Medical Radiation Exposure and Human Carcinogenesis-Genetic and Epigenetic Mechanisms

Ionizing radiation （IR） is a potential carcinogen. Evidence for the carcinogenic effect of IR radiation has been shown after long-term animal investigations and observations on survivors of the atom bombs in Hiroshima and Nagasaki. However, IR has been widely used in a controlled manner in the medical imaging for diagnosis and monitoring of various diseases and also in cancer therapy. The collective radiation dose from medical imagings has increased six times in the last two decades, and grow continuously day to day. A large number of evidence has revealed the increased cancer risk in the people who had frequently exposed to x-rays, especially in childhood. It has also been shown that secondary malignancy may develop within the five years in cancer survivors who have received radiotherapv, because of IR-mediated damage to healthy cells. In this article, we review the current knowledge about the role of medical x-ray exposure in cancer development in humans, and recently recognized epigenetic mechanisms in IR-induced carcinogenesis.

Implementation of safety and security standards for high dose rate brachytherapy sealed radioactive source used in a medical radiation facility

Objective:To provide guidance on basic concepts and elements for radiation safety and security measures for a HDR brachytherapy sealed radioactive source in a medical radiation facility.Methods:Brachytherapy sources are Category 2(High risk-very dangerous)radioactive source and Security Level B applied to cover the range of security measures needed for the associated risk with remote afterloading HDR brachytherapy sources.These security measures were applied based on a risk informed graded approach.A series of in-build and operational safety measures were implemented for equipment and radiation installation.Results:The medical radiation facility equipped with adequate radiation protection,detection and monitoring equipment such as survey meter,digital contamination monitor,gamma zone monitor,digital radiation monitor,personnel dosimeter,pocket dosimeter,long handled forceps,shielding material and emergency source storage container etc.to deal with radiological incidences.The contingency plan with security objectives for incidents and procedures for action was prepared in order to implement response function to fulfill the goal of adequate security of radioactive source.The emergency response plan documented against emergency scenarios during transport,loss of radioactive source,theft,sabotage,natural calamities/disasters such as fire,flood and earthquake.Conculsions:The paper provides various radiation safety and security aspects for the HDR brachytherapy.The HDR brachytherapy radioactive sources are Type A packages.Transport of radioactive material is the responsibility of consignors,consignee and carriers under the legislation,supervision and control of regulatory authority.