S M J Mortazavi - Professor of Medical Physics, Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Gh Mortazavi - Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
S A R Mortazavi - Student of Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
M Paknahad - Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran

Man has been exposed to different levels of natural background radiation since the creation of human life. There are inhabited areas around the world with extraordinary levels of natural background radiation. The level of natural radiation in these areas is up to two orders of magnitude higher than other places. Areas such as Yangjiang, China; Guarapari, Brazil; and Kerala, India are among the areas with high levels of natural radiation. Ramsar a coastal city in North Iran has some inhabited areas with the highest known levels of background radiation around the world. People who live in high background radiation areas (HBRAs) such as Ramsar do not record any detrimental biological effects. While some cytogenetic studies conducted in HBRAs have shown increased frequencies of unstable chromosome aberration, other investigations failed to find a significant difference. This short review is an attempt to verify if induction of chromosomal anomalies in the lymphocytes of the residents of high background radiation areas is associated with increased cancer risk.

Human Lymphocytes, High Background Radiation Areas, Natural Radiation, Cancer Risk