SU‐GG‐J‐123: Dose Increase in Radiotherapy Evaluated to Biocompatible Levels of Gold Nanoparticle: A Quantitative Analysis by MRI Gel Dosimetry and Monte Carlo Spectrometry

Purpose: Apply gel dosimetry to evaluate the dose‐increase dependency with nanoparticle concentration in a tissue‐simulator dosimeter irradiated with 250kV Radiotherapy beam. Quantify the components of dose contribution by Monte Carlo spectrometry. Material and Methods: Gold nanoparticles (AuNP) were embedded in MAGIC‐f gel in different biocompatible concentrations: 0.11mM(A), 0.06mM(B) and 0.03mM(C). Dosimetric control measures with gel without AuNP were made in the 250kV x‐ray beam studied. An acrylic box was positioned behind the gel samples to guarantee backscattered conditions similar to clinical situations accessed with the beam studied. A dose of 5Gy was delivered to all samples. Polymer gel readings were proffered in a 3Tesla nuclear‐magnetic‐resonance by relaxometry: 5 echoes; Echo‐time=20ms; Repetition‐time=4000ms; Pixel‐size=250μm; Time‐delay‐to‐reading: 12h. Monte Carlo simulations were performed in PENELOPE code precisely reproducing all experimental conditions. Results: Signal of non‐irradiated gel samples (with and without AuNP) presents no significant variation (