Evaluation of the Patient Exposure in General Radiography for Some Facilities: Comparison with DRL and Evaluation of the Difference among Facilities

Abstract

The first diagnostic reference levels (DRLs 2015) in Japan were published in June 2015. The purpose of this study was to compare the calculated entrance surface doses with the values of DRLs 2015, and evaluate differences in patient exposure among facilities. Semiconductor dosimeter was installed, and dosimetry was performed using equipment and radiographic condition of each facility. As a result, a dose higher than the value of DRLs 2015 was used in 12 kinds of examination. In child chest examination, the doses of the three facilities (0.26 mGy, 0.28 mGy, 0.60 mGy) exceeded the value of DRLs 2015 (0.2 mGy). Review of the radiographic condition is necessary because the doses exceeding DRLs 2015 tended to have a high current time product. The examination with the largest difference between facilities was the lateral of thoracic spine, with a difference of about 46 times, and the examination with the smallest difference was the ankle joint, with a difference of about three times. When reviewing, it is necessary to focus mainly on examinations that have a large difference between facilities. In the future, it can be said that it is necessary to set diagnostic reference range (DRR) or achievable dose (AD) to understand how high or low dose of the own facility are compared with facilities nationwide.