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Suitability of point kernel dose calculation techniques in brachytherapy treatment planning

Brachytherapy treatment planning system (TPS) is necessary to estimate the dose to target volume and organ at risk (OAR). TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software pa...

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Autores principales: Lakshminarayanan, Thilagam, Subbaiah, K. V., Thayalan, K., Kannan, S. E.
Formato: Texto
Lenguaje:English
Publicado: Medknow Publications 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884310/
https://www.ncbi.nlm.nih.gov/pubmed/20589118
http://dx.doi.org/10.4103/0971-6203.62202
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author Lakshminarayanan, Thilagam
Subbaiah, K. V.
Thayalan, K.
Kannan, S. E.
author_facet Lakshminarayanan, Thilagam
Subbaiah, K. V.
Thayalan, K.
Kannan, S. E.
author_sort Lakshminarayanan, Thilagam
collection PubMed
description Brachytherapy treatment planning system (TPS) is necessary to estimate the dose to target volume and organ at risk (OAR). TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software packages estimate the absorbed dose at a point, taking care of only the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. There are some degrees of uncertainties in dose rate estimations under realistic clinical conditions. In this regard, an attempt is made to explore the suitability of point kernels for brachytherapy dose rate calculations and develop new interactive brachytherapy package, named as BrachyTPS, to suit the clinical conditions. BrachyTPS is an interactive point kernel code package developed to perform independent dose rate calculations by taking into account the effect of these heterogeneities, using two regions build up factors, proposed by Kalos. The primary aim of this study is to validate the developed point kernel code package integrated with treatment planning computational systems against the Monte Carlo (MC) results. In the present work, three brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, namely (i) Board of Radiation Isotope and Technology (BRIT) low dose rate (LDR) applicator and (ii) Fletcher Green type LDR applicator (iii) Fletcher Williamson high dose rate (HDR) applicator, are studied to test the accuracy of the software. Dose rates computed using the developed code are compared with the relevant results of the MC simulations. Further, attempts are also made to study the dose rate distribution around the commercially available shielded vaginal applicator set (Nucletron). The percentage deviations of BrachyTPS computed dose rate values from the MC results are observed to be within plus/minus 5.5% for BRIT LDR applicator, found to vary from 2.6 to 5.1% for Fletcher green type LDR applicator and are up to −4.7% for Fletcher-Williamson HDR applicator. The isodose distribution plots also show good agreements with the results of previous literatures. The isodose distributions around the shielded vaginal cylinder computed using BrachyTPS code show better agreement (less than two per cent deviation) with MC results in the unshielded region compared to shielded region, where the deviations are observed up to five per cent. The present study implies that the accurate and fast validation of complicated treatment planning calculations is possible with the point kernel code package.
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spelling pubmed-28843102010-06-29 Suitability of point kernel dose calculation techniques in brachytherapy treatment planning Lakshminarayanan, Thilagam Subbaiah, K. V. Thayalan, K. Kannan, S. E. J Med Phys Original Article Brachytherapy treatment planning system (TPS) is necessary to estimate the dose to target volume and organ at risk (OAR). TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software packages estimate the absorbed dose at a point, taking care of only the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. There are some degrees of uncertainties in dose rate estimations under realistic clinical conditions. In this regard, an attempt is made to explore the suitability of point kernels for brachytherapy dose rate calculations and develop new interactive brachytherapy package, named as BrachyTPS, to suit the clinical conditions. BrachyTPS is an interactive point kernel code package developed to perform independent dose rate calculations by taking into account the effect of these heterogeneities, using two regions build up factors, proposed by Kalos. The primary aim of this study is to validate the developed point kernel code package integrated with treatment planning computational systems against the Monte Carlo (MC) results. In the present work, three brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, namely (i) Board of Radiation Isotope and Technology (BRIT) low dose rate (LDR) applicator and (ii) Fletcher Green type LDR applicator (iii) Fletcher Williamson high dose rate (HDR) applicator, are studied to test the accuracy of the software. Dose rates computed using the developed code are compared with the relevant results of the MC simulations. Further, attempts are also made to study the dose rate distribution around the commercially available shielded vaginal applicator set (Nucletron). The percentage deviations of BrachyTPS computed dose rate values from the MC results are observed to be within plus/minus 5.5% for BRIT LDR applicator, found to vary from 2.6 to 5.1% for Fletcher green type LDR applicator and are up to −4.7% for Fletcher-Williamson HDR applicator. The isodose distribution plots also show good agreements with the results of previous literatures. The isodose distributions around the shielded vaginal cylinder computed using BrachyTPS code show better agreement (less than two per cent deviation) with MC results in the unshielded region compared to shielded region, where the deviations are observed up to five per cent. The present study implies that the accurate and fast validation of complicated treatment planning calculations is possible with the point kernel code package. Medknow Publications 2010 /pmc/articles/PMC2884310/ /pubmed/20589118 http://dx.doi.org/10.4103/0971-6203.62202 Text en © Journal of Medical Physics http://creativecommons.org/licenses/by/2.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Article
Lakshminarayanan, Thilagam
Subbaiah, K. V.
Thayalan, K.
Kannan, S. E.
Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title_full Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title_fullStr Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title_full_unstemmed Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title_short Suitability of point kernel dose calculation techniques in brachytherapy treatment planning
title_sort suitability of point kernel dose calculation techniques in brachytherapy treatment planning
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884310/
https://www.ncbi.nlm.nih.gov/pubmed/20589118
http://dx.doi.org/10.4103/0971-6203.62202
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