Sains Malaysiana 49(3)(2020): 693-701

http://dx.doi.org/10.17576/jsm-2020-4903-24

 

Monte Carlo Investigation on Neutron Dosimetry Parameters of 252Cf Isotron Brachytherapy Source

(Kajian Monte Carlo ke atas Parameter Dosimetri Neutron Sumber Brakiterapi 252Cf Isotron)

 

OME LEILA AHMADI & HOSSEIN TAVAKOLI-ANBARAN*

 

Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran

 

Received: 22 June 2019/Accepted: 11 November 2019

 

Abstract

In the present study, all dosimetry parameters around the 252Cf Isotron source for neutron brachytherapy were calculated. The 252Cf neutron energy spectrum was modeled using the Maxwellian spectrum. The calculations were performed using MCNPX.2.6.0 code based on the TG-43U1 protocol in the water medium. The neutron air kerma strength for the 252Cf Isotron source was computed as 0.3098 ± 0.0002 cGy cm2gh and the neutron dose rate constant was 6.559 ± 0.003 cGy/Uh. The anisotropy functions were calculated at intervals of 1, 2, 3, 4, and 5cm at different polar angles in the range of θ = 0̊ to 90º in respect to the source long axis in a water Phantom. The uncertainty of the calculated data at all distances is less than 1%. The radial dose function at different distances from the source for the Isotron model was compared with the theoretical HDR 252Cf source model. The discrepancies between the results were the highest at the distance of 0.5 cm, with relative differences of 5.64 %. For the 252Cf Isotron source, the data presented in this study provides better understanding on the dosimetric distribution of a theoretical neutron brachytherapy source, for potential clinical application.

 

Keywords: Brachytherapy; Isotron; neutron dosimetry; 252Cf

 

Abstrak

Dalam kajian ini, semua parameter dosimetri sekitar sumber Isotron 252Cf  untuk brakiterapi neutron dihitung. Spektrum tenaga neutron 252Cf dimodelkan menggunakan spektrum Maxwellian. Pengiraan dilakukan menggunakan kod MCNPX.2.6.0 berdasarkan protokol TG-43U1 dalam medium air. Kekuatan kerma udara neutron untuk sumber Isotron 252Cf dihitung sebagai 0.30986 ± 0.0002 cGy cm2gh dan kadar dos neutron tetap ialah 6.559 ± 0.003 cGy/Uh. Fungsi anisotropi dihitung pada selang 1, 2, 3, 4 dan 5 cm pada sudut polar yang berbeza dalam julat θ = 0º hingga 90º berkenaan dengan paksi panjang sumber dalam Phantom air. Ketidakpastian data yang dihitung pada semua jarak adalah kurang daripada 1%. Fungsi dos radial pada jarak yang berbeza daripada sumber untuk model Isotron dibandingkan dengan model sumber HDR 252Cf teoritis. Perbezaan antara keputusan adalah yang tertinggi pada jarak 0.5 cm, dengan perbezaan relatif 5.64%. Bagi sumber Isotron 252Cf, data yang dibentangkan dalam kajian ini memberikan pemahaman yang lebih baik mengenai pengagihan dosimetri sumber brakiterapi neutron teoritis, untuk aplikasi klinikal yang berpotensi.

 

Kata kunci: Brakiterapi; dosimetri neutron; Isotron; 252Cf

 

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*Corresponding author; email: tavakoli-anbaran@shahroodut.ac.ir

 

 

 

 

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