Document Type: Brief Communication
Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Student Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Diagnostic Imaging Department, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
Considering current controversies regarding the health effects of low doses of ionizing radiation, study of the high background radiation areas such as Ramsar, Iran can help scientists better evaluate the validity of linear no-threshold (LNT) hypothesis. Ramsar is a coastal city in northern Iran with some areas known to have the highest levels of natural background radiation in the world. The mean annual dose of the residents of high background radiation areas (HBRAs) of Ramsar is 10 times higher than the public dose limit recommended by the ICRP (1 mSv/year) and a proportion of the residents receive annual doses as large as 260 mSv (13 times higher than the occupational dose limit recommended by the ICRP). A report published in Popular Science proclaims that background radiation in Ramsar approaches that of the Martian surface. However, estimates show that the maximum annual radiation dose in HBRAs of Ramsar can be much higher than that of the Martian surface (260 mGy/y vs 76 mGy/y). Furthermore, a Guardian report introduces Talesh Mahalleh, a district in Ramsar, as an inhabited area with the highest levels of natural radioactivity in the world and C Net claims that the best Mars colonists may come from places like Iran and Brazil. In spite of current concerns, nearly all residents still live in their paternal dwellings and there are not consistent reports on any detrimental effects. It is worth noting that, due to small sample size, to draw a firm conclusion about the health effects of high level natural radiation in Ramsar, in particular about the cancer risk, current information is not sufficient and further studies are needed.
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