Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

  • Mahdi Ghorbani Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
  • Mohammad Mehrpouyan Bioinformatics Research Center, Radiology and Radiotherapy Department, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
  • David Davenport Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA
  • Toktam Ahmadi Moghaddas Department of Basic Medical Sciences, Neyshabur University of Medical Sciences, Neyshabur, Iran

Abstract

Aim: 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. Background: Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. Materials and methods: 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. Results: Dose rate constant values show 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 show minor differences in most of distances and angles. There is not any detectable difference between the isodose contours. Conclusion: Dosimetric parameters obtained with different photon spectra are 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.

Author Biographies

Mahdi Ghorbani, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Medical Physics Research Center, Mashhad University of Medical Sciences
Mohammad Mehrpouyan, Bioinformatics Research Center, Radiology and Radiotherapy Department, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
Bioinformatics Research Center, Radiology and Radiotherapy Department, Faculty of Medicine, Sabzevar University of Medical Sciences
David Davenport, Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA
Comprehensive Cancer Centers of Nevada
Toktam Ahmadi Moghaddas, Department of Basic Medical Sciences, Neyshabur University of Medical Sciences, Neyshabur, Iran
Department of Basic Medical Sciences
Published
2016-05-10
How to Cite
Ghorbani, M., Mehrpouyan, M., Davenport, D., & Ahmadi Moghaddas, T. (2016). Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources. Radiology and Oncology, 50(2). Retrieved from https://radioloncol.com/index.php/ro/article/view/2491
Section
Medical Physics