Examination of the Disposal Procedure for Nuclear Medical Test with ¹²⁵I through In-vitro Test

Nuclear medicine in vitro tests are performed on an average of 14 million cases annually in Korea. $^{125}I$, a nuclear species mainly used for in vitro tests, was estimated to have a longer shelf-life than other nuclides because the half-life was longer than other nuclides. Most institutions have judged that the radioactive waste will be about 1/1000 of the original radioactivity when it was stored for a period corresponding to 10 times the half-life of the radioactive waste, and thus the disposal will be satisfied. However, as the amount of radioactive materials remaining in the waste generated by the mechanization and modernization of the inspection method was reduced, it is necessary to reasonably infer the storage period. As a result, the storage period can be calculated reasonably. Waste generated from this test include tubes, beads, vials, tips, and other miscellaneous flammable substances(tissue paper, gauze, paper, etc.). To estimate the reasonable storage of these wastes, the amount of residual radioactive material was measured using a DREAM GAMMA-10 counter, and the period was calculated based on this value. For the purpose of this study, all tubes and beads used for the tests during the year 2016 were measured at a medical checkup hospital in Seoul. A total of 398,879 testing tubes, with 4,155 tubes per box, with a minimum number of 2,792 and a maximum number of 4,374, were used. As a results indicate, the self-disposable period of the tube was measured as 14 days, the beads as 234 days, plastic vials as 177 days, and gauze as 365 days. It was deduced that there is no economical gain because it is not necessary to store for 1 year and 6 months, 10 times the half-life period of $^{125}I$, which was a conservative calculation method.