Simulator Education Initiatives for On-Campus Practical Training in Nuclear Medicine Technology.

Because nuclear medicine diagnostic equipment has not been installed at our educational institution, we had not been able to incorporate nuclear medicine techniques into on-campus training until now. Methods: We have introduced a diagnostic image processing simulator to replace nuclear medicine diagnostic equipment. The simulator was used to conduct on-campus practical training on nuclear medicine technology. We also conducted a questionnaire survey of students regarding their experience with on-campus practical training using the simulators. Results: The survey results revealed that the on-campus practical training using simulators deepened students' understanding of the content they had encountered in classroom lectures. Conclusion: We successfully implemented on-campus practical training in nuclear medicine technology using a diagnostic image-processing simulator. According to the results of our questionnaire, it is possible to provide on-campus practical training to students using simulators that enhance understanding of nuclear medicine technology.

Clinical Use of Hematoma Volume Based On Automated Segmentation of Chronic Subdural Hematoma Using 3D U-Net.

PURPOSE: To propose a method for calculating hematoma volume based on automatic segmentation of chronic subdural hematoma (CSDH) using 3D U­net and investigate whether it can be used clinically to predict recurrence. METHODS: Hematoma volumes manually measured from pre- and postoperative computed tomography (CT) images were used as ground truth data to train 3D U­net in 200 patients (400 CT scans). A total of 215 patients (430 CT scans) were used as test data to output segmentation results from the trained 3D U­net model. The similarity with the ground truth data was evaluated using Dice scores for pre and postoperative separately. The recurrence prediction accuracy was evaluated by obtaining receiver operating characteristic (ROC) curves for the segmentation results. Using a typical mobile PC, the computation time per case was measured and the average time was calculated. RESULTS: The median Dice score of the test data were preoperative hematoma volume (Pre-HV): 0.764 and postoperative subdural cavity volume (Post-SCV): 0.741. In ROC analyses assessing recurrence prediction, the area under the curve (AUC) of the manual was 0.755 in Pre-HV, whereas the 3D U­net was 0.735. In Post-SCV, the manual AUC was 0.779; the 3D U­net was 0.736. No significant differences were found between manual and 3D U­net for all results. Using a mobile PC, the average time taken to output the test data results was 30 s per case. CONCLUSION: The proposed method is a simple, accurate, and clinically applicable; it can contribute to the widespread use of recurrence prediction scoring systems for CSDH.

Intra-individual comparison of liver stiffness measurements by magnetic resonance elastography and two-dimensional shear-wave elastography in 888 patients.

PURPOSE: Quantitative elastography methods, such as ultrasound two-dimensional shear-wave elastography (2D-SWE) and magnetic resonance elastography (MRE), are used to diagnose liver fibrosis. The present study compared liver stiffness determined by 2D-SWE and MRE within individuals and analyzed the degree of agreement between the two techniques. METHODS: In total, 888 patients who underwent 2D-SWE and MRE were analyzed. Bland-Altman analysis was performed after both types of measurements were log-transformed to a normal distribution and converted to a common set of units using linear regression analysis for differing scales. The expected limit of agreement (LoA) was defined as the square root of the sum of the squares of 2D-SWE and MRE precision. The percentage difference was expressed as (2D-SWEMRE)/ mean of the two methods×100. RESULTS: A Bland-Altman plot showed that the bias and upper and lower LoAs (ULoA and LLoA) were 0.0002 (95% confidence interval [CI], -0.0057 to 0.0061), 0.1747 (95% CI, 0.1646 to 0.1847), and -0.1743 (95% CI, -0.1843 to -0.1642), respectively. In terms of percentage difference, the mean, ULoA, and LLoA were -0.5944%, 19.8950%, and -21.0838%, respectively. The calculated expected LoA was 17.1178% (95% CI, 16.6353% to 17.6002%), and 789 of 888 patients (88.9%) had a percentage difference within the expected LoA. The intraclass correlation coefficient of the two methods indicated an almost perfect correlation (0.8231; 95% CI, 0.8006 to 0.8432; P<0.001). CONCLUSION: Bland-Altman analysis demonstrated that 2D-SWE and MRE were interchangeable within a clinically acceptable range.

Changing Methods of Education During a Pandemic: Questionnaire Survey about Examinations for Nuclear Medicine Technology at Educational Institutions in Japan.

Coronavirus disease 2019 (COVID-19) has spread around the world. Its effects go far beyond health care: education has to be conducted so as to prevent infection among students and faculty. Accordingly, changes have occurred in Japan's educational institutions, including methods of preparing students for examinations for nuclear medicine. To assess the quality of training for radiologic technologists, we investigated the related changes undertaken at educational institutions. We investigated the lecture format for teaching nuclear medicine technology at Japanese institutions during COVID-19 and efforts to ensure the quality of conventional education. Methods: We sent a questionnaire to 19 Japanese institutions. It addressed the lecture format and initiatives in examinations for nuclear medicine technology in the first and second semesters of 2020. Results: We obtained responses from 17 institutions. In the first semester of 2020, the lecture format for nuclear medicine technology included remote, hybrid (combination of remote and face-to-face), and video-on-demand lectures. To reinforce the effect of the new teaching formats, institutions adopted various methods, such as enhancing the possibility of allowing students to ask questions, increasing the number of quizzes during lectures, delivering lectures to YouTube, and introducing an e-learning system. In the second semester of 2020, the lecture format included face-to-face, remote, hybrid, and video-on-demand lectures. In that second semester, the number of institutions providing face-to-face lectures while taking thorough measures against infection showed a marked increase. Conclusion: The institutions introduced various educational techniques and initiatives. They prioritized students' understanding of lecture content and applied what they considered the best teaching methods. Sharing information about the changes adopted at different institutions should help promote good radiologic technologists-even during a pandemic.

Evaluation of the usefulness of cystic duct three-dimensional computed tomography with non-contrast for before laparoscopic cholecystectomy and endoscopic transpapillary gallbladder drainage in comparison to magnetic resonance cholangiopancreatography.

INTRODUCTION: The purpose of this study is to evaluate whether anatomical variations of the cystic duct and accessory bile duct can be grasped by cystic duct three-dimensional (3D)-computed tomography (CT) using non-contrast CT and to examine the possibility of omitting magnetic resonance cholangiopancreatography (MRCP). METHODS: Of patients who underwent non-contrast abdominal CT between May and October 2019, those who underwent MRCP within 1 month before and afterwards were targeted. Seven assessors visually evaluated the cystic duct 3D-CT images on a 5-point scale. Average scores of ≥3 and <3 points were assigned as the good and poor groups, respectively. Regions of interest (ROIs) were placed inside the cystic duct and four places around it, and the CT values in those ROIs were measured. The CT value difference was calculated by subtracting the surrounding CT values from the CT value in the cystic duct and converting the result to an absolute value. The CT value difference was classified into good and poor groups, and statistical analysis was performed. Seven assessors evaluated anatomical variations of the cystic duct and the presence of the accessory bile duct. The results were compared with the MRCP interpretation results to calculate sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: The average visual evaluation score was 3.8. The good and poor groups were comprised by 53 (85.5%) and 9 (14.5%) patients, respectively. The CT difference value averages were 54.7 and 15.9 for the good and poor groups, respectively, and the value was significantly higher in the good group (p = 0.001). The comparison results with MRCP were sensitivity=83.3%, specificity=78.0%, positive predictive value=47.6%, and negative predictive value=95.1%. CONCLUSION: Cystic duct 3D-CT using non-contrast CT is a useful technique for understanding anatomical variations of the cystic duct and accessory bile duct. Our method may reduce the number of MRCP sessions performed.

Educational Effect of Remote Lectures for Students Aiming to Become Radiologic Technologists: Questionnaire on Nuclear Medicine Examinations.

In the latter half of 2019, coronavirus disease 2019 (COVID-19) began spreading worldwide. To prevent COVID-19 infection, all teaching at Suzuka University of Medical Sciences from April to June 2020 took place as remote lectures, not in the face-to-face format. This study analyzed postlecture questionnaire responses regarding face-to-face and remote teaching on the subject of nuclear medicine technology examinations. We examined the educational effect of using remote lectures. Methods: We conducted a questionnaire survey among students by means of a 5-point evaluation scale about satisfaction, comprehension, concentration, preparation, reviewing, and the question environment for face-to-face and remote lectures. Results: We present the results as means and SDs. Satisfaction results for face-to-face and remote lectures were 3.30 ± 0.72 and 3.36 ± 0.88, respectively. Comprehension results for face-to-face and remote lectures were 3.30 ± 0.71 and 3.30 ± 0.83, respectively. Concentration results for face-to-face and remote lectures were 3.50 ± 0.69 and 3.05 ± 0.90, respectively. The preparation results for face-to-face and remote lectures were 2.57 ± 0.88 and 2.67 ± 0.94, respectively. The reviewing results for face-to-face and remote lectures were 2.84 ± 0.85 and 3.39 ± 0.89, respectively. The question environment results for face-to-face and remote lectures lessons were 2.94 ± 0.90 and 3.43 ± 0.84, respectively. There were no significant differences between face-to-face and remote lectures in terms of satisfaction, comprehension, or preparation. There were significant differences between face-to-face and remote lectures in terms of concentration, reviewing, and the questioning environment (P < 0.001). Conclusion: This comparative analysis of the postlecture questionnaire responses for face-to-face and remote formats in nuclear medicine technology examinations showed that remote lectures have a strong educational effect. We believe that, in future, remote lectures should be considered a tool in student education.

Comparison Between Prone and Upright Imaging of the Inferior Wall Using 201TlCl Myocardial Perfusion SPECT.

Because it suppresses attenuation artifacts from the diaphragm, prone SPECT is suitable for evaluating the cardiac inferior wall. A solid-state dedicated cardiac camera allows upright imaging, which can also be used to avoid attenuation artifacts from the diaphragm. We compared prone and upright imaging for inferior wall evaluation using 201TlCl myocardial perfusion SPECT (MPS). Methods: The study targeted 45 patients. The prone imaging group included 23 subjects who underwent additional prone imaging because supine imaging indicated that the inferior wall had reduced uptake. The upright imaging group included 22 subjects who, in the past, had shown reduced uptake in the inferior wall during supine imaging. Using the MPS stress images and analysis software, we created a polar map showing the incorporation of the radioisotope throughout the whole of the myocardium; this polar map was then classified into 17 segments. The percentage uptake ratios of the inferior/anterior wall were calculated for the prone and upright acquisitions. These ratios were used as the ratio of percentage uptake in each segment of the anterior wall to percentage uptake in each segment of the inferior wall. In addition, 6 reviewers visually evaluated the uniformity within the inferior wall for both the prone and the upright imaging. Results: There was a significant difference in percentage uptake ratios between the prone and upright images in segments 4/1 (basal inferior/basal anterior; P < 0.05), 11/12 (mid inferolateral/mid anterolateral; P < 0.001), and 15/13 (apical inferior/apical anterior; P < 0.05). There were no significant differences between the prone and upright images in visual evaluations of uniformity within the inferior wall. Conclusion: In comparison with upright imaging, prone imaging has a higher rate of suppression of attenuation artifacts from the diaphragm. However, this difference does not seem to affect the images visually. Therefore, upright and prone imaging can be used interchangeably to evaluate the inferior wall.

Criteria for the addition of prone imaging to myocardial perfusion single-photon emission computed tomography for inferior wall.

OBJECTIVE: Myocardial perfusion single-photon emission computed tomography (SPECT) is occasionally suspected to generate images that represent either ischemia or infarction for the inferior wall [right coronary artery (RCA) disease] or attenuation artifacts because of the diaphragm. We often encounter this. The application of prone imaging is advantageous in the differentiation of RCA disease because of attenuation artifacts. If decreased accumulation of radioisotopes is observed at the site with either RCA disease or attenuation artifacts, then a criterion that enables the addition of prone imaging should be implemented. Then, we evaluated sites where RCA disease and attenuation artifacts would likely appear and investigated the threshold of decreased accumulation that enables utilization of prone imaging. PATIENTS AND METHODS: The patients in this study were divided into two groups: group A (20 patients) suspected to have attenuation artifacts because of the diaphragm and group B (14 patients) with RCA disease. Additional evaluation by prone imaging was performed in all patients. We utilized a 20-segment quantitative perfusion SPECT polar map in the supine and prone positions to compare the percentage increase in Thallium chloride (Tl) in both groups. We then investigated the percent uptake (%uptake) value of decreased accumulation in the inferior wall for the addition of prone imaging. RESULTS: The highest %uptake was present in segments 3, 4, 5, and 10 in group A after the prone imaging. Detection of attenuation artifacts from the diaphragm was easy in segments 3, 4, 5, and 10, and we set the %uptake threshold at 62, 61, 71, and 76%, respectively, in the supine position for the addition of prone imaging. CONCLUSION: A decrease of the %uptake in segments 3, 4, 5, and 10 after supine imaging is presumed to result from attenuation artifact or RCA disease. We established evaluation criteria for the addition of prone imaging in patients with decreased accumulation in the inferior wall during supine imaging.

Tumor growth-inhibitory effect of an angiotensin-converting enzyme inhibitor (captopril) in a lung cancer xenograft model analyzed using 18F-FDG-PET/CT.

INTRODUCTION: We administered an angiotensin-converting enzyme inhibitor (captopril) to mice implanted with a human lung adenocarcinoma epithelial cell line (A549 cells) and investigated the tumor growth-inhibitory effect of captopril from the viewpoint of glucose metabolism using (18)F-fluorodeoxyglucose ((18)F-FDG)-PET/CT. METHODS: Subcutaneous implantation of A549 cells (1.9×10(6) cells) was carried out in the lower right flank of mice. Fifteen days after the transplantation of A549 cells, mice (six in each group) were treated with captopril (3.0 mg/mouse) or saline (1000 µl/mouse) for 5 days. We performed (18)F-FDG-PET/CT imaging of the mice before and after the treatment and evaluated the degree of (18)F-FDG accumulation in tumors. In both groups (the captopril-administrated and control groups), values for the metabolic tumor volume (MTV), maximum standardized uptake value, total lesion glycolysis, and tumor volume after treatment had a tendency to increase. However, tumor growth was suppressed in the captopril-administrated group compared with the control group. RESULTS: In terms of the growth rate, the MTV and tumor volume were significantly different (P<0.05). It was found that captopril exerted a potential tumor growth-inhibitory effect; this was because the captopril-administrated group showed low values of MTV, maximum standardized uptake value, total lesion glycolysis, and tumor volume in comparison with the control group.