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 outbreak the number of radiological examinations have increased significantly. The number of repeated radiological examinations increased as well. Although the risk of cancer from single radiological scanning is small, risk from multiple imaging has not been estimated yet. The development 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 radiological examinations of any type. The validity of the developed approach was tested on the example of assessment of lifetime attributable risk (LAR) of cancer incidence from multiple computed tomography (CT) examinations, the results are discussed in the paper. The authors developed the method for estimating radiation detriment from multiple radiological CT scans for remaining 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, thyroid and other solid. The authors estimated cancer risks for a female, she was exposed to radiation from CT scanning. The female’s risks assessed with the developed methodology were compared with radiation risks estimated with mathematical model ICRP (Publication 103). The comparison 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 accounted, medical and demographic data applicable to the Russian population were taken into account as well.