Essay --

The X - ray was discovered in 1985 by a German physicist, Sir W. C. Roentgen. Since then, the application of radiation has been widely used in radiology, nuclear medicine and radiotherapy for both diagnostic and treatment of different kind of diseases encountered by the human beings.(Luk, Leung, & Cheng, 2010).Even though the radiation play important place in diagnostic and treating the patient, the biological effect caused by medical radiation is more concerned in recent survey(Arslanolu et al., 2007). Due to the advanced tuition of medical equipments such as multi - detector row computed tomography and nuclear medicine there is significant increase in the populations cumulative exposure(Rehani & Berris, 2012).The application of computer tomography has increased dramatically since 1970,with the number of annual scan go up to 72 million in 2007 random variable 2 million in 1980s (Baumann et al., 2011).The radiological examination performed every year crossed 3.6 billion and t he number is expected to increase in future(Nations, Committee, & Radiation, 2010).since the radiological exam...