Year : 2019 | Volume
: 15 | Issue : 1 | Page : 237--244
Tissue composition effect on dose distribution in radiotherapy with a 6 MV photon beam of a medical linac
Mahdi Ghorbani1, Atefeh Vejdani Noghreiyan2, Zahra Sadat Tabatabaei2, Delaram Pakravan3, David Davenport4
1 Department of Biomedical Engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2 Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
3 Department of Physics, Faculty of Basic Sciences, Islamic Azad University, Ahvaz, Iran
4 Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA
Aim: The aim of this study is to evaluate soft-tissue composition effect on dose distribution for various soft tissues in radiotherapy with a 6 MV photon beam of a medical linac.
Background: The compositions of various soft tissues are different which could affect dose calculations.
Materials and Methods: A phantom and Siemens Primus linear accelerator were simulated using MCNPX Monte Carlo code. In a homogeneous cubic phantom, six types of soft tissue and three types of tissue-equivalent materials were defined separately. The soft tissues were muscle (skeletal), adipose tissue, blood (whole), breast tissue, soft tissue (9-component), and soft tissue (4-component). The tissue-equivalent materials included water, A-150 tissue equivalent plastic and perspex. Photon dose relative to dose in 9-component soft tissue at various depths on the beam's central axis was determined for the 6 MV photon beam. The relative dose was also calculated and compared for various MCNPX tallies including *F8, F6, and *F4.
Results: The results of the relative photon dose in various materials relative to dose in 9-component soft tissue using different tallies are reported in the form of tabulated data. Minor differences between dose distributions in various soft tissues and tissue-equivalent materials were observed. The results from F6 and F4 were practically the same but differ with the *F8 tally.
Conclusions: Based on the calculations performed, the differences in dose distributions in various soft tissues and tissue-equivalent materials are minor but they could be corrected in radiotherapy calculations to upgrade the accuracy of the dosimetric calculations.
Dr. Atefeh Vejdani Noghreiyan
Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad
|How to cite this article:|
Ghorbani M, Noghreiyan AV, Tabatabaei ZS, Pakravan D, Davenport D. Tissue composition effect on dose distribution in radiotherapy with a 6 MV photon beam of a medical linac.J Can Res Ther 2019;15:237-244
|How to cite this URL:|
Ghorbani M, Noghreiyan AV, Tabatabaei ZS, Pakravan D, Davenport D. Tissue composition effect on dose distribution in radiotherapy with a 6 MV photon beam of a medical linac. J Can Res Ther [serial online] 2019 [cited 2020 Jul 13 ];15:237-244
Available from: http://www.cancerjournal.net/article.asp?issn=0973-1482;year=2019;volume=15;issue=1;spage=237;epage=244;aulast=Ghorbani;type=0