1Professor of Medical Physics, Medical Physics Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
2Instructor, Medical Physics Department, Faculty of Medicine, Kurdistan University of Medical Sciences, Kurdistan, Iran
Background & Aims: Studying about background radiation is important because human beings are continuously exposed to these radiations which leave energy in tissues and the transferred energy leads to undesirable biologic effects. The level of background radiation differs in indoor and outdoor places. Since, people spend more time indoors, in this research environmental gamma dose rate for indoor and outdoor places of Kurdistan towns was determined and compared. Methods: To estimate dose rate at outdoors, four stations in the length of main directions and one in the center of each city were selected. To estimate dose rate at indoors, two stations in each town according to the type of buildings were selected. In each station gamma dose rate was measured for one hour by RDS-110 servimeter at one meter height from the earth. Results: The average of outdoor and indoor environmental gamma dose rate for Kurdistan towns obtained as follows: Baneh 134 (SD=5), 166 (SD=25) nSv/h, Bijar 113 (SD=17), 141 (SD=8) nSv/h, Divandareh 110 (SD=8), 134 (SD=12) nSv/h, Saqez 105 (SD=12), 134 (SD=11) nSv/h, Sanandaj 110 (SD=12), 133 (SD=4) nSv/h, Qorve 114 (SD=20), 160 (SD=4) nSv/h, Kamyaran 92 (SD=4), 115 (SD=14) nSv/h, Marivan 110 (SD=9), 122 (SD=18) nSv/h. Conclusion: Data shows that indoor dose rates in Baneh (%24), Bijar (%24), Divandareh (%22), Saqez (%28), Sanandaj (%21), Qorveh (%40), Kamyaran (%25) and Marivan (%11) exceed outdoor dose rate in these towns.