<abstract xmlns="http://www.w3.org/1999/xhtml"><sec id="j_raon-2017-0009_s_333_w2aab3b8c11b1b7b1aab1c16b1Aa"><h3>Background</h3><p>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 <sup>153</sup>Gd source were obtained for use in I-RSBT.</p></sec><sec id="j_raon-2017-0009_s_334_w2aab3b8c11b1b7b1aab1c16b2Aa"><h3>Materials and methods</h3><p>A <sup>153</sup>Gd 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.</p></sec><sec id="j_raon-2017-0009_s_335_w2aab3b8c11b1b7b1aab1c16b3Aa"><h3>Results</h3><p>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.</p></sec><sec id="j_raon-2017-0009_s_336_w2aab3b8c11b1b7b1aab1c16b4Aa"><h3>Conclusions</h3><p>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 <sup>153</sup>Gd source for the non-shielded and the shielded sources can be used in the treatment planning system (TPS).</p></sec></abstract>

BackgroundInterstitial 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 methodsA 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.ResultsThe 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.ConclusionsExistence 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).

Determination of dosimetric parameters for shielded <sup>153</sup>Gd source in prostate cancer brachytherapy

Biomedical Engineering and Medical Physics Department, Faculty of Medicine

Medical Physics Department, School of Medicine

Radiology and Radiotherapy Department, Faculty of Medicine

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.

Determination of dosimetric parameters for shielded Gd source in prostate cancer brachytherapy

BackgroundInterstitial rotating shield brachytherapy (I-RSBT) is a recently developed method for treatment of prostate cancer. In the present study TG-43...

Determination of dosimetric parameters for shielded ¹⁵³Gd source in prostate cancer brachytherapy

Article Category: Research Article

Published Online: Feb 22, 2017

Page range: 101 - 112

Received: Jun 22, 2016

Accepted: Dec 27, 2016

DOI: https://doi.org/10.1515/raon-2017-0009

Keywords
interstitial rotating shield brachytherapy, Gd, TG-43 dosimetric parameters, Monte Carlo simulation

© 2017 Mahdi Ghorbani, Benyamin Khajetash, Najmeh Ghatei, Mohammad Mehrpouyan, Ali S. Meigooni, Ramin Shahraini

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.

Determination of dosimetric parameters for shielded 153Gd source in prostate cancer brachytherapy

Article Category: Research Article

Published Online: Feb 22, 2017

Page range: 101 - 112

Received: Jun 22, 2016

Accepted: Dec 27, 2016

DOI: https://doi.org/10.1515/raon-2017-0009

Keywordsinterstitial rotating shield brachytherapy, Gd, TG-43 dosimetric parameters, Monte Carlo simulation

© 2017 Mahdi Ghorbani, Benyamin Khajetash, Najmeh Ghatei, Mohammad Mehrpouyan, Ali S. Meigooni, Ramin Shahraini

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.

Determination of dosimetric parameters for shielded ¹⁵³Gd source in prostate cancer brachytherapy

Keywords
interstitial rotating shield brachytherapy, Gd, TG-43 dosimetric parameters, Monte Carlo simulation