Nihon Hoshasen Gijutsu Gakkai zasshi最新文献_第7页

[Impact of Imaging and Reconstruction Parameters for Cone-beam Computed Tomography on Three-dimensional Star Shot Using an X-ray CT-based Gel Dosimeter]. [基于x射线ct凝胶剂量计的锥形束计算机断层成像和重建参数对三维星射的影响]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-1465

Shinichi Takahashi, Hidenobu Tachibana, Riki Oshika, Rie Tachibana, Masashi Itou

{"title":"[Impact of Imaging and Reconstruction Parameters for Cone-beam Computed Tomography on Three-dimensional Star Shot Using an X-ray CT-based Gel Dosimeter].","authors":"Shinichi Takahashi, Hidenobu Tachibana, Riki Oshika, Rie Tachibana, Masashi Itou","doi":"10.6009/jjrt.25-1465","DOIUrl":"10.6009/jjrt.25-1465","url":null,"abstract":"Previous studies have not demonstrated the influence of various imaging acquisition and reconstruction conditions on three-dimensional star shot analysis using an X-ray-based gel dosimeter. Therefore, we investigated the effects of image acquisition and reconstruction conditions on the method in this study and evaluated the robustness of the method. Firstly, we set a reference condition (80 kVp, 1080 mAs, full fan, full trajectory, 1800 projection number, iterative reconstruction) and nine other comparison conditions (80-125 kVp, 540-2160 mAs, half or full fan, full or half trajectory, 420-5400 projection number and iterative reconstruction or filtered back projection). Cone-beam computed tomography scans were performed under each condition before and after irradiation of the single gel dosimeter, and the position of the radiation isocenter relative to the image isocenter, beam isocentricity, and contrast-to-noise ratio (CNR) was measured. The differences compared to the reference were as follows: for isocenter distance, 0.0±0.1 mm on the X-axis, 0.0±0.2 mm on the Y-axis, and 0.1±0.3 mm on the Z-axis. The beam isocentricity was 0.0±0.2 mm. The CNR ranged from a maximum of 5.8 to a minimum of 2.6 in median comparisons. In contrast, compared to the results under the reference condition, the results under other conditions matched within a range of ±0.25 mm. This investigation showed that analysis is feasible within an uncertainty of 0.25 mm under imaging conditions where CNR is 3 or higher.","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":"143383793","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}

引用次数: 0

[A Simple Method for Measuring the Anisotropic Two-dimensional Noise Power Spectrum in Helical CT Scan]. [一种测量螺旋CT扫描各向异性二维噪声功率谱的简单方法]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-1528

Yuki Ohsugi, Akihiro Narita, Masaki Ohkubo, Kenichi Sakai, Yoshiyuki Noto

{"title":"[A Simple Method for Measuring the Anisotropic Two-dimensional Noise Power Spectrum in Helical CT Scan].","authors":"Yuki Ohsugi, Akihiro Narita, Masaki Ohkubo, Kenichi Sakai, Yoshiyuki Noto","doi":"10.6009/jjrt.25-1528","DOIUrl":"10.6009/jjrt.25-1528","url":null,"abstract":"Purpose: Recently, a new method has been devised to measure the anisotropic 2-dimensional noise power spectrum (2D-NPS) in computed tomography. The 2D-NPS varied with the X-ray tube angle θ in the helical scan; it was defined as 2D-NPSθ. However, the method requires many scans to obtain the 2D-NPSθ for each θ with less statistical variability and is laborious. In the present study, the 2D-NPSθ was assumed to be an identical anisotropic 2D-NPS that rotated around the origin of the spatial frequency domain in conjunction with the rotation of the X-ray tube. We defined the identical 2D-NPS as 2D-NPSrot and proposed its measurement method with fewer scans.Methods: The 2D-NPSθ (θ from 0° to 180° in an increment of 30°) were obtained from noise images acquired by a hundred scans of a water phantom. In the proposed method, the 2D-NPSθ were obtained from noise images by 2 scans, rotated backward around the origin by θ to generate the identical 2D-NPS, and averaged to generate the 2D-NPSrot.Results: The 2D-NPSrot, when it was rotated by θ, agreed well with the corresponding 2D-NPSθ. Absolute values of the mean and standard deviation of percentage errors of the 2D-NPSrot with the corresponding 2D-NPSθ at each θ were less than 0.70% and 6.12%, respectively.Conclusion: The proposed method was suggested to be valid for simple measurement of anisotropic 2D-NPS.","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"81 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495049","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}

引用次数: 0

[Report of the Workshop for 2024 and Future Plans of X-Ray Leakage Measurement Expert Qualification for X-Ray Examination Rooms]. 【2024年车间报告及x射线检查室x射线泄漏测量专家资格认定未来规划】。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0406

Daisuke Kotani

引用次数: 0

[JRC2024 ITEM Tour Experience Reports]. [JRC2024项目旅游体验报告]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0306

引用次数: 0

[5. History of Radiation Effects Research]. (5。辐射效应研究的历史]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0202

Yoshiaki Hirofuji

引用次数: 0

[Paper Review: PET Detectors with Depth-of-interaction and Time-of-flight Capabilities]. [论文综述：PET探测器与相互作用深度和飞行时间能力]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0205

Hideo Murayama

引用次数: 0

[Accuracy of Setup in Deep-inspiration Breath-hold Irradiation Following Left Mastectomy Using Surface Imaging Guidance]. [表面成像引导下左乳切除术后深度吸气屏气照射设置的准确性]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-1538

Minori Tanoue, Norimasa Matsushita, Makoto Sasaki, Takahiro Fujimoto, Manabu Nakata, Yuka Ono, Michio Yoshimura, Takashi Mizowaki

引用次数: 0

[Effect of Parameters Related to Sampling Time on Resolution Characteristics of Fast TSE Dixon Method]. [采样时间相关参数对快速TSE Dixon方法分辨率特性的影响]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-1459

Heita Uno, Makoto Suzuki, Kazutaka Nashiki, Hidemichi Kawata

{"title":"[Effect of Parameters Related to Sampling Time on Resolution Characteristics of Fast TSE Dixon Method].","authors":"Heita Uno, Makoto Suzuki, Kazutaka Nashiki, Hidemichi Kawata","doi":"10.6009/jjrt.25-1459","DOIUrl":"https://doi.org/10.6009/jjrt.25-1459","url":null,"abstract":"Purpose: Fast turbo spin echo (TSE) Dixon method, which acquires both in-phase and opposed-phase in a single echo train, resulting in a 50% reduction in imaging times compared to the TSE Dixon method. However, it has been observed that the Fast TSE Dixon method exhibits degraded resolution characteristics when scanned under the same parameters as the TSE Dixon method. This study aimed to reveal suitable scan parameters for the Fast TSE Dixon method by examining its resolution characteristics when altering the parameter of the receiver bandwidth (BW) and asymmetric echoes related to sampling time.Methods: The BW was adjusted to 400, 600, 800, and 1000 Hz/pixel for the TSE Dixon and Fast TSE Dixon methods. In addition, the parameter of asymmetric echoes was changed to on (weak), and off of the Fast TSE Dixon method. The modulation transfer function (MTF) of each sequence was assessed using the edge spread function in the frequency encoding direction and phase encoding direction.Results: The findings indicated that the MTFs of the TSE Dixon method remained constant despite alterations in the sampling time. Conversely, the MTFs of the Fast TSE Dixon method showed that resolution characteristics improved by shortening sampling time when the BW was expanded, and the asymmetric echoes were changed to on.Conclusion: We revealed suitable scan parameters for the Fast TSE Dixon method have been found to improve resolution characteristics by shortening sampling time when the BW was expanded and the asymmetric echoes were changed to on.","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":"144144749","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}

引用次数: 0

[9. Clinical Operation of 1.5 T MRI Linac "Elekta Unity"]. (9。1.5 T MRI直线机“Elekta Unity”的临床操作。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0601

Kiyokazu Sato

引用次数: 0

[Introduction of "JIRA Activity in 2025"]. 【“2025年JIRA活动介绍”】。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2025-01-01 DOI: 10.6009/jjrt.25-0608

Munehiro Takahashi, Susumu Tabata

引用次数: 0