Improved Dose Response of N -(hydroxymethyl)acrylamide Gel Dosimeter with Calcium Chloride for Radiotherapy.

The impact of calcium chloride (CaCl 2 ) on the performance of N -(hydroxymethyl)acrylamide (NHMA) polymer gel dosimeter is studied in this article. The dosimeter was exposed to doses of up to 10 Gy with radiation beam-energy of 10 MV and dose-rates of 300 cGy/min. The relaxation rate (R 2 ) parameter was utilized to explore the performance of irradiated NHMAGAT gels. The dose response in terms of R 2 increased from 0.29 to 0.63 Gy -1 ·s -1 with increasing calcium chloride concentration from 0 to 1000 mM. The results show no substantial impact of dose-rates as well as radiation energies on NHMAGAT samples. For the steadiness of irradiated NHMAGAT dosimeters, it was found that there is no apparent variation in R 2 (less than ±3%; standard deviation) up to 3 days. The overall uncertainty of the gel dosimeter with calcium chloride is 4.96% (double standard deviation, 95% confidence level).