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 role in diagnostic and treating the patient, the biological effect caused by medical radiation is more concerned in recent survey(Arslanoğlu et al., 2007). Due to the advanced development of medical equipment’s such as multi - detector row computed tomography and nuclear medicine there is significant increase in the population’s 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 form 2 million in 1980s (Baumann et al., 2011).The radiological examination performed every year crossed 3.6 bill ion and the number is expected to increase in future(Nations, Committee, & Radiation, 2010).since the radiological exam...