Purpose: We investigated how a radiologic technologist explains to a patient about the risk of radiation exposure involved by the radiological examination. Methods: In this institutional review board-approved, cross-sectional study, an online questionnaire link was emailed to 650 radiological technologists who are members of the National Hospital Kanto Koshinetsu Radiological Technologist Association. The questions to survey risk communication included the ideal and reality explanation for radiation exposure to patients, the respondentʼs educational background, and years of experience. Statistical analysis was performed using the Kruskal-Wallis test and Bonferroni correction as a multiple comparison test. Results: Among the 650 radiological technologists, 245 (37.7%) completed the online questionnaire. The most common response was to compare and convey the doses of radiation during examination and background radiation when asked by a patient about risk. In the cross-analysis, the Kruskal-Wallis test showed no significant difference in what was explained according to educational background. According to years of experience, a significant difference in the content was found about explanation of the risk to patients. Conclusions: We clarified the actual condition of risk communication related to the exposure in radiological examinations. In the future, development of risk communication is expected by improving the knowledge and information of “risk” and giving explanations requested by patients.

Purpose: Quantitative analysis using a standardized uptake value (SUV) has become possible for single-photon emission computed tomography-computed tomography (SPECT-CT) of bone. However, previous research was targeted to the trunk area, and there are few studies for the head and neck region. Therefore, the purpose of this study was to determine the optimal image reconstruction conditions for bone SPECT of the head and neck using a phantom study. Method: The radioactivity concentration of the ^99mTc solution enclosed in the cylindrical phantom was set to the same count rate as in clinical cases, and six hot spheres (10, 13, 17, 22, 28, 37 mm) with four times the concentration were placed within it. The image reconstruction was 3D-OSEM, and the reconstruction conditions were varied by the number of iterative updates and the width of the Gaussian filter. Quantitative evaluations of the image quality were performed using the % contrast, background variability, and SUV for the hot spheres and background. A visual evaluation was performed by four observers to determine the optimal image reconstruction conditions for bone SPECT of the head and neck region. Result: The concentration of the ^99mTc solution enclosed in the phantom was 6.95 (kBq/ml). Based on the results of the quantitative and visual evaluations, the optimal image reconstruction conditions were iterative updates=60 (subset: 10, iteration: 6) and a Gaussian filter of 7.8 mm. Conclusion: The optimal image reconstruction conditions were subset=10, iterations=6, and a Gaussian filter of 7.8 mm.

The purpose of this study was to educate operators regarding cardiac catheterization using radiation protection slides prepared for this study and to consider whether or not this radiation protection education contributes to reducing the exposure of the operatorʼs ocular lens. Thermoluminescent dosimeter (TLD) was installed at the outside left, inside left, outside right, and inside right of the X-ray protective eyewear of the operators performing the cardiac catheterization. The exposure dose rate before and after radiation protection education for 3 operators performing cardiac catheterization was compared. The exposure dose ratio was defined by dividing the TLD measurement value, which is the air kerma calculated by the X-ray diagnosis apparatus for the angiography. In other words, this can calculate the ratio of how much the operators are exposed to radiation from the dose of the patient per examination. When comparing the radiation dose ratio obtained from the dosimeter installed on the right outer side before and after education, p-value was <0.05 in the left anterior oblique-cranial and right anterior oblique- cranial, and a significant difference was recognized. The radiation protection education carried out in this study contributes to a reduction in the exposure dose of the operators.

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.

Purpose: The administration accuracy of the automated infusion device for the positron emission radiopharmaceutical affects to calculation of the standardized uptake value (SUV) in ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET examination. The purpose of this study was to investigate the administration error in the clinical use of an automated infusion device for quantitative management in PET examination. Methods: We assumed clinical use of the automated infusion device and investigated two types of administration errors. First, for investigating the administration error over time in a day (error_day), a total of 13 infusion works were performed every 30 minutes. Second, for investigating the long period administration error (error_period), the infusion work was performed once before clinical use of an automated infusion device. The dispensed radioactivity was set to 150 MBq. The administration error was calculated using output values from the automated infusion device and measured values from the dose calibrator. Results: The administration error_day was 0.9±1.3%, and the maximum error was 2.7%. The administration error_period was 1.1±2.0%, and the maximum error was 5.9%. Conclusion: We investigated the administration error of the automated infusion device. We confirmed the approximately 1% administration error and high-accuracy injection in an automated-device method.