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 CTDIvol 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 CTDIvol 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.

Radiation exposure of interventional cardiologists during coronary angiography: evaluation by phantom measurement and computer simulation.

During interventional cardiological procedures, operators are exposed to patients' scatter radiation. Therefore, we measured the radiation exposure of the operator's eyeball, thyroid, and chest wall during angiography. We used the optically stimulated luminescence dosimeter in the anthropomorphic phantom and developed Monte Carlo simulations using the Korean human voxel phantom. At 15 frames/s, the radiation dose of the operator's right eyeball (RE), left eyeball (LE), thyroid (T), and chest wall (CW) at the femoral artery puncture position (FAPP) with protective equipment (PE) was 0.015, 0.16, 0.012, and 0.014 mGy, respectively. At 7.5 frames/sec, the radiation dose of the operator's RE, LE, T, and CW at FAPP with PE was 33.33%, 18.75%, 52.94%, and 45.00% lower than that of those at the radial artery puncture position (RAPP), respectively. At 15 frames/s, the radiation dose of the operator's RE, LE, T, and CW at RAPP without PE was 1.76 times, 2.23 times, 2.76 times, and 2.05 times higher than that of those with PE. Per the simulation results, the absorbed radiation dose of the eye ball, thyroid gland, and myocardium of the heart at FAPP with and without PE under 15 frame/s was 9.68%, 13.04%, 8.33% and 9.98%, 6.00%, 8.82% lower than at RAPP under similar conditions. Effective measures for occupational radiological protection are lower frame rate exposure, increased distance from the X-ray source, and PE use. Radiologist protection in interventional cardiology cannot be handled independently of patient protection, owing to several correlations; thus, reducing the patient dose will reduce the operator dose.

Occupational radiation exposure in femoral artery approach is higher than radial artery approach during coronary angiography or percutaneous coronary intervention.

Medical radiation exposure is a significant concern for interventional cardiologists (IC). This study was aimed at estimating the radiation exposure of IC operators and assistants in real clinical practice. The radiation exposure of the operator and assistant was evaluated by conducting two types of procedures via coronary angiography (CAG) and percutaneous coronary intervention (PCI) on 1090 patients in 11-cardiovascular centers in Korea. Radiation exposure was measured using an electronic personal dosimeter (EPD). EPD were attached at 3 points on each participant: on the apron on the left anterior chest (A1), under the apron on the sternum (A2), and on the thyroid shield (T). Average radiation exposure (ARE) of operators at A1, A2, and T was 19.219 uSv, 4.398 uSv, and 16.949 uSv during CAG and 68.618 uSv, 15.213 uSv, and 51.197 uSv during PCI, respectively. ARE of assistants at A1, A2, and T was 4.941 uSv, 0.860 uSv, and 5.232 uSv during CAG and 20.517 uSv, 4.455 uSv, and 16.109 uSv during PCI, respectively. AED of operator was 3.4 times greater during PCI than during CAG.

Evaluation of the Patient Effective Dose in Whole Spine Scanography Based on the Automatic Image Pasting Method for Digital Radiography.

BACKGROUND: Whole spine scanography (WSS) is a radiologic examination that requires whole body X-ray exposure. Consequently, the amount of patient radiation exposure is higher than the radiation dose following routine X-ray examination. OBJECTIVES: Several studies have evaluated the patient effective dose (ED) following single exposure film-screen WSS. The objective of this study was to evaluate patient ED during WSS, based on the automatic image pasting method for multiple exposure digital radiography (APMDR). Further, the calculated EDs were compared with the results of previous studies involving single exposure film-screen WSS. PATIENTS AND METHODS: We evaluated the ED of 50 consecutive patients (M:F = 28:22) who underwent WSS using APMDR. The anterior-posterior (AP) and lateral (LAT) projection EDs were evaluated based on the Monte Carlo simulation. RESULTS: Using APMDR, the mean number of exposures was 6.1 for AP and 6.5 for LAT projections. LAT projections required more exposures (6.55%) than AP projections. The mean ED was 0.6276 mSv (AP) and 0.6716 mSv (LAT). The mean ED for LAT projections was 0.6061 mSv in automatic exposure control (AEC) and 0.7694 mSv in manual mode. The relationship between dose-area-product (DAP) and ED revealed a proportional correlation (AP, R(2) = 0.943; LAT, R(2) = 0.773). Compared to prior research involving single exposure screen-film WSS, the patient ED following WSS using APMDR was lower on AP than on LAT projections. CONCLUSION: Despite multiple exposures, ED control is more effective if WSS is performed using APMDR in the AEC mode.

Development of Diagnostic Reference Levels Using a Real-Time Radiation Dose Monitoring System at a Cardiovascular Center in Korea.

Digital cardiovascular angiography accounts for a major portion of the radiation dose among the examinations performed at cardiovascular centres. However, dose-related information is neither monitored nor recorded systemically. This report concerns the construction of a radiation dose monitoring system based on digital imaging and communications in medicine (DICOM) data and its use at the cardiovascular centre of the University Hospitals in Korea. The dose information was analysed according to DICOM standards for a series of procedures, and the formulation of diagnostic reference levels (DRLs) at our cardiovascular centre represents the first of its kind in Korea. We determined a dose area product (DAP) DRL for coronary angiography of 75.6 Gy cm(2) and a fluoroscopic time DRL of 318.0 s. The DAP DRL for percutaneous transluminal coronary intervention was 213.3 Gy cm(2), and the DRL for fluoroscopic time was 1207.5 s.