Abstract
The purpose of the data was to determine excess lifetime cancer risk (ELCR) and risk of lung cancer from inhalation of radon in radiotherapy staff at Tehran radiotherapy Centers in 2015.The concentration of radon gas was extracted from a study done at Tehran radiotherapy centers, and then ELCR and risk of lung cancer were calculated in all centers by standard equations. The excess lifetime cancer risk and risk of lung cancer were 1.89 and 8.46 cases per 100,000 people in radiotherapy centers in Tehran City. The data indicate that the excess lifetime cancer risk and risk of lung cancer in radiotherapy centers are lower than the standard values which presented by UNSCEAR 2000.