Comparison of the dosage effect of implant materials in small field radytherapy treatments using nanoDot OSLDs and Monte Carlo method

In this study, dose accuracy of optically stimulated luminescence dosimeters (nanoDot OSLDs) for small radiation treatment fields in homogeneous and heterogeneous environments were analyzed. For the homogeneous medium, the difference between the depth dose curves of OSLDs and the Monte Carlo (MC) calculations was found within 3% statistical uncertainty for small field sizes. For the heterogeneous environment, implant materials of stainless steel (SS), titanium alloy (Ti5) and alumina (Al) were used. OSLD results at the phantom-implant upper interface measured a lower-than-expected dose compared to MC. Our OSLD results at the implant-phantom lower interface were in agreement with the MC measurements. Although OSLDs are a useful dosimeter for radiotherapy dosimetry in homogeneous medium in small field sizes, it has been found that it is not suitable for measuring interface dose values in heterogeneous medium.