238U and 232Th concentrations measured in different medical drugs by using solid-state nuclear track detectors and resulting radiation doses to the skin of patients

Urban populations in Morocco receive free medical drugs as prescribed by doctors in district health centres. To explore the exposure pathway of U-238 and Th-232 and their decay products on the skin of patients, these radionuclides were measured in various medical drugs by using solid-state nuclear track detectors (SSNTDs). The measured concentrations range of U-238 and Th-232 in the medical drug samples of interest vary from (4.3 +/- 0.3) to (11.1 +/- 0.7) mBq l(-1) and (0.49 +/- 0.03) to (1.3 +/- 0.1) mBq l(-1), respectively. A new dosimetric model, based on the concept of specific alpha-dose and alpha-particle residual energy, was developed for evaluating radiation doses to skin following the application of different medical drugs by patients. The maximum total equivalent effective dose to skin due to the U-238 and Th-232 series from cutaneous application of different medical drugs by patients was found to be 2.8 mSv year(-1) cm(-2).