Nihon Hoshasen Gijutsu Gakkai zasshi最新文献

{"title":"[Quantitative Evaluation of Average Intensity Projection Images in Radiotherapy Planning for Primary Lung Cancer].","authors":"Hiromu Nonaka, Noriyuki Nagami, Keiichi Ohira, Kenta Inoue, Osamu Togao","doi":"10.6009/jjrt.26-1657","DOIUrl":"https://doi.org/10.6009/jjrt.26-1657","url":null,"abstract":"<p><strong>Purpose: </strong>Average intensity projection (AIP) is an image generation method obtained by averaging the images of each phase of 4D-CT. This study aimed to evaluate tumor respiratory motion and, using the union of contours from all 4D-CT phases (4D<sub>Total</sub>) as the reference, to compare contour agreement among contours derived from 3D-CT, maximum intensity projection (MIP), and AIP images. In addition, dose metrics in treatment planning were evaluated to explore the dosimetric impact of contour differences among the image sets.</p><p><strong>Methods: </strong>Eight patients who underwent lung stereotactic body radiotherapy (SBRT) at our institution were included. Tumor motion was first characterized from centroid positions across ten 4D-CT phases. Next, 4D<sub>Total</sub> was generated by taking the union of the contours extracted from each phase. Finally, contours from 4D-CT AIP, 4D-CT MIP, and slow-scan 3D-CT (3D<sub>Slow</sub>) were compared with 4D<sub>Total</sub> using volume difference, centroid difference, Dice similarity coefficient (DSC), Jaccard index, 95th percentile Hausdorff distance (HD95), mean surface distance (MSD), and surface Dice similarity coefficient with a 2-mm tolerance. In addition, treatment plans were generated using each contour set, and Dmax (cGy), lung V5 (%), lung V20 (%), conformity index (CI), and homogeneity index (HI) were compared.</p><p><strong>Results: </strong>Tumor motion was greatest in the inferior-superior direction and was generally multi-directional. For AIP, centroid difference was ≤1 mm in each direction (LR/AP/IS), and the median values of DSC, Jaccard index, HD95, MSD, and surface DSC (2 mm) were 0.831, 0.711, 1.707 mm, 0.451 mm, and 0.981, respectively, showing good geometric agreement with 4D<sub>Total</sub>. No significant differences were observed between AIP and MIP, whereas both AIP and MIP showed better agreement than 3D<sub>Slow</sub>. In the dose evaluation, no significant overall differences were observed for any metric among the four contour sets. In the exploratory analysis, paired comparisons using 4D<sub>Total</sub> as the reference showed a directional decrease in lung V20 for AIP and a directional increase in CI for MIP. These findings should not be interpreted as definitive conclusions, but rather as results of an exploratory analysis based on a limited number of cases.</p><p><strong>Conclusion: </strong>The AIP method showed good geometric approximation to 4D<sub>Total</sub> and may represent the time-dependent displacement of tumor position within a single dataset. In this limited exploratory analysis, no major disadvantage in treatment planning was observed. However, the observed changes in dose metrics, including lung V20, should not be interpreted as evidence of dosimetric superiority and require further validation. Because of uncertainty in the reference contour and the limited number of cases, further investigation is needed to clarify its clinical sign","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149129370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[2. Utilization of Data and AI in Society (2): Utilization in Real-world Settings].","authors":"Satoshi Kasai","doi":"10.6009/jjrt.26-0203","DOIUrl":"https://doi.org/10.6009/jjrt.26-0203","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147277706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[8. Photon-counting CT: Principles and Clinical Applications-Advancing CT Imaging through X-ray Detector Innovation].","authors":"Yukihiro Enchi","doi":"10.6009/jjrt.26-0708","DOIUrl":"https://doi.org/10.6009/jjrt.26-0708","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148537788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[The 59th Annual Meeting of TWSRT and the International Conference of Medical Imaging].","authors":"Shinya Misawa, Kenji Yasue, Mei Hashimoto","doi":"10.6009/jjrt.26-0705","DOIUrl":"https://doi.org/10.6009/jjrt.26-0705","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148537828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Fujibuchi Labolatory, Radiological Protection in Medicine, Faculty of Medical Sciences, Department of Health Sciences, Division of Medical Quantum Sciences, Kyushu University].","authors":"Toshioh Fujibuchi","doi":"10.6009/jjrt.26-0806","DOIUrl":"https://doi.org/10.6009/jjrt.26-0806","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[6. Motion Managements and 4D Dose Evaluations for Moving Targets in Particle Therapy].","authors":"Yuki Tominaga","doi":"10.6009/jjrt.26-0810","DOIUrl":"https://doi.org/10.6009/jjrt.26-0810","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Concluding Remarks: Evolution of X-ray Computed Tomography Systems].","authors":"Takashi Hoshino","doi":"10.6009/jjrt.26-0807","DOIUrl":"https://doi.org/10.6009/jjrt.26-0807","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[4. Radiation Exposure in Computed Tomography: Fundamentals and Personalized Dose Assessment].","authors":"Kosuke Matsubara","doi":"10.6009/jjrt.26-0308","DOIUrl":"https://doi.org/10.6009/jjrt.26-0308","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 3","pages":"65-71"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147500870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Paper Review: Correction and Utilization of the Washout Effect in Range-verification PET for Particle Therapy].","authors":"Mitsutaka Kanazawa","doi":"10.6009/jjrt.26-0401","DOIUrl":"https://doi.org/10.6009/jjrt.26-0401","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147724974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Evaluation of Residual Ratio and Optimization of Residual Setting in Automated Infusion Device for ¹⁸F-florbetapir Administration].","authors":"Ryu Emura, Ayana Tanji, Kouki Suzuki, Yuka Nakamura, Masayoshi Ikeda, Katsuya Seki, Hirotaro Nakanishi, Shigeru Kiryu","doi":"10.6009/jjrt.26-1656","DOIUrl":"https://doi.org/10.6009/jjrt.26-1656","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to quantify residual radioactivity in medical devices used during ¹⁸F-florbetapir administration with the UG-02 automated infusion device and to identify the optimal residual setting for accurate dose calculation.</p><p><strong>Methods: </strong>We analyzed 52 amyloid positron emission tomography (PET) examinations performed at our institution. After radiotracer administration, residual radioactivity was measured in the drug vial, infusion circuit, route, residual solution, and individual circuit components. Administration rates and residual ratios were calculated after decay correction to the injection time. Residual ratios estimated by the UG-02 system were compared with measured values, and the optimal residual setting was determined using least-squares optimization. Statistical analyses were performed using paired t-tests, with statistical significance set at P<0.05.</p><p><strong>Results: </strong>The mean administered dose was 348.0±33.3 MBq, whereas the mean residual activity was 93.1±12.6 MBq, corresponding to an administration rate of 77.8% and a residual ratio of 22.2%. The infusion circuit exhibited the highest residual ratio (18.0%), primarily attributable to the air vent filter (13.5%) and infusion set (4.0%). The UG-02 system significantly overestimated the residual ratio in the drug vial compared with the measured value (1.5% vs. 0.9%, P<0.01). The optimal residual setting was 16.1%, reducing the relative error of the displayed dose from 17.1% to 0.08%.</p><p><strong>Conclusion: </strong>This study characterized residual distribution within the UG-02 automated infusion system and identified an optimal residual setting for ¹⁸F-florbetapir administration. Implementing this setting improves dose calculation accuracy, reduces underdosing risk, and may contribute to improving the quantitative reliability of amyloid PET imaging.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148901741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}