Development of quality assurance dosimeter for brachytherapy based on CsPbBr₃ and evaluation of applicability

Abstract

In brachytherapy, since a radioactive source is inserted into the human body to kill tumor tissue, it is important to accurately determine the positional accuracy of the source. In this study, we aimed to develop a dosimeter that can be used for brachytherapy using CsPbBr3. This material can replace existing materials for radiation detectors because it is cheaper than others and has a simple manufacturing process. In addition, the basic performance of the dosimeter was evaluated by analyzing reproducibility, linearity, position (distance) dependence, and angular dependence with the 192Ir source. As a result of the reproducibility evaluation, the relative standard deviation (RSD) was 1.07%, which satisfied the standard deviation criteria of 1.50%. As a result of the linearity evaluation by linear regression analysis, the R 2 value was 0.9991, which was higher than the standard criterion of an R 2 value of 0.9990. As a result of the position (distance) dependence evaluation, the signal value decreased exponentially and uniformly according to the inverse square law of the distance up to 3 cm. As a result of angular dependence evaluation, the signal value of the dosimeter 10 cm away from the front of the source was 5.64 μC, and the signal values of the dosimeter 10 cm away from the sides of the source were 8.49 μC on the left and 8.91 μC on the right. From these four results of reproducibility, linearity, position (distance) dependence, and angular dependence, we anticipate that the manufactured CsPbBr3 dosimeter with performance outcomes beyond the standards can be used as a dosimeter for brachytherapy.