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Chen ZJ, Li XA, Brenner DJ, Hellebust TP, Hoskin P, Joiner MC, Kirisits C, Nath R, Rivard MJ, Thomadsen BR, Zaider M. AAPM Task Group Report 267: A joint AAPM GEC-ESTRO report on biophysical models and tools for the planning and evaluation of brachytherapy. Med Phys 2024; 51:3850-3923. [PMID: 38721942 DOI: 10.1002/mp.17062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 06/05/2024] Open
Abstract
Brachytherapy utilizes a multitude of radioactive sources and treatment techniques that often exhibit widely different spatial and temporal dose delivery patterns. Biophysical models, capable of modeling the key interacting effects of dose delivery patterns with the underlying cellular processes of the irradiated tissues, can be a potentially useful tool for elucidating the radiobiological effects of complex brachytherapy dose delivery patterns and for comparing their relative clinical effectiveness. While the biophysical models have been used largely in research settings by experts, it has also been used increasingly by clinical medical physicists over the last two decades. A good understanding of the potentials and limitations of the biophysical models and their intended use is critically important in the widespread use of these models. To facilitate meaningful and consistent use of biophysical models in brachytherapy, Task Group 267 (TG-267) was formed jointly with the American Association of Physics in Medicine (AAPM) and The Groupe Européen de Curiethérapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO) to review the existing biophysical models, model parameters, and their use in selected brachytherapy modalities and to develop practice guidelines for clinical medical physicists regarding the selection, use, and interpretation of biophysical models. The report provides an overview of the clinical background and the rationale for the development of biophysical models in radiation oncology and, particularly, in brachytherapy; a summary of the results of literature review of the existing biophysical models that have been used in brachytherapy; a focused discussion of the applications of relevant biophysical models for five selected brachytherapy modalities; and the task group recommendations on the use, reporting, and implementation of biophysical models for brachytherapy treatment planning and evaluation. The report concludes with discussions on the challenges and opportunities in using biophysical models for brachytherapy and with an outlook for future developments.
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Affiliation(s)
- Zhe Jay Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - X Allen Li
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Medical Center, New York, New York, USA
| | - Taran P Hellebust
- Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Peter Hoskin
- Mount Vernon Cancer Center, Mount Vernon Hospital, Northwood, UK
- University of Manchester, Manchester, UK
| | - Michael C Joiner
- Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Christian Kirisits
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Ravinder Nath
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Brown University School of Medicine, Providence, Rhode Island, USA
| | - Bruce R Thomadsen
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
| | - Marco Zaider
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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Berger D, Van Dyk S, Beaulieu L, Major T, Kron T. Modern Tools for Modern Brachytherapy. Clin Oncol (R Coll Radiol) 2023:S0936-6555(23)00182-6. [PMID: 37217434 DOI: 10.1016/j.clon.2023.05.003] [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: 10/14/2022] [Revised: 03/28/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023]
Abstract
This review aims to showcase the brachytherapy tools and technologies that have emerged during the last 10 years. Soft-tissue contrast using magnetic resonance and ultrasound imaging has seen enormous growth in use to plan all forms of brachytherapy. The era of image-guided brachytherapy has encouraged the development of advanced applicators and given rise to the growth of individualised 3D printing to achieve reproducible and predictable implants. These advances increase the quality of implants to better direct radiation to target volumes while sparing normal tissue. Applicator reconstruction has moved beyond manual digitising, to drag and drop of three-dimensional applicator models with embedded pre-defined source pathways, ready for auto-recognition and automation. The simplified TG-43 dose calculation formalism directly linked to reference air kerma rate of high-energy sources in the medium water remains clinically robust. Model-based dose calculation algorithms accounting for tissue heterogeneity and applicator material will advance the field of brachytherapy dosimetry to become more clinically accurate. Improved dose-optimising toolkits contribute to the real-time and adaptive planning portfolio that harmonises and expedites the entire image-guided brachytherapy process. Traditional planning strategies remain relevant to validate emerging technologies and should continue to be incorporated in practice, particularly for cervical cancer. Overall, technological developments need commissioning and validation to make the best use of the advanced features by understanding their strengths and limitations. Brachytherapy has become high-tech and modern by respecting tradition and remaining accessible to all.
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Affiliation(s)
- D Berger
- International Atomic Energy Agency, Vienna International Centre, Vienna, Austria.
| | - S Van Dyk
- Radiation Therapy Services, Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - L Beaulieu
- Service de Physique Médicale et Radioprotection, et Axe Oncologie du Centre de Recherche du CHU de Québec, CHU de Québec, Québec, Canada; Département de Physique, de Génie Physique et d'Optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Canada
| | - T Major
- Radiotherapy Centre, National Institute of Oncology, Budapest, Hungary; Department of Oncology, Semmelweis University, Budapest, Hungary
| | - T Kron
- Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
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Brand DH, Kirby AM, Yarnold JR, Somaiah N. How Low Can You Go? The Radiobiology of Hypofractionation. Clin Oncol (R Coll Radiol) 2022; 34:280-287. [PMID: 35260319 DOI: 10.1016/j.clon.2022.02.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/25/2022] [Accepted: 02/11/2022] [Indexed: 12/25/2022]
Abstract
Hypofractionated radical radiotherapy is now an accepted standard of care for tumour sites such as prostate and breast cancer. Much research effort is being directed towards more profoundly hypofractionated (ultrahypofractionated) schedules, with some reaching UK standard of care (e.g. adjuvant breast). Hypofractionation exerts varying influences on each of the major clinical end points of radiotherapy studies: acute toxicity, late toxicity and local control. This review will discuss these effects from the viewpoint of the traditional 5 Rs of radiobiology, before considering non-canonical radiobiological effects that may be relevant to ultrahypofractionated radiotherapy. The principles outlined here may assist the reader in their interpretation of the wealth of clinical data presented in the tumour site-specific articles in this special issue.
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Affiliation(s)
- D H Brand
- The Institute of Cancer Research, London, UK
| | - A M Kirby
- The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK
| | - J R Yarnold
- The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK
| | - N Somaiah
- The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK.
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Dosimetric and radiobiological investigation of permanent implant prostate brachytherapy based on Monte Carlo calculations. Brachytherapy 2019; 18:875-882. [PMID: 31400953 DOI: 10.1016/j.brachy.2019.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 06/18/2019] [Accepted: 06/24/2019] [Indexed: 11/23/2022]
Abstract
PURPOSE Permanent implant prostate brachytherapy plays an important role in prostate cancer treatment, but dose evaluations typically follow the water-based TG-43 formalism, ignoring patient anatomy and interseed attenuation. The purpose of this study is to investigate advanced TG-186 model-based dose calculations via retrospective dosimetric and radiobiological analysis for a new patient cohort. METHODS AND MATERIALS A cohort of 155 patients treated with permanent implant prostate brachytherapy from The Ottawa Hospital Cancer Centre is considered. Monte Carlo (MC) dose calculations are performed using tissue-based virtual patient models. Dose-volume histogram (DVH) metrics (target, organs at risk) are extracted from 3D dose distributions and compared with those from calculations under TG-43 assumptions (TG43). Equivalent uniform biologically effective dose and tumor control probability are calculated. RESULTS For the target, D90 (V100) is 136.7 ± 20.6 Gy (85.8% ± 7.8%) for TG43 and 132.8 ± 20.1 Gy (84.1% ± 8.2%) for MC; D90 is 3.0% ± 1.1% lower for MC than TG43. For organs at risk, MC D1cc = 104.4 ± 27.4 Gy (TG43: 106.3 ± 28.3 Gy) for rectum and 80.8 ± 29.7 Gy (TG43: 78.4 ± 28.4 Gy) for bladder; D1cc = 185.9 ± 30.2 Gy (TG43: 191.1 ± 32.0 Gy) for urethra. Equivalent uniform biologically effective dose and tumor control probability are generally lower when evaluated using MC doses. The largest dosimetric and radiobiological discrepancies between TG43 and MC are for patients with intraprostatic calcifications, for whom there are low doses (cold spots) in the vicinity of calcifications within the target, identified with MC but not TG43. CONCLUSIONS DVH metrics and radiobiological indices evaluated with TG43 are systematically inaccurate by upward of several percent compared with MC patient-specific models. Mean cohort DVH metrics and their MC:TG43 variances are sensitive to patient cohort and clinical practice, underlining the importance of further retrospective MC studies toward widespread clinical adoption of advanced model-based dose calculations.
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Clinical analysis of the approximate, 3-dimensional, biological effective dose equation in multiphase treatment plans. Med Dosim 2017; 43:11-22. [PMID: 28867367 DOI: 10.1016/j.meddos.2017.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 06/12/2017] [Accepted: 07/25/2017] [Indexed: 11/21/2022]
Abstract
A multiphase, approximate biological effective dose (BEDA) equation was introduced because most treatment planning systems (TPS) are incapable of calculating the true BED (BEDT). This work investigates the accuracy and precision of the multiphase BEDA relative to the BEDT in clinical cases. Ten patients with head and neck cancer and 10 patients with prostate cancer were studied using their treatment plans from Pinnacle3 9.2 (Philips Medical, Fitchburg, WI). The organs at risk (OARs) that were studied are the normal brain, left and right optic nerves, optic chiasm, spinal cord, brainstem, bladder, and rectum. BEDA and BEDT distributions were calculated using MATLAB 2010b (MathWorks, Natick, MA) and analyzed on a voxel basis for percent error, percent error volume histograms (PEVHs), Pearson correlation coefficient, and Bland-Altman analysis. The maximum BED values that were calculated using the BEDA and BEDT methods were also analyzed. BEDA was found to always underestimate BEDT. The accuracy and precision of BEDA distributions varied between the organs: for optic chiasm and brainstem, 50% of the patients had an overall BEDA percent error of <1%; for left and right optic nerves, rectum, and bladder, 60% to 70% of the patients had an overall BEDA percent error of <1%; and for normal brain and spinal cord, 80% of the patients had an overall BEDA percent error of <1%. BEDA distributions had maximum errors ranging from 2% to 11%, with the 11% error occurring for bladder. BEDA produced much more accurate maximum BED values with adjacent organs such as normal brain, bladder, and rectum. This study has shown that BEDA can calculate BED distributions with acceptable accuracy under certain circumstances. However, its consistency and accuracy strongly depend on the dose distributions of the different treatment phases. One should be cautious when using BEDA.
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Miksys N, Haidari M, Vigneault E, Martin AG, Beaulieu L, Thomson RM. Coupling I-125 permanent implant prostate brachytherapy Monte Carlo dose calculations with radiobiological models. Med Phys 2017; 44:4329-4340. [PMID: 28455849 DOI: 10.1002/mp.12306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/23/2016] [Accepted: 04/04/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the coupling of radiobiological models with patient-specific Monte Carlo (MC) dose calculations for permanent implant prostate brachytherapy (PIPB). To compare radiobiological indices evaluated with different radiobiological models using MC and simulated AAPM TG-43 dose calculations. METHODS Three-dimensional dose distributions previously computed using MC techniques with two types of patient models, TG43sim (AAPM TG-43 water-based conditions) and MCDmm (realistic tissues and interseed effects), for 613 PIPB patients are coupled with biological dose and tumour control probability (TCP) models. Two approaches and their extensions are considered to evaluate biological doses, biologically effective dose (BED) and isoeffective dose (IED), as well as two methods to evaluate TCP. Three novel extensions of equivalent uniform biologically effective dose (EUBED) are suggested which consider the spatial distribution of doses within the target volume. Adopted radiobiological model parameter values (α, β, etc) are those suggested by AAPM TG-137, and sensitivity to parameter choice is discussed. RESULTS MCDmm dose calculations can reveal low doses in the prostate target volume, due to tissue heterogeneities or inter-seed effects; considering these low doses in EUBED calculations can lower TCP estimates by up to 70%, with largest differences in patients with calcifications. There are large variations in biological doses and TCPs evaluated over the 613 patient cohort for each radiobiological model considered, reflecting the spectrum of physical doses calculated for these patients with either MCDmm or TG43sim. Depending on the model details, BED, IED and EUBED are, on average, 6.0-9.8%, 7.4-9.2% and 1.8-15% higher, respectively, with TG43sim than MCDmm. TCP estimates computed using MCDmm dose distributions are much lower than expected based on past treatment outcome studies, suggesting a need to re-assess model parameters when evaluating radiobiological indices coupled with heterogeneous tissue model-based dose calculations. CONCLUSIONS Cohort average differences in biological dose and TCP estimates between radiobiological models are generally larger than differences for any one radiobiological model evaluated with TG43sim or MCDmm dose calculations. However, heterogeneous tissue dose calculations, like MCDmm, can identify clinically-relevant low dose volumes, e.g., in patients with calcifications, which would otherwise be missed with TG-43. In addition to affecting physical dose distributions, these low dose volumes can largely impact radiobiological dose and TCP estimates, which further motivates the clinical implementation of model-based dose calculations for PIPB.
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Affiliation(s)
- Nelson Miksys
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Mehan Haidari
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Eric Vigneault
- Centre de recherche sur le cancer, Université Laval, Québec, QC, G1R 3S3, Canada.,Département de Radio-Oncologie et Centre de recherche du CHU de Québec, Québec, QC, G1R 2J6, Canada
| | - Andre-Guy Martin
- Centre de recherche sur le cancer, Université Laval, Québec, QC, G1R 3S3, Canada.,Département de Radio-Oncologie et Centre de recherche du CHU de Québec, Québec, QC, G1R 2J6, Canada
| | - Luc Beaulieu
- Département de Radio-Oncologie et Centre de recherche du CHU de Québec, Québec, QC, G1R 2J6, Canada.,Département de Physique et Centre de recherche sur le cancer, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, ON, K1S 5B6, Canada
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Boonstra PS, Taylor JMG, Smolska-Ciszewska B, Behrendt K, Dworzecki T, Gawkowska-Suwinska M, Bialas B, Suwinski R. Alpha/beta (α/β) ratio for prostate cancer derived from external beam radiotherapy and brachytherapy boost. Br J Radiol 2016; 89:20150957. [PMID: 26903392 DOI: 10.1259/bjr.20150957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE There is disagreement regarding the value of the α/β ratio for prostate cancer. Androgen deprivation therapy (ADT) may dominate the effects of dose fractionation on prostate-specific antigen (PSA) response and confound estimates of the α/β ratio. We estimate this ratio from combined data on external beam radiation therapy (EBRT) and brachytherapy (BT)-treated patients, providing a range of doses per fraction, while accounting for the effects of ADT. METHODS We analyse data on 289 patients with local prostate cancer treated with EBRT (2 Gy per fraction) or EBRT plus one or two BT boosts of 10 Gy each. The timing of ADT was heterogeneous. We develop statistical models to estimate the α/β ratio based upon PSA measurements at 1 year as a surrogate for the surviving fraction of cancer cells as well as combined biochemical + clinical recurrence-free survival (bcRFS), controlling for ADT. RESULTS For the PSA-based end point, the α/β ratio estimate is 7.7 Gy [95% confidence interval (CI): 4.1 to 12.5]. Based on the bcRFS end point, the estimate is 18.0 Gy (95% CI: 8.2 to ∞). CONCLUSION Our model-based estimates of the α/β ratio, which account for the effects of ADT and other important confounders, are higher than some previous estimates. ADVANCES IN KNOWLEDGE Although dose inhomogeneities and other limitations may limit the scope of our findings, the data suggest caution regarding the assumptions of the α/β ratio for prostate cancer in some clinical environments.
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Affiliation(s)
- Philip S Boonstra
- 1 Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Jeremy M G Taylor
- 1 Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Beata Smolska-Ciszewska
- 2 Radiotherapy Clinic and Teaching Hospital, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
| | - Katarzyna Behrendt
- 2 Radiotherapy Clinic and Teaching Hospital, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
| | - Tomasz Dworzecki
- 2 Radiotherapy Clinic and Teaching Hospital, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
| | - Marzena Gawkowska-Suwinska
- 2 Radiotherapy Clinic and Teaching Hospital, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
| | - Brygida Bialas
- 3 Department of Brachytherapy, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
| | - Rafal Suwinski
- 2 Radiotherapy Clinic and Teaching Hospital, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Poland
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