Influence of the components of a radiochromic PVA – Iodide gel dosimeter on the optical dose response

A novel radiochromic gel dosimeter based on a poly(vinyl alcohol)-iodide complex (PVA-I) has been developed with the aim of using it in optical computed tomography (CT). The PVA-I gel dosimeter exhibits excellent characteristics such as high sensitivity, dose rate independence, a wide dose range, and especially reusability. The standard PVA-I gel dosimeter is composed of poly(vinyl alcohol) (average degree of polymerization 1000 and degree of saponification 88 mol%), iodide (potassium iodide), reducing sugar (fructose), gelling agent (gellan gum), and water. In this study, the influence on dose response is investigated upon substitution of the components by PVAs with different degrees of polymerization (500, 1500, 3500) and saponification (80 mol%, 98 mol%), different iodide salts (LiI, NaI, NH₄I), and different reducing sugars (glucose, maltose, lactose). The results show that these substitutions have little effect on the dose rate dependence, while the iodide salt affects the sensitivity. (paper)