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Yousif YAM, Osman AFI, Halato MA. A review of dosimetric impact of implementation of model-based dose calculation algorithms (MBDCAs) for HDR brachytherapy. Phys Eng Sci Med 2021; 44:871-886. [PMID: 34142317 DOI: 10.1007/s13246-021-01029-8] [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: 11/26/2020] [Accepted: 06/14/2021] [Indexed: 11/29/2022]
Abstract
To obtain dose distributions more physically representative to the patient anatomy in brachytherapy, calculation algorithms that can account for heterogeneity are required. The current standard AAPM Task Group No 43 (TG-43) dose calculation formalism has some clinically relevant dosimetric limitations. Lack of tissue heterogeneity and scattered dose corrections are the major weaknesses of the TG-43 formalism and could lead to systematic dose errors in target volumes and organs at risk. Over the last decade, model-based dose calculation algorithms (MBDCAs) have been clinically offered as complementary algorithms beyond the TG43 formalism for high dose rate (HDR) brachytherapy treatment planning. These algorithms provide enhanced dose calculation accuracy by using the information in the patient's computed tomography images, which allows modeling the patient's geometry, material compositions, and the treatment applicator. Several researchers have investigated the implementation of MBDCAs in HDR brachytherapy for dose optimization, but moving toward using them as primary algorithms for dose calculations is still lagging. Therefore, an overview of up-to-date research is needed to familiarize clinicians with the current status of the MBDCAs for different cancers in HDR brachytherapy. In this paper, we review the MBDCAs for HDR brachytherapy from a dosimetric perspective. Treatment sites covered include breast, gynecological, lung, head and neck, esophagus, liver, prostate, and skin cancers. Moreover, we discuss the current status of implementation of MBDCAs and the challenges.
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Affiliation(s)
- Yousif A M Yousif
- Department of Radiation Oncology, North West Cancer Centre-Tamworth Hospital, Tamworth, Australia.
| | - Alexander F I Osman
- Department of Medical Physics, Al-Neelain University, 11121, Khartoum, Sudan.
| | - Mohammed A Halato
- Department of Medical Physics, Al-Neelain University, 11121, Khartoum, Sudan
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Cawston-Grant B, Morrison H, Sloboda RS, Menon G. Experimental assessment of the Advanced Collapsed-cone Engine for scalp brachytherapy treatments. Brachytherapy 2017; 17:489-499. [PMID: 29239813 DOI: 10.1016/j.brachy.2017.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE To experimentally assess the performance of the Advanced Collapsed-cone Engine (ACE) for 192Ir high-dose-rate brachytherapy treatment planning of nonmelanoma skin cancers of the scalp. METHODS AND MATERIALS A layered slab phantom was designed to model the head (skin, skull, and brain) and surface treatment mold using tissue equivalent materials. Six variations of the phantom were created by varying skin thickness, skull thickness, and size of air gap between the mold and skin. Treatment planning was initially performed using the Task Group 43 (TG-43) formalism with CT images of each phantom variation. Doses were recalculated using standard and high accuracy modes of ACE. The plans were delivered to Gafchromic EBT3 film placed between different layers of the phantom. RESULTS Doses calculated by TG-43 and ACE and those measured by film agreed with each other at most locations within the phantoms. For a given phantom variation, average TG-43- and ACE-calculated doses were similar, with a maximum difference of (3 ± 12)% (k = 2). Compared to the film measurements, TG-43 and ACE overestimated the film-measured dose by (13 ± 12)% (k = 2) for one phantom variation below the skull layer. CONCLUSIONS TG-43- and ACE-calculated and film-measured doses were found to agree above the skull layer of the phantom, which is where the tumor would be located in a clinical case. ACE appears to underestimate the attenuation through bone relative to that measured by film; however, the dose to bone is below tolerance levels for this treatment.
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Affiliation(s)
- Brie Cawston-Grant
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Hali Morrison
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Ron S Sloboda
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Geetha Menon
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
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Cawston-Grant B, Morrison H, Menon G, Sloboda RS. Experimental verification of Advanced Collapsed-cone Engine for use with a multichannel vaginal cylinder applicator. J Appl Clin Med Phys 2017; 18:16-27. [PMID: 28317325 PMCID: PMC5689852 DOI: 10.1002/acm2.12061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/09/2017] [Accepted: 01/26/2017] [Indexed: 01/16/2023] Open
Abstract
Model‐based dose calculation algorithms have recently been incorporated into brachytherapy treatment planning systems, and their introduction requires critical evaluation before clinical implementation. Here, we present an experimental evaluation of Oncentra® Brachy Advanced Collapsed‐cone Engine (ACE) for a multichannel vaginal cylinder (MCVC) applicator using radiochromic film. A uniform dose of 500 cGy was specified to the surface of the MCVC using the TG‐43 dose formalism under two conditions: (a) with only the central channel loaded or (b) only the peripheral channels loaded. Film measurements were made at the applicator surface and compared to the doses calculated using TG‐43, standard accuracy ACE (sACE), and high accuracy ACE (hACE). When the central channel of the applicator was used, the film measurements showed a dose increase of (11 ± 8)% (k = 2) above the two outer grooves on the applicator surface. This increase in dose was confirmed with the hACE calculations, but was not confirmed with the sACE calculations at the applicator surface. When the peripheral channels were used, a periodic azimuthal variation in measured dose was observed around the applicator. The sACE and hACE calculations confirmed this variation and agreed within 1% of each other at the applicator surface. Additionally for the film measurements with the central channel used, a baseline dose variation of (10 ± 4)% (k = 2) of the mean dose was observed azimuthally around the applicator surface, which can be explained by offset source positioning in the central channel.
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Affiliation(s)
- Brie Cawston-Grant
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, T6G 1Z2, Canada.,Department of Oncology, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Hali Morrison
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, T6G 1Z2, Canada.,Department of Oncology, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Geetha Menon
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, T6G 1Z2, Canada.,Department of Oncology, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Ron S Sloboda
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, T6G 1Z2, Canada.,Department of Oncology, University of Alberta, Edmonton, AB, T6G 2R3, Canada
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Ghorbani M, Hashempour M, Azizi M, Meigooni AS. Evaluating the effect of various intracavitary applicators on dosimetric parameters of 192Ir, 137Cs, and 60Co sources. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:477-91. [DOI: 10.1007/s13246-016-0441-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 03/30/2016] [Indexed: 01/08/2023]
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Sung W, Kim S, Kim JI, Lee JG, Shin YJ, Jung JY, Ye SJ. Dosimetric perturbations due to an implanted cardiac pacemaker in MammoSite® treatment. Med Phys 2012; 39:6185-91. [DOI: 10.1118/1.4752088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Uniyal SC, Naithani UC, Sharma SD, Srivastava AK. Radiochromic film dosimetry of rectal inhomogeneity and applicator attenuation in high dose rate brachytherapy of uterine cervix. J Appl Clin Med Phys 2012; 13:3654. [PMID: 22231217 PMCID: PMC5716133 DOI: 10.1120/jacmp.v13i1.3654] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 09/08/2011] [Accepted: 09/12/2011] [Indexed: 01/08/2023] Open
Abstract
Heterogeneities existing in the patient during treatment are neglected, as the treated subject is considered homogeneous in most of the commercially‐available treatment planning systems (TPSs) used for high dose rate (HDR) brachytherapy. The choice of a suitable dosimeter for experimental dosimetry near the HDR source is crucial, mainly due to existence of steep dose gradients. The present work aimed to assess the effect of rectal air heterogeneity and applicator attenuation in the HDR Ir‐192 brachytherapy treatment of carcinoma uterine cervix by utilizing GAFCHROMIC EBT2 film dosimetry. The dose to rectal walls under the condition of rectal air heterogeneity was measured experimentally using EBT2 film in a rectal phantom, and the measurements were validated by the Monte Carlo (MC) simulations. The applicator attenuation was measured by EBT2 film for a commonly used stainless steel uterine tube in a homogeneous water equivalent phantom. The measured doses were compared with the TPS calculated values. In case of the air cavity, the measured dose at the closest rectal surface was 12.8% less than the TPS calculated value due to lack of back scattering, whereas at the farthest rectal surface, it was higher by 24.5% due to no attenuation. The magnitude of attenuation due to the metal applicator was measured as high as 2% when compared with the TPS calculation. The dose reduction at the nearest rectal surface due to the effect of rectal air has indicated a clinically favorable dose distribution within the rectum, whereas the shielding effect posed by the metallic applicator was found to be less significant. Mutual agreement of the measured doses with the MC calculated dose values confirmed the suitability of EBT2 film for clinical dosimetry in HDR brachytherapy. PACS numbers: 87.53.Bn, 87.53.Jw, 87.56.bg, 87.55.Qr
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Affiliation(s)
- Satish C Uniyal
- Department of Radiology, Himalayan Institute of Medical Sciences, HIHT University, Jolly Grant, Dehradun 248140, India.
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Afsharpour H, Landry G, Reniers B, Pignol JP, Beaulieu L, Verhaegen F. Tissue modeling schemes in low energy breast brachytherapy. Phys Med Biol 2011; 56:7045-60. [DOI: 10.1088/0031-9155/56/22/004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Sadeghi M, Taghdiri F, Saidi P. Dosimetric characteristics of the ¹⁹²Ir high-dose-rate afterloading brachytherapy source. Jpn J Radiol 2011; 29:324-9. [PMID: 21717300 DOI: 10.1007/s11604-011-0562-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Accepted: 01/10/2011] [Indexed: 11/30/2022]
Abstract
PURPOSE For the treatment of some cancerous tumors using brachytherapy, an American Association of Physicists in Medicine (AAPM) Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for a Ir2.A85-2 brachytherapy source design. MATERIALS AND METHODS Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. RESULTS The Monte Carlo calculated dose rate constant, Λ, of the Ir2.A85-2 source was found to be 1.113 ± 0.033 cGyU(-1)h(-1). Also in this study, the line-source radial dose function, g ( l )(r) and the anisotropy function, F(r,θ), have been calculated at distances from 0.5 to 10 cm. The results of these calculations have been compared with the published data for the same source. CONCLUSION All the results are in good concordance with previously published data, with a few exceptions in small angles and short distances. The dosimetric parameters calculated in this work can be used as input data in a treatment planning system (TPS) for exact brachytherapy treatment planning or to verify the calculations of the TPS used in brachytherapy.
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Affiliation(s)
- Mahdi Sadeghi
- Agricultural, Medical, and Industrial Research School, Nuclear Science and Technology Research Institute, PO Box 31485/498, Karaj, Tehran, Iran.
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Price MJ, Kry SF, Eifel PJ, Salehpour M, Mourtada F. Dose perturbation due to the polysulfone cap surrounding a Fletcher-Williamson colpostat. J Appl Clin Med Phys 2010; 11:3146. [PMID: 20160700 PMCID: PMC5719781 DOI: 10.1120/jacmp.v11i1.3146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 09/24/2009] [Accepted: 10/28/2009] [Indexed: 01/07/2023] Open
Abstract
We conducted a Monte Carlo evaluation of the dosimetric impact of the polysulfone cap used with the Fletcher‐Williamson (FW) colpostat for I192r high‐dose rate and pulsed‐dose rate intracavitary brachytherapy. Polysulfone caps with diameters of 30 mm, 25 mm, 20 mm, and 16 mm (mini‐ovoid) were simulated, and the absorbed dose rate in surrounding water was calculated and compared to the dose rate calculated for a bare I192r source in water. The dose perturbation depended on the cap diameter, distance away from the cap surface, and angular position around the cap. The largest dose rate reductions were found to be where the cap is thickest, in the general direction of the tumor bed. The range of perturbation mainly from the polysulfone cap over all depths and cap diameters was +2.8% (dose enhancement) to −6.8% (dose reduction); this perturbation is separate from the well‐documented attenuation of the rectal and bladder tungsten shields of the colpostat. Based on the impact of the polysulfone cape, the FW colpostat cap's material composition should be modified to reduce this dosimetric effect, or brachytherapy treatment planning dose algorithms should be improved to account for this perturbation. PACS numbers: 87.10.Rt 87.53.‐j 87.53.Bn 87.53.Jw
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Affiliation(s)
- Michael J Price
- Department of Medical Physics, Mary Bird Perkins Cancer Center, Louisiana State University Baton Rouge, LA, USA
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Sureka CS, Aruna P, Ganesan S, Sunny CS, Subbaiah KV. Computation of relative dose distribution and effective transmission around a shielded vaginal cylinder with Ir192 HDR source using MCNP4B. Med Phys 2006; 33:1552-61. [PMID: 16872062 DOI: 10.1118/1.2184437] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The present work is primarily focused on the estimation of relative dose distribution and effective transmission around a shielded vaginal cylinder with an 192Ir source using the Monte Carlo technique. The MCNP4B code was used to evaluate the dose distribution around a tungsten shielded vaginal cylinder as a function of thickness and angular shielding. The dose distribution and effective transmission of 192Ir by 0.8 cm thickness tungsten were also compared with that for gold and lead. Dose distributions were evaluated for different distances starting from 1.35 cm to 10.15 cm from the center of the cylinder. Dose distributions were also evaluated sequentially from 0 degrees to 180 degrees for every 5 degrees interval. Studies show that all the shielding material at 0.8 cm thickness contribute tolerable doses to normal tissues and also protect the critical organs such as the rectum and bladder. However, the computed dose values are in good agreement with the reported experimental values. It was also inferred that the higher the shielding angles, the more the protection of the surrounding tissues. Among the three shielding materials, gold has been observed to have the highest attenuation and hence contribute lowest transmission in the shielded region. Depending upon the shielding angle and thickness, it is possible to predict the dose distribution using the MCNP4B code. In order to deliver the higher dose to the unshielded region, lead may be considered as the shielding material and further it is highly economic over other materials.
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Affiliation(s)
- Chandra Sekaran Sureka
- Division of Medical Physics and Lasers, Department of Physics, Anna University, Chennai 600 025, India
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