Purpose: To perform a precise Gafchromic EBT3 ﬁlm dosimetry to evaluate the dose enhancement factor (DEF) of The PEGylated gold nanoparticles in breast cancer MCF-7 cell line under irradiation of 50 kV X-rays Intraoperative radiotherapy (IORT).
Methods: The PEG-GNPs were synthesized and characterized, ranging from 40 to 60nm in diameter. The different concentrations cytotoxicity effects of the PEG-GNPs on MCF-7 cells were evaluated using MTT assay. The untreated and treated MCF-7 Cells with 1200μl of 25, 75, and 150μg/mL concentrations PEG-GNPs were placed on the surface EBT3 film and irradiated with a calibrated system IORT with the 5 cm spherical applicator at a single dose of 4Gy. The standard EBT3 films were selected for physical DEF calculation after dosimetric evaluation. Experimental DEFs were calculated using the optical density (OD) data obtained from the selected densitometer type. The films were exposed to 6MV and (50 KV) X-rays IORT using 2Gy/min up to 7Gy radiation doses. The films were scanned in the red channel to obtain the OD–dose curves
Results: DEF is measured by the EBT3 film for MCF-7 cells with 25, 75, and 150 µg/mL concentrations of PEG-GNP exposed to X-rays in IORT is 1.014, 1.051, and 1.078, respectively. In the buildup region, no significant effect has been seen on the absorbed dose measured for cells treated with PEG-GNP by the film. The Rx of films presents significant energy response at (50 KV) IORT relative to that for 6-MV x-rays varied from 0.85–0.79 for doses 50–200 cGy.
Conclusion: PEG-GNPs demonstrated acceptable dose enhancement efficacy in IORT with low-energy X-rays (50kV), which is also the optimal beam energy for dose enhancement (DE). Gafchromic™ EBT3 film dosimetry revealed significant physical DE signals when the PEG-GNP is used as a radiosensitizer with MCF-7 human breast cancer cell line.