uncertainties in range and RBE on small field proton therapy. ACTA ACUST UNITED AC 2019; 64:205005. [DOI: 10.1088/1361-6560/ab448f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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15
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Sánchez‐Parcerisa D, López‐Aguirre M, Dolcet Llerena A, Udías JM. MultiRBE: Treatment planning for protons with selective radiobiological effectiveness. Med Phys 2019; 46:4276-4284. [DOI: 10.1002/mp.13718] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 06/19/2019] [Accepted: 07/10/2019] [Indexed: 12/12/2022] Open
Affiliation(s)
- Daniel Sánchez‐Parcerisa
- Grupo de Física Nuclear & IPARCOS, Departamento de Estructura de la Materia, Física Térmica y Electrónica CEI Moncloa Universidad Complutense de Madrid 28040Madrid Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC) Madrid Spain
| | - Miguel López‐Aguirre
- Grupo de Física Nuclear & IPARCOS, Departamento de Estructura de la Materia, Física Térmica y Electrónica CEI Moncloa Universidad Complutense de Madrid 28040Madrid Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC) Madrid Spain
| | | | - José Manuel Udías
- Grupo de Física Nuclear & IPARCOS, Departamento de Estructura de la Materia, Física Térmica y Electrónica CEI Moncloa Universidad Complutense de Madrid 28040Madrid Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC) Madrid Spain
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16
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Tensaouti F, Ducassou A, Chaltiel L, Bolle S, Habrand JL, Alapetite C, Coche-Dequeant B, Bernier V, Claude L, Carrie C, Padovani L, Muracciole X, Supiot S, Huchet A, Leseur J, Kerr C, Hangard G, Lisbona A, Goudjil F, Ferrand R, Laprie A. Feasibility of Dose Escalation in Patients With Intracranial Pediatric Ependymoma. Front Oncol 2019; 9:531. [PMID: 31293971 PMCID: PMC6598548 DOI: 10.3389/fonc.2019.00531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Background and purpose: Pediatric ependymoma carries a dismal prognosis, mainly owing to local relapse within RT fields. The current prospective European approach is to increase the radiation dose with a sequential hypofractionated stereotactic boost. In this study, we assessed the possibility of using a simultaneous integrated boost (SIB), comparing VMAT vs. IMPT dose delivery. Material and methods: The cohort included 101 patients. The dose to planning target volume (PTV59.4) was 59.4/1.8 Gy, and the dose to SIB volume (PTV67.6) was 67.6/2.05 Gy. Gross tumor volume (GTV) was defined as the tumor bed plus residual tumor, clinical target volume (CTV59.4) was GTV + 5 mm, and PTV59.4 was CTV59.4 + 3 mm. PTV67.6 was GTV+ 3 mm. After treatment plan optimization, quality indices and doses to target volume and organs at risk (OARs) were extracted and compared with the standard radiation doses that were actually delivered (median = 59.4 Gy [50.4 59.4]). Results: In most cases, the proton treatment resulted in higher quality indices (p < 0.001). Compared with the doses that were initially delivered, mean, and maximum doses to some OARs were no higher with SIB VMAT, and significantly lower with protons (p < 0.001). In the case of posterior fossa tumor, there was a lower dose to the brainstem with protons, in terms of V59 Gy, mean, and near-maximum (D2%) doses. Conclusion: Dose escalation with intensity-modulated proton or photon SIB is feasible in some patients. This approach could be considered for children with unresectable residue or post-operative FLAIR abnormalities, particularly if they have supratentorial tumors. It should not be considered for infratentorial tumors encasing the brainstem or extending to the medulla.
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Affiliation(s)
- Fatima Tensaouti
- ToNIC, Toulouse NeuroImaging Center, Universite de Toulouse, Inserm, Toulouse, France
- Department of Radiation Oncology, Institut Claudius Regaud, Institut Universitaire du, Cancer de Toulouse-Oncopole, Toulouse, France
| | - Anne Ducassou
- Department of Radiation Oncology, Institut Claudius Regaud, Institut Universitaire du, Cancer de Toulouse-Oncopole, Toulouse, France
| | - Léonor Chaltiel
- Department of Biostatistics, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Stéphanie Bolle
- Department of Radiotherapy Oncology, Institut Gustave Roussy, Villejuif, France
| | - Jean Louis Habrand
- Department of Radiation Oncology, Centre Francois Baclesse, Caen, France
| | | | | | - Valérie Bernier
- Department of Radiation Oncology, Centre Alexis Vautrin, Vandœuvre-lès-Nancy, France
| | - Line Claude
- Department of Radiation Oncology, Centre Léon Bérard, Lyon, France
| | - Christian Carrie
- Department of Radiation Oncology, Centre Léon Bérard, Lyon, France
| | | | | | - Stéphane Supiot
- Department of Radiation Oncology, Institut de Cancerologie de l'Ouest, Nantes, France
| | - Aymeri Huchet
- Department of Radiation Oncology, Centre Hospitalier et Universitaire, Bordeaux, France
| | - Julie Leseur
- Department of Radiation Oncology, Centre Eugéne Marquis, Rennes, France
| | - Christine Kerr
- Department of Radiation Oncology, Institut Regional du Cancer Montpellier, Val d'Aurelle, Montpellier, France
| | - Grégorie Hangard
- Department of Engineering and Medical Physics, Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Albert Lisbona
- Department of Radiation Oncology, Institut de Cancerologie de l'Ouest, Nantes, France
| | - Farid Goudjil
- Department of Radiation Oncology, Institut Curie, Paris, France
| | - Régis Ferrand
- Department of Engineering and Medical Physics, Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Anne Laprie
- ToNIC, Toulouse NeuroImaging Center, Universite de Toulouse, Inserm, Toulouse, France
- Department of Radiation Oncology, Institut Claudius Regaud, Institut Universitaire du, Cancer de Toulouse-Oncopole, Toulouse, France
- Université Toulouse III Paul Sabatier, Toulouse, France
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17
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Marteinsdottir M, Paganetti H. Applying a variable relative biological effectiveness (RBE) might affect the analysis of clinical trials comparing photon and proton therapy for prostate cancer. ACTA ACUST UNITED AC 2019; 64:115027. [DOI: 10.1088/1361-6560/ab2144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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18
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Whitaker TJ, Routman DM, Schultz H, Harmsen WS, Corbin KS, Wong WW, Choo R. IMPT versus VMAT for Pelvic Nodal Irradiation in Prostate Cancer: A Dosimetric Comparison. Int J Part Ther 2019; 5:11-23. [PMID: 31788504 PMCID: PMC6874187 DOI: 10.14338/ijpt-18-00048.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/22/2019] [Indexed: 12/26/2022] Open
Abstract
Purpose: To compare dosimetric data of the organs at risk (OARs) and clinical target volumes (CTVs) between intensity-modulated proton therapy (IMPT) and volumetric-modulated arc therapy (VMAT) for patients undergoing prostate and elective, pelvic lymph node radiotherapy in the setting of unfavorable, intermediate and high-risk prostate carcinoma. Methods and Materials: A study of moderately hypofractionated proton therapy (6750 centigray [cGy] in 25 fractions) is in progress for unfavorable, intermediate and high-risk prostate cancer where treatment includes an elective pelvic nodal CTV (4500 cGy in 25 fractions). Ten consecutively accrued patients were the subjects for dose-volume histogram comparison between IMPT and VMAT. Two treatment plans (IMPT and VMAT) were prepared for each patient with predefined planning objectives for target volumes and OARs. The IMPT plans were prepared with 2 lateral beams and VMAT plans with 2 arcs. Results: The CTV coverage was adequate for both plans with 99% of CTVs receiving ≥ 100% of the prescription doses. Mean doses to the bladder, rectum, large bowel, and small bowel were lower with IMPT versus VMAT. Mean femoral head dose was greater with IMPT. The percentage of volumes of rectum receiving ≤ 47.5 Gy, large bowel receiving ≤ 27.5 Gy, small bowel receiving ≤ 30 Gy, and bladder receiving ≤ 37.5 Gy was less with IMPT versus VMAT, largely because of reduction in the low-dose “bath” associated with VMAT. Conclusions: In the setting of prostate and elective, pelvic nodal radiotherapy for prostate cancer, IMPT can significantly reduce the dose to OARs, in comparison to VMAT, and provide adequate target coverage.
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Affiliation(s)
| | - David M Routman
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Heather Schultz
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | | | | | - William W Wong
- Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ, USA
| | - Richard Choo
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
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19
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Busch K, Muren LP, Thörnqvist S, Andersen AG, Pedersen J, Dong L, Petersen JBB. On-line dose-guidance to account for inter-fractional motion during proton therapy. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 9:7-13. [PMID: 33458420 PMCID: PMC7807653 DOI: 10.1016/j.phro.2018.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/26/2018] [Indexed: 11/13/2022]
Abstract
Background and purpose Proton therapy (PT) of extra-cranial tumour sites is challenged by density changes caused by inter-fractional organ motion. In this study we investigate on-line dose-guided PT (DGPT) to account inter-fractional target motion, exemplified by internal motion in the pelvis. Materials and methods On-line DGPT involved re-calculating dose distributions with the isocenter shifted up to 15 mm from the position corresponding to conventional soft-tissue based image-guided PT (IGPT). The method was applied to patient models with simulated prostate/seminal vesicle target motion of ±3, ±5 and ±10 mm along the three cardinal axes. Treatment plans were created using either two lateral (gantry angles of 90°/270°) or two lateral oblique fields (gantry angles of 35°/325°). Target coverage and normal tissue doses from DGPT were compared to both soft-tissue and bony anatomy based IGPT. Results DGPT improved the dose distributions relative to soft-tissue based IGPT for 39 of 90 simulation scenarios using lateral fields and for 50 of 90 scenarios using lateral oblique fields. The greatest benefits of DGPT were seen for large motion, e.g. a median target coverage improvement of 13% was found for 10 mm anterior motion with lateral fields. DGPT also improved the dose distribution in comparison to bony anatomy IGPT in all cases. The best strategy was often to move the fields back towards the original target position prior to the simulated target motion. Conclusion DGPT has the potential to better account for large inter-fractional organ motion in the pelvis than IGPT.
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Affiliation(s)
- Kia Busch
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Ludvig P Muren
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Sara Thörnqvist
- Department of Physics and Technology, University of Bergen, Norway.,Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | - Andreas G Andersen
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Jesper Pedersen
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, USA
| | - Jørgen B B Petersen
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
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20
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Yepes P, Adair A, Frank SJ, Grosshans DR, Liao Z, Liu A, Mirkovic D, Poenisch F, Titt U, Wang Q, Mohan R. Fixed- versus Variable-RBE Computations for Intensity Modulated Proton Therapy. Adv Radiat Oncol 2018; 4:156-167. [PMID: 30706024 PMCID: PMC6349601 DOI: 10.1016/j.adro.2018.08.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 11/30/2022] Open
Abstract
Purpose To evaluate how using models of proton therapy that incorporate variable relative biological effectiveness (RBE) versus the current practice of using a fixed RBE of 1.1 affects dosimetric indices on treatment plans for large cohorts of patients treated with intensity modulated proton therapy (IMPT). Methods and Materials Treatment plans for 4 groups of patients who received IMPT for brain, head-and-neck, thoracic, or prostate cancer were selected. Dose distributions were recalculated in 4 ways: 1 with a fast-dose Monte Carlo calculator with fixed RBE and 3 with RBE calculated to 3 different models—McNamara, Wedenberg, and repair-misrepair-fixation. Differences among dosimetric indices (D02, D50, D98, and mean dose) for target volumes and organs at risk (OARs) on each plan were compared between the fixed-RBE and variable-RBE calculations. Results In analyses of all target volumes, for which the main concern is underprediction or RBE less than 1.1, none of the models predicted an RBE less than 1.05 for any of the cohorts. For OARs, the 2 models based on linear energy transfer, McNamara and Wedenberg, systematically predicted RBE >1.1 for most structures. For the mean dose of 25% of the plans for 2 OARs, they predict RBE equal to or larger than 1.4, 1.3, 1.3, and 1.2 for brain, head-and-neck, thorax, and prostate, respectively. Systematically lower increases in RBE are predicted by repair-misrepair-fixation, with a few cases (eg, femur) in which the RBE is less than 1.1 for all plans. Conclusions The variable-RBE models predict increased doses to various OARs, suggesting that strategies to reduce high-dose linear energy transfer in critical structures should be developed to minimize possible toxicity associated with IMPT.
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Affiliation(s)
- Pablo Yepes
- Physics and Astronomy Department, Rice University, Houston, Texas.,Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Antony Adair
- Physics and Astronomy Department, Rice University, Houston, Texas.,Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Steven J Frank
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas
| | - David R Grosshans
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas.,Experimental Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Zhongxing Liao
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Amy Liu
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Dragan Mirkovic
- Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Falk Poenisch
- Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Uwe Titt
- Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Qianxia Wang
- Physics and Astronomy Department, Rice University, Houston, Texas.,Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
| | - Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer, Houston, Texas
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Stewart RD, Carlson DJ, Butkus MP, Hawkins R, Friedrich T, Scholz M. A comparison of mechanism-inspired models for particle relative biological effectiveness (RBE). Med Phys 2018; 45:e925-e952. [PMID: 30421808 DOI: 10.1002/mp.13207] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND SIGNIFICANCE The application of heavy ion beams in cancer therapy must account for the increasing relative biological effectiveness (RBE) with increasing penetration depth when determining dose prescriptions and organ at risk (OAR) constraints in treatment planning. Because RBE depends in a complex manner on factors such as the ion type, energy, cell and tissue radiosensitivity, physical dose, biological endpoint, and position within and outside treatment fields, biophysical models reflecting these dependencies are required for the personalization and optimization of treatment plans. AIM To review and compare three mechanism-inspired models which predict the complexities of particle RBE for various ion types, energies, linear energy transfer (LET) values and tissue radiation sensitivities. METHODS The review of models and mechanisms focuses on the Local Effect Model (LEM), the Microdosimetric-Kinetic (MK) model, and the Repair-Misrepair-Fixation (RMF) model in combination with the Monte Carlo Damage Simulation (MCDS). These models relate the induction of potentially lethal double strand breaks (DSBs) to the subsequent interactions and biological processing of DSB into more lethal forms of damage. A key element to explain the increased biological effectiveness of high LET ions compared to MV x rays is the characterization of the number and local complexity (clustering) of the initial DSB produced within a cell. For high LET ions, the spatial density of DSB induction along an ion's trajectory is much greater than along the path of a low LET electron, such as the secondary electrons produced by the megavoltage (MV) x rays used in conventional radiation therapy. The main aspects of the three models are introduced and the conceptual similarities and differences are critiqued and highlighted. Model predictions are compared in terms of the RBE for DSB induction and for reproductive cell survival. RESULTS AND CONCLUSIONS Comparisons of the RBE for DSB induction and for cell survival are presented for proton (1 H), helium (4 He), and carbon (12 C) ions for the therapeutically most relevant range of ion beam energies. The reviewed models embody mechanisms of action acting over the spatial scales underlying the biological processing of potentially lethal DSB into more lethal forms of damage. Differences among the number and types of input parameters, relevant biological targets, and the computational approaches among the LEM, MK and RMF models are summarized and critiqued. Potential experiments to test some of the seemingly contradictory aspects of the models are discussed.
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Affiliation(s)
- Robert D Stewart
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific Street, Box 356043, Seattle, WA, 98195, USA
| | - David J Carlson
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Michael P Butkus
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Roland Hawkins
- Radiation Oncology Center, Ochsner Clinic Foundation, New Orleans, LA, 70121, USA
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22
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Wedenberg M, Beltran C, Mairani A, Alber M. Advanced Treatment Planning. Med Phys 2018; 45:e1011-e1023. [PMID: 30421811 DOI: 10.1002/mp.12943] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/22/2018] [Accepted: 04/22/2018] [Indexed: 12/15/2022] Open
Abstract
Treatment planning for protons and heavier ions is adapting technologies originally developed for photon dose optimization, but also has to meet its particular challenges. Since the quality of the applied dose is more sensitive to geometric uncertainties, treatment plan robust optimization has a much more prominent role in particle therapy. This has led to specific planning tools, approaches, and research into new formulations of the robust optimization problems. Tools for solution space navigation and automatic planning are also being adapted to particle therapy. These challenges become even greater when detailed models of relative biological effectiveness (RBE) are included into dose optimization, as is required for heavier ions.
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Affiliation(s)
| | - Chris Beltran
- Division of Medical Physics, Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Andrea Mairani
- Heidelberg Ion Therapy Center (HIT), Heidelberg University Hospital, Heidelberg, Germany.,National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.,The National Centre for Oncological Hadrontherapy (CNAO), Pavia, Italy
| | - Markus Alber
- The National Centre for Oncological Hadrontherapy (CNAO), Pavia, Italy.,Section for Medical Physics, Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
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23
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Proton therapy for prostate cancer: A review of the rationale, evidence, and current state. Urol Oncol 2018; 37:628-636. [PMID: 30527342 DOI: 10.1016/j.urolonc.2018.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/07/2018] [Accepted: 11/12/2018] [Indexed: 12/17/2022]
Abstract
Men diagnosed with localized prostate cancer have many curative treatment options including several different radiotherapeutic approaches. Proton radiation is one such radiation treatment modality and, due to its unique physical properties, offers the appealing potential of reduced side effects without sacrificing cancer control. In this review, we examine the intriguing dosimetric rationale and theoretical benefit of proton radiation for prostate cancer and highlight the results of preclinical modeling studies. We then discuss the current state of the clinical evidence for proton efficacy and toxicity, derived from both large claim-based datasets and prospective patient-reported data. The result is that the data are mixed, and clinical equipoise persists in this area. We place these studies into context by summarizing the economics of proton therapy and the changing practice patterns of prostate proton irradiation. Finally, we await the results of a large prospective randomized clinical trial currently accruing and also a large prospective pragmatic comparative study which will provide more rigorous evidence regarding the clinical and comparative effectiveness of proton therapy for prostate cancer.
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24
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Henry T, Ödén J. Interlaced proton grid therapy – Linear energy transfer and relative biological effectiveness distributions. Phys Med 2018; 56:81-89. [DOI: 10.1016/j.ejmp.2018.10.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/03/2018] [Accepted: 10/30/2018] [Indexed: 12/25/2022] Open
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25
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Rørvik E, Fjæra LF, Dahle TJ, Dale JE, Engeseth GM, Stokkevåg CH, Thörnqvist S, Ytre-Hauge KS. Exploration and application of phenomenological RBE models for proton therapy. Phys Med Biol 2018; 63:185013. [PMID: 30102240 DOI: 10.1088/1361-6560/aad9db] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The relative biological effectiveness (RBE) of protons varies with multiple physical and biological factors. Phenomenological RBE models have been developed to include such factors in the estimation of a variable RBE, in contrast to the clinically applied constant RBE of 1.1. In this study, eleven published phenomenological RBE models and two plan-based models were explored and applied to simulated patient cases. All models were analysed with respect to the distribution and range of linear energy transfer (LET) and reference radiation fractionation sensitivity ((α/β) x ) of their respective experimental databases. Proton therapy plans for a spread-out Bragg peak in water and three patient cases (prostate adenocarcinoma, pituitary adenoma and thoracic sarcoma) were optimised using an RBE of 1.1 in the Eclipse™ treatment planning system prior to recalculation and modelling in the FLUKA Monte Carlo code. Model estimated dose-volume parameters for the planning target volumes (PTVs) and organs at risk (OAR) were compared. The experimental in vitro databases for the various models differed greatly in the range of (α/β) x values and dose-averaged LET (LETd). There were significant variations between the model estimations, which arose from fundamental differences in the database definitions and model assumptions. The greatest variations appeared in organs with low (α/β) x and high LETd, e.g. biological doses given to late responding OARs located distal to the target in the treatment field. In general, the variation in maximum dose (D2%) was larger than the variation in mean dose and other dose metrics, with D2% of the left optic nerve ((α/β) x = 2.1 Gy) in the pituitary adenoma case showing the greatest discrepancies between models: 28-52 Gy(RBE), while D2% for RBE1.1 was 30 Gy(RBE). For all patient cases, the estimated mean RBE to the PTV was in the range 1.09-1.29 ((α/β) x = 1.5/3.1/10.6 Gy). There were considerable variations between the estimations of RBE and RBE-weighted doses from the different models. These variations were a consequence of fundamental differences in experimental databases, model assumptions and regression techniques. The results from the implementation of RBE models in dose planning studies should be evaluated in light of these deviations.
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Affiliation(s)
- Eivind Rørvik
- Department of Physics and Technology, University of Bergen, Bergen, Norway. Author to whom any correspondence should be addressed
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26
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Underwood TS, McMahon SJ. Proton relative biological effectiveness (RBE): a multiscale problem. Br J Radiol 2018; 92:20180004. [PMID: 29975153 DOI: 10.1259/bjr.20180004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Proton radiotherapy is undergoing rapid expansion both within the UK and internationally, but significant challenges still need to be overcome if maximum benefit is to be realised from this technique. One major limitation is the persistent uncertainty in proton relative biological effectiveness (RBE). While RBE values are needed to link proton radiotherapy to our existing experience with photon radiotherapy, RBE remains poorly understood and is typically incorporated as a constant dose scaling factor of 1.1 in clinical plans. This is in contrast to extensive experimental evidence indicating that RBE is a function of dose, tissue type, and proton linear energy transfer, among other parameters. In this article, we discuss the challenges associated with obtaining clinically relevant values for proton RBE through commonly-used assays, and highlight the wide range of other experimental end points which can inform our understanding of RBE. We propose that accurate and robust optimization of proton radiotherapy ultimately requires a multiscale understanding of RBE, integrating subcellular, cellular, and patient-level processes.
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Affiliation(s)
- Tracy Sa Underwood
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Stephen J McMahon
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, UK
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Relative Biological Effectiveness Uncertainties and Implications for Beam Arrangements and Dose Constraints in Proton Therapy. Semin Radiat Oncol 2018; 28:256-263. [DOI: 10.1016/j.semradonc.2018.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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28
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Ödén J, DeLuca PM, Orton CG. The use of a constant RBE=1.1 for proton radiotherapy is no longer appropriate. Med Phys 2017; 45:502-505. [PMID: 29091284 DOI: 10.1002/mp.12646] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 02/03/2023] Open
Affiliation(s)
- Jakob Ödén
- Department of Physics, Medical Radiation Physics, Stockholm University, S-171 76, Stockholm, Sweden
- RaySearch Laboratories, S-111 34, Stockholm, Sweden
| | - Paul M DeLuca
- Department of Medical Physics, University of Wisconsin, Madison, WI, 53705-2275, USA
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29
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Pedersen J, Petersen JBB, Stokkevåg CH, Ytre-Hauge KS, Flampouri S, Li Z, Mendenhall N, Muren LP. Biological dose and complication probabilities for the rectum and bladder based on linear energy transfer distributions in spot scanning proton therapy of prostate cancer. Acta Oncol 2017; 56:1413-1419. [PMID: 29037095 DOI: 10.1080/0284186x.2017.1373198] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND The increased linear energy transfer (LET) at the end of the Bragg peak causes concern for an elevated and spatially varying relative biological effectiveness (RBE) of proton therapy (PT), often in or close to dose-limiting normal tissues. In this study, we investigated dose-averaged LET (LETd) distributions for spot scanning PT of prostate cancer patients using different beam angle configurations. In addition, we derived RBE-weighted (RBEw) dose distributions and related normal tissue complication probabilities (NTCPs) for the rectum and bladder. MATERIAL AND METHODS A total of 21 spot scanning proton plans were created for each of six patients using a prescription dose of 78 Gy(RBE1.1), with each plan using two 'mirrored' beams with gantry angles from 110°/250° to 70°/290°, in steps of 2°. Physical dose and LETd distributions were calculated as well as RBEw dose distributions using either RBE = 1.1 or three different variable RBE models. The resulting biological dose distributions were used as input to NTCP models for the rectum and bladder. RESULTS For anterior oblique (AO) configurations, the rectum LETd volume and RBEw dose increased with increasing angles off the lateral opposing axis, with the RBEw rectum dose being higher than for all posterior oblique (PO) configurations. For PO configurations, the corresponding trend was seen for the bladder. Using variable RBE models, the rectum NTCPs were highest for the AO configurations with up to 3% for the 80°/280° configuration while the bladder NTCPs were highest for the PO configurations with up to 32% for the 100°/260°. The rectum D1cm3 constraint was fulfilled for most patients/configurations when using uniform RBE but not for any patient/configuration with variable RBE models. CONCLUSIONS Compared to using constant RBE, the variable RBE models predicted increased biological doses to the rectum, bladder and prostate, which in turn lead to substantially higher estimated rectum and bladder NTCPs.
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Affiliation(s)
- Jesper Pedersen
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Jørgen B. B. Petersen
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
| | - Camilla H. Stokkevåg
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | | | - Stella Flampouri
- University of Florida Proton Therapy Institute, Gainesville, FL, USA
| | - Zuofeng Li
- University of Florida Proton Therapy Institute, Gainesville, FL, USA
| | - Nancy Mendenhall
- University of Florida Proton Therapy Institute, Gainesville, FL, USA
| | - Ludvig P. Muren
- Department of Medical Physics, Aarhus University Hospital/Aarhus University, Aarhus, Denmark
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30
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Paganetti H. Relating the proton relative biological effectiveness to tumor control and normal tissue complication probabilities assuming interpatient variability in α/β. Acta Oncol 2017; 56:1379-1386. [PMID: 28918679 DOI: 10.1080/0284186x.2017.1371325] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Proton therapy uses a constant relative biological effectiveness (RBE) of 1.1. The use of variable RBE values has been suggested but is currently not feasible due to uncertainties. The impact of variable RBE has solely been studied using dosimetric indices. This work elucidates the impact of RBE variations on tumor control and normal tissue complication probabilities (TCP/NTCP). METHODS Models to estimate TCP and NTCP were used in combination with an empirical proton RBE model. Variations in outcome as a function of linear-quadratic model parameters for cellular radiosensitivity were determined for TCP in prostate and ependymoma. In addition, NTCP analysis was done for brainstem necrosis. RESULTS Considering a variable proton RBE as a dose-modifying factor for prescription doses and dose constraints is misleading, as TCP/NTCP do not simply scale with RBE. The dependency of RBE on α/β cannot be interpreted independent of TCP/NTCP because variations in radiosensitivity affect both photon and proton treatments. Assuming interpatient variability in radiosensitivity results in lower TCP for patients with low α/β. In proton therapy, the magnitude of TCP variations is reduced due to an RBE increase as α/β decreases. The TCP in proton therapy is less affected by interpatient variability in α/β. On the other hand, patients with a lower α/β would have a lower complication probability, which is counteracted by an increase in RBE as α/β decreases. Toxicities in proton therapy would be more affected by α/β variations compared to photon therapy. CONCLUSIONS Assessment of variable RBE in proton therapy should be based on TCP and NTCP. Potential interpatient variability in radiosensitivity causes a smaller variance in TCP but a larger variance in NTCP for proton patients. The relative TCP as a function of α/β was found to be higher than the RBE, whereas the relative NTCP was lower than a calculated RBE.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA, USA
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31
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Grimes DR, Warren DR, Partridge M. An approximate analytical solution of the Bethe equation for charged particles in the radiotherapeutic energy range. Sci Rep 2017; 7:9781. [PMID: 28852130 PMCID: PMC5574894 DOI: 10.1038/s41598-017-10554-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/11/2017] [Indexed: 01/26/2023] Open
Abstract
Charged particles such as protons and carbon ions are an increasingly important tool in radiotherapy. There are however unresolved physics issues impeding optimal implementation, including estimation of dose deposition in non-homogeneous tissue, an essential aspect of treatment optimization. Monte Carlo (MC) methods can be employed to estimate radiation profile, and whilst powerful, these are computationally expensive, limiting practicality. In this work, we start from fundamental physics in the form of the Bethe equation to yield a novel approximate analytical solution for particle range, energy and linear energy transfer (LET). The solution is given in terms of the exponential integral function with relativistic co-ordinate transform, allowing application at radiotherapeutic energy levels (50-350 MeV protons, 100-600 Mev/a.m.u carbon ions). Model results agreed closely for protons and carbon-ions (mean error within ≈1%) of literature values. Agreement was high along particle track, with some discrepancy manifesting at track-end. The model presented has applications within a charged particle radiotherapy optimization framework as a rapid method for dose and LET estimation, capable of accounting for heterogeneity in electron density and ionization potential.
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Affiliation(s)
- David Robert Grimes
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
| | - Daniel R Warren
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Mike Partridge
- Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK
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32
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Ödén J, Eriksson K, Toma-Dasu I. Incorporation of relative biological effectiveness uncertainties into proton plan robustness evaluation. Acta Oncol 2017; 56:769-778. [PMID: 28464736 DOI: 10.1080/0284186x.2017.1290825] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND The constant relative biological effectiveness (RBE) of 1.1 is typically assumed in proton therapy. This study presents a method of incorporating the variable RBE and its uncertainties into the proton plan robustness evaluation. MATERIAL AND METHODS The robustness evaluation was split into two parts. In part one, the worst-case physical dose was estimated using setup and range errors, including the fractionation dependence. The results were fed into part two, in which the worst-case RBE-weighted doses were estimated using a Monte Carlo method for sampling the input parameters of the chosen RBE model. The method was applied to three prostate, breast and head and neck (H&N) plans for several fractionation schedules using two RBE models. The uncertainties in the model parameters, linear energy transfer and α/β were included. The resulting DVH error bands were compared with the use of a constant RBE without uncertainties. RESULTS All plans were evaluated as robust using the constant RBE. Applying the proposed methodology using the variable RBE models broadens the DVH error bands for all structures studied. The uncertainty in α/β was the dominant factor. The variable RBE also shifted the nominal DVHs towards higher doses for most OARs, whereas the direction of this shift for the clinical target volumes (CTVs) depended on the treatment site, RBE model and fractionation schedule. The average RBE within the CTV, using one of the RBE models and 2 Gy(RBE) per fraction, varied between 1.11-1.26, 1.06-1.16 and 1.14-1.25 for the breast, H&N and prostate patients, respectively. CONCLUSIONS A method of incorporating RBE uncertainties into the robustness evaluation has been proposed. By disregarding the variable RBE and its uncertainties, the variation in the RBE-weighted CTV and OAR doses may be underestimated. This could be an essential factor to take into account, especially in normal tissue complication probabilities based comparisons between proton and photon plans.
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Affiliation(s)
- Jakob Ödén
- Department of Physics, Medical Radiation Physics, Stockholm University, Stockholm, Sweden
- RaySearch Laboratories, Stockholm, Sweden
| | | | - Iuliana Toma-Dasu
- Department of Physics, Medical Radiation Physics, Stockholm University, Stockholm, Sweden
- Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, Sweden
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Underwood TSA, Voog JC, Moteabbed M, Tang S, Soffen E, Cahlon O, Lu HM, Zietman AL, Efstathiou JA, Paganetti H. Hydrogel rectum-prostate spacers mitigate the uncertainties in proton relative biological effectiveness associated with anterior-oblique beams. Acta Oncol 2017; 56:575-581. [PMID: 28075206 DOI: 10.1080/0284186x.2016.1275781] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Anterior-oblique (AO) proton beams can form an attractive option for prostate patients receiving external beam radiotherapy (EBRT) as they avoid the femoral heads. For a cohort with hydrogel prostate-rectum spacers, we asked whether it was possible to generate AO proton plans robust to end-of-range elevations in linear energy transfer (LET) and modeled relative biological effectiveness (RBE). Additionally we considered how rectal spacers influenced planned dose distributions for AO and standard bilateral (SB) proton beams versus intensity-modulated radiotherapy (IMRT). MATERIAL AND METHODS We studied three treatment strategies for 10 patients with rectal spacers: (A) AO proton beams, (B) SB proton beams and (C) IMRT. For strategy (A) dose and LET distributions were simulated (using the TOPAS Monte Carlo platform) and the McNamara model was used to calculate proton RBE as a function of LET, dose per fraction, and photon α/β. All calculations were performed on pretreatment scans: inter- and intra-fractional changes in anatomy/set-up were not considered. RESULTS For 9/10 patients, rectal spacers enabled generation of AO proton plans robust to modeled RBE elevations: rectal dose constraints were fulfilled even when the variable RBE model was applied with a conservative α/β = 2 Gy. Amongst a subset of patients the proton rectal doses for the planning target volume plans were remarkably low: for 2/10 SB plans and 4/10 AO plans, ≤10% of the rectum received ≥20 Gy. AO proton plans delivered integral doses a factor of approximately three lower than IMRT and spared the femoral heads almost entirely. CONCLUSION Typically, rectal spacers enabled the generation of anterior beam proton plans that appeared robust to modeled variation in RBE. However, further analysis of day-to-day robustness would be required prior to a clinical implementation of AO proton beams. Such beams offer almost complete femoral head sparing, but their broader value relative to IMRT and SB protons remains unclear.
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Affiliation(s)
- Tracy S. A. Underwood
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Medical Physics and Bioengineering, University College London, London, UK
| | - Justin C. Voog
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Maryam Moteabbed
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shikui Tang
- ProCure Proton Therapy Center, Somerset, NJ, USA
| | | | - Oren Cahlon
- ProCure Proton Therapy Center, Somerset, NJ, USA
| | - Hsiao-Ming Lu
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anthony L. Zietman
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jason A. Efstathiou
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Ödén J, Eriksson K, Toma-Dasu I. Inclusion of a variable RBE into proton and photon plan comparison for various fractionation schedules in prostate radiation therapy. Med Phys 2017; 44:810-822. [PMID: 28107554 DOI: 10.1002/mp.12117] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 11/29/2016] [Accepted: 01/12/2017] [Indexed: 11/06/2022] Open
Abstract
PURPOSE A constant relative biological effectiveness (RBE) of 1.1 is currently used in proton radiation therapy to account for the increased biological effectiveness compared to photon therapy. However, there is increasing evidence that proton RBE vary with the linear energy transfer (LET), the dose per fraction, and the type of the tissue. Therefore, this study aims to evaluate the impact of disregarding variations in RBE when comparing proton and photon dose plans for prostate treatments for various fractionation schedules using published RBE models and several α/β assumptions. METHODS Photon and proton dose plans were created for three generic prostate cancer cases. Three BED3Gy equivalent schedules were studied, 78, 57.2, and 42.8 Gy in 39, 15, and 7 fractions, respectively. The proton plans were optimized assuming a constant RBE of 1.1. By using the Monte Carlo calculated dose-averaged LET (LETd ) distribution and assuming α/β values on voxel level, three variable RBE models were applied to the proton dose plans. The impact of the variable RBE was studied in the plan comparison, which was based on the dose distribution, DVHs, and normal tissue complication probabilities (NTCP) for the rectum. Subsequently, the physical proton dose was reoptimized for each proton plan based on the LETd distribution, to achieve a homogeneous RBE-weighted target dose when applying a specific RBE model and still fulfill the clinical goals for the rectum and bladder. RESULTS All the photon and proton plans assuming RBE = 1.1 met the clinical goals with similar target coverage. The proton plans fulfilled the robustness criteria in terms of range and setup uncertainty. Applying the variable RBE models generally resulted in higher target doses and rectum NTCP compared to the photon plans. The increase was most pronounced for the fractionation dose of 2 Gy(RBE), whereas it was of less magnitude and more dependent on model and α/β assumption for the hypofractionated schedules. The reoptimized proton plans proved to be robust and showed similar target coverage and doses to the organs at risk as the proton plans optimized with a constant RBE. CONCLUSIONS Model predicted RBE values may differ substantially from 1.1. This is most pronounced for fractionation doses of around 2 Gy(RBE) with higher doses to the target and the OARs, whereas the effect seems to be of less importance for the hypofractionated schedules. This could result in misleading conclusions when comparing proton plans to photon plans. By accounting for a variable RBE in the optimization process, robust and clinically acceptable dose plans, with the potential of lowering rectal NTCP, may be generated by reoptimizing the physical dose. However, the direction and magnitude of the changes in the physical proton dose to the prostate are dependent on RBE model and α/β assumptions and should therefore be used conservatively.
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Affiliation(s)
- Jakob Ödén
- Department of Physics, Medical Radiation Physics, Stockholm University, Stockholm, 17176, Sweden.,RaySearch Laboratories, Stockholm, 11134, Sweden
| | | | - Iuliana Toma-Dasu
- Department of Physics, Medical Radiation Physics, Stockholm University, Stockholm, 17176, Sweden.,Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, 17176, Sweden
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35
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Moteabbed M, Trofimov A, Sharp GC, Wang Y, Zietman AL, Efstathiou JA, Lu HM. Proton therapy of prostate cancer by anterior-oblique beams: implications of setup and anatomy variations. Phys Med Biol 2017; 62:1644-1660. [DOI: 10.1088/1361-6560/62/5/1644] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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36
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Proton therapy for paediatric CNS tumours — improving treatment-related outcomes. Nat Rev Neurol 2016; 12:334-45. [DOI: 10.1038/nrneurol.2016.70] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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