NanoDot™ OSLDs in verifying radiotherapy dose calculations in the presence of metal implants: A Monte Carlo assisted research

The goal of this work is to evaluate the dosimetric accuracy of nanoDot optically stimulated luminescence dosimeters (OSLDs) for small field sizes both at phantom-implant interfaces and deeper depths of a phantom. The central axis percentage depth-dose (PDD) curves were obtained by 6 MV flattening-filter-free (FFF) photon beams in conjunction with the homogeneous and nonhomogeneous RW3 slab phantoms with aluminum (Al), titanium alloy grade 5 (Ti5), and stainless steel grade 316 L (SS) implant material sheets inserted into, in small fields: 2 × 2 cm2 and 4 × 4 cm2. Three different depths were defined within the heterogeneous phantoms created to compare the measured and calculated doses: The soft tissue/metal implant upper interface (level I), metal implant/soft tissue lower interface (level II), and deeper depth from the implant (level III). The assessment of OSLDs was performed at defined depths comparing by Monte Carlo simulation (EGSnrc-based DOSXYZnrc/BEAMnrc) and Acuros XB (AXB) algorithm with GafChromic™ EBT3 film and PTW 31014 pinpoint ion chamber (IC) measurements. The PDDs using OSLDs were compared to those predicted by MC, and AXB, and those measured by EBT3 and IC and found to agree with uncertainty (