Updated National Diagnostic Reference Levels and Achievable Doses for CT Protocols: A National Survey of Korean Hospitals

Background: In 2021, the Korean government proposed a new CT diagnostic reference level. This study performed a nationwide survey and developed new DRLs and AD for 13 common CT examinations. We compared other countries’ DRLs for CT examinations. Methods: This study investigated the CTDI_vol and DLP of the 12 types of CT protocols for adults and brain CT protocol for pediatrics. A total of 7829 CT examinations were performed using 225 scanners. We defined the DRLs values in the distribution of radiation exposure levels to determine the nationwide patient dose and distribution status of the dose. Results: This study showed that the new Korean national CT DRLs are slightly higher or similar to those of previous surveys and are similar or lower than those of other countries. In some protocols, although the DLP value increased, the CTDI_vol decreased; therefore, it can be concluded that the patient’s dose in CT examinations was well managed. Conclusions: The new CT DRLs were slightly higher than or similar to that of the previous survey and were evaluated to be similar or lower than CT DRLs of other countries. These DRLs will be used for radiation optimization and effective dose calculation for an individual.

Patient dose measurements in diagnostic radiology procedures in Korea

This study is the first nationwide investigation aimed at estimating the patient dose for radiographic examinations in Korea including gastrointestinal studies, computed tomography and mammography. The survey data from 161 hospitals and the dose data from 32 hospitals were analysed. The third quartile entrance surface dose, dose area product (DAP), weighted CT dose index (CTDIw) and mean glandular dose (MGD) were reported. All the estimated doses were less than the stated International Atomic Energy Agency (IAEA) reference levels for radiographic examinations. However, DAPs for the fluoroscopic examinations had higher dose values than the IAEA reference levels. In addition, the CTDIw and MGD were lower than the IAEA reference levels.