Environmental Impact of Pre-occupational radon level measurements in medical imaging facilities of a tertiary hospital in south-west Nigeria

Abstract Radiation facilities are placed in an enclosed environment to prevent scattered radiation from getting out of the room, by so doing the rooms foil gas exchange from the outdoor environment, thereby increasing the radon concentration in the indoor air. This study aimed at estimating the occupational radon exposure level in medical facility room in order to estimate the radiological risk in such environment. RAD7 electronic device was used to measure the indoor radon concentration in the five proposed rooms in the newly built Radiology department of a University Teaching Hospital while a digital thermometer was used to measure the ambient temperature. The radon concentrations ranged between 12.09 Bq/m 3 and 58.52 Bq/m 3 . The ultrasound room has the least average value of 12.09 Bqm −3 and the Fluoroscopy room has the maximum average value of 58.52 Bqm −3 . The radon level translated into the effective dose, working level and excess life-time cancer risk for any worker staying for a period of nine hours per day, over a year. Fluoroscopy facility was estimated to present the highest annual absorbed dose and annual effective dose with 0.73 mSvy −1 and 0.8858 mSv y −1 , respectively. The mean radon concentration for the five rooms was 41.96Bq/m3. The calculated annual effective dose rate and the mean annual absorbed dose rate to the lung within the radiation facilities rooms were 0.529 mSvy −1 and 0.6350 mSv y −1 , respectively. The indoor radon concentrations measured and the effective dose value of 200 Bq/m 3 and 1 mSvy −1 respectively is below the reference limit set by International Commission Radiation Protection (ICRP) Agency. This implies that the radiation facility rooms are in conformity with international best practices and this is in agreement with SDG 3 (Good Health and well –being)