Dose-response dependencies of Turnbull blue, modified Fricke, VIPET, and Presage® gel dosimeters in high-dose-rate radiation fields

Dose-response dependencies of the radiochromic Turnbull blue (TB), modified Fricke gel (FXO), polymer gel VIPET, and solid-state Presage (R) dosimeters were investigated, in high-dose-rate radiation fields, using spec-trophotometry. A sealed radionuclide source (60Co) with a dose rate up to 9 Gy s-1 was used for irradiation. Standard liquid Fricke solution was used as a reference dosimeter. It was found that the properties of different types of gel dosimeters are affected by the dose rate. The results were compared with the predictions derived from the physical-chemical irradiation response principles. Considerable dose-rate dependencies were observed for all investigated 3D dosimeters. Dose responses of TB, VIPET, and FXO were decreased by 30-40% while the Presage (R) response were decreased by approximately 20% for dose rates from 7.2 x 10-3 to 9.01 Gy s-1. Pre-sented results could have practical impact on some clinical applications, and therefore proper corrections might be needed.