Effective dose and concentration of radon and thoron gases at hospitals of Kermanshah University of Medical Sciences (2012)

Considering the health care importance of indoor radon، especially in the case of lung cancer، this study was aimed to evaluate indoor radon and thoron levels in three hospitals of Kermanshah city with high recourse. Measurements of indoor radon and thoron levels in Imam Reza، Imam Khomaini and Taleghani hospital buildings in Kermanshah city in different parts، including ICU، inpatient wards، operating rooms and offices were done using RTM 1688-2 radon meter. Measurements were performed in three months of fall season in 2012 (once per month)، and totally 102 measurements were done. The annual effective dose was assessed using the equation for annual effective dose calculation introduced by United Nations Scientific Committee on the Effects of Atomic Radiation. Average indoor radon and thoron levels were 11. 44±4. 9 Bq/m3 and 4±3. 9 Bq/m3، respectively. Maximum radon concentration was measured in Imam Raza hospital (13. 7±4. 3 Bq/m3) and minimum radon concentration was observed in Imam khomaini hospital (6. 8±4. 4 Bq/m3). The average annual effective dose due to radon and thoron was estimated to be 0. 13 mSv/y. Based on the results، radon and thoron levels and their average effective dose in all hospital buildings were below the proposed limits. The concentrations of radon and thoron were influenced by natural and artificial ventilation of the rooms and building materials used for walls and floors. Radon and thoron concentration level was reported high in ICU.