Determination of radiation doses to the skin due to ²³⁸U and ²³²Th series for the therapeutic application in the Merzouga sand baths

In this work, we used CR-39 and LR-115 type II solid-state nuclear track detectors to measure ²³⁸U, ²³²Th,²²²Rn and ²²⁰Rn concentrations in Merzouga sand. The measured concentrations of ²³⁸U and ²³²Th in the studied sand samples vary from (332.59±16.62) mBq·cm⁻³ to (335.54±20.13) mBq·cm⁻³ and (80.43±4.02) mBq·cm⁻³ to (84.75±5.08) mBq·cm⁻³, respectively. We evaluated the radiation doses to the skin from the application of different sand baths by the patients by using a model based on specific alpha-dose and alpha-particle residual energy concepts. The maximum total equivalent dose to the skin due to the ²³⁸U and ²³²Th series from the cutaneous application of different sand baths by patients was found equal to (148.12±11.85) µSv y⁻¹cm⁻²