ASSESSMENT OF INDOOR GAMMA RADIATION AND DETERMINATION OF EXCESS LIFETIME CANCER RISK IN TEHRAN IN WINTER AND SPRING 2017.

Natural radiation is a feature of the environment in which we live. One of the contributions of human exposure to ionizing radiation due to natural sources arises from gamma radiation. Therefore, present study was aimed to evaluate and map indoor gamma dose rate in Tehran. The corresponding annual effective dose (AED) and excess lifetime cancer risk (ELCR) were also calculated. All measurements were performed by a Geiger Muller detector in 43 dwellings in Tehran. The average indoor gamma dose rate in Tehran was appointed as 343.2 nGy/h. AED and ELCR were calculated as 2.4 mSv and 10.3 × 10-3, respectively. The evaluated indoor gamma dose rate and calculated AEDs and lifetime cancer risk were found higher than the world average value.