Radiation exposure from radioactive iodine 131I in and surrounding the patients' room

The purpose of this study is to measure the environmental radiation exposure in and surrounding the room of patients treated with 131I. Absorbed dose rates were measured using thermoluminescence dosemeters, type TLD-200 (CaF2:Dy), in a continuous monitoring programme. It is found that the estimated annual shallow and deep dose rates are 226 and 175 mGy at the patient bed; 94 and 72 mGy in the bathroom; and 12 and 10 mGy at the visitor chair, respectively. The annual absorbed dose in the corridor is almost at the background level. It is found that the annual doses at the patient bed and in bathroom were above the limit for radiation workers, whereas the dose rate at the visitor chair was within the accepted limit for radiation workers and above the limit for the public. (authors)