[Examination of Optimization of Exposure Dose by IVR Procedure Based on DRLs 2020].

DRLs 2020 has been revised, and Ka,r and PKA for each procedure have been set for IVR along with the reference fluoroscopic dose rate. The total dose of IVR includes fluoroscopic and digital acquisition (DA) doses, but in actual clinical practice, the ratio varies greatly depending on the procedure (diagnosis/treatment purpose and procedure content), and there are not many detailed data on the ratio. Therefore, we evaluated previous efforts that optimized radiation protection through examining dose for each procedure and the ratio of fluoroscopic and DA doses to total dose, and reviewing protocols. Since the ratio of fluoroscopy and DA dose differs depending on the procedure, it was suggested that the radiation dose exposed to patients can be optimized by sharing the dose information with physicians and constructing a protocol while considering the image quality for each procedure.

[Multicenter Evaluation of Cine Angiography and Digital Subtraction Angiography Dose Rate for Various Angiography Programs: Comparison with Fluoroscopic Dose Rate].

We conducted a nationwide multicenter survey of various interventional radiology (IVR) procedures. Data were collected from 385 X-ray systems in 126 institutions, including 432 cine programs and 380 digital subtraction angiography (DSA) programs for diagnostic catheterization, percutaneous coronary intervention (PCI), ablation, transcatheter aortic valve implantation (TAVI), neurologic IVR, thorax IVR, abdominal IVR, and endovascular therapy (EVT). Fluoroscopic and cine dose rates were 10.1 mGy/min and 110.7 mGy/min, respectively, whereas for DSA programs, the median fluoroscopic and DSA dose rates were 8.0 mGy/min and 224.8 mGy/min, respectively. The DSA dose rate was more than twice the cine dose rate. The largest difference between dose rates was for diagnostic catheterization, which had a cine dose rate of 142.6 mGy/min and a fluoroscopic dose rate of 12.6 mGy/min (by a factor of 12.5), followed by EVT, which had a DSA dose rate of 216.0 mGy/min and a fluoroscopic dose rate of 7.7 mGy/min (by a factor of 29.6). The smallest difference between dose rates was for TAVI, which had a cine dose rate of 96.8 mGy/min and a fluoroscopic dose rate of 12.0 mGy/min (by a factor of 8.9), followed by neurologic IVR, which had a DSA dose rate of 227.9 mGy/min and a fluoroscopic dose rate of 9.6 mGy/min (by a factor of 22.6). Compared with the fluoroscopic dose rates, the cine dose rates were 9-13 times higher and the DSA dose rates were 22-30 times higher; the DSA dose rates were more than double the cine dose rates.

Validation of a Metal Artifact Reduction Algorithm Using 1D Linear Interpolation for Cone Beam CT after Endovascular Coiling Therapy for Cerebral Aneurysms.

This study aimed to evaluate the effect of a metal artifact reduction (MAR) algorithm using 1D linear interpolation on cone-beam CT (CBCT). We performed phantom and clinical qualitative studies with and without MAR application using 1D linear interpolation. In the phantom study, the standard deviation (SD) was estimated from the images obtained from the water phantom in which a metal coil was placed at the center, and observed the changes in the SDs before and after MAR application. In the clinical qualitative study, the clinical images after endovascular treatment (EVT) for cerebral aneurysms were visually evaluated before and after MAR application. In the phantom study, the SDs after MAR application decreased by 56 to 35% compared with that before MAR application. In the clinical qualitative study, the artifacts from the metal coil decreased or increased depending on locations, and the contrasts of gray matter and white matter were attenuated when MAR was applied. In conclusion, the metal artifact decreases when MAR using 1D linear interpolation is applied to cerebral CBCT. However, another artifacts increase or soft tissue contrast is changed in some cases. MAR largely contributes to the reduction of streaking artifacts, whereas it may induce cerebral parenchyma at distant metal body or quality deterioration of the image not including the metal body. This should be taken into account in the diagnosis of secondary hemorrhage or infarction.

[Effect of Kiken-Yochi training (KYT) induction on patient safety at the department of radiological technology].

PURPOSE: In this report, we evaluated whether radiological technologists' (RTs') awareness of patient safety would improve and what kind of effects would be seen at the department of radiological technology by introducing KYT [K: kiken (hazard), Y: yochi (prediction), T: (training)]. METHODS: KYT was carried out by ten RTs based on a KYT sheet for the department of radiological technology. To evaluate the effects of KYT, we asked nine questions each to ten participants before and after KYT enforcement with regard to their attitude to patient safety and to operating procedures for working safely. RESULTS: Significant improvements after KYT enforcement were obtained in two items concerning medical safety: It is important for any risk to be considered by more than one person; The interest in preventive measures against medical accident degree conducted now) and one concerning operating procedures (It is necessary to have a nurse assist during testing with the mobile X-ray apparatus) (p<0.05). CONCLUSIONS: Performing KYT resulted in improved awareness of the importance of patient safety. KYT also enabled medical staffers to evaluate objectively whether the medical safety measures currently performed would be effective for patients.