Development of Oxide-Based Lead (II) Iodide Radiotherapeutic Dosimeter for Stable Dosimetry

As the use of high-energy radiation therapy devices has increased in the medical field, routine quality assurance and continuous quality-process improvement are necessary to ensure accurate measurement of radiation doses. Gas-filled ionization chambers and semiconducting silicon (Si) diodes, which are commonly used to detect high-energy radiation therapeutic doses through ionization reaction mechanisms, exhibit limited continuous-dose detection because of the large ionization-chamber size and high work function, which slow the electron-hole pairs. In this study, we aim to develop a dosimeter with improved ability to stably and continuously detect radiation doses. A high-energy radiation dosimeter was developed using a mixture of lead (II) iodide (Pbl(2)) with SiO2 and TiO2, and its reproducibility, linearity, and sensitivity were assessed. The oxide-mixing ratio was found to be important for improving the stability and reproducibility. Our experiment indicated that the dosimeter reproducibility increased by 10%. The best reproducibility was observed with a TiO2 mass fraction of 5%. We also assessed the linearity of the dosimeter and found an R-2 value greater than 0.99, indicating excellent linearity. Our oxide-based Pbl(2) dosimeters satisfied all response properties for dose detection.