Dose Measurement in Simulated X-Ray Exposure Accidents Involving an X-Ray Computed Tomography System

Background: Accidents involving radiographic exposure occur worldwide. During inspection, a large amount of X-ray exposure occurs when the operator is near the source. Therefore, understanding the amount of radiation exposure that can occur in an accident during X-ray work is important.Materials and Methods: X-ray spectra of an X-ray computed tomography (CT) system were measured at 50, 100, and 200 kV. Gafchromic film external beam therapy 4 (EBT4) was used to measure direct X-rays from the Be window of the X-ray CT. Directed and scattered X-ray doses were evaluated using a thermoluminescent dosimeter (TLD-100H) (Thermo Fisher Scientific Inc.).Results and Discussion: Characteristic L-X-ray emitted from the tungsten filament of an X-ray CT machine were observed at 8–10 keV in an open-tube X-ray CT system without a metal filter. The dose rate of personal dose equivalent at a depth of 0.07 mm (Hp(0.07)) was 2.0 Sv/min at 3.7 cm from the X-ray source. The results of Hp(10) for the direct and scattered X-rays showed that the maximum was 7.5 mSv/min.Conclusion: It is important to note that exposure levels can become extremely high if work is performed near an X-ray source without realizing that X-rays are being emitted. We recommend the use of interlock functions and alarm-type personal dosimeters to prevent accidental exposure.