Evaluation of Dose Enhancement in Radiosensitizer Aided Tumor: A Study on Influential Factors

Abstract

Radiotherapy is one of the most important branches of medical radiation physics, which deals with the treatment using ionizing radiation. Recurrence of the disease is a known problem with this treatment method. Recently, nanoparticles are introduced as sensitizer agents for the tumors. Their experimental evaluation confirmed their ability to improve the treatment. However, their quantitative assessment is required for clinical application. The current study employed the Monte Carlo method to quantitatively evaluate several influential factors. A slab head phantom with real material composition of brain tissues was simulated. Photon energy, type, and concentration of nanoparticles were investigated as influential factors. Gold, platinum, and silver were evaluated in the current study. There was an optimal energy for each nanoparticle near to the corresponding K-edge energy. The results also demonstrated that linear dose enhancement increased with an increase in the concentration of nanoparticles. Overall, the current study calculations highlighted silver nanoparticles as the most efficient nanoparticles in terms of impact on dose enhancement.

<p>Monte Carlo Evaluation of Dose Enhancement Due to CuATSM or GNP Uptake in Hypoxic Environments with External Beam Radiation</p>

“…Simple geometrical representations have previously served as tumor models, as they provide a basis for extension to more complex features. 2,12,[38][39][40] A cuboidal phantom with dimensions 5 cm x 5 cm x 5 cm with pure water as base material was used to simulate a simple 125 mm 3 tumor with a 8 mm 3 hypoxic core with differential uptakes of metal by oxygen concentration (Figure 3). 19,21,41,42 The DEF in the hypoxic tumor model was calculated for the low energy SARRP beam as it resulted in the most enhancement in the phantom model.…”

“…In all cases, normal tissue, surrounding the simulated tumor was assumed to have zero uptake of radiosensitizing metal. [38][39][40] Within the tumor, uptake of gold or copper was determined for normoxic and hypoxic tissue uptake.…”