Nihon Hoshasen Gijutsu Gakkai zasshi最新文献_第3页

[Feasibility of Effective Source-to-surface Distance Calculation Using an Electron Monte Carlo Algorithm for Electron Beams]. 用电子蒙特卡罗算法计算电子束源到表面距离的可行性。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-1548

Shoma Okada, Reina Goto, Honomi Nishino, Shoma Hiramatsu, Kenji Matsumoto, Masakazu Otsuka, Takahiro Saika, Masahiko Okumura

{"title":"[Feasibility of Effective Source-to-surface Distance Calculation Using an Electron Monte Carlo Algorithm for Electron Beams].","authors":"Shoma Okada, Reina Goto, Honomi Nishino, Shoma Hiramatsu, Kenji Matsumoto, Masakazu Otsuka, Takahiro Saika, Masahiko Okumura","doi":"10.6009/jjrt.26-1548","DOIUrl":"10.6009/jjrt.26-1548","url":null,"abstract":"Purpose: In radiation therapy, the absorbed dose is corrected for changes in the nominal treatment distance using the inverse square law. However, in the case of electron beams, the inverse square law using the nominal treatment distance is invalid. Therefore, an effective source-to-surface distance (SSD) should be determined. The effective SSD must be measured for all electron beam energies and applicator sizes. Here, we calculated the effective SSD using a radiotherapy planning system with an electron Monte Carlo (eMC) calculation algorithm and evaluated its usefulness.Methods: The effective SSD was calculated from the absorbed dose ratio at dmax at extended SSDs under 5 gap conditions, using both eMC calculations and LINAC measurements. The consistency between calculated and measured values was evaluated based on the absorbed dose ratio at dmax, effective SSD, and distance correction factor.Results: The difference in the absorbed dose ratio at dmax between eMC calculations and measurements at extended SSDs was within 1.38%, and the effective SSD values agreed within 5.40 cm. Larger discrepancies in effective SSD were observed under conditions of high energy with large field sizes and low energy with small field sizes.Conclusion: The good agreement in absorbed dose ratio at dmax, effective SSD, and distance correction factor between eMC calculations and measurements indicates that effective SSD calculation using eMC is feasible and can be employed for comparative verification against measured values.","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":"146144493","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

[Estimation of Air Kerma-area Product Using Real-time Dosimeter in Mobile X-ray Fluoroscopy System]. [在移动x射线透视系统中使用实时剂量计估算空气克尔玛面积产品]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-1636

Junichi Taoka, Hideyuki Kato, Tetsuharu Kasahara, Kenta Tako, Takashi Iimori

{"title":"[Estimation of Air Kerma-area Product Using Real-time Dosimeter in Mobile X-ray Fluoroscopy System].","authors":"Junichi Taoka, Hideyuki Kato, Tetsuharu Kasahara, Kenta Tako, Takashi Iimori","doi":"10.6009/jjrt.26-1636","DOIUrl":"https://doi.org/10.6009/jjrt.26-1636","url":null,"abstract":"Purpose: This study aimed to estimate the air kerma-area product of a mobile X-ray fluoroscopy system by using a real-time dosimeter in situations where an area dosimeter is not available.Methods: A real-time dosimeter was mounted on the C-arm of a mobile X-ray fluoroscopy system. Using an ionization dosimeter as a reference, we evaluated the correlation between the air kerma-area product measured by the fluoroscopy system and the readings obtained from the mounted real-time dosimeter. Tube voltage was varied from 60 to 110 kV in 10-kV increments, and phantom thickness varied from 5 to 20 cm in 5-cm increments. In addition, the irradiation field area was adjusted across five levels, ranging from 168.1 to 75.5 cm2.Results: A strong linear relationship was observed between the real-time dosimeter readings x-axis and the air kerma-area product values y-axis, expressed as the regression equation y=36.181x+0.2188. The correlation coefficient was r=0.99.Conclusion: This study suggests that the air kerma-area product can be estimated by placing a real-time dosimeter on a mobile X-ray fluoroscopy system without an area dosimeter.","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148414126","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

[The Future of Radiological Medicine Expanding through 'Connections']. [通过“连接”扩展放射医学的未来]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-0306

Hidetaka Hayashi

引用次数: 0

[14. The Role of Radiological Technology Science in Targeted Radionuclide Therapy: Integrating Radiation Safety, Quantitative Imaging, and Dosimetry]. (14。放射技术科学在靶向放射性核素治疗中的作用：整合放射安全、定量成像和剂量学[j]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-0608

Kenta Miwa, Noriaki Miyaji, Tensho Yamao, Masaki Masubuchi, Kaito Wachi, Naochika Akiya, Arata Komatsu, Takuma Horikawa, Yuto Kamitaka

引用次数: 0

[6. Data Literacy (4): Important Things to Keep in Mind When Analyzing Data]. (6。数据素养(4)：分析数据时要牢记的重要事项]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-0605

Ayako Yagahara

引用次数: 0

[Diagnostic Performance of Automated Intracranial Hemorrhage Detection Software and Analysis of Volume and Hounsfield Unit Metrics in False-positive Cases]. [颅内出血自动检测软件在假阳性病例中的诊断性能及容积和霍斯菲尔德单位指标分析]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-1628

Shunichi Ishizuka, Shun Muramatsu, Tomomi Ohmura

{"title":"[Diagnostic Performance of Automated Intracranial Hemorrhage Detection Software and Analysis of Volume and Hounsfield Unit Metrics in False-positive Cases].","authors":"Shunichi Ishizuka, Shun Muramatsu, Tomomi Ohmura","doi":"10.6009/jjrt.26-1628","DOIUrl":"10.6009/jjrt.26-1628","url":null,"abstract":"Purpose: To compare the diagnostic performance of syngo.CT Brain Hemorrhage (BH) (Siemens Healthcare, Forchheim, Germany) with physician interpretations on noncontrast head CT in patients with suspected intracranial hemorrhage (ICH), and to elucidate the volume and Hounsfield unit (HU) metrics of false-positive (FP) cases.Methods: We analyzed 509 noncontrast head CT examinations obtained for suspected ICH. Presence or absence of hemorrhage was determined by board-certified radiologists or clinicians. Among positive cases, hemorrhage subtypes were labeled as intraparenchymal hemorrhage (IPH), intraventricular hemorrhage (IVH), subdural hematoma (SDH), epidural hematoma (EDH), and subarachnoid hemorrhage (SAH). BH outputs were categorized as true positive (TP), false positive (FP), false negative (FN), or true negative (TN). For FP cases, lesion location and BH-derived quantitative indices-lesion volume and HU values (minimum, maximum, mean, and standard deviation)-were compared with TP cases.Results: BH achieved a sensitivity 100%, a specificity 82.2%, a FP rate 17.8%, and an FN rate 0%. TP cases comprised IPH 64, SAH 33, SDH 83, EDH 11, and IVH 14. FP findings were located in cerebral sulci (n=22), brain parenchyma (n=12), vessels (n=10), dura mater (n=5), and bone (n=5). All BH indices differed between FP and TP cases (p<0.01).Conclusion: BH showed favorable diagnostic performance relative to physician interpretations, and FP cases exhibited statistically significant differences from TP cases in lesion volume and HU-based metrics.","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147693962","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

[5. Image Guidance and Setup Accuracy in Particle Therapy]. (5。粒子治疗中的图像引导和设置精度[j]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-0710

Kiyotaka Wada

引用次数: 0

[Domestic Market Trend for Medical Imaging and Radiological System]. 【医学影像与放射系统国内市场趋势】。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-0801

Osamu Uchiyama

引用次数: 0

[Impact of Matrix Size and Magnification Ratio on PET Imaging Using a Semiconductor PET/CT System]. [矩阵尺寸和放大倍率对半导体PET/CT成像系统的影响]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-1616

Shogo Fujita, Yukito Maeda, Masatoshi Morimoto, Yayoi Taniguchi, Yusuke Uehara, Akihiro Oishi, Keigo Omori, Keisuke Matsumoto, Keisuke Matsunami, Nobuyuki Kudomi, Takanobu Iwasaki

{"title":"[Impact of Matrix Size and Magnification Ratio on PET Imaging Using a Semiconductor PET/CT System].","authors":"Shogo Fujita, Yukito Maeda, Masatoshi Morimoto, Yayoi Taniguchi, Yusuke Uehara, Akihiro Oishi, Keigo Omori, Keisuke Matsumoto, Keisuke Matsunami, Nobuyuki Kudomi, Takanobu Iwasaki","doi":"10.6009/jjrt.26-1616","DOIUrl":"https://doi.org/10.6009/jjrt.26-1616","url":null,"abstract":"Purpose: We investigated the effects of matrix size and magnification ratio on positron emission tomography (PET) image quantitative characteristics using a semiconductor detector PET/CT.Methods: Three types of phantom were filled with 18F-fluorodeoxyglucose solution and scanned. Images were reconstructed using the ordered-subsets expectation-maximization method, with matrix sizes of 128, 220, 256, 440, 512, and 880, and magnification ratios of 1.0, 1.5, 2.0, 2.5, and 3.0. We evaluated the maximum standardized uptake value (SUVmax), percentage coefficient of variation (%CV), and full width at half maximum (FWHM).Results: Minimal differences in the SUVmax, %CV, and FWHM were observed between the matrix sizes of 128 and 220, and between 440, 512 and 880. However, significant differences were observed between the matrix sizes of 220 and 256, as the largest difference, and between 256 and 440. The influence of the magnification ratio on the image quality was small.Conclusion: The magnification ratio has a minor effect on quantitative values and image quality, whereas the impact of matrix size is significant. A noticeable difference in evaluation was observed between matrix sizes of 220 and 256. This was considered an important factor in determining the matrix size for this device.","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148882288","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

[Evaluating the Effect of Log-linear Interpolation on Half-value Layers Using Monte Carlo Simulation]. [用蒙特卡罗模拟评价对数线性插值对半值层的影响]。

Nihon Hoshasen Gijutsu Gakkai zasshi Pub Date : 2026-01-01 DOI: 10.6009/jjrt.26-1526

Noriyo Yokotsuka, Hiroki Saito, Sho Maruyama

{"title":"[Evaluating the Effect of Log-linear Interpolation on Half-value Layers Using Monte Carlo Simulation].","authors":"Noriyo Yokotsuka, Hiroki Saito, Sho Maruyama","doi":"10.6009/jjrt.26-1526","DOIUrl":"10.6009/jjrt.26-1526","url":null,"abstract":"The half-value layer (HVL), an indicator of X-ray quality, is defined as the thickness of an aluminum (Al) filter that reduces the air kerma by half and is used to calculate the backscatter coefficient. HVL is determined from the attenuation curve of air kerma using log-linear interpolation. However, there are no references detailing the specific measurement method. This study aims to investigate the impact of varying the interval of Al filters used in the log-linear interpolation on the HVL, using Monte Carlo simulations. The Monte Carlo simulation was performed using Particle and Heavy Ion Transport code System (PHITS) Ver. 3.29. A photon point source was placed in the air, and the rectangular irradiation field was set to 5×5 cm at the detector position. The detector, simulated as a volume of 1 cm3 of air, was positioned 100 cm from the source. The Al filter thickness for the HVL was varied in increments of 0.1 mm. The HVL was calculated by linear interpolation, and the relative error was determined based on the minimum Al spacing. The X-ray tube voltages used were those of the RQR series (40, 50, 60, 70, 80, 90, 100, 120, and 150 kV). The beam qualities obtained from the measurements and the Monte Carlo simulation system were consistent with those specified for the RQR series in IEC 61267 within ±3.5%. The relative error of HVL for each tube voltage determined by simulation ranged from -0.5 to 4.6%, with a mean±standard deviation (median) of 1.12±0.95% (0.88%). The relative error was larger when the difference between the Al filter combinations was large and the interpolation coefficient α was 0.5. When the filter spacing is less than half the HVL, the accuracy of log-linear interpolation in HVL is less than ±1.5% relative error.","PeriodicalId":74309,"journal":{"name":"Nihon Hoshasen Gijutsu Gakkai zasshi","volume":"82 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121334","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