Investigation on the long-term storage condition of the PVA-GTA-I gel dosimeter

Abstract

Radiochromic gel materials are of special interest for application to three-dimensional dosimetry, particularly in clinical settings of radiation therapy. The authors previously developed a radiochromic gel complex composed of polyvinyl alcohol (PVA), glutaraldehyde (GTA) and iodide (I) which is abbreviated hereafter as the “PVA-GTA-I gel”. While showing promising features such as linear dose response and good reusability, the PVA-GTA-I gel has suffered from natural coloration due to auto-oxidation during the long-term storage for a week or more. To find a practical solution for this issue, we examined the color intensity changes of the PVA-GTA-I gel for up to nearly two months under seven storage conditions with the variables of temperature (5.5 °C or 20 °C), air flow (in air or vacuum), and lighting (under fluorescent light or in darkness). The results showed that the condition setting of the samples stored in a vacuum case at 20 °C in darkness could significantly prevent the color intensity change of the PVA-GTA-I gel during long-term storage. This finding could give a certain practical advantage to the PVA-GTA-I gel dosimeter for future applications.