Nihon Hoshasen Gijutsu Gakkai zasshi最新文献

{"title":"[4. One Question, One Answer about Radiological Protection].","authors":"Tomonori Isobe, Yutaro Mori, Yoshiaki Nagai","doi":"10.6009/jjrt.25-0102","DOIUrl":"https://doi.org/10.6009/jjrt.25-0102","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 1","pages":"56-61"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143017832","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 Auto-segmentation in the Head and Neck Region].","authors":"Issei Matsuo, Masayuki Tachibana, Hirofumi Honda, Hiroki Namba","doi":"10.6009/jjrt.25-1475","DOIUrl":"10.6009/jjrt.25-1475","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this study was to perform auto-segmentation on cases in the head and neck region and to elucidate the characteristics of the extraction performance.</p><p><strong>Methods: </strong>Auto-segmentation was performed on 100 cases in the head and neck region in Japan. The Auto-segmentation contours were compared with the clinical contours. The evaluation structures were the brain, brainstem, spinal cord, mandible, parotid gland, larynx, and eyeballs. DSC and HD were used for similarity evaluation.</p><p><strong>Results: </strong>Overall, there was a high similarity in the eyeball and spinal cord. However, the lower the contrast with neighboring objects and the greater the variation in shape, the lower the similarity. In addition, metal artifacts lowered the similarity in some areas.</p><p><strong>Conclusion: </strong>When auto-segmentation extraction was performed, differences were observed in the degree of similarity between organs. Depending on the case and morphology, the accuracy of auto-segmentation extraction varied from site to site, even for the same organ. The characteristics of the extractability found in this study make it useful for the manual modification of contouring.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143383792","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":"[Impact of Differences in Radiopharmaceuticals on Brain Perfusion SPECT Phantom Examination Using the Hoffman 3D Brain Phantom].","authors":"Norikazu Matsutomo, Koya Hayakawa, Eiji Hisano, Takaaki Konno, Mitsuha Fukami, Tomoaki Yamamoto","doi":"10.6009/jjrt.25-1539","DOIUrl":"10.6009/jjrt.25-1539","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to clarify the effects of radiopharmaceuticals and buffer solutions on the accuracy of the Hoffman phantom examination.</p><p><strong>Methods: </strong>The Hoffman phantom was prepared using the water immersion method and was injected with 3 different solutions: ¹²³I-MIBG, ¹²³I-IMP only, and ¹²³I-IMP plus buffer solution. Single photon emission computed tomography (SPECT) / computed tomography (CT) imaging was performed at 3-time points: immediately after encapsulation, after 10 min of stirring, and after 20 min of stirring. The relative SPECT counts and left-right ratios of the images obtained under each condition were evaluated.</p><p><strong>Results: </strong>The results revealed that the buffer solution facilitated the mixing of ¹²³I-IMP, affecting the initial distribution of the radiopharmaceutical. However, after 20 min of stirring, no significant differences were observed in the relative SPECT counts and the left-right ratio of SPECT images among the different solutions, regardless of the radiopharmaceutical type or the presence of the buffer, in most regions.</p><p><strong>Conclusion: </strong>Buffer solution promotes the mixing process; however, it was confirmed that sufficient agitation alone can produce comparable SPECT images, indicating that the use of a buffer may not be necessary if proper agitation is ensured during phantom preparation.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143756416","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: Deep Learning-based PET Image Denoising and Reconstruction: A Review].","authors":"Kenta Miwa, Tensho Yamao","doi":"10.6009/jjrt.25-0303","DOIUrl":"https://doi.org/10.6009/jjrt.25-0303","url":null,"abstract":"","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 3","pages":"34-35"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702338","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":"[Study on the Effectiveness of QA/QC Methods for Non-physical Wedges by Comparing EPID and 2D Array Detector Beam Profiles].","authors":"Yusuke Ohtani, Masayuki Tachibana","doi":"10.6009/jjrt.25-1478","DOIUrl":"https://doi.org/10.6009/jjrt.25-1478","url":null,"abstract":"<p><strong>Purpose: </strong>Beam profiles of enhanced dynamic wedge (EDW), a non-physical wedge, were obtained using EPID and 2D array detector, and the effectiveness of the QA/QC method for EDW using EPID was investigated.</p><p><strong>Methods: </strong>Using a radiotherapy unit (Clinac iX; Varian Medical Systems, Palo Alto, CA, USA), the EDW beam profile was measured 10 times with an EPID (aS1000; Varian Medical Systems) and a 2D array detector (Profiler2; Sun Nuclear, Melbourne, FL, USA) to evaluate the reproducibility of the set-up and the EDW beam profiles. The beam profiles of the physical wedge were also obtained with EPID and Profiler2 as a comparison for the EDW beam profiles. In addition, EDW irradiation logs were obtained to analyze output fluctuations during EDW irradiation.</p><p><strong>Results: </strong>Comparing the EPID and Profiler2 reproducibility of beam profiles, the EPID showed better setup position reproducibility, but the Profiler2 showed better EDW reproducibility of beam profiles. The coefficient of variation for the physical wedge reproducibility of beam profiles was equal or smaller for EPID, and for the EDW irradiation log, the variation was more significant for larger EDW angles.</p><p><strong>Conclusion: </strong>The effectiveness of the QA/QC method for EDW by EPID is high because EPID is considered to capture the EDW variation in detail and the installation accuracy is also excellent.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144082626","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":"[Verification of Image Reconstruction Error Improvement Effect of Stent Enhancement Processing Using Region of Interest Function in Percutaneous Coronary Intervention].","authors":"Kazuya Mori, Kouhei Makabe, Ryou Sekiguchi, Toru Negishi","doi":"10.6009/jjrt.25-1515","DOIUrl":"https://doi.org/10.6009/jjrt.25-1515","url":null,"abstract":"<p><strong>Purpose: </strong>Stent enhancement processing (SV) is an image processing technique that improves the visibility of coronary artery stents, and its usefulness in percutaneous coronary intervention (PCI) has been reported. However, the re-acquisition of image reconstruction errors increases patient exposure dose. This study aims to retrospectively evaluate cases of SV and identify the effect of improving image reconstruction errors using the region of interest (ROI) function of SV.</p><p><strong>Methods: </strong>The evaluation targets were 584 PCI cases where SV was used from January 2016 to December 2020. SV error was defined as the image reconstruction error in SV imaging. We evaluated the improvement of SV errors by using the ROI function of SV for images that exhibited SV errors. Significant differences in the improvement effect on SV error by using the ROI function of SV were determined using a paired t-test. A chi-squared test was performed to determine the significance of the relationship between each evaluation item and the SV error.</p><p><strong>Results: </strong>There were 53 cases of SV errors when the ROI function of SV was not used. The ROI function of SV improved SV errors in 52 cases (p<0.05). In addition, there was no significant relationship between SV errors when using the ROI function of SV and each evaluation item.</p><p><strong>Conclusion: </strong>The ROI function of SV improved the SV error in 98.11% of the cases where the SV error occurred. The ROI function of SV is useful for reducing SV errors.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144082629","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":"[Investigation of Factors Related to Operator's Eye Lens Doses during Cardiac Catheterization Using a Specially Made Acrylic Phantom].","authors":"Yoshinori Ogawa, Kosuke Matsubara, Thunyarat Chusin, Saori Shoji, Shigeto Matsuyama","doi":"10.6009/jjrt.25-1513","DOIUrl":"https://doi.org/10.6009/jjrt.25-1513","url":null,"abstract":"<p><strong>Purpose: </strong>We investigated the factors that influence the eye lens dose to the operator during cardiac catheterization using a cylindrical acrylic phantom, which can place small dosimeters at 3-mm depth from the surface.</p><p><strong>Methods: </strong>A cylindrical acrylic phantom was placed on top of the thoracic phantom, which was used as the operator's phantom. The absorbed doses at the assumed positions of the eye lenses of the operator's phantom were measured by two irradiation modes. It was integrated from two projections in fluoroscopy mode. In cine mode, it was integrated from 15 projections. The measurement was performed by changing height of eye lenses (150, 165, and 180 cm), orientation of the cylindrical phantom (0°, 15°, 30°, and 45°), and the position of the operator's phantom (radial access, femoral access, and the position of the second operator).</p><p><strong>Results: </strong>The lens doses decreased as the phantom height increased. The doses at the left neck were 1.2 to 1.4 times higher than those at the eye lens. The lens doses tended to decrease as the cylindrical phantom was oriented away from the X-ray tube, and it was the highest when the phantom was at the radial access approach position.</p><p><strong>Conclusions: </strong>During cardiac catheterization, the absorbed dose of the operator's lens depends on the operator's height, head orientation, and position. If the dosimeter is placed on the neck, the eye lens dose can be conservatively estimated.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144059427","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":"[Multicenter Survey of Exposure Dose in Coronary Artery Angiography and IVR].","authors":"Kazuki Maekawa, Masakazu Sato, Toshihiro Hayashi, Ryota Hasegawa, Kazuki Noguchi, Kazuya Takeda, Koushi Sakiyama, Hajime Sakamoto, Osamu Tajima, Hisaya Sato, Eiji Ishikawa","doi":"10.6009/jjrt.25-1525","DOIUrl":"10.6009/jjrt.25-1525","url":null,"abstract":"<p><strong>Purpose: </strong>In DRLs 2020, in addition to the fluoroscopic dose rate, air kerma at the patient entrance reference point (K_a,r) and air kerma-area product (P_KA) by types of medical treatment and diseases were set as DRL quantity. We surveyed the current equipment setting dose at each facility and the exposure dose in clinical practice. We considered the optimal DRL classification of K_a,r and P_KA for the next DRLs update.</p><p><strong>Methods: </strong>We conducted a questionnaire survey of 428 facilities in Japan with angiography devices and analyzed the obtained angiography dose data.</p><p><strong>Results: </strong>Fluoroscopic dose rate, K_a,r, and P_KA were lower values compared to past studies and DRLs 2020 data, and significant differences were observed in K_a,r and P_KA by procedure.</p><p><strong>Conclusion: </strong>Equipment setting doses have been optimized at each facility, and it is expected that radiological protection will be optimized by setting DRL values that reflect the current situation.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257624","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":"[Accuracy of Proton Density Fat Fraction Measurement Using Chemical Shift-encoded MRI with Fast Imaging Techniques].","authors":"Tomofumi Misaka, Satoshi Takenaka, Takayuki Ishida","doi":"10.6009/jjrt.25-1464","DOIUrl":"10.6009/jjrt.25-1464","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate the accuracy of proton density fat fraction (PDFF) measurement using chemical shift-encoded MRI (CSE-MRI) with fast imaging techniques in a phantom.</p><p><strong>Methods: </strong>A 1.5T imaging system (Prodiva; Philips Healthcare) and PDFF phantom (Fat Fraction Phantom Model 300; Calimetrix) were used in this study. The acquisitions without fast imaging techniques (conventional acquisition), with parallel imaging in phase-encode direction (SENSE acquisition), with compressed sensing (CS-SENSE acquisition), and with parallel imaging in both phase-encode and slice-encode direction (Dual-SENSE acquisition) were performed. The following acceleration factors in SENSE and CS-SENSE acquisition were used: 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, and 8.0. For Dual-SENSE acquisition, the same acceleration factors (1.5, 2.0, 3.0, 4.0, 5.0) were set in each of the two directions. The relationships between reference PDFF values and PDFF measurements obtained using each acquisition were assessed using linear regression analysis and Bland-Altman analysis.</p><p><strong>Results: </strong>According to the linear regression analysis, the slopes and intercepts of regression lines were from 0.87 to 1.02 and from 0.06% to 3.55%, respectively. According to Bland-Altman analysis, there were fixed bias between reference PDFF values and PDFF measurements obtained using SENSE acquisition with reduction factor 8.0 and Dual-SENSE acquisition with reduction factor 5.0. For CS-SENSE acquisition with reduction factor from 7.0 to 8.0, SENSE acquisition with reduction factor from 3.0 to 8.0, and Dual-SENSE acquisition with reduction factor from 2.0 to 5.0, some vials had ±1.5% or more errors between the reference PDFF values and PDFF measurements in the range of 0% to 50% PDFF.</p><p><strong>Conclusion: </strong>In CS-SENSE acquisition, the accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 6.0. The accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 2.0 in SENSE acquisition and a reduction factor 1.5 in Dual-SENSE acquisition.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 3","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257623","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":"[Spatial Resolution and Uniformity of a Full-ring CZT SPECT/CT System: Comparison with a Conventional Anger-type SPECT/CT Instrument].","authors":"Takashi Takeuchi, Yoshitaka Tanaka, Yasuhiro Kodama, Hayato Odagiri","doi":"10.6009/jjrt.25-1527","DOIUrl":"https://doi.org/10.6009/jjrt.25-1527","url":null,"abstract":"<p><strong>Purpose: </strong>StarGuide (GE HealthCare, Haifa, Israel) is a full-ring SPECT/CT system based on Cadmium Zinc Telluride (CZT) technology. In this study, we aimed to compare the image quality of this CZT-based SPECT/CT to a conventional Anger-type SPECT/CT system (NM/CT 870 DR, 870DR; GE HealthCare).</p><p><strong>Methods: </strong>Tomographic sensitivity was calculated by recording the total number of counts detected during tomographic acquisition for a point source. We evaluated spatial resolution and image uniformity on each system using the full width half maximum (FWHM) of line sources and root mean square uniformity (%RMSU) of pool phantom, respectively. The voxel size of the StarGuide SPECT images was 2.46×2.46×2.46 mm³, compared to 4.42×4.42×4.42 mm³ on 870DR. These projection data were reconstructed using 3D-OSEM with a resolution recovery technique (RR). We compared 3 different algorithms: non-correction (NCRR), scatter correction (SCRR), and attenuation correction and scatter correction (ACSCRR).</p><p><strong>Results: </strong>Tomographic sensitivity of StarGuide and 870DR were estimated at 200.0 counts・s^-1・MBq^-1 and 193.3 counts・s^-1・MBq^-1, respectively. Spatial resolution at the center of the FOV was estimated at 2.6 mm for StarGuide and 5.4 mm for 870DR with ACSCRR. Likewise, the %RMSU was 21.7 for StarGuide and 24.6 for 870DR.</p><p><strong>Conclusion: </strong>The full-ring CZT SPECT/CT system has a superior spatial resolution and better image uniformity than the conventional Anger-type SPECT instrument, whereas tomographic sensitivity remains similar.</p>","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144044075","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}