Investigation of the dose enhancement effect due to gold nanoparticles at 18 MV radiotherapy using MAGIC-f and Monte Carlo methods Thoraco-Lumbar spinal cord fMRI in 3T Magnetic field

Introduction: Normoxic MAGIC-f polymer gels are established dosimeters used for three dimensional dos uantifications in radiotherapy. The high atomic number nanoparticles such as gold are nov adiosensitizers used to enhance doses delivered to tumors. The aim of this study was t vestigate the effect of gold nanoparticles (GNPs) in enhancing percentage depth doses (PDD ithin the MAGIC-f gel exposed to linac high energy photon beams (18MV).   Materials and methods: The MAGIC-f gel was fabricated based on its standard composition with some modifications an oured into falcon tubes. The PDDs in the tubes containing the gel were calculated using a commo onte Carlo code (MCNPX) followed by experimental verifications. Then, the GNPs with a verage diameter of 15 nm and a concentration of 0.1 mM were embedded in the gel, poured int milar falcon tubes and irradiated to 18 MV beams of a Varian 2100 linac. Finally, simila xperimental and Monte Carlo (MC) calculations were conducted to determine the effect of usin e GNPs on some dosimetric parameters of interest. Results: The results of experimental measurements and simulated MC calculations showed a dos nhancement factor (DEF) of 1.12±0.07 and 1.13±0.06 respectively due to the use of the GNP hen exposed to 18 MV linac energies. Conclusion: The results indicated that the fabricated MAGIC-f gel could be recommended as a suitable tool fo ree dimensional dosimetric investigations at high energy radiotherapy procedures wherein th NPs are used.