Effect of lithium chloride inorganic salt on the performance of N-(Hydroxymethyl)acrylamide polymer-gel dosimeter in radiation therapy

The impact of lithium chloride inorganic salt (LiCl) on the response of radiated N-(Hydroxymethyl) acrylamide (NHMA) polymer gel dosimeters was presented in this article. The NHMA-LiCl polymer dosimeters were positioned in a cubic water-phantom and then irradiated by a linac to different dose ranging from 0 to 10 Gy. The response of gel to X-ray radiation was evaluated using NMR spin–spin relaxation rate (R2 = 1/T2). Linearity relationship of dose–response s were obtained in the dose-range of 0–6 Gy. The polymer showed a significant increase in dose-sensitivity (about 50%) when LiCl concentration was increased from 0 to 2.1wt% in the linearity region of 0–6 Gy. The dependency of irradiated gel on the dose rate and the photon beam energy were not observed by adding LiCl over the range studied (less than 5%). The R2 values were decreased with increasing the scanning temperature. The gel was fairly stable after four days of irradiation. The LiCl acts as an excellent sensitizer to the polymerization of irradiated gel dosimeters.