Indian Journal of Science and Technology

Abstract

Objective: The objective of the current study was to estimate the energy spectrum and energy deposition of the photons emitted from 125I seed model 6711 with and without the presence of titanium capsule using Monte-Carlo N-Particle code (MCNP) in order to investigate whether the titanium capsule attenuates photons and how much would be the attenuation. Materials and Methods: Two models were built and simulated using MCNPX code, in the first model, the simulation was performed assuming the geometry of 125I seed provided by the manufacturers. Whereas in the second model, the simulation was performed assuming that 125I seed without titanium encapsulation. For both models, the energy and energy deposition of the photons were estimated. Results: MCNPX computations showed that the energy spectrum released from 125I seed with the presence of the capsule was lower than that released without the presence of the capsule for all energies in the spectrum by approximately 19 %. Further, the energy deposition computed with the presence of titanium capsule was lower than that computed without the presence of titanium capsule by nearly 31%. Conclusion: The titanium capsule has an impact on the energy spectrum as well as energy deposition of the photons emitted by 125I seed. According to the MCNPX results, titanium capsule attenuates the energy and energy deposition of the radiation emerged from the seed by nearly 19% and 31% respectively. 

Keywords: Brachytherapy, Energy Deposition, Energy Spectrum, 125I Seed, Model 6711, MCNP