Use of gold nanoparticles in MAGIC-f gels to 18 MeV photon enhancement

Normoxic MAGIC-f polymer gels are established dosimeters used for three dimensional dose quantifications in radiotherapy. Nanoparticles with high atomic number such as gold are novel radiosensitizers used to enhance doses delivered to tumors. The aim of this study was to investigate the effect of gold nanoparticles (GNPs) in enhancing percentage depth doses (PDDs) within the MAGIC-f gel exposed to linear accelerator (linac) high energy photon beams. The MAGIC-f gel was fabricated based on its standard composition with some modifications. The PDDs in tubes containing the gel were calculated by using a common Monte Carlo code (Geant4) followed by experimental verifications. Then, GNPs with an average diameter of 15 nm and a concentration of 0.1 mM were embedded in the gel, poured into falcon tubes and irradiated with 18 MeV beams of an Elekta linac. Finally, similar experimental and Monte Carlo (MC) calculations were made to determine the effect of using GNPs on some dosimetric parameters of interest. The results of experimental measurements and simulated MC calculations showed a dose enhancement factor (DEF) of 1.12±0.08 and 1.13±0.04, respectively due to the use of GNPs when exposed to 18 MeV linac energies. The results indicated that the fabricated MAGIC-f gel could be recommended as a suitable tool for three dimensional dosimetric investigations at high energy radiotherapy procedures wherein GNPs are used.