Abstract
X-ray computed tomography (CT) examinations are frequently used in diagnosing various diseases as they can provide high-definition images of arbitrary physical cross-sections in a short time. However, it has been known that CT examinations provide relatively higher radiation doses to patients than other radiological image diagnostic examinations. Furthermore, an increase in carcinogenic rates has been observed in children who have undergone multiple CT examinations, according to the latest epidemiological survey for children. But it is not as if the carcinogenic risk due to CT examinations cannot decrease. If only we correctly understand the correlation between the advantage to patients that image quality brings and the disadvantages regarding radiation doses, the carcinogenic risk to patients of useless radiation exposure could possibly be reduced. To realize this, it is first necessary to more precisely determine the exposure doses of patients undergoing CT examinations. This paper introduces the dose level of patients undergoing CT examinations and some trials for optimization of radiation protection for patients in Japan.
