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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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2
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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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3
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Song WY, Robar JL, Morén B, Larsson T, Carlsson Tedgren Å, Jia X. Emerging technologies in brachytherapy. Phys Med Biol 2021; 66. [PMID: 34710856 DOI: 10.1088/1361-6560/ac344d] [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: 07/09/2021] [Accepted: 10/28/2021] [Indexed: 01/15/2023]
Abstract
Brachytherapy is a mature treatment modality. The literature is abundant in terms of review articles and comprehensive books on the latest established as well as evolving clinical practices. The intent of this article is to part ways and look beyond the current state-of-the-art and review emerging technologies that are noteworthy and perhaps may drive the future innovations in the field. There are plenty of candidate topics that deserve a deeper look, of course, but with practical limits in this communicative platform, we explore four topics that perhaps is worthwhile to review in detail at this time. First, intensity modulated brachytherapy (IMBT) is reviewed. The IMBT takes advantage ofanisotropicradiation profile generated through intelligent high-density shielding designs incorporated onto sources and applicators such to achieve high quality plans. Second, emerging applications of 3D printing (i.e. additive manufacturing) in brachytherapy are reviewed. With the advent of 3D printing, interest in this technology in brachytherapy has been immense and translation swift due to their potential to tailor applicators and treatments customizable to each individual patient. This is followed by, in third, innovations in treatment planning concerning catheter placement and dwell times where new modelling approaches, solution algorithms, and technological advances are reviewed. And, fourth and lastly, applications of a new machine learning technique, called deep learning, which has the potential to improve and automate all aspects of brachytherapy workflow, are reviewed. We do not expect that all ideas and innovations reviewed in this article will ultimately reach clinic but, nonetheless, this review provides a decent glimpse of what is to come. It would be exciting to monitor as IMBT, 3D printing, novel optimization algorithms, and deep learning technologies evolve over time and translate into pilot testing and sensibly phased clinical trials, and ultimately make a difference for cancer patients. Today's fancy is tomorrow's reality. The future is bright for brachytherapy.
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Affiliation(s)
- William Y Song
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - James L Robar
- Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - 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 Medical and Health Sciences, Linköping University, Linköping, Sweden.,Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden.,Department of Oncology Pathology, Karolinska Institute, Stockholm, Sweden
| | - Xun Jia
- Innovative Technology Of Radiotherapy Computations and Hardware (iTORCH) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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4
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Feng W, Rivard MJ, Carey EM, Hearn RA, Pai S, Nath R, Kim Y, Thomason CL, Boyce DE, Zhang H. Recommendations for intraoperative mesh brachytherapy: Report of AAPM Task Group No. 222. Med Phys 2021; 48:e969-e990. [PMID: 34431524 DOI: 10.1002/mp.15191] [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: 12/20/2020] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 11/11/2022] Open
Abstract
Mesh brachytherapy is a special type of a permanent brachytherapy implant: it uses low-energy radioactive seeds in an absorbable mesh that is sutured onto the tumor bed immediately after a surgical resection. This treatment offers low additional risk to the patient as the implant procedure is carried out as part of the tumor resection surgery. Mesh brachytherapy utilizes identification of the tumor bed through direct visual evaluation during surgery or medical imaging following surgery through radiographic imaging of radio-opaque markers within the sources located on the tumor bed. Thus, mesh brachytherapy is customizable for individual patients. Mesh brachytherapy is an intraoperative procedure involving mesh implantation and potentially real-time treatment planning while the patient is under general anesthesia. The procedure is multidisciplinary and requires the complex coordination of multiple medical specialties. The preimplant dosimetry calculation can be performed days beforehand or expediently in the operating room with the use of lookup tables. In this report, the guidelines of American Association of Physicists in Medicine (AAPM) are presented on the physics aspects of mesh brachytherapy. It describes the selection of radioactive sources, design and preparation of the mesh, preimplant treatment planning using a Task Group (TG) 43-based lookup table, and postimplant dosimetric evaluation using the TG-43 formalism or advanced algorithms. It introduces quality metrics for the mesh implant and presents an example of a risk analysis based on the AAPM TG-100 report. Recommendations include that the preimplant treatment plan be based upon the TG-43 dose calculation formalism with the point source approximation, and the postimplant dosimetric evaluation be performed by using either the TG-43 approach, or preferably the newer model-based algorithms (viz., TG-186 report) if available to account for effects of material heterogeneities. To comply with the written directive and regulations governing the medical use of radionuclides, this report recommends that the prescription and written directive be based upon the implanted source strength, not target-volume dose coverage. The dose delivered by mesh implants can vary and depends upon multiple factors, such as postsurgery recovery and distortions in the implant shape over time. For the sake of consistency necessary for outcome analysis, prescriptions based on the lookup table (with selection of the intended dose, depth, and treatment area) are recommended, but the use of more advanced techniques that can account for real situations, such as material heterogeneities, implant geometric perturbations, and changes in source orientations, is encouraged in the dosimetric evaluation. The clinical workflow, logistics, and precautions are also presented.
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Affiliation(s)
- Wenzheng Feng
- Department of Radiation Oncology, Saint Barnabas Medical Center, Livingston, New Jersey, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | | | - Robert A Hearn
- Department of Radiation Physics at Theragenics, Theragenics Corp., Buford, Georgia, USA
| | - Sujatha Pai
- Department of Radiation Oncology, Memorial Hermann Texas Medical Center, Houston, Texas, USA
| | - Ravinder Nath
- Department of Therapeutic Radiology, School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Yongbok Kim
- Department of Radiation Oncology, University of Arizona, Tucson, Arizona, USA
| | - Cynthia L Thomason
- Department of Radiation Oncology, Loyola University Medical Center, Maywood, Illinois, USA
| | | | - Hualin Zhang
- Department of Radiation Oncology, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois, USA
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5
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Dupere JM, Munro JJ, Medich DC. Shielded high dose rate ocular brachytherapy using Yb-169. Phys Med Biol 2021; 66. [PMID: 34010825 DOI: 10.1088/1361-6560/ac02d6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/19/2021] [Indexed: 11/12/2022]
Abstract
Purpose.We propose an approach for treating ocular melanoma using a new type of brachytherapy treatment device. This device couples Yb-169, a middle-energy high dose rate (HDR) brachytherapy source, with a gold shielded ring applicator to better conform radiation exposures to the tumor. In this study, we computationally test the dosimetric output of our proposed shielded ring applicator design using MCNP6 and validate it against an I-125 COMS plaque.Methods.The proposed Yb-169 ring applicator consists of an assembly of discrete sources delivered into an applicator with a conical collimated opening; this opening is tangent to the outside of the source tube. Using MCNP6, we simulated the dosimetric output of a ring of Yb-169 pellets placed within the collimator at various conical diameters and angles to demonstrate the dosimetric distribution for various prescription dose depths and target sizes using static intensity modulation.Results.Using various angles of collimation, the prescription dose was delivered to target apex depths of 3.5-8.0 mm into the eye covering target sizes ranging from 10 to 15 mm in diameter. This proposed device reduced the maximum absorbed dose to critical structures relative to I-125 by 5.2% to the posterior lens, 9.3% to the iris, 13.8% to the optic nerve, and 1.3% to the sclera.Conclusions.This proposed eye plaque design provides a more conformal dose distribution to the ocular tumor while minimizes dose to healthy ocular structures. In addition, the use of a middle-energy HDR brachytherapy source allows the use of a remote afterloader to expose the tumor after the plaque is sutured in place. This system is inherently safer and eliminates dose to the surgeon's hands.
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Affiliation(s)
- Justine M Dupere
- Worcester Polytechnic Institute, Worcester, MA 01609, United States of America
| | - John J Munro
- Montrose Technology Inc., North Andover, MA, 01845, United States of America
| | - David C Medich
- Worcester Polytechnic Institute, Worcester, MA 01609, United States of America
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6
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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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7
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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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Adams Q, Hopfensperger KM, Kim Y, Wu X, Flynn RT. 169 Yb-based rotating shield brachytherapy for prostate cancer. Med Phys 2020; 47:6430-6439. [PMID: 33051866 DOI: 10.1002/mp.14533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/02/2020] [Accepted: 09/27/2020] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To present a system for the treatment of prostate cancer in a single-fraction regimen using 169 Yb-based rotating shield brachytherapy (RSBT) with a single-catheter robotic delivery system. The proposed system is innovative because it can deliver RSBT through multiple implanted needles independently, in serial, using flexible catheters, with no inter-needle shielding effects and without the need to rotate multiple shielded catheters inside the needles simultaneously, resulting in a simple, mechanically robust, delivery approach. RSBT was compared to conventional 192 Ir-based high-dose-rate brachytherapy (HDR-BT) in a treatment planning study with dose escalation and urethral sparing goals, representing single-fraction brachytherapy monotherapy and brachytherapy as a boost to external beam radiotherapy, respectively. A prototype mechanical delivery system was constructed and quantitatively evaluated as a proof of concept. METHODS Treatment plans for twenty-six patients with single fraction prescriptions of 20.5 and 15 Gy, were created for dose escalation and urethral sparing, respectively. The RSBT and HDR-BT delivery systems were modeled with one partially shielded 999 GBq (27 Ci) 169 Yb source and one 370 GBq (10 Ci) 192 Ir source, respectively. A prototype angular drive system for helical source delivery was constructed. Mechanical accuracy measurements of source translational position and angular orientation in a simulated treatment delivery setup were obtained using the prototype system. RESULTS For dose escalation, with equivalent urethra D10% , PTV D90% for RSBT vs HDR-BT increased from 22.6 ± 0.0 Gy (average ± standard deviation) to 29.3 ± 0.9 Gy, or 29.9 % ± 3.0%, with treatment times of 51.4 ± 6.1 min for RSBT and 15.8 ± 2.3 min for 10 Ci 192 Ir-based HDR-BT. For urethra sparing, with equivalent PTV D90 % , urethra D10% for RSBT vs HDR-BT decreased for RSBT vs HDR-BT from 15.6 ± 0.4 Gy to 12.0 ± 0.4 Gy, or 23.1% ± 3.5%, with treatment times of 30.0 ± 3.7 min for RSBT and 12.3 ± 1.8 min for HDR-BT. Differences between measured vs predicted rotating catheter positions (corresponding to source position) were within 0.18 mm ± 0.12 mm longitudinally and 0.07° ± 0.78°. CONCLUSION 169 Yb-based RSBT can increase PTV D90% or decrease urethral D10% relative to HDR-BT with treatment times of less than 1 h using a single-source robotic delivery system with treatment delivered in a single fraction. The prototype helical delivery system was able to demonstrate adequate mechanical accuracy.
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Affiliation(s)
- Quentin Adams
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Karolyn M Hopfensperger
- Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa, 52242, USA
| | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Xiaodong Wu
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa, 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
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
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Hopfensperger KM, Adams Q, Kim Y, Wu X, Xu W, Patwardhan K, Thammavong B, Caster J, Flynn RT. Needle-free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the 169 Yb Isotope. Med Phys 2020; 47:2061-2071. [PMID: 32073669 DOI: 10.1002/mp.14101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To assess the capability of an intracavitary 169 Yb-based helical multishield rotating shield brachytherapy (RSBT) delivery system to treat cervical cancer. The proposed RSBT delivery system contains a pair of 1.25 mm thick platinum partial shields with 45° and 180° emission angles, which travel in a helical pattern within the applicator. METHODS A helically threaded tandem applicator with a 45° tandem curvature containing a helically threaded catheter was designed. A 0.6 mm diameter 169 Yb source with a length of 10.5 mm was simulated. A 37-patient treatment planning study, based on Monte Carlo dose calculations using MCNP5, was conducted with high-risk clinical target volumes (HR-CTVs) of 41.2-192.8 cm3 (average ± standard deviation of 79.9 ± 35.8 cm3 ). All patients were assumed to receive 25 fractions of 1.8 Gy of external beam radiation therapy (EBRT) before receiving 5 fractions of high-dose-rate brachytherapy (HDR-BT). For each patient, 192 Ir-based intracavitary (IC) HDR-BT, 192 Ir-based intracavitary/interstitial (IC/IS) HDR-BT using a hybrid applicator with eight IS needles, and 169 Yb-based RSBT plans were generated. RESULTS For the IC, IC/IS, and RSBT treatment plans, 38%, 84%, and 86% of the plans, respectively, met the planning goal of an HR-CTV D90 (minimum dose to hottest 90%) of 85 GyEQD2 (α/β = 10 Gy). Median (25th percentile, 75th percentile) treatment times for IC, IC/IS, and RSBT were 11.71 (6.62, 15.40) min, 68.00 (45.02, 80.02) min, and 25.30 (13.87, 35.39) min, respectively. 192 Ir activities ranging from 159.1-370 GBq (4.3-10 Ci) and 169 Yb activities ranging from 429.2-999 GBq (11.6-27 Ci) were used, which correspond to the same clinical ranges of dose rates at 1 cm off-source-axis in water. Extra needle insertion and planning time beyond that needed for intracavitary-only approaches was accounted for in the IC/IS treatment time calculations. CONCLUSION 169 Yb-based RSBT for cervical cancer met the HR-CTV D90 goal of 85 Gy in a greater percentage of the patients considered than IC/IS (86% vs 84%, respectively) and can reduce overall treatment time relative to IC/IS. 169 Yb-based RSBT could be used to replace IC/IS in instances where IC/IS treatment is not available, especially in instances when HR-CTV volumes are ≥30 cm3 .
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Affiliation(s)
- Karolyn M Hopfensperger
- Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Quentin Adams
- 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
| | - Xiaodong Wu
- 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
| | - Kaustubh Patwardhan
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | | | - Joseph Caster
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
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Famulari G, Alfieri J, Duclos M, Vuong T, Enger SA. Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy? Brachytherapy 2020; 19:255-263. [DOI: 10.1016/j.brachy.2019.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/12/2019] [Accepted: 12/15/2019] [Indexed: 01/03/2023]
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Cunha JAM, Flynn R, Bélanger C, Callaghan C, Kim Y, Jia X, Chen Z, Beaulieu L. Brachytherapy Future Directions. Semin Radiat Oncol 2020; 30:94-106. [DOI: 10.1016/j.semradonc.2019.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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12
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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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13
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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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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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Adams Q, Hopfensperger KM, Kim Y, Wu X, Xu W, Shukla H, McGee J, Caster JM, Flynn RT. Effectiveness of Rotating Shield Brachytherapy for Prostate Cancer Dose Escalation and Urethral Sparing. Int J Radiat Oncol Biol Phys 2018; 102:1543-1550. [PMID: 30092333 PMCID: PMC6363898 DOI: 10.1016/j.ijrobp.2018.07.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/08/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE To compare single-fraction 153Gd-based rotating shield brachytherapy (RSBT) for prostate cancer with conventional 192Ir-based high-dose-rate brachytherapy (HDR-BT) in a planning study that radiobiologically accounts for dose rate and relative biological effectiveness. RSBT was used for planning target volume (PTV) dose escalation without increasing urethral dose for monotherapy, or for urethral sparing without decreasing PTV dose as a boost to external beam radiation therapy. METHODS AND MATERIALS Twenty-six patients were studied. PTV doses were expressed as equivalent dose delivered in 2 Gy fractions (EQD2), accounting for relative biological effectiveness (1.00 for 192Ir and 1.15 for 153Gd), dose protraction (114-minute repair half-time), and tumor dose response (α/β of 3.41 Gy). HDR-BT dose was prescribed such that 90% of the PTV received 110% of the prescription dose of 19 Gy for dose escalation and 15 Gy for urethral sparing, corresponding to EQD290% values (minimum EQD2 to the hottest 90% of the PTV) of 93.9 GyEQD2 and 60.7 GyEQD2, respectively. Twenty 90.95 GBq 153Gd RSBT sources and one 370 GBq 192Ir HDR-BT source were modeled. RESULTS For dose escalation with fresh sources, RSBT increased PTV EQD290% by 42.5% ± 8.4% (average ± standard deviation) without increasing urethral D10%, with treatment times of 216.8 ± 28.9 minutes versus 15.1 ± 2.1 minutes. After 1 half-life (240.4 days for 153Gd and 73.8 days for 192Ir), EQD290% increased 20.5% ± 9.1%. For urethral sparing with fresh sources, RSBT decreased urethral D10% by 26.0% ± 3.4% without decreasing PTV EQD290%, with treatment times of 133.6 ± 16.5 minutes versus 12.0 ± 1.7 minutes. After 1 half-life, urethral D10% decreased 20.2% ± 4.8%. CONCLUSIONS RSBT can increase PTV EQD90% or decrease urethral D10% relative to HDR-BT at the cost of increased treatment time. Source aging reduces RSBT benefit, but RSBT remains theoretically superior to HDR-BT by >20% after 1 half-life has elapsed.
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Affiliation(s)
- Quentin Adams
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
| | | | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Xiaodong Wu
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa; Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa
| | - Weiyu Xu
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa
| | | | - James McGee
- OSF Saint Francis Medical Center, Peoria, Illinois
| | - Joseph M Caster
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
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16
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Famulari G, Pater P, Enger SA. Microdosimetric Evaluation of Current and Alternative Brachytherapy Sources—A Geant4-DNA Simulation Study. Int J Radiat Oncol Biol Phys 2018; 100:270-277. [DOI: 10.1016/j.ijrobp.2017.09.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/09/2017] [Accepted: 09/18/2017] [Indexed: 12/12/2022]
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17
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Dadkhah H, Hopfensperger KM, Kim Y, Wu X, Flynn RT. Multisource Rotating Shield Brachytherapy Apparatus for Prostate Cancer. Int J Radiat Oncol Biol Phys 2017; 99:719-728. [PMID: 28843372 DOI: 10.1016/j.ijrobp.2017.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/02/2017] [Accepted: 06/08/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE Our purpose is to present a novel multisource rotating shield brachytherapy (RSBT) apparatus for the simultaneous precise angular and linear positioning of partially shielded 153Gd brachytherapy sources in interstitial needles for the treatment of locally advanced prostate cancer. It is designed to lower the dose to nearby healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy techniques. METHODS AND MATERIALS Following needle implantation through the patient template, an angular drive mechanism is docked to the patient template. Each needle is coupled to a multisource afterloader catheter by a connector passing through a shaft. The shafts are rotated about their axes by translating a moving template between 2 stationary templates. The shafts' surfaces and moving template holes are helically threaded with the same pattern such that translation of the moving template causes simultaneous rotation of the shafts. The rotation of each shaft is mechanically transmitted to the catheter-source-shield combination, inside the needles, via several key-keyway pairs. The catheter angles are simultaneously incremented throughout treatment, and only a single 360° rotation of all catheters is needed for a full treatment. For each rotation angle, source depth in each needle is controlled by a multisource afterloader, which is proposed as an array of belt-driven linear actuators, each of which drives a wire that controls catheter depth in a needle. RESULTS Treatment plans demonstrated that RSBT with the proposed apparatus reduced urethral D0.1cm3 (the minimum dose delivered to the hottest 0.1cm3 of the urethra) below that of conventional high-dose-rate brachytherapy by 31% for urethral dose gradient volume within 3 mm of the urethra surface. Treatment time to deliver 20 Gy with the proposed multisource RSBT apparatus by use of nineteen 62.4-GBq 153Gd sources was 122 minutes. CONCLUSIONS The proposed RSBT delivery apparatus enables a mechanically feasible urethra-sparing treatment technique for prostate cancer in a clinically reasonable time frame.
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Affiliation(s)
- Hossein Dadkhah
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | | | - Yusung Kim
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Xiaodong Wu
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa; Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
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18
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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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19
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Famulari G, Urlich T, Armstrong A, Enger SA. Practical aspects of 153Gd as a radioactive source for use in brachytherapy. Appl Radiat Isot 2017; 130:131-139. [PMID: 28963960 DOI: 10.1016/j.apradiso.2017.09.028] [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: 02/03/2017] [Revised: 05/25/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
The goal of this study was to investigate the production, purification and immobilization techniques for a 153Gd brachytherapy source. We have investigated the maximum attainable specific activity of 153Gd through the irradiation of Gd2O3 enriched to 30.6% 152Gd at McMaster Nuclear Reactor. The advantage of producing 153Gd through this production pathway is the possibility to irradiate pre-sealed pellets of 152Gd enriched Gd2O3, thereby removing the need to perform chemical separation with large quantities of radio-impurities. However, small amounts of long-lived impurities are produced from the irradiation of enriched 152Gd targets due to traces of Eu in the sample. If the amount of impurities produced is deemed unacceptable, 153Gd can be isolated as an aqueous solution, chemically separated from impurities and loaded onto a sorbent with a high affinity for Gd before encapsulation.
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Affiliation(s)
- Gabriel Famulari
- Medical Physics Unit, McGill University, Montreal, QC, Canada H4A 3J1.
| | - Tomas Urlich
- Department of Radiation Sciences, McMaster University, Hamilton, ON, Canada L8S 4L8
| | - Andrea Armstrong
- McMaster Nuclear Reactor (Isotope Development), McMaster University, Hamilton, ON, Canada L8S 4L8
| | - Shirin A Enger
- Medical Physics Unit, McGill University, Montreal, QC, Canada H4A 3J1; Department of Oncology, McGill University, Montreal, Quebec, Canada H4A 3J1; Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada H3H 2L9
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20
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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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21
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Ghorbani M, Khajetash B, Ghatei N, Mehrpouyan M, Meigooni AS, Shahraini R. Determination of dosimetric parameters for shielded 153Gd source in prostate cancer brachytherapy. Radiol Oncol 2017; 51:101-112. [PMID: 28265239 PMCID: PMC5330175 DOI: 10.1515/raon-2017-0009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 12/27/2016] [Indexed: 11/15/2022] Open
Abstract
Background Interstitial rotating shield brachytherapy (I-RSBT) is a recently developed method for treatment of prostate cancer. In the present study TG-43 dosimetric parameters of a 153Gd source were obtained for use in I-RSBT. Materials and methods A 153Gd source located inside a needle including a Pt shield and an aluminum window was simulated using MCNPX Monte Carlo code. Dosimetric parameters of this source model, including air kerma strength, dose rate constant, radial dose function and 2D anisotropy function, with and without the shields were calculated according to the TG-43 report. Results The air kerma strength was found to be 6.71 U for the non-shielded source with 1 GBq activity. This value was found to be 0.04 U and 6.19 U for the Pt shield and Al window cases, respectively. Dose rate constant for the non-shielded source was found to be 1.20 cGy/(hU). However, for a shielded source with Pt and aluminum window, dose rate constants were found to be 0.07 cGy/(hU) and 0.96 cGy/(hU), on the shielded and window sides, respectively. The values of radial dose function and anisotropy function were tabulated for these sources. Additionally, isodose curves were drawn for sources with and without shield, in order to evaluate the effect of shield on dose distribution. Conclusions Existence of the Pt shield may greatly reduce the dose to organs at risk and normal tissues which are located toward the shielded side. The calculated air kerma strength, dose rate constant, radial dose function and 2D anisotropy function data for the 153Gd source for the non-shielded and the shielded sources can be used in the treatment planning system (TPS).
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Affiliation(s)
- Mahdi Ghorbani
- Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Benyamin Khajetash
- Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Najmeh Ghatei
- Radiotherapy Department, Namazi Hospital, Shiraz, Iran
| | - Mohammad Mehrpouyan
- Radiology and Radiotherapy Department, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Ali S Meigooni
- Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA
| | - Ramin Shahraini
- Radiology and Radiotherapy Department, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
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Shi C, Wang B. Preliminary Monte Carlo Investigation of Using Ir-192 as the Source for Real Time Imaging Purpose. INTERNATIONAL JOURNAL OF MEDICAL PHYSICS, CLINICAL ENGINEERING AND RADIATION ONCOLOGY 2017; 6:21-30. [PMID: 28824832 PMCID: PMC5562365 DOI: 10.4236/ijmpcero.2017.61003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The purpose of this study is to investigate the potential use of Ir-192 as the source for real time imaging during HDR (High Dose Rate) brachytherapy treatment. Phantom measurement was performed to determine outside of the body dose. Monte Carlo code, EGSnrcMP egs_inprz, was used for the simulation to calculate the outside of the body x-ray signal for CT reconstruction. Matlab code was developed to reconstruct the Ir-192 source and for 3D visualization in order to assess reconstructed CT resolution, signal-to-noise ratio, and imaging dose information. The measured dose was 0.67 ± 0.04 cGy, which was comparable to the Monte Carlo simulation result 0.71 ± 0.20 cGy. The reconstructed source diameter dimension was 1.3 mm compared with 1.1 mm for the real source dimension. The signal-to-noise ratio was 19.91 db following de-noising. Source position was within a 1 mm difference between programmed and simulated results. Although the Ir-192 signal is weak for CT imaging, it is possible to use it as a CT imaging x-ray source for HDR treatment localization, verification and dosimetry purposes. Further study is needed for the detailed design of an outside of the body CT-like device for use in brachytherapy imaging.
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Affiliation(s)
- Chengyu Shi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Brian Wang
- Department of Radiation Oncology, James Brown Cancer Center, The University of Louisville, Louisville, KY, USA
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23
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Shearman R, Collins S, Keightley J, Pearce A, Garnier J. Absolute intensities of the γ-ray emissions originating from the electron capture decay of 153Gd. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714610008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Rivard MJ. A directional 103Pd brachytherapy device: Dosimetric characterization and practical aspects for clinical use. Brachytherapy 2016; 16:421-432. [PMID: 28039011 DOI: 10.1016/j.brachy.2016.11.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/10/2016] [Accepted: 11/29/2016] [Indexed: 02/08/2023]
Abstract
PURPOSE A brachytherapy (BT) device has been developed with shielding to provide directional BT for preferentially irradiating malignancies while sparing healthy tissues. The CivaSheet is a flexible low-dose-rate BT device containing CivaDots with 103Pd shielded by a thin Au disk. This is the first report of a clinical dosimetric characterization of the CivaSheet device. METHODS AND MATERIALS Radiation dose distributions near a CivaDot were estimated using the MCNP6 radiation transport code. CivaSheet arrays were also modeled to evaluate the dose superposition principle for treatment planning. The resultant data were commissioned in a treatment planning system (TPS) (VariSeed 9.0), and the accuracy of the dose superposition principle was evaluated for summing individual elements comprising a planar CivaSheet. RESULTS The dose-rate constant (0.579 cGy/h/U) was lower than for 103Pd seeds due to Au L-shell x-rays increasing the air-kerma strength. Radial dose function values at 0.1, 0.5, 2, 5, and 10 cm were 1.884, 1.344, 0.558, 0.088, and 0.0046, respectively. The two-dimensional anisotropy function exhibited dramatic reduction between the forward (0°) and rearward (180°) directions by a factor of 276 at r = 0.1 cm, 24 at r = 1 cm, and 5.3 at r = 10 cm. This effect diminished due to increasingly scattered radiation. The largest gradient in the two-dimensional anisotropy function was in contact with the device at 92° due to the Au disk shielding. TPS commissioning and dose superposition accuracies were typically within 2%. CONCLUSIONS Simulations of the CivaDot yielded comprehensive dosimetry parameters that were entered into a TPS and deemed acceptable for clinical use. Dosimetry measurements of the CivaSheet are also of interest to the BT community.
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Affiliation(s)
- Mark J Rivard
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, MA.
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Petric P, Hudej R, Al-Hammadi N, Segedin B. Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy. Radiol Oncol 2016; 50:433-441. [PMID: 27904452 PMCID: PMC5120583 DOI: 10.1515/raon-2016-0048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/29/2016] [Indexed: 11/22/2022] Open
Abstract
Background Standard applicators for cervical cancer Brachytherapy (BT) do not always achieve acceptable balance between target volume and normal tissue irradiation. We aimed to develop an innovative method of Target-volume Density Mapping (TDM) for modelling of novel applicator prototypes with optimal coverage characteristics. Patients and methods. Development of Contour-Analysis Tool 2 (CAT-2) software for TDM generation was the core priority of our task group. Main requests regarding software functionalities were formulated and guided the coding process. Software validation and accuracy check was performed using phantom objects. Concepts and terms for standardized workflow of TDM post-processing and applicator development were introduced. Results CAT-2 enables applicator-based co-registration of Digital Imaging and Communications in Medicine (DICOM) structures from a sample of cases, generating a TDM with pooled contours in applicator-eye-view. Each TDM voxel is assigned a value, corresponding to the number of target contours encompassing that voxel. Values are converted to grey levels and transformed to DICOM image, which is transported to the treatment planning system. Iso-density contours (IDC) are generated as lines, connecting voxels with same grey levels. Residual Volume at Risk (RVR) is created for each IDC as potential volume that could contain organs at risk. Finally, standard and prototype applicators are applied on the TDM and virtual dose planning is performed. Dose volume histogram (DVH) parameters are recorded for individual IDC and RVR delineations and characteristic curves generated. Optimal applicator configuration is determined in an iterative manner based on comparison of characteristic curves, virtual implant complexities and isodose distributions. Conclusions Using the TDM approach, virtual applicator prototypes capable of conformal coverage of any target volume, can be modelled. Further systematic assessment, including studies on clinical feasibility, safety and effectiveness are needed before routine use of novel prototypes can be considered.
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Affiliation(s)
- Primoz Petric
- National Center for Cancer Care and Research, Hamad Medical Corporation, Doha, Qatar; Institute of Oncology Ljubljana, Ljubljana, Slovenia
| | - Robert Hudej
- Institute of Oncology Ljubljana, Ljubljana, Slovenia
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Evaluation of hypothetical (153)Gd source for use in brachytherapy. Rep Pract Oncol Radiother 2016; 21:17-24. [PMID: 26900353 DOI: 10.1016/j.rpor.2015.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/06/2015] [Accepted: 05/24/2015] [Indexed: 11/23/2022] Open
Abstract
AIM The purpose of this work is to evaluate the dosimetric parameters of a hypothetical (153)Gd source for use in brachytherapy and comparison of the dosimetric parameters with those of (192)Ir and (125)I sources. MATERIALS AND METHODS Dose rate constant, the radial dose function and the two dimensional (2D) anisotropy function data for the hypothetical (153)Gd source were obtained by simulation of the source using MCNPX code and then were compared with the corresponding data reported by Enger et al. A comprehensive comparison between this hypothetical source and a (192)Ir source with similar geometry and a (125)I source was performed as well. RESULTS Excellent agreement was shown between the results of the two studies. Dose rate constant values for the hypothetical (153)Gd, (192)Ir, (125)I sources are 1.173 cGyh(-1) U(-1), 1.044 cGyh(-1) U(-1), 0.925 cGyh(-1) U(-1), respectively. Radial dose function for the hypothetical (153)Gd source has an increasing trend, while (192)Ir has more uniform and (125)I has more rapidly falling off radial dose functions. 2D anisotropy functions for these three sources indicate that, except at 0.5 cm distance, (192)Ir and (125)I have more isotropic trends as compared to the (153)Gd source. CONCLUSION A more uniform radial dose function, and 2D anisotropy functions with more isotropy, a much higher specific activity are advantages of (192)Ir source over (153)Gd. However, a longer half-life of (153)Gd source compared to the other two sources, and lower energy of the source with respect to (192)Ir are advantages of using (153)Gd in brachytherapy versus (192)Ir source.
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Evaluation of (101)Rh as a brachytherapy source. J Contemp Brachytherapy 2015; 7:171-80. [PMID: 26034499 PMCID: PMC4444454 DOI: 10.5114/jcb.2015.50662] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 12/12/2014] [Accepted: 02/15/2015] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Recently a number of hypothetical sources have been proposed and evaluated for use in brachytherapy. In the present study, a hypothetical (101)Rh source with mean photon energy of 121.5 keV and half-life of 3.3 years, has been evaluated as an alternative to the existing high-dose-rate (HDR) sources. Dosimetric characteristics of this source model have been determined following the recommendation of the Task Group 43 (TG-43) of the American Association of the Physicist in Medicine (AAPM), and the results are compared with the published data for (57)Co source and Flexisource (192)Ir sources with similar geometries. MATERIAL AND METHODS MCNPX Monte Carlo code was used for simulation of the (101)Rh hypothetical HDR source design. Geometric design of this hypothetical source was considered to be similar to that of Flexisource (192)Ir source. Task group No. 43 dosimetric parameters, including air kerma strength per mCi, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated for the (101)Rh source through simulations. RESULTS Air kerma strength per activity and dose rate constant for the hypothetical (101)Rh source were 1.09 ± 0.01 U/mCi and 1.18 ± 0.08 cGy/(h.U), respectively. At distances beyond 1.0 cm in phantom, radial dose function for the hypothetical (101)Rh source is higher than that of (192)Ir. It has also similar 2D anisotropy functions to the Flexisource (192)Ir source. CONCLUSIONS (101)Rh is proposed as an alternative to the existing HDR sources for use in brachytherapy. This source provides medium energy photons, relatively long half-life, higher dose rate constant and radial dose function, and similar 2D anisotropy function to the Flexisource (192)Ir HDR source design. The longer half-life of the source reduces the frequency of the source exchange for the clinical environment.
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