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Robitaille M, Ménard C, Famulari G, Béliveau-Nadeau D, Enger SA. 169Yb-based high dose rate intensity modulated brachytherapy for focal treatment of prostate cancer. Brachytherapy 2024; 23:523-534. [PMID: 39038997 DOI: 10.1016/j.brachy.2024.05.005] [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: 10/27/2023] [Revised: 04/24/2024] [Accepted: 05/20/2024] [Indexed: 07/24/2024]
Abstract
PURPOSE This study compares conventional 192Ir-based high dose rate brachytherapy (HDR-BT) with 169Yb-based HDR intensity modulated brachytherapy (IMBT) for focal prostate cancer treatment. Additionally, the study explores the potential to generate less invasive treatment plans with IMBT by reducing the number of catheters needed to achieve acceptable outcomes. METHODS AND MATERIALS A retrospective dosimetric study of ten prostate cancer patients initially treated with conventional 192Ir-based HDR-BT and 5-14 catheters was employed. RapidBrachyMCTPS, a Monte Carlo-based treatment planning system was used to calculate and optimize dose distributions. For 169Yb-based HDR IMBT, a custom 169Yb source combined with 0.8 mm thick platinum shields placed inside 6F catheters was used. Furthermore, dose distributions were investigated when iteratively removing catheters for less invasive treatments. RESULTS With IMBT, the urethra D10 and D0.1cc decreased on average by 15.89 and 15.65 percentage points (pp) and the rectum V75 and D2cc by 1.53 and 11.54 pp, respectively, compared to the conventional clinical plans. Similar trends were observed when the number of catheters decreased. On average, there was an observed increase in PTV V150 from 2.84 pp with IMBT when utilizing all catheters to 8.83 pp when four catheters were removed. PTV V200 increased from 0.42 to 2.96 pp on average. Hotspots in the body were however lower with IMBT compared to conventional clinical plans. CONCLUSIONS 169Yb-based HDR IMBT for focal treatment of prostate cancer has the potential to successfully deliver clinically acceptable, less invasive treatment with reduced dose to organs at risk.
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Affiliation(s)
- Maude Robitaille
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada; Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
| | - Cynthia Ménard
- Department of Radiation Oncology, CHUM, Montreal, Quebec, Canada
| | - Gabriel Famulari
- Department of Radiation Oncology, Jewish General Hospital, Montreal, Quebec, Canada; Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | | | - Shirin A Enger
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada; Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
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2
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Aloraibi HA, Siavashpour Z, Ghorbani M, Abtahi M, Jassim H, Gholami S. Evaluating dose distributions of high dose rate 60Co brachytherapy in an asymmetric tumor: A comparison of different designs of vaginal cylindrical applicators. Appl Radiat Isot 2024; 204:111124. [PMID: 38029638 DOI: 10.1016/j.apradiso.2023.111124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 11/21/2023] [Accepted: 11/21/2023] [Indexed: 12/01/2023]
Abstract
The aim of this study is to evaluate organ-at-risk (OAR) doses obtained from different designs of intracavitary cylinder applicators during high-dose-rate (HDR) brachytherapy of an asymmetric vaginal tumor. Dose distributions around five cylinder applicators were obtained using the Geant4 toolkit. Three of these applicators are commercially available: single-channel, multi-channel, and shielded. Additionally, two proposed sub-configurations were evaluated: (I) a combination of the multichannel applicator with a central shield and (II) a dynamically modulated cylinder (DMC). The dose distributions of the proposed applicators were compared to those of the single-channel cylinder applicator. The results showed that using a cylindrical applicator with a higher degree of freedom in plan optimization can improve OAR, sparing up to 60% for the rectum and 20% for the bladder. In conclusion, this work suggests using a new design of a cylindrical applicator to enhance the therapeutic ratio of brachytherapy for asymmetric and irregularly shaped vaginal tumors.
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Affiliation(s)
- Hayder Adil Aloraibi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Siavashpour
- Radiotherapy Oncology Department, Shohada-e Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahdi Ghorbani
- Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marzieh Abtahi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Hussam Jassim
- Department of Radiotherapy Physics, General Al-Najaf Hospital, Najaf, Iraq
| | - Somayeh Gholami
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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3
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aloraibi HA, Siavashpour Z, Ghorbani M, Abtahi M, jassim H, Gholami S. Evaluating dose distributions of high dose rate 60Co brachytherapy in an asymmetric tumor: A comparison of different designs of vaginal cylindrical applicators. Appl Radiat Isot 2023:111124. [DOI: https:/doi.org/10.1016/j.apradiso.2023.111124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
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4
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Hopfensperger KM, Adams QE, Kim Y, Wu X, Xu W, Patwardhan K, Flynn RT. The population percentile allowance method for determining systematic spatial error tolerances for temporary intensity modulated brachytherapy. Med Phys 2023; 50:6469-6478. [PMID: 37643427 PMCID: PMC10592112 DOI: 10.1002/mp.16668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 07/03/2023] [Accepted: 07/18/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Multiple approaches are under development for delivering temporary intensity modulated brachytherapy (IMBT) using partially shielded applicators wherein the delivered dose distributions are sensitive to spatial uncertainties in both the applicator position and shield orientation, rather than only applicator position as with conventional high-dose-rate brachytherapy (HDR-BT). Sensitivity analyses to spatial uncertainties have been reported as components of publications on these emerging technologies, however, a generalized framework for the rigorous determination of the spatial uncertainty tolerances of dose-volume parameters is needed. PURPOSE To derive and present the population percentile allowance (PPA) method, a generalized mathematical and statistical framework to evaluate the tolerance of temporary IMBT approaches to spatial uncertainties in applicator position and shield orientation. METHODS A mathematical formalism describing geometric applicator position and shield orientation shifts was derived that supports straight and curved applicators and applies to serial and helical rotating shield brachytherapy (RSBT) and direction modulated brachytherapy (DMBT). The PPA method entails defining the percentage of a patient population receiving a given therapy that is, allowed to receive dose-volume errors in the target volume and specified organs at risk of a defined percentage or less, then determining what combinations of applicator position and shield orientation systematic errors would be expected to produce that outcome in the population. The PPA method was applied to the use case of multi-shield helical 169 Yb-based RSBT for cervical cancer, with 45° and 180° shield emission angles. A total of 37 cervical cancer patients were considered in the population, with average (± 1 standard deviation) HR-CTV volumes of 79 cm3 ± 37 cm3 and optimized baseline treatment plans (no spatial uncertainties applied) created for each patient to meet dose-volume requirements of 85 GyEQD2 (equivalent uniform dose in 2 Gy fraction), with D2cc tolerance doses of 90 GyEQD2 , 75 GyEQD2 , and 75 GyEQD2 for bladder, rectum, and sigmoid colon, respectively. RESULTS For the PPA requirement that 90% of cervical cancer patients receiving multi-shield helical RSBT could have a maximum dose-volume uncertainty of 10% for high-risk clinical target volume (HR-CTV) D90 (minimum dose to hottest 90%) and bladder, rectum, and sigmoid colon D2cc (minimum dose to hottest 2 cm3 ), the tolerance systematic applicator position and shield orientation uncertainties were approximately ± 1.0 mm and ± 4.25°, respectively. For ± 1.5 mm and ± 5° systematic applicator position and shield orientation tolerances, 90% of the patients considered would have a maximum dose-volume uncertainty of 12.8% or less. CONCLUSION The PPA method was formalized to determine the temporary IMBT spatial uncertainty tolerances that would be expected to result in an allowed percentage of a population of patients receiving relative dose-volume errors above a defined percentage. Multi-shield, helical 169 Yb-based RSBT for cervical cancer was evaluated and tolerances determined, which, if applied on each treatment fraction, would represent an extreme situation. The PPA method is applicable to a variety of temporary IMBT approaches and can be used to rigorously determine the design parameters for the delivery systems such as mechanical driver motor accuracy, shield angle backlash, applicator rotation, and applicator fixation stability.
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Affiliation(s)
| | - Quentin E Adams
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, USA
| | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, USA
| | - Xiaodong Wu
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, USA
- Department of Electrical and Computer Engineering, Seamans Center for the Engineering Arts and Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Weiyu Xu
- Department of Electrical and Computer Engineering, Seamans Center for the Engineering Arts and Sciences, University of Iowa, Iowa City, Iowa, USA
| | | | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, USA
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5
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Beaulieu L, Ballester F, Granero D, Tedgren ÅC, Haworth A, Lowenstein JR, Ma Y, Mourtada F, Papagiannis P, Rivard MJ, Siebert FA, Sloboda RS, Smith RL, Thomson RM, Verhaegen F, Fonseca G, Vijande J. AAPM WGDCAB Report 372: A joint AAPM, ESTRO, ABG, and ABS report on commissioning of model-based dose calculation algorithms in brachytherapy. Med Phys 2023; 50:e946-e960. [PMID: 37427750 DOI: 10.1002/mp.16571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 07/11/2023] Open
Abstract
The introduction of model-based dose calculation algorithms (MBDCAs) in brachytherapy provides an opportunity for a more accurate dose calculation and opens the possibility for novel, innovative treatment modalities. The joint AAPM, ESTRO, and ABG Task Group 186 (TG-186) report provided guidance to early adopters. However, the commissioning aspect of these algorithms was described only in general terms with no quantitative goals. This report, from the Working Group on Model-Based Dose Calculation Algorithms in Brachytherapy, introduced a field-tested approach to MBDCA commissioning. It is based on a set of well-characterized test cases for which reference Monte Carlo (MC) and vendor-specific MBDCA dose distributions are available in a Digital Imaging and Communications in Medicine-Radiotherapy (DICOM-RT) format to the clinical users. The key elements of the TG-186 commissioning workflow are now described in detail, and quantitative goals are provided. This approach leverages the well-known Brachytherapy Source Registry jointly managed by the AAPM and the Imaging and Radiation Oncology Core (IROC) Houston Quality Assurance Center (with associated links at ESTRO) to provide open access to test cases as well as step-by-step user guides. While the current report is limited to the two most widely commercially available MBDCAs and only for 192 Ir-based afterloading brachytherapy at this time, this report establishes a general framework that can easily be extended to other brachytherapy MBDCAs and brachytherapy sources. The AAPM, ESTRO, ABG, and ABS recommend that clinical medical physicists implement the workflow presented in this report to validate both the basic and the advanced dose calculation features of their commercial MBDCAs. Recommendations are also given to vendors to integrate advanced analysis tools into their brachytherapy treatment planning system to facilitate extensive dose comparisons. The use of the test cases for research and educational purposes is further encouraged.
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Affiliation(s)
- Luc Beaulieu
- Service de Physique Médicale et Radioprotection et Axe Oncologie du Centre de Recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Québec, Canada
- Département de Physique, de Génie Physique et d'Optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Québec, Canada
| | - Facundo Ballester
- Departamento de Física Atómica, Molecular y Nuclear, IRIMED, IIS-La Fe-Universitat de Valencia, Burjassot, Spain
| | - Domingo Granero
- Departamento de Física Atómica, Molecular y Nuclear, IRIMED, IIS-La Fe-Universitat de Valencia, Burjassot, Spain
| | - Åsa Carlsson Tedgren
- Department of Health, Medicine and Caring Sciences (HMV), Radiation Physics, Linköping University, Linköping, Sweden
- Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
- Department of Oncology Pathology, Karolinska Institute, Stockholm, Sweden
| | | | - Jessica R Lowenstein
- Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, Texas, USA
| | - Yunzhi Ma
- Service de Physique Médicale et Radioprotection et Axe Oncologie du Centre de Recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Québec, Canada
- Département de Physique, de Génie Physique et d'Optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Québec, Canada
| | - Firas Mourtada
- Department of Radiation Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Panagiotis Papagiannis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Mark J Rivard
- Department of Radiation Oncology, Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Frank-André Siebert
- Clinic of Radiotherapy, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Ron S Sloboda
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Ryan L Smith
- Alfred Health Radiation Oncology, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada
| | - Frank Verhaegen
- Department of Radiation Oncology (MAASTRO), GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Gabriel Fonseca
- Department of Radiation Oncology (MAASTRO), GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Javier Vijande
- Departamento de Física Atómica, Molecular y Nuclear, IRIMED, IIS-La Fe-Universitat de Valencia, Burjassot, Spain
- Instituto de Física Corpuscular, IFIC (UV-CSIC), Burjassot, Spain
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6
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Antaki M, Renaud MA, Morcos M, Seuntjens J, Enger SA. Applying the column generation method to the intensity modulated high dose rate brachytherapy inverse planning problem. Phys Med Biol 2023; 68. [PMID: 36791469 DOI: 10.1088/1361-6560/acbc63] [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: 12/28/2021] [Accepted: 02/15/2023] [Indexed: 02/17/2023]
Abstract
Objective.Intensity modulated high dose rate brachytherapy (IMBT) is a rapidly developing application of brachytherapy where anisotropic dose distributions can be produced at each source dwell position. This technique is made possible by placing rotating metallic shields inside brachytherapy needles or catheters. By dynamically directing the radiation towards the tumours and away from the healthy tissues, a more conformal dose distribution can be obtained. The resulting treatment planning involves optimizing dwell position and shield angle (DPSA). The aim of this study was to investigate the column generation method for IMBT treatment plan optimization.Approach.A column generation optimization algorithm was developed to optimize the dwell times and shield angles. A retrospective study was performed on 10 prostate cases using RapidBrachyMCTPS. At every iteration, the plan was optimized with the chosen DPSA which would best improve the cost function that was added to the plan. The optimization process was stopped when the remaining DPSAs would not add value to the plan to limit the plan complexity.Main results.The average number of DPSAs and voxels were 2270 and 7997, respectively. The column generation approach yielded near-optimal treatment plans by using only 11% of available DPSAs on average in ten prostate cases. The coverage and organs at risk constraints passed in all ten cases.Significance.The column generation method produced high-quality deliverable prostate IMBT plans. The treatment plan quality reached a plateau, where adding more DPSAs had a minimal effect on dose volume histogram parameters. The iterative nature of the column generation method allows early termination of the treatment plan creation process as soon as the dosimetric indices from dose volume histogram satisfy the clinical requirements or if their values stabilize.
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Affiliation(s)
- Majd Antaki
- Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Marc-André Renaud
- Polytechnique Montréal, Department of Mathematical and Industrial Engineering, Montreal, Canada
| | - Marc Morcos
- Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, H4A 3J1, Canada.,Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, United States of America.,Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States of America
| | - Jan Seuntjens
- Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, H4A 3J1, Canada.,Research Institute of the McGill University Health Centre, Montreal, Quebec, H3H 2L9, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, H3T 1E2, Canada
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7
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Morén B, Antaki M, Famulari G, Morcos M, Larsson T, Enger SA, Tedgren ÅC. Dosimetric impact of a robust optimization approach to mitigate effects from rotational uncertainty in prostate intensity-modulated brachytherapy. Med Phys 2023; 50:1029-1043. [PMID: 36478226 DOI: 10.1002/mp.16134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 10/17/2022] [Accepted: 11/01/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Intensity-modulated brachytherapy (IMBT) is an emerging technology for cancer treatment, in which radiation sources are shielded to shape the dose distribution. The rotatable shields provide an additional degree of freedom, but also introduce an additional, directional, type of uncertainty, compared to conventional high-dose-rate brachytherapy (HDR BT). PURPOSE We propose and evaluate a robust optimization approach to mitigate the effects of rotational uncertainty in the shields with respect to planning criteria. METHODS A previously suggested prototype for platinum-shielded prostate 169 Yb-based dynamic IMBT is considered. We study a retrospective patient data set (anatomical contours and catheter placement) from two clinics, consisting of six patients that had previously undergone conventional 192 Ir HDR BT treatment. The Monte Carlo-based treatment planning software RapidBrachyMCTPS is used for dose calculations. In our computational experiments, we investigate systematic rotational shield errors of ±10° and ±20°, and the same systematic error is applied to all dwell positions in each scenario. This gives us three scenarios, one nominal and two with errors. The robust optimization approach finds a compromise between the average and worst-case scenario outcomes. RESULTS We compare dose plans obtained from standard models and their robust counterparts. With dwell times obtained from a linear penalty model (LPM), for 10° errors, the dose to urethra ( D 0.1 c c $D_{0.1cc}$ ) and rectum ( D 0.1 c c $D_{0.1cc}$ and D 1 c c $D_{1cc}$ ) increase with up to 5% and 7%, respectively, in the worst-case scenario, while with the robust counterpart, the corresponding increases were 3% and 3%. For all patients and all evaluated criteria, the worst-case scenario outcome with the robust approach had lower deviation compared to the standard model, without compromising target coverage. We also evaluated shield errors up to 20° and while the deviations increased to a large extent with the standard models, the robust models were capable of handling even such large errors. CONCLUSIONS We conclude that robust optimization can be used to mitigate the effects from rotational uncertainty and to ensure the treatment plan quality of IMBT.
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Affiliation(s)
- Björn Morén
- Department of Mathematics, Linköping University, Linköping, Sweden
| | - Majd Antaki
- Department of Oncology, Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Gabriel Famulari
- Department of Oncology, Medical Physics Unit, McGill University, Montreal, QC, Canada.,Département de Radio-oncologie, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - Marc Morcos
- Department of Oncology, Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Torbjörn Larsson
- Department of Mathematics, Linköping University, Linköping, Sweden
| | - Shirin A Enger
- Department of Oncology, Medical Physics Unit, McGill University, Montreal, QC, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Åsa Carlsson Tedgren
- Radiation Physics, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden.,Department of Oncology Pathology, Karolinska Institute, Stockholm, Sweden
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8
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Melhus CS, Simiele SJ, Aima M, Richardson S. Learning from the past: a century of accuracy, aspirations, and aspersions in brachytherapy. Br J Radiol 2022; 95:20220500. [PMID: 35969474 PMCID: PMC9733622 DOI: 10.1259/bjr.20220500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 11/05/2022] Open
Abstract
The oldest form of radiation therapy, brachytherapy, has been investigated and reported in the scientific and medical literature for well over a century. Known by many names over the years, radium-based, empirical practices evolved over decades to contemporary practice. This includes treatment at various dose rates using multiple radionuclides or even electrically generated photon sources. Predictions or prognostications of what may happen in the future enjoy a history that spans centuries, e.g. those by Nostradamus in the 1500s. In this review article, publications from several eras of past practice between the early 1900s and the late 2010s where the authors address the "future of brachytherapy" are presented, and for many of these publications, one can use the benefit of the intervening years to comment on the accuracy or the inaccuracies inherent in those publications. Finally, recently published papers are reviewed to examine current expectations for the future practice of brachytherapy.
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Affiliation(s)
- Christopher S Melhus
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts
| | - Samantha J Simiele
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Manik Aima
- Department of Radiation Oncology, Stanford University, Stanford, California, United States
| | - Susan Richardson
- Department of Radiation Oncology, Swedish Medical Center, Seattle, Washington, United States
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9
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A Novel Workflow with a Customizable 3D Printed Vaginal Template and a Direction Modulated Brachytherapy (DMBT) Tandem Applicator for Adaptive Interstitial Brachytherapy of the Cervix. J Clin Med 2022; 11:jcm11236989. [PMID: 36498563 PMCID: PMC9738087 DOI: 10.3390/jcm11236989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/21/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
A novel clinical workflow utilizing a direction modulated brachytherapy (DMBT) tandem applicator in combination with a patient-specific, 3D printed vaginal needle-track template for an advanced image-guided adaptive interstitial brachytherapy of the cervix. The proposed workflow has three main steps: (1) pre-treatment MRI, (2) an initial optimization of the needle positions based on the DMBT tandem positioning and patient anatomy, and a subsequent inverse optimization using the combined DMBT tandem and needles, and (3) rapid 3D printing. We retrospectively re-planned five patient cases for two scenarios; one plan with the DMBT tandem (T) and ovoids (O) with the original needle (ND) positions (DMBT + O + ND) and another with the DMBT T&O and spatially reoptimized needles (OptN) positions (DMBT + O + OptN). All retrospectively reoptimized plans have been compared to the original plan (OP) as well. The accuracy of 3D printing was verified through the image registration between the planning CT and the CT of the 3D-printed template. The average difference in D2cc for the bladder, rectum, and sigmoid between the OPs and DMBT + O + OptNs were -8.03 ± 4.04%, -18.67 ± 5.07%, and -26.53 ± 4.85%, respectively. In addition, these average differences between the DMBT + O + ND and DMBT + O + OptNs were -2.55 ± 1.87%, -10.70 ± 3.45%, and -22.03 ± 6.01%, respectively. The benefits could be significant for the patients in terms of target coverage and normal tissue sparing and increase the optimality over free-hand needle positioning.
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10
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Joya M, Nedaie HA, Geraily G, Seiri M, Ghorbani M, Sheikhzadeh P. Intensity-modulated brachytherapy for vaginal cancer. Radiol Phys Technol 2022; 15:387-397. [PMID: 36069978 DOI: 10.1007/s12194-022-00680-4] [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: 04/15/2022] [Revised: 08/27/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
Abstract
This study aimed to evaluate the dose modulation potential of static and dynamic steel-shielded applicators using the Geant4 Application for Emission Tomography (GATE) Monte Carlo code for the treatment of vaginal cancer. The GATE TOOLKIT (version 9.0) was used to simulate vaginal cancer intensity-modulated brachytherapy (IMBT) in a pelvic water-equivalent phantom. IMBT performance of a multichannel static and single-channel dynamic steel-shielded applicator was compared to that of a conventional multichannel Plexiglas applicator. DoseActors were defined to calculate the absorbed dose and attached to the voxelized target and organs at risk (OARs). 60Co and 192Ir high-dose-rate seeds were used as irradiation sources. Dynamic IMBT decreased the D2cc of the rectum and bladder by 28.67 and 28.11% using the 60Co source and by 40.00 and 36.34% using the 192Ir source, respectively. Static IMBT decreased the D2cc for the rectum and bladder by 11.69 and 9.29% using the 60Co source and by 22.21 and 17.71% using the 192Ir source, respectively. In contrast, absorbed dose parameters (D5, D90, and D100) for the target in the three techniques showed a mean relative variation of 0.96% (0.00-7.49%) for both sources. Static and dynamic IMBT using steel-shielded applicators provided relatively better OAR protection while maintaining similar target coverage in the treatment of vaginal cancer.
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Affiliation(s)
- Musa Joya
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran. .,Radiology Department, Kabul University of Medical Sciences, Kabul, Afghanistan.
| | - Hassan Ali Nedaie
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghazale Geraily
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahnaz Seiri
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahdi Ghorbani
- Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Peyman Sheikhzadeh
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Department of Nuclear Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
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11
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De Sanctis V, Facondo G, Vullo G. Principles and indications of brachytherapy. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00063-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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12
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Kim H, Goh Y, Kim DW, Kim JS, Lim YK. Integration of rotatable tandem applicator to conventional ovoid applicator toward complete framework of intensity modulated brachytherapy (IMBT) for cervical cancer. Phys Med 2021; 91:131-139. [PMID: 34800907 DOI: 10.1016/j.ejmp.2021.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/29/2021] [Accepted: 10/31/2021] [Indexed: 10/19/2022] Open
Abstract
A new tandem applicator with tungsten shield for Ir-192 radiation source used in intra-cavitary brachytherapy (ICBT) enabled intensity modulated brachytherapy (IMBT) in cervical cancer treatment through fluence-modulation by rotating shield. Our previous work employed group-wise and element-wise sparsity constraints for plan optimization of tandem applicator to minimizes the number of activated angles and source dwell points for delivery efficiency. It, however, did not incorporate the ovoid applicators into the optimizing process, which is generally used to prevent cancer recurrence. To integrate ovoid applicators to the new tandem applicator, this work proposed a comprehensive framework that modifies 1) dose deposition matrix for inverse planning, and 2) plan optimizing algorithm. The dose deposition matrix was newly formulated by the Monte-Carlo simulated dose distribution for 10 positions of ovoid applicators, followed by combining those with tandem-associated dose deposition matrix. The plan optimizing algorithm decomposed entire elements into tandem and ovoid applicators, which were governed by different constraints adaptive to specified plan objectives. The integrated framework was compared against conventional ICBT, and IMBT with tandem only for three patients with asymmetric dose distributions. Integrated IMBT framework resulted in the most optimal plans. Including fluence-modulation by rotating-shield outperformed conventional ICBT in dose sparing to critical organs. Adopting ovoid applicators to the optimization yielded more conformal dose distribution around inferior, laterally expanded region of target volume. The resulting plans reduced D5cc and D2cc by 30.9% and 27.8% for critical organs over conventional ICBT, and by 20.6% and 21.5% for target volume over IMBT with tandem only.
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Affiliation(s)
- Hojin Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Youngmoon Goh
- Department of Radiation Oncology, Asan Medical Center, Seoul, South Korea
| | - Dong Wook Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea.
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang, South Korea.
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Park H, Paganetti H, Schuemann J, Jia X, Min CH. Monte Carlo methods for device simulations in radiation therapy. Phys Med Biol 2021; 66:10.1088/1361-6560/ac1d1f. [PMID: 34384063 PMCID: PMC8996747 DOI: 10.1088/1361-6560/ac1d1f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/12/2021] [Indexed: 11/12/2022]
Abstract
Monte Carlo (MC) simulations play an important role in radiotherapy, especially as a method to evaluate physical properties that are either impossible or difficult to measure. For example, MC simulations (MCSs) are used to aid in the design of radiotherapy devices or to understand their properties. The aim of this article is to review the MC method for device simulations in radiation therapy. After a brief history of the MC method and popular codes in medical physics, we review applications of the MC method to model treatment heads for neutral and charged particle radiation therapy as well as specific in-room devices for imaging and therapy purposes. We conclude by discussing the impact that MCSs had in this field and the role of MC in future device design.
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Affiliation(s)
- Hyojun Park
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Xun Jia
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75235, United States of America
| | - Chul Hee Min
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
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14
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Morén B, Larsson T, Tedgren ÅC. Optimization in treatment planning of high dose-rate brachytherapy - Review and analysis of mathematical models. Med Phys 2021; 48:2057-2082. [PMID: 33576027 DOI: 10.1002/mp.14762] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/12/2020] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Treatment planning in high dose-rate brachytherapy has traditionally been conducted with manual forward planning, but inverse planning is today increasingly used in clinical practice. There is a large variety of proposed optimization models and algorithms to model and solve the treatment planning problem. Two major parts of inverse treatment planning for which mathematical optimization can be used are the decisions about catheter placement and dwell time distributions. Both these problems as well as integrated approaches are included in this review. The proposed models include linear penalty models, dose-volume models, mean-tail dose models, quadratic penalty models, radiobiological models, and multiobjective models. The aim of this survey is twofold: (i) to give a broad overview over mathematical optimization models used for treatment planning of brachytherapy and (ii) to provide mathematical analyses and comparisons between models. New technologies for brachytherapy treatments and methods for treatment planning are also discussed. Of particular interest for future research is a thorough comparison between optimization models and algorithms on the same dataset, and clinical validation of proposed optimization approaches with respect to patient outcome.
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Affiliation(s)
- Björn Morén
- Department of Mathematics, Linköping University, Linköping, Sweden
| | - Torbjörn Larsson
- Department of Mathematics, Linköping University, Linköping, Sweden
| | - Åsa Carlsson Tedgren
- Radiation Physics, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden.,Department of Oncology Pathology, Karolinska Institute, Stockholm, Sweden
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15
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Morcos M, Antaki M, Viswanathan AN, Enger SA. A novel minimally invasive dynamic-shield, intensity-modulated brachytherapy system for the treatment of cervical cancer. Med Phys 2020; 48:71-79. [PMID: 32916763 DOI: 10.1002/mp.14459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/14/2020] [Accepted: 08/06/2020] [Indexed: 12/26/2022] Open
Abstract
PURPOSE To present a novel, MRI-compatible dynamicshield intensity modulated brachytherapy (IMBT) applicator and delivery system using 192 Ir, 75 Se, and 169 Yb radioisotopes for the treatment of locally advanced cervical cancer. Needle-free IMBT is a promising technique for improving target coverage and organs at risk (OAR) sparing. METHODS AND MATERIALS The IMBT delivery system dynamically controls the rotation of a novel tungsten shield placed inside an MRI-compatible, 6-mm wide intrauterine tandem. Using 36 cervical cancer cases, conventional intracavitary brachytherapy (IC-BT) and intracavitary/interstitial brachytherapy (IC/IS-BT) (10Ci 192 Ir) plans were compared to IMBT (10Ci 192 Ir; 11.5Ci 75 Se; 44Ci 169 Yb). All plans were generated using the Geant4-based Monte Carlo dose calculation engine, RapidBrachyMC. Treatment plans were optimized then normalized to the same high-risk clinical target volume (HR-CTV) D90 and the D2cc for bladder, rectum, and sigmoid in the research brachytherapy planning system, RapidBrachyMCTPS. Plans were renormalized until either of the three OAR reached dose limits to calculate the maximum achievable HR-CTV D90 and D98 . RESULTS Compared to IC-BT, IMBT with either of the three radionuclides significantly improves the HR-CTV D90 and D98 by up to 5.2% ± 0.3% (P < 0.001) and 6.7% ± 0.5% (P < 0.001), respectively, with the largest dosimetric enhancement when using 169 Yb followed by 75 Se and then 192 Ir. Similarly, D2cc for all OAR improved with IMBT by up to 7.7% ± 0.6% (P < 0.001). For IC/IS-BT cases, needle-free IMBT achieved clinically acceptable plans with 169 Yb-based IMBT further improving HR-CTV D98 by 1.5% ± 0.2% (P = 0.034) and decreasing sigmoid D2cc by 1.9% ± 0.4% (P = 0.048). Delivery times for IMBT are increased by a factor of 1.7, 3.3, and 2.3 for 192 Ir, 75 Se, and 169 Yb, respectively, relative to conventional 192 Ir BT. CONCLUSIONS Dynamic shield IMBT provides a promising alternative to conventional IC- and IC/IS-BT techniques with significant dosimetric enhancements and even greater improvements with intermediate energy radionuclides. The ability to deliver a highly conformal, OAR-sparing dose without IS needles provides a simplified method for improving the therapeutic ratio less invasively and in a less resource intensive manner.
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Affiliation(s)
- Marc Morcos
- Medical Physics Unit, McGill University, Montreal, QC, Canada
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Majd Antaki
- Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Akila N Viswanathan
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Shirin A Enger
- Medical Physics Unit, McGill University, Montreal, QC, Canada
- Department of Oncology, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
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16
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Skinner LB, Niedermayr T, Prionas N, Perl J, Fahimian B, Kidd EA. Intensity modulated Ir-192 brachytherapy using high-Z 3D printed applicators. Phys Med Biol 2020; 65:155018. [PMID: 32521512 DOI: 10.1088/1361-6560/ab9b54] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Gynecologic cancers are often asymmetric, yet current Ir-192 brachytherapy techniques provide only limited radial modulation of the dose. The shielded solutions investigated here solve this by providing the ability to modulate between highly asymmetric and radially symmetric dose distributions at a given location. To find applicator designs that can modulate between full dose and less than 50% dose, at the dimensions of the urethra, a 2D calculation algorithm was developed to narrow down the search space. Two shielding design types were then further investigated using Monte Carlo and Boltzmann-solver dose calculation algorithms. 3D printing techniques using ISO 10993 certified biocompatible plastics and 3D printable tungsten-loaded plastics were tested. It was also found that shadowing effects set by the shape of the shielding cannot be easily modulated out, hence careful design is required. The shielded applicator designs investigated here, allow for reduction of the dose by over 50% at 5 mm from the applicator surface in desired regions, while also allowing radially symmetric dose with isodose line deviations less than 0.5 mm from circular. The shielding designs were also chosen with treatment delivery time in mind. Treatment times for these shielded designs were found to be less than 1.4 times longer than a 6-channel unshielded cylinder for the equivalent fully symmetric dose distribution. The 2D calculation methods developed here provide a simple way to rapidly evaluate shielding designs, while the 3D printing techniques also allow for devices with novel shapes to be rapidly prototyped. Both TOPAS Monte Carlo and Acuros BV calculations show that significant dose shaping and organ at risk sparing can be achieved without significantly compromising the plan in regions that require the full dose.
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Affiliation(s)
- Lawrie B Skinner
- Radiation Oncology, Stanford University, Stanford, CA, United States of America
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17
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Plan optimization with L0-norm and group sparsity constraints for a new rotational, intensity-modulated brachytherapy for cervical cancer. PLoS One 2020; 15:e0236585. [PMID: 32722692 PMCID: PMC7386578 DOI: 10.1371/journal.pone.0236585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/08/2020] [Indexed: 11/19/2022] Open
Abstract
The aim of this work is to build a framework that comprehends inverse planning procedure and plan optimization algorithm tailored to a novel directional beam intensity-modulated brachytherapy (IMBT) of cervical cancer using a rotatable, single-channel radiation shield. Inverse planning is required for finding optimal beam emitting direction, source dwell position and dwell time, which begin with creating a kernel matrix for each structure based on Monte-Carlo simulated dose distribution in the rotatable shield. For efficient beam delivery and less transit dose, the number of source dwell positions and angles needs to be minimized. It can be solved by L0-norm regularization for fewest possible dwell points, and by group sparsity constraint in L2,p-norm (0≤p<1) besides L0-norm for fewest active applicator rotating angles. The dose distributions from our proposed algorithms were compared to those of conventional tandem-based intracavitary brachytherapy (ICR) plans for six cervical cancer patients. The algorithmic performance was evaluated in delivery efficiency and plan quality relative to the unconstrained algorithm. The proposed framework yielded substantially enhanced plan quality over the conventional ICR plans. The L0-norm and (group sparsity+L0-norm) constrained algorithms reduced the number of source dwell points by 60 and 70% and saved 5 and 8 rotational angles on average (7 and 11 angles for highly modulated cases), relative to the unconstrained algorithm, respectively. Though both algorithms reduced the optimal source dwell positions and angles, the group sparsity constrained optimization with L0-norm was more effective than the L0-norm constraint only, mainly because of considering physical constraints of the new IMBT applicator. With much fewer dwell points compared to the unconstrained, the proposed algorithms led to statistically similar plan quality in dose volume histograms and iso-dose lines. It also demonstrated that the plan optimized by rotating the applicator resulted in much better plan quality than that of conventional applicator-based plans.
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18
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Famulari G, Duclos M, Enger SA. A novel
169
Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer. Med Phys 2019; 47:859-868. [DOI: 10.1002/mp.13959] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/04/2019] [Accepted: 12/06/2019] [Indexed: 12/17/2022] Open
Affiliation(s)
- Gabriel Famulari
- Medical Physics Unit McGill University Montréal Québec H4A 3J1Canada
| | - Marie Duclos
- Department of Oncology McGill University Montréal Québec H4A 3J1Canada
| | - Shirin A. Enger
- Medical Physics Unit McGill University Montréal Québec H4A 3J1Canada
- Department of Oncology McGill University Montréal Québec H4A 3J1Canada
- Research Institute of the McGill University Health Centre Montréal Québec H3H 2R9Canada
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19
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Callaghan CM, Adams Q, Flynn RT, Wu X, Xu W, Kim Y. Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques. Int J Radiat Oncol Biol Phys 2019; 105:206-221. [DOI: 10.1016/j.ijrobp.2019.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/27/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023]
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20
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Dynamic Modulated Brachytherapy (DMBT) Balloon Applicator for Accelerated Partial Breast Irradiation. Int J Radiat Oncol Biol Phys 2019; 104:953-961. [PMID: 30910767 DOI: 10.1016/j.ijrobp.2019.03.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/07/2019] [Accepted: 03/17/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To propose a novel high-dose-rate brachytherapy applicator for balloon-based dynamic modulated brachytherapy (DMBT) for accelerated partial breast irradiation (APBI) and to demonstrate its dosimetric advantage compared to the widely used Contura applicator. METHODS AND MATERIALS The DMBT balloon device consists of a fixed central channel enabling real-time, in vivo dosimetry and an outer motion-dynamic, adjustable-radius channel capable of moving to any angular position within the balloon. This design allows placement of dwell positions anywhere within the balloon volume, guaranteeing optimal placement and generation of the applicator and treatment plan, respectively. Thirteen clinical treatment plans for patients with early-stage breast cancer receiving APBI after lumpectomy using Contura were retrospectively obtained under institutional review board approval. New treatment plans were created by replacing the Contura with the DMBT device. DMBT plans were limited to 4 angular positions and an outer channel radius of 1.5 cm. The new plans were optimized to limit dose to ribs and skin while maintaining target coverage similar to that of the clinical plan. RESULTS Similar target coverage was obtained for the DMBT plans compared with clinical Contura plans. Across all patients the mean (standard deviation) reductions in D0.1 cc to the ribs and skin were 6.70% (6.28%) and 5.13% (6.54%), respectively. A threshold separation distance between the balloon surface and the organ at risk (OAR), below which dosimetric changes of greater than 5% were obtained, was observed to be 12 mm for ribs and skin. When both OARs were far from the balloon, DMBT plans were of similar quality to Contura plans, as expected. CONCLUSIONS This study demonstrates the superior ability of the APBI DMBT applicator to spare OARs while achieving target coverage comparable to current treatment plans, especially when in close proximity. The DMBT balloon may enable new modes of dynamic high-dose-rate treatment delivery and allow for ultrahypofractionated dose regimens to be safely used.
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21
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Devic S, Bekerat H, Garant A, Vuong T. Optimization of HDRBT boost dose delivery for patients with rectal cancer. Brachytherapy 2019; 18:559-563. [DOI: 10.1016/j.brachy.2019.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/31/2019] [Accepted: 02/11/2019] [Indexed: 10/27/2022]
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22
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Flynn RT, Adams QE, Hopfensperger KM, Wu X, Xu W, Kim Y. Efficient 169 Yb high-dose-rate brachytherapy source production using reactivation. Med Phys 2019; 46:2935-2943. [PMID: 31054163 DOI: 10.1002/mp.13563] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/16/2019] [Indexed: 01/20/2023] Open
Abstract
PURPOSE To present and quantify the effectiveness of a method for the efficient production of 169 Yb high-dose-rate brachytherapy sources with 27 Ci activity upon clinical delivery, which have about the same dose rate in water at 1 cm from the source center as 10 Ci 192 Ir sources. MATERIALS A theoretical framework for 169 Yb source activation and reactivation using thermal neutrons in a research reactor and 168 Yb-Yb2 O3 precursor is derived and benchmarked against published data. The model is dependent primarily on precursor 168 Yb enrichment percentage, active source volume of the active element, and average thermal neutron flux within the active source. RESULTS Efficiency gains in 169 Yb source production are achievable through reactivation, and the gains increase with active source volume. For an average thermal neutron flux within the active source of 1 × 1014 n cm-2 s-1 , increasing the active source volume from 1 to 3 mm3 decreased reactor-days needed to generate one clinic-year of 169 Yb from 256 days yr-1 to 59 days yr-1 , and 82%-enriched precursor dropped from 80 mg yr-1 to 21 mg yr-1 . A resource reduction of 74%-77% is predicted for an active source volume increase from 1 to 3 mm3 . CONCLUSIONS Dramatic cost savings are achievable in 169 Yb source production costs through reactivation if active sources larger than 1 mm3 are used.
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Affiliation(s)
- Ryan T Flynn
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Quentin E Adams
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Karolyn M Hopfensperger
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, 5601 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Xiaodong Wu
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA.,Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Weiyu Xu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Yusung Kim
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA
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Safigholi H, van Veelen B, Niatsetski Y, Song WY. Modeling of the direction modulated brachytherapy tandem applicator using the Oncentra Brachy advanced collapsed cone engine. Brachytherapy 2018; 17:1030-1036. [PMID: 30181054 DOI: 10.1016/j.brachy.2018.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 07/24/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE The direction modulated brachytherapy (DMBT) magnetic resonance-compatible tandem applicator, made from a tungsten alloy rod, has six symmetric peripheral grooves, designed specifically to enhance intensity modulation capacity through achieving directional radiation dose profiles. In this work, the directional dose distributions of the DMBT tandem were modeled and calculated with the Oncentra Brachy advanced collapsed cone engine (ACE), which was validated against Monte Carlo (MC) calculations. METHODS AND MATERIAL The prototype 3D tandem applicator model was created for use in the Oncentra Brachy treatment planning system. The 192Ir source was placed inside a DMBT tandem in one and six channels as a single dwell position (DP) per channel with the same index length, as well as 1 DP in a standard tandem. Dose distributions were calculated in a water medium by both ACE and MC and compared. RESULTS For 1DP/6DP inside the DMBT and 1DP inside the standard tandem, respectively, the mean dose differences were 3.5/3.3% and <2.8% with the range of 0.1%-6.5%/0.2%-5% and 0.1%-5%, between ACE and MC, respectively. CONCLUSIONS The DMBT tandem is successfully modeled in a commercial treatment planning system. The ACE algorithm is capable of accurately calculating highly directional dose distributions generated by a dense tungsten alloy contained within the DMBT tandem, with agreements achieved within <3.5%.
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Affiliation(s)
- Habib Safigholi
- Department of Electrical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
| | | | | | - William Y Song
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA
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24
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Safigholi H, Han DY, Soliman A, Song WY. Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material. Med Phys 2018; 45:3524-3533. [PMID: 29858499 DOI: 10.1002/mp.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023] Open
Abstract
PURPOSE To investigate the dose modulation capability of a novel MRI-compatible direction modulated brachytherapy (DMBT) tandem applicator design with various high-density shielding materials for brachytherapy treatment of cervical cancer. The shield materials that have been evaluated are tantalum (Ta), pure tungsten (W), gold (Au), rhenium (Re), osmium (Os), platinum (Pt), iridium (Ir), and W' tungsten alloy (95%W, 3.5%Ni, 1.5%Cu). MATERIALS AND METHODS The recently proposed six-channel DMBT tandem is composed of nonmagnetic tungsten alloy (W') rod with diameter of 5.4 mm and coated with 0.3-mm thick bio-safe plastic sheath. The tandem shielding material can, however, be individually replaced with various other shields to create directional radiation. Monte Carlo N-Particle (MCNP) code was used to calculate the three-dimensional (3D) dose distributions in a water phantom for an HDR 192 Ir (mHDR-v2) source inside each DMBT tandem with various shields and a plastic conventional tandem (Con.T). Then, the 3D dose distributions were imported into an in-house-coded inverse planning optimization algorithm to obtain optimal plans for 12 clinical cases chosen at random from the international RetroEMBRACE dataset involving conventional tandem and ring (Con.T&R) applicators. All plans generated by the DMBT tandem and ring (DMBT&R) with the tungsten alloy [DMBT(W')&R] were compared with the corresponding Con.T&R plans, to generate benchmark results. These benchmark results were then considered as reference plans for other shields performances. Plans were normalized to receive the same high-risk clinical target volume (CTVHR ) D90 . The D100 , D10 , and V100 for CTVHR , and D2cm3 for organs at risk (OARs) of bladder, sigmoid, and rectum were calculated and compared. RESULTS Transmission factor (TF), that is, the dose in the backside of the DMBT shield over that in the front opening, at a 5 cm distance, were 36.6%, 34.8%, 31.9%, 28.9%, 27.9%, 26.2%, 26.2%, and 25.5%, for Ta, W', W, Re, Au, Os, Pt, and Ir shields, respectively. On average, the CTVHR values for D100 , V100 , D10 were not significantly different across all DMBT&R shields and the Con.T&R plans (P > 0.219). For the D2cm3 , the benchmark results showed significant reductions (P < 0.03), that is, on average, -8.3% for bladder, -10.7% for rectum, and -10.1% for sigmoid, compared to the Con.T&R plans. However, the various shields showed little improvement from the tungsten alloy (W'), where on average, rectum (bladder) [sigmoid] D2cm3 were reduced by -1.32% (-0.85%) [-1.01%], -1.25% (-0.78%) [-0.91%], -1.22% (-0.75%) [-0.86%], -0.94% (-0.60%) [-0.70%], -0.84% (-0.51%) [-0.59%], and -0.38% (-0.24%) [-0.23%] for Ir, Pt, Os, Au, Re, and W shields, relative to the benchmark W' DMBT plans, respectively. These corresponding values for Ta increased by +0.28% (+0.08%) [+0.25%], respectively. CONCLUSION The Ir, Pt, Os, Au, Re, and W shielding materials, respectively, in descending order, lead to better OAR sparing than the DMBT(W')&R plans. However, the amount of improvement is limited and clinically insignificant. This finding suggests that the initial W' shield remains a suitable choice given the proven MR compatibility, for use in MR-guided adaptive brachytherapy of cervical cancer.
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Affiliation(s)
- Habib Safigholi
- Department of Electrical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
| | - Dae Yup Han
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - Abraam Soliman
- R&D Clinical Excellence (MRI), Philips Healthcare, Best, The Netherlands
| | - William Y Song
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA
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25
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Elzibak AH, Kager PM, Soliman A, Paudel MR, Safigholi H, Han DY, Karotki A, Ravi A, Song WY. Quantitative CT assessment of a novel direction-modulated brachytherapy tandem applicator. Brachytherapy 2017; 17:465-475. [PMID: 29174936 DOI: 10.1016/j.brachy.2017.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/12/2017] [Accepted: 10/12/2017] [Indexed: 12/15/2022]
Abstract
PURPOSE The purpose of this study was to quantitatively assess the CT metal-induced artifacts from a novel direction-modulated brachytherapy (DMBT) tandem applicator prototype, recently designed for cervical cancer treatments. METHODS AND MATERIALS A water-based pelvic phantom was constructed for CT scanning. The DMBT applicator was imaged using our institutional protocol, one with higher kVp and mAs settings, and repetition of these protocols using 3-mm slices. A conventional stainless steel applicator was also scanned. In addition to the standard reconstructed images, applicator images were reconstructed using a commercial metal artifact-reduction (MAR) algorithm and an in-house-developed research algorithm. Subsequently, image quality and artifact severity were evaluated. RESULTS Artifact severity, measured in terms of SDs in CT numbers, decreased asymptotically to background water levels with the distance away from the applicator. Artifact-reduction algorithms lead to significant and visible improvements in image quality, with >50% and >20% decrease in artifact severity achieved at a 10-mm distance for the DMBT and stainless steel applicators, respectively. Differences in artifact severity were minimal between the four imaging protocols. DMBT dimensions were the same on images with and without the commercial MAR algorithm, within <1 mm of the theoretical value. Both the commercial and in-house algorithms restored the CT numbers outside the applicator, albeit a better performance was achieved by the in-house algorithm. CONCLUSIONS The artifacts produced by both applicators were minimized with the use of MAR algorithms. Adoption of the DMBT and stainless steel applicators for CT-guided brachytherapy is anticipated as MAR algorithms are widely available on CT scanners.
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Affiliation(s)
- Alyaa H Elzibak
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada.
| | - Petronella M Kager
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Abraam Soliman
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Moti R Paudel
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Habib Safigholi
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Electrical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
| | - Dae Yup Han
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA
| | - Aliaksandr Karotki
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Ananth Ravi
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - William Y Song
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada; Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA
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Safigholi H, Han DY, Mashouf S, Soliman A, Meigooni AS, Owrangi A, Song WY. Direction modulated brachytherapy (DMBT) for treatment of cervical cancer: A planning study with 192 Ir, 60 Co, and 169 Yb HDR sources. Med Phys 2017; 44:6538-6547. [PMID: 28940520 DOI: 10.1002/mp.12598] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/27/2017] [Accepted: 09/18/2017] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To evaluate plan quality of a novel MRI-compatible direction modulated brachytherapy (DMBT) tandem applicator using 192 Ir, 60 Co, and 169 Yb HDR brachytherapy sources, for various cervical cancer high-risk clinical target volumes (CTVHR ). MATERIALS AND METHODS The novel DMBT tandem applicator has six peripheral grooves of 1.3-mm diameter along a 5.4-mm thick nonmagnetic tungsten alloy rod. Monte Carlo (MC) simulations were used to benchmark the dosimetric parameters of the 192 Ir, 60 Co, and 169 Yb HDR sources in a water phantom against the literature data. 45 clinical cases that were treated using conventional tandem-and-ring applicators with 192 Ir source (192 Ir-T&R) were selected consecutively from intErnational MRI-guided BRAchytherapy in CErvical cancer (EMBRACE) trial. Then, for each clinical case, 3D dose distribution of each source inside the DMBT and conventional applicators were calculated and imported onto an in-house developed inverse planning optimization code to generate optimal plans. All plans generated by the DMBT tandem-and-ring (DMBT T&R) from all three sources were compared to the respective 192 Ir-T&R plans. For consistency, all plans were normalized to the same CTVHR D90 achieved in clinical plans. The D2 cm3 for organs at risk (OAR) such as bladder, rectum, and sigmoid, and D90, D98, D10, V100, and V200 for CTVHR were calculated. RESULTS In general, plan quality significantly improved when a conventional tandem (Con.T) is replaced with the DMBT tandem. The target coverage metrics were similar across 192 Ir-T&R and DMBT T&R plans with all three sources (P > 0.093). 60 Co-DMBT T&R generated greater hot spots and less dose homogeneity in the target volumes compared with the 192 Ir- and 169 Yb-DMBT T&R plans. Mean OAR doses in the DMBT T&R plans were significantly smaller (P < 0.0084) than the 192 Ir-T&R plans. Mean bladder D2 cm3 was reduced by 4.07%, 4.15%, and 5.13%, for the 192 Ir-, 60 Co-, and 169 Yb-DMBT T&R plans respectively. Mean rectum (sigmoid) D2 cm3 was reduced by 3.17% (3.63%), 2.57% (3.96%), and 4.65% (4.34%) for the 192 Ir-, 60 Co-, and 169 Yb-DMBT T&R plans respectively. The DMBT T&R plans with the 169 Yb source generally resulted in the greatest OAR sparing when the CTVHR were larger and irregular in shape, while for smaller and regularly shaped CTVHR (<30 cm3 ), OAR sparing between the sources were comparable. CONCLUSIONS The DMBT tandem provides a promising alternative to the Con.T design with significant improvement in the plan quality for various target volumes. The DMBT T&R plans generated with the three sources of varying energies generated superior plans compared to the conventional T&R applicators. Plans generated with the 169 Yb-DMBT T&R produced best results for larger and irregularly shaped CTVHR in terms of OAR sparing. Thus, this study suggests that the combination of the DMBT tandem applicator with varying energy sources can work synergistically to generate improved plans for cervical cancer brachytherapy.
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Affiliation(s)
- Habib Safigholi
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Dae Yup Han
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - Shahram Mashouf
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Abraam Soliman
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Ali S Meigooni
- Department of Radiation Therapy, Comprehensive Cancer centers of Nevada, Las Vegas, NV, USA
| | - Amir Owrangi
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - William Y Song
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.,Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA
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Cho M, Wu X, Dadkhah H, Yi J, Flynn RT, Kim Y, Xu W. Fast dose optimization for rotating shield brachytherapy. Med Phys 2017; 44:5384-5392. [PMID: 28744870 DOI: 10.1002/mp.12486] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/25/2017] [Accepted: 07/17/2017] [Indexed: 02/05/2023] Open
Abstract
PURPOSE To provide a fast computational method, based on the proximal graph solver (POGS) - A convex optimization solver using the alternating direction method of multipliers (ADMM), for calculating an optimal treatment plan in rotating shield brachytherapy (RSBT). RSBT treatment planning has more degrees of freedom than conventional high-dose-rate brachytherapy due to the addition of emission direction, and this necessitates a fast optimization technique to enable clinical usage. METHODS The multi-helix RSBT (H-RSBT) delivery technique was investigated for five representative cervical cancer patients. Treatment plans were generated for all patients using the POGS method and the commercially available solver IBM ILOG CPLEX. The rectum, bladder, sigmoid colon, high-risk clinical target volume (HR-CTV), and HR-CTV boundary were the structures included in our optimization, which applied an asymmetric dose-volume optimization with smoothness control. Dose calculation resolution was 1 × 1 × 3 mm3 for all cases. The H-RSBT applicator had 6 helices, with 33.3 mm of translation along the applicator per helical rotation and 1.7 mm spacing between dwell positions, yielding 17.5° emission angle spacing per 5 mm along the applicator. RESULTS For each patient, HR-CTV D90 , HR-CTV D100 , rectum D2cc , sigmoid D2cc , and bladder D2cc matched within 1% for CPLEX and POGS methods. Also, similar EQD2 values between CPLEX and POGS methods were obtained. POGS was around 18 times faster than CPLEX. For all patients, total optimization times were 32.1-65.4 s for CPLEX and 2.1-3.9 s for POGS. CONCLUSIONS POGS reduced treatment plan optimization time approximately 18 times for RSBT with similar HR-CTV D90 , organ at risk (OAR) D2cc values, and EQD2 values compared to CPLEX, which is significant progress toward clinical translation of RSBT.
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Affiliation(s)
- Myung Cho
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, IA, 52242, USA
| | - Xiaodong Wu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, IA, 52242, USA.,Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Hossein Dadkhah
- Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center, Iowa City, IA, 52242, USA
| | - Jirong Yi
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, IA, 52242, USA
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Weiyu Xu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, IA, 52242, USA
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Nath R, Rivard MJ, DeWerd LA, Dezarn WA, Thompson Heaton H, Ibbott GS, Meigooni AS, Ouhib Z, Rusch TW, Siebert FA, Venselaar JLM. Guidelines by the AAPM and GEC-ESTRO on the use of innovative brachytherapy devices and applications: Report of Task Group 167. Med Phys 2017; 43:3178-3205. [PMID: 27277063 DOI: 10.1118/1.4951734] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence-based medicine, it is rarely used in the evaluation of innovative devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining the equivalence of the innovative treatment modality to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of innovative radiotherapy devices or applications is a critical part in which physicists should be actively involved. The physicist's role, along with physician colleagues, in this process is highlighted for innovative brachytherapy devices and applications and includes evaluation of (1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, (2) risks and benefits from a regulatory and safety perspective, and (3) resource assessment and preparedness. Further, it is suggested that any developed calibration methods be traceable to a primary standards dosimetry laboratory (PSDL) such as the National Institute of Standards and Technology in the U.S. or to other PSDLs located elsewhere such as in Europe. Clinical users should follow standards as approved by their country's regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the Accredited Dosimetry Calibration Laboratories in the U.S. is encouraged before a source is introduced into widespread routine clinical use. The American Association of Physicists in Medicine and the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO) have developed guidelines for the safe and consistent application of brachytherapy using innovative devices and applications. The current report covers regulatory approvals, calibration, dose calculations, radiobiological issues, and overall safety concerns that should be addressed during the commissioning stage preceding clinical use. These guidelines are based on review of requirements of the U.S. Nuclear Regulatory Commission, U.S. Department of Transportation, International Electrotechnical Commission Medical Electrical Equipment Standard 60601, U.S. Food and Drug Administration, European Commission for CE Marking (Conformité Européenne), and institutional review boards and radiation safety committees.
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Affiliation(s)
- Ravinder Nath
- Department of Therapeutic Radiology, School of Medicine, Yale University, New Haven, Connecticut 06510
| | - Mark J Rivard
- Department of Radiation Oncology, School of Medicine, Tufts University, Boston, Massachusetts 02111
| | - Larry A DeWerd
- Accredited Dosimetry and Calibration Laboratory, University of Wisconsin, Madison, Wisconsin 53706
| | - William A Dezarn
- Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157
| | | | - Geoffrey S Ibbott
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Ali S Meigooni
- Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada 89169
| | - Zoubir Ouhib
- Radiation Oncology, Lynn Regional Cancer Center, Delray Beach, Florida 33484
| | - Thomas W Rusch
- Xoft, Inc., A Subsidiary of iCAD, Inc., San Jose, California 95134
| | - Frank-André Siebert
- Clinic of Radiotherapy, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel 24105, Germany
| | - Jack L M Venselaar
- Department of Medical Physics and Engineering, Instituut Verbeeten, Tilburg LA 5000, The Netherlands
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Soliman AS, Owrangi A, Ravi A, Song WY. Metal artefacts in MRI-guided brachytherapy of cervical cancer. J Contemp Brachytherapy 2016; 8:363-9. [PMID: 27648092 PMCID: PMC5018526 DOI: 10.5114/jcb.2016.61817] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 07/28/2016] [Indexed: 11/29/2022] Open
Abstract
The importance of assessing the metal-induced artefacts in magnetic resonance imaging (MRI)-guided brachytherapy is growing along with the increasing interest of integrating MRI into the treatment procedure of cervical cancer. Examples of metal objects in use include intracavitary cervical applicators and interstitial needles. The induced artefacts increase the uncertainties in the clinical workflow and can be a potential obstacle for the accurate delivery of the treatment. Overcoming this problem necessitates a good understanding of its originating sources. Several efforts are recorded in the literature to quantify the extent of such artefacts, in phantoms and in clinical practice. Here, we elaborate on the origin of metal-induced artefacts in the light of brachytherapy applications, while summarizing recent efforts that have been made to assess and overcome the induced distortions.
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Affiliation(s)
- Abraam S Soliman
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto; Physical Sciences Platform, Sunnybrook Research Institute, Toronto
| | - Amir Owrangi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Ananth Ravi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto; Physical Sciences Platform, Sunnybrook Research Institute, Toronto; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - William Y Song
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto; Physical Sciences Platform, Sunnybrook Research Institute, Toronto; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
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Soliman AS, Elzibak A, Easton H, Kim JY, Han DY, Safigholi H, Mashouf S, Owrangi A, Ravi A, Song WY. Quantitative MRI assessment of a novel direction modulated brachytherapy tandem applicator for cervical cancer at 1.5T. Radiother Oncol 2016; 120:500-506. [PMID: 27443448 DOI: 10.1016/j.radonc.2016.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND PURPOSE The purpose of this work is to quantitatively investigate the artifacts and image distortions induced in the MR images by a recently proposed direction modulated brachytherapy (DMBT) tandem applicator prototype. This new MRI-compatible applicator allows better sparing of organs-at-risk (OAR) for cervical cancer patients, while providing conformal dose distributions to target volumes. MATERIALS AND METHODS Specific phantom and tools were designed and manufactured for this study. The phantom was filled with a tissue-like solution and MR images were acquired with clinical protocols as per GEC-ESTRO recommendations. Images were obtained at 6 different orientations that mimic possible clinical settings and full-width-at-half-maximum (FWHM) was recorded at multiple locations/angles. The accuracy of detecting the centerline of the tandem was assessed using a novel radial-fiducials mount. RESULTS FWHM from all line profiles at all angles and all orientations was 6.14±0.7mm (compared to 6mm of the actual DMBT tandem diameter). The in-plane spatial-shift observed at para-axial and para-sagittal views was less than 0.5mm. CONCLUSIONS This work demonstrated that the novel DMBT tandem applicator prototype has minimal artifact in T2-weighted images employed in clinical practice, suggesting the applicator might be a good candidate for MRI-guided adaptive brachytherapy.
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Affiliation(s)
- Abraam S Soliman
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Canada
| | - Alyaa Elzibak
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Harry Easton
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada
| | - James Y Kim
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Canada
| | - Dae Yup Han
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of California San Francisco, California, United States
| | - Habib Safigholi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Canada
| | - Shahram Mashouf
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Amir Owrangi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Ananth Ravi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - William Y Song
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
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Liu Y, Flynn RT, Kim Y, Dadkhah H, Bhatia SK, Buatti JM, Xu W, Wu X. Paddle-based rotating-shield brachytherapy. Med Phys 2016; 42:5992-6003. [PMID: 26429274 DOI: 10.1118/1.4930807] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC), consisting of retractable paddles, to achieve intensity modulation in high-dose-rate brachytherapy. METHODS Five cervical cancer patients using an intrauterine tandem applicator were considered to assess the potential benefit of the P-RSBT method. The P-RSBT source used was a 50 kV electronic brachytherapy source (Xoft Axxent™). The paddles can be retracted independently to form multiple emission windows around the source for radiation delivery. The MLC was assumed to be rotatable. P-RSBT treatment plans were generated using the asymmetric dose-volume optimization with smoothness control method [Liu et al., Med. Phys. 41(11), 111709 (11pp.) (2014)] with a delivery time constraint, different paddle sizes, and different rotation strides. The number of treatment fractions (fx) was assumed to be five. As brachytherapy is delivered as a boost for cervical cancer, the dose distribution for each case includes the dose from external beam radiotherapy as well, which is 45 Gy in 25 fx. The high-risk clinical target volume (HR-CTV) doses were escalated until the minimum dose to the hottest 2 cm(3) (D(2cm(3)) of either the rectum, sigmoid colon, or bladder reached their tolerance doses of 75, 75, and 90 Gy3, respectively, expressed as equivalent doses in 2 Gy fractions (EQD2 with α/β = 3 Gy). RESULTS P-RSBT outperformed the two other RSBT delivery techniques, single-shield RSBT (S-RSBT) and dynamic-shield RSBT (D-RSBT), with a properly selected paddle size. If the paddle size was angled at 60°, the average D90 increases for the delivery plans by P-RSBT on the five cases, compared to S-RSBT, were 2.2, 8.3, 12.6, 11.9, and 9.1 Gy10, respectively, with delivery times of 10, 15, 20, 25, and 30 min/fx. The increases in HR-CTV D90, compared to D-RSBT, were 16.6, 12.9, 7.2, 3.7, and 1.7 Gy10, respectively. P-RSBT HR-CTV D90-values were insensitive to the paddle size for paddles angled at less than 60°. Increasing the paddle angle from 5° to 60° resulted in only a 0.6 Gy10 decrease in HR-CTV D90 on average for five cases when the delivery times were set to 15 min/fx. The HR-CTV D90 decreased to 2.5 and 11.9 Gy10 with paddle angles of 90° and 120°, respectively. CONCLUSIONS P-RSBT produces treatment plans that are dosimetrically and temporally superior to those of S-RSBT and D-RSBT, although P-RSBT systems may be more mechanically challenging to develop than S-RSBT or D-RSBT. A P-RSBT implementation with 4-6 shield paddles would be sufficient to outperform S-RSBT and D-RSBT if delivery times are constrained to less than 15 min/fx.
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Affiliation(s)
- Yunlong Liu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
| | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
| | - Hossein Dadkhah
- Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center, Iowa City, Iowa 52242
| | - Sudershan K Bhatia
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
| | - John M Buatti
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
| | - Weiyu Xu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242
| | - Xiaodong Wu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
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Han DY, Safigholi H, Soliman A, Ravi A, Leung E, Scanderbeg DJ, Liu Z, Owrangi A, Song WY. Direction Modulated Brachytherapy for Treatment of Cervical Cancer. II: Comparative Planning Study With Intracavitary and Intracavitary-Interstitial Techniques. Int J Radiat Oncol Biol Phys 2016; 96:440-448. [PMID: 27598809 DOI: 10.1016/j.ijrobp.2016.06.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/12/2016] [Accepted: 06/10/2016] [Indexed: 01/26/2023]
Abstract
PURPOSE To perform a comprehensive comparative planning study evaluating the utility of the proposed direction modulated brachytherapy (DMBT) tandem applicator against standard applicators, in the setting of image guided adaptive brachytherapy of cervical cancer. METHODS AND MATERIALS A detailed conceptual article was published in 2014. The proposed DMBT tandem applicator has 6 peripheral grooves of 1.3-mm width, along a 5.4-mm-thick nonmagnetic tungsten alloy rod of density 18.0 g/cm(3), capable of generating directional dose profiles. We performed a comparative planning study with 45 cervical cancer patients enrolled consecutively in the prospective observational EMBRACE study. In all patients, MRI-based planning was performed while utilizing various tandem-ring (27 patients) and tandem-ring-needles (18 patients) applicators, in accordance with the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology recommendations. For unbiased comparisons, all cases were replanned with an in-house-developed inverse optimization code while enforcing a uniform set of constraints that are reflective of the clinical practice. All plans were normalized to the same high-risk clinical target volume D90 values achieved in the original clinical plans. RESULTS In general, if the standard tandem was replaced with the DMBT tandem while maintaining all other planning conditions the same, there was consistent improvement in the plan quality. For example, among the 18 tandem-ring-needles cases, the average D2cm(3) reductions achieved were -2.48% ± 11.03%, -4.45% ± 5.24%, and -5.66% ± 6.43% for the bladder, rectum, and sigmoid, respectively. An opportunity may also exist in avoiding use of needles altogether for when the total number of needles required is small (approximately 2 to 3 needles or less), if DMBT tandem is used. CONCLUSIONS Integrating the novel DMBT tandem onto both intracavitary and intracavitary-interstitial applicator assembly enabled consistent improvement in the sparing of the OARs, over a standard "single-channel" tandem, though individual variations in benefit were considerable. Although at an early stage of development, the DMBT concept design is demonstrated to be useful and pragmatic for potential clinical translation.
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Affiliation(s)
- Dae Yup Han
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of California, San Francisco, San Francisco, California; Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California
| | - Habib Safigholi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Abraam Soliman
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Ananth Ravi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Eric Leung
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Daniel J Scanderbeg
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Zhaowei Liu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California
| | - Amir Owrangi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - William Y Song
- Department of Medical Physics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.
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Omidvari S, Zohourinia S, Ansari M, Ghahramani L, Zare-Bandamiri M, Mosalaei A, Ahmadloo N, Pourahmad S, Nasrolahi H, Hamedi SH, Mohammadianpanah M. Efficacy and Safety of Low-Dose-Rate Endorectal Brachytherapy as a Boost to Neoadjuvant Chemoradiation in the Treatment of Locally Advanced Distal Rectal Cancer: A Phase-II Clinical Trial. Ann Coloproctol 2015; 31:123-30. [PMID: 26361613 PMCID: PMC4564663 DOI: 10.3393/ac.2015.31.4.123] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 06/25/2015] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Despite advances in rectal cancer treatment over the last decade, local control and risk of late side effects due to external beam radiation therapy (EBRT) remain as concerns. The present study aimed to investigate the efficacy and the safety of low-dose-rate endorectal brachytherapy (LDRBT) as a boost to neoadjuvant chemoradiation for use in treating locally advanced distal rectal adenocarcinomas. METHODS This phase-II clinical trial included 34 patients (as the study arm) with newly diagnosed, locally advanced (clinical T3-T4 and/or N1/N2, M0) lower rectal cancer. For comparative analysis, 102 matched patients (as the historical control arm) with rectal cancer were also selected. All the patients were treated with LDRBT (15 Gy in 3 fractions) and concurrent chemoradiation (45-50.4 Gy). Concurrent chemotherapy consisted of oxaliplatin 130 mg/m(2) intravenously on day 1 plus oral capecitabine 825 mg/m(2) twice daily during LDRBT and EBRT. RESULTS The study results revealed a significant differences between the study arm and the control arm in terms in the pathologic tumor size (2.1 cm vs. 3.6 cm, P = 0.001), the pathologic tumor stage (35% T3-4 vs. 65% T3-4, P = 0.003), and the pathologic complete response (29.4% vs. 11.7%, P < 0.028). Moreover, a significantly higher dose of EBRT (P = 0.041) was found in the control arm, and a longer time to surgery was observed in the study arm (P < 0.001). The higher rate of treatment-related toxicities, such as mild proctitis and anemia, in the study arm was tolerable and easily manageable. CONCLUSION A boost of LDRBT can optimize the pathologic complete response, with acceptable toxicities, in patients with distal rectal cancer.
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Affiliation(s)
- Shapour Omidvari
- Department of Radiation Oncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Shadi Zohourinia
- Department of Radiation Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mansour Ansari
- Department of Radiation Oncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Leila Ghahramani
- Colorectal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Ahmad Mosalaei
- Shiraz Institute for Cancer Research, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Niloofar Ahmadloo
- Department of Radiation Oncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saeedeh Pourahmad
- Department of Biostatistics, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamid Nasrolahi
- Department of Radiation Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sayed Hasan Hamedi
- Department of Radiation Oncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
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Klein EE, Dong L, Paganetti H, Tanderup K. The far-reaching subject matter of medical physics in radiation oncology. Int J Radiat Oncol Biol Phys 2015; 91:697-700. [PMID: 25752380 DOI: 10.1016/j.ijrobp.2014.10.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 10/14/2014] [Accepted: 10/14/2014] [Indexed: 11/29/2022]
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Han DY, Webster MJ, Scanderbeg DJ, Yashar C, Choi D, Song B, Devic S, Ravi A, Song WY. Direction-modulated brachytherapy for high-dose-rate treatment of cervical cancer. I: theoretical design. Int J Radiat Oncol Biol Phys 2014; 89:666-73. [PMID: 24751413 DOI: 10.1016/j.ijrobp.2014.02.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/11/2014] [Accepted: 02/26/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To demonstrate that utilization of the direction-modulated brachytherapy (DMBT) concept can significantly improve treatment plan quality in the setting of high-dose-rate (HDR) brachytherapy for cervical cancer. METHODS AND MATERIALS The new, MRI-compatible, tandem design has 6 peripheral holes of 1.3-mm diameter, grooved along a nonmagnetic tungsten-alloy rod (ρ = 18.0 g/cm(3)), enclosed in Delrin tubing (polyoxymethylene, ρ = 1.41 g/cm(3)), with a total thickness of 6.4 mm. The Monte Carlo N-Particle code was used to calculate the anisotropic (192)Ir dose distributions. An in-house-developed inverse planning platform, geared with simulated annealing and constrained-gradient optimization algorithms, was used to replan 15 patient cases (total 75 plans) treated with a conventional tandem and ovoids (T&O) applicator. Prescription dose was 6 Gy. For replanning, we replaced the conventional tandem with that of the new DMBT tandem for optimization but left the ovoids in place and kept the dwell positions as originally planned. All DMBT plans were normalized to match the high-risk clinical target volume V100 coverage of the T&O plans. RESULTS In general there were marked improvements in plan quality for the DMBT plans. On average, D2cc for the bladder, rectum, and sigmoid were reduced by 0.59 ± 0.87 Gy (8.5% ± 28.7%), 0.48 ± 0.55 Gy (21.1% ± 27.2%), and 0.10 ± 0.38 Gy (40.6% ± 214.9%) among the 75 plans, with best single-plan reductions of 3.20 Gy (40.8%), 2.38 Gy (40.07%), and 1.26 Gy (27.5%), respectively. The high-risk clinical target volume D90 was similar, with 6.55 ± 0.96 Gy and 6.59 ± 1.06 Gy for T&O and DMBT, respectively. CONCLUSIONS Application of the DMBT concept to cervical cancer allowed for improved organ at risk sparing while achieving similar target coverage on a sizeable patient population, as intended, by maximally utilizing the anatomic information contained in 3-dimensional imaging. A series of mechanical and clinical validations are to be followed.
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Affiliation(s)
- Dae Yup Han
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California
| | - Matthew J Webster
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Physics, University of California San Diego, La Jolla, California
| | - Daniel J Scanderbeg
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Catheryn Yashar
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Dongju Choi
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Bongyong Song
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Slobodan Devic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada
| | - Ananth Ravi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - William Y Song
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
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Webster MJ, Devic S, Vuong T, Han DY, Scanderbeg D, Choi D, Song B, Song WY. HDR brachytherapy of rectal cancer using a novel grooved-shielding applicator design. Med Phys 2013; 40:091704. [DOI: 10.1118/1.4816677] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ghobadifar MA, Zarei S. Effect of collimation on radiation exposure and image quality. Korean J Pain 2013; 26:307-8. [PMID: 23862008 PMCID: PMC3710948 DOI: 10.3344/kjp.2013.26.3.307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/31/2013] [Indexed: 01/16/2023] Open
Affiliation(s)
- Mohamed Amin Ghobadifar
- Department of Student Research Committee, Jahrom University of Medical Sciences, Jahrom, Iran
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Liu Y, Flynn RT, Yang W, Kim Y, Bhatia SK, Sun W, Wu X. Rapid emission angle selection for rotating-shield brachytherapy. Med Phys 2013; 40:051720. [PMID: 23635268 DOI: 10.1118/1.4802750] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The authors present a rapid emission angle selection (REAS) method that enables the efficient selection of the azimuthal shield angle for rotating shield brachytherapy (RSBT). The REAS method produces a Pareto curve from which a potential RSBT user can select a treatment plan that balances the tradeoff between delivery time and tumor dose conformity. METHODS Two cervical cancer patients were considered as test cases for the REAS method. The RSBT source considered was a Xoft Axxent(TM) electronic brachytherapy source, partially shielded with 0.5 mm of tungsten, which traveled inside a tandem intrauterine applicator. Three anchor RSBT plans were generated for each case using dose-volume optimization, with azimuthal shield emission angles of 90°, 180°, and 270°. The REAS method converts the anchor plans to treatment plans for all possible emission angles by combining neighboring beamlets to form beamlets for larger emission angles. Treatment plans based on exhaustive dose-volume optimization (ERVO) and exhaustive surface optimization (ERSO) were also generated for both cases. Uniform dwell-time scaling was applied to all plans such that that high-risk clinical target volume D90 was maximized without violating the D2cc tolerances of the rectum, bladder, and sigmoid colon. RESULTS By choosing three azimuthal emission angles out of 32 potential angles, the REAS method performs about 10 times faster than the ERVO method. By setting D90 to 85-100 Gy10, the delivery times used by REAS generated plans are 21.0% and 19.5% less than exhaustive surface optimized plans used by the two clinical cases. By setting the delivery time budget to 5-25 and 10-30 min∕fx, respectively, for two the cases, the D90 contributions for REAS are improved by 5.8% and 5.1% compared to the ERSO plans. The ranges used in this comparison were selected in order to keep both D90 and the delivery time within acceptable limits. CONCLUSIONS The REAS method enables efficient RSBT treatment planning and delivery and provides treatment plans with comparable quality to those generated by exhaustive replanning with dose-volume optimization.
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Affiliation(s)
- Yunlong Liu
- Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242, USA
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