Methodology for assessment of radiation risks from medical exposure on the example of multiple computed tomography

Currently the application of diagnostic imaging procedures is extended. After the COVID-19 out-break the number of radiological examinations have increased significantly. The number of re-peated radiological examinations increased as well. Although the risk of cancer from single radi-ological scanning is small, risk from multiple imaging has not been estimated yet. The develop-ment of methodology for assessment of cancer risks from multiple radiological examinations is needed. This paper presents the procedure for assessment of radiation risks from multiple radio-logical examinations of any type. The validity of the developed approach was tested on the ex-ample of assessment of lifetime attributable risk (LAR) of cancer incidence from multiple com-puted tomography (CT) examinations, the results are discussed in the paper. The authors devel-oped the method for estimating radiation detriment from multiple radiological CT scans for re-maining life years. The method is based on equivalent radiation doses to organs and tissues of a patient’s body. Tables of LARs values per dose unit for males and females within the age range 0-95 years and a step of 5 years were designed. The tables were computed for the following cancer sites: bladder, breast, colon, bone marrow, liver, lungs, esophagus, ovary, stomach, thy-roid and other solid. The authors estimated cancer risks for a female, she was exposed to radia-tion from CT scanning. The female’s risks assessed with the developed methodology were com-pared with radiation risks estimated with mathematical model ICRP (Publication 103). The com-parison showed that the difference between risks estimated with the developed method and the risks estimated with the ICRP model did not exceed 12%. In models sex and age were account-ed, medical and demographic data applicable to the Russian population were taken into account as well.