Dosimetric investigation of a new high dose rate 192Ir brachytherapy source, IRAsource, by Monte Carlo method

Atefeh Rostami; Mahdi Hoseini; Mahdi Ghorbani; Courtney Knaup

doi:10.1016/j.rpor.2019.12.022

Dosimetric investigation of a new high dose rate ¹⁹²Ir brachytherapy source, IRAsource, by Monte Carlo method

Rep Pract Oncol Radiother. 2020 Jan-Feb;25(1):139-145. doi: 10.1016/j.rpor.2019.12.022. Epub 2019 Dec 26.

Authors

Atefeh Rostami¹, Mahdi Hoseini², Mahdi Ghorbani³, Courtney Knaup⁴

Affiliations

¹ Department of Medical Physics and Radiological Sciences, Faculty of Paramedical Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran.
² Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
³ Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
⁴ Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA.

Abstract

Purpose: The purpose of the present study was to perform an independent calculation of dosimetric parameters associated with a new ¹⁹²Ir brachytherapy source model, IRAsource.

Materials and methods: The parameters of air kerma strength (AKS), dose rate constant (DRC), geometry function (GF), radial dose function (RDF), as well as two-dimensional (2D) anisotropy function (AF) of IRAsource ¹⁹²Ir source model were calculated in this study. The MC n-particle extended (MCNPX) code was also employed for simulating high dose rate (HDR), IRAsource and ¹⁹²Ir source; and formalism was used for calculating dosimetry parameters based on task group number 43 updated report (TG-43 U1).

Results: The results of this study were consistent with the ones reported about the IRAsource source by Sarabiasl et al. The AKS per 1 mCi activity and the DRC values were also equal to 3.65 cGycm² h^-1 mCi^-1 and 1.094 cGyh^-1U^-1; respectively. The comparison of the results of the DRC and the RDF reported by Sarabiasl et al. also validated the ¹⁹²Ir IRAsource simulation in this study. Moreover, the AFs of IRAsource source model were in a good agreement with those of Sarabiasl et al. at different distances, which could be attributed to identical geometries.

Conclusion: In line with those reported by Sarabiasl et al., the results of this study confirmed the IRAsource ¹⁹²Ir source for clinical uses. The calculated dosimetric parameters of the IRAsource source could be utilized in clinical practices as input data sets or for validation of treatment planning system calculations.

Keywords: Brachytherapy; Dosimetric parameters; IRAsource source; MCNPX.