MATERIALS AND METHODS: PC/Bi2O3 nanocomposites at concentrations of 0, 5, 20, 40, and 50 Bi2O3 wt% were fabricated via a solution method. Afterward, the samples were irradiated by gamma rays of cobalt-60 (60Co) related to Picker V-9, and Therarton-780 machines at 30-254 mGy/min. Dosimetric characteristics were carried out including linearity, angular dependency, energy, bias-polarity, field size, and repeatability.
RESULTS: Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses exhibited an appropriate dispersion state. The dosimeter response was linear at 30-254 mGy/min for the all samples. The 50 wt% sample exhibited the highest sensitivity at 4.61 nC/mGy. A maximum angular variation of approximately 15% was recorded in normal beam incidence. The energy dependence at two energies of 662 and 1250 keV was obtained as 0.7%. Bias-polarity for the 40, and 50 wt% samples at 400 V were measured as 15.9% and 9.0%, respectively. The dosimetry response was significantly dependent on the radiation field size. Also, the repeatability of the dosimeter response was measured as 0.4%.
CONCLUSIONS: Considering the dosimetry characteristics of PC-Bi2O3 nanocomposites, and appropriate correction factors, this material can be used as a real-time dosimeter for the photon fields at therapy level.