<abstract xmlns="http://www.w3.org/1999/xhtml"><sec><h3>Aim</h3><p>The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters.</p></sec><sec><h3>Background</h3><p>Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources.</p></sec><sec><h3>Materials and methods</h3><p>MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared.</p></sec><sec><h3>Results</h3><p>Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours.</p></sec><sec><h3>Conclusions</h3><p>Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.</p></sec></abstract>

AimThe aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters.BackgroundDifferent photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources.Materials and methodsMCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared.ResultsDose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours.ConclusionsDosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

Bioinformatics Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran

Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA

Department of Basic Medical Sciences, Neyshabur University of Medical Sciences, Neyshabur, Iran

Radiology and Oncology

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

AimThe aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric...

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

Article Category: Research Article

Published Online: Mar 31, 2016

Page range: 238 - 246

Received: Nov 02, 2015

Accepted: Jan 29, 2016

DOI: https://doi.org/10.1515/raon-2016-0019

Keywords
photon energy spectrum, brachytherapy, TG-43 dosimetric parameters, dose distribution

© 2016 Radiol Oncol

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

Article Category: Research Article

Published Online: Mar 31, 2016

Page range: 238 - 246

Received: Nov 02, 2015

Accepted: Jan 29, 2016

DOI: https://doi.org/10.1515/raon-2016-0019

Keywordsphoton energy spectrum, brachytherapy, TG-43 dosimetric parameters, dose distribution

© 2016 Radiol Oncol

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Keywords
photon energy spectrum, brachytherapy, TG-43 dosimetric parameters, dose distribution