Radiological Physics and Technology最新文献_第4页

Clinical application of single-shot fast spin-echo sequence for cerebrospinal fluid flow MR imaging. 脑脊液流磁共振成像中单次快速自旋回波序列的临床应用。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-07-19 DOI: 10.1007/s12194-024-00825-7

Takahito Bessho, Tatsuya Hayashi, Shuhei Shibukawa, Kazuyuki Kourin, Takashi Shouda

{"title":"Clinical application of single-shot fast spin-echo sequence for cerebrospinal fluid flow MR imaging.","authors":"Takahito Bessho, Tatsuya Hayashi, Shuhei Shibukawa, Kazuyuki Kourin, Takashi Shouda","doi":"10.1007/s12194-024-00825-7","DOIUrl":"10.1007/s12194-024-00825-7","url":null,"abstract":"In normal-pressure hydrocephalus, disturbances in cerebrospinal fluid (CSF) circulation occur; therefore, understanding CSF dynamics is crucial. The two-dimensional phase-contrast (2D-PC) method, a common approach for visualizing CSF flow on MRI, often presents challenges owing to prominent vein signals and excessively high contrast, hindering the interpretation of morphological information. Therefore, we devised a new imaging method that utilizes T2-weighted high-signal intensification of the CSF and saturation pulses, without requiring specialized imaging sequences. This sequence utilized a T2-weighted single-shot fast spin-echo combined with multi-phase imaging synchronized with a pulse wave. Optimal imaging conditions (repetition time, presence/absence of fast recovery, and echo time) were determined using self-made contrast and single-plate phantoms to evaluate signal-to-noise ratio, contrast ratio, and spatial resolution. In certain clinical cases of hydrocephalus, confirming CSF flow using 2D-PC was challenging. However, our method enabled the visualization of CSF flow, proving to be useful in understanding the pathophysiology of hydrocephalus.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141724711","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

Evaluation of monthly variations in electrometer calibration coefficients using a charge generator for radiation therapy. 使用用于放射治疗的电荷发生器评估电量计校准系数的月度变化。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-08-01 DOI: 10.1007/s12194-024-00830-w

Motohiro Kawashima, Maria Varnava, Shuichi Ozawa, Hiromitsu Higuchi, Yoshihiko Hoshino, Mutsumi Tashiro

{"title":"Evaluation of monthly variations in electrometer calibration coefficients using a charge generator for radiation therapy.","authors":"Motohiro Kawashima, Maria Varnava, Shuichi Ozawa, Hiromitsu Higuchi, Yoshihiko Hoshino, Mutsumi Tashiro","doi":"10.1007/s12194-024-00830-w","DOIUrl":"10.1007/s12194-024-00830-w","url":null,"abstract":"Electrometers are important devices that are part of the standard dosimetry system. Therefore, we evaluated the variation of electrometer calibration coefficients (kelec) over 1 year in this study. We investigated two types of electrometers: a rate mode and an integrate mode. Each electrometer was connected to a charge generator, a constant charge was applied, and kelec was determined by measuring the current. The current measurements were repeated once a month. For electrometers with multiple ranges, measurements were taken at low and medium ranges. Almost all kelec measurements agreed within 0.2% of the initial measurements. However, the low range of the electrometer with an integrate mode showed seasonal variation, with a variation greater than 0.2%. This study shows that electrometers may exhibit errors that cannot be detected through annual inspections. The importance of quality assurance using a charge generator at one's own institution was demonstrated.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11341583/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141876265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of Gd-EOB-DTPA on proton-density fat fraction in the liver using chemical shift-encoded magnetic resonance imaging at 3-T. 利用 3 T 化学位移编码磁共振成像技术研究 Gd-EOB-DTPA 对肝脏质子密度脂肪分数的影响。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-05-10 DOI: 10.1007/s12194-024-00811-z

Makoto Suzuki, Tatsuya Hayashi, Kazutaka Nashiki, Hidemichi Kawata, Shuji Nagata, Toshi Abe

{"title":"Influence of Gd-EOB-DTPA on proton-density fat fraction in the liver using chemical shift-encoded magnetic resonance imaging at 3-T.","authors":"Makoto Suzuki, Tatsuya Hayashi, Kazutaka Nashiki, Hidemichi Kawata, Shuji Nagata, Toshi Abe","doi":"10.1007/s12194-024-00811-z","DOIUrl":"10.1007/s12194-024-00811-z","url":null,"abstract":"Non-alcoholic fatty liver disease (NAFLD) and its advanced stage, non-alcoholic steatohepatitis (NASH), have become increasingly prevalent owing to the rise in metabolic syndromes. Accurate assessment of hepatic fat deposition and inflammation is crucial for diagnosing and managing NAFLD/NASH. We investigated the influence of Gd-EOB-DTPA, (EOB) on proton-density fat fraction (PDFF) measurements using chemical shift-encoded magnetic resonance imaging (CSE-MRI) at 3-T. In total, 431 patients who underwent EOB contrast-enhanced MRI were included. PDFF measurements were obtained from pre- and post-contrast CSE-MRI. Linear regression and Bland-Altman analyses were performed to assess the correlation and agreement between pre- and post-EOB PDFF measurements. Relative enhancement (RE) of the liver was calculated as an EOB uptake index. There was a significant decrease in PDFF following EOB administration compared with the pre-contrast values (P < 0.0001), which was observed across all PDFF ranges (< 10% and ≥ 10%). Linear regression analysis revealed high correlation between pre- and post-EOB PDFF measurements. Bland-Altman analysis indicated a small bias between pre- and post-EOB PDFF values. Subgroup analysis based on RE showed a significant difference in ΔPDFF between patients with high RE (> 120%) and those with lower RE levels. EOB administration resulted in a slight decrease in PDFF measurements obtained using CSE-MRI at 3-T. We were able to generalize and clarify that the PDFF of the liver on 3D CSE-MRI at 3-T was slightly decreased after EOB administration as we used a larger group of patients compared to previous studies.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140904933","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

PET detectors with depth-of-interaction and time-of-flight capabilities. 具有交互深度和飞行时间功能的 PET 探测器。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-06-18 DOI: 10.1007/s12194-024-00821-x

Eiji Yoshida, Taiga Yamaya

{"title":"PET detectors with depth-of-interaction and time-of-flight capabilities.","authors":"Eiji Yoshida, Taiga Yamaya","doi":"10.1007/s12194-024-00821-x","DOIUrl":"10.1007/s12194-024-00821-x","url":null,"abstract":"In positron emission tomography (PET), measurements of depth-of-interaction (DOI) information and time-of-flight (TOF) information are important. DOI information reduces the parallax error, and TOF information reduces noise by measuring the arrival time difference of the annihilation photons. Historically, these have been studied independently, and there has been less implementation of both DOI and TOF capabilities because previous DOI detectors did not have good TOF resolution. However, recent improvements in PET detector performance have resulted in commercial PET scanners achieving a coincidence resolving time of around 200 ps, which result in an effect even for small objects. This means that TOF information can now be utilized even for a brain PET scanner, which also requires DOI information. Therefore, various methods have been proposed to obtain better DOI and TOF information. In addition, the cost of PET detectors is also an important factor to consider, since several hundred detectors are used per PET scanner. In this paper, we review the latest DOI-TOF detectors including the history of detector development. When put into practical use, these DOI-TOF detectors are expected to contribute to the improvement of imaging performance in brain PET scanners.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141421355","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

Two-step optimization for accelerating deep image prior-based PET image reconstruction. 两步优化，加速基于深度图像先验的 PET 图像重建。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-08-03 DOI: 10.1007/s12194-024-00831-9

Fumio Hashimoto, Yuya Onishi, Kibo Ote, Hideaki Tashima, Taiga Yamaya

引用次数: 0

Recommendation for reducing the crystalline lens exposure dose by reducing imaging field width in cone-beam computed tomography for image-guided radiation therapy: an anthropomorphic phantom study. 建议在图像引导放射治疗的锥束计算机断层扫描中通过减少成像视野宽度来降低晶状体照射剂量：一项拟人化模型研究。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-04-30 DOI: 10.1007/s12194-024-00810-0

Tatsuya Yoshida, Koji Sasaki, Tomoki Hayakawa, Toshiyuki Kawadai, Takako Shibasaki, Yoshiyuki Kawasaki

{"title":"Recommendation for reducing the crystalline lens exposure dose by reducing imaging field width in cone-beam computed tomography for image-guided radiation therapy: an anthropomorphic phantom study.","authors":"Tatsuya Yoshida, Koji Sasaki, Tomoki Hayakawa, Toshiyuki Kawadai, Takako Shibasaki, Yoshiyuki Kawasaki","doi":"10.1007/s12194-024-00810-0","DOIUrl":"10.1007/s12194-024-00810-0","url":null,"abstract":"In cone-beam computed tomography (CBCT) for image-guided radiation therapy (IGRT) of the head, we evaluated the exposure dose reduction effect to the crystalline lens and position-matching accuracy by narrowing one side (X2) of the X-ray aperture (blade) in the X-direction. We defined the ocular surface dose of the head phantom as the crystalline lens exposure dose and measured using a radiophotoluminescence dosimeter (RPLD, GD-352 M) in the preset field (13.6 cm) and in each of the fields when blade X2 aperture was reduced in 0.5 cm increments from 10.0 to 5.0 cm. Auto-bone matching was performed on CBCT images acquired five times with blade X2 aperture set to 13.6 cm and 5.0 cm at each position when the head phantom was moved from - 5.0 to + 5.0 mm in 1.0 mm increment. The maximum reduction rate in the crystalline lens exposure dose was - 38.7% for the right lens and - 13.2% for the left lens when blade X2 aperture was 5.0 cm. The maximum difference in the amount of position correction between blade X2 aperture of 13.6 cm and 5.0 cm was 1 mm, and the accuracy of auto-bone matching was similar. In CBCT of the head, reduced blade X2 aperture is a useful technique for reducing the crystalline lens exposure dose while ensuring the accuracy of position matching.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140869945","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

Multi-institutional questionnaire-based survey on online adaptive radiotherapy performed using commercial systems in Japan in 2023. 2023 年日本使用商业系统进行在线自适应放射治疗的多机构问卷调查。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-07-19 DOI: 10.1007/s12194-024-00828-4

Hiraku Iramina, Masato Tsuneda, Hiroyuki Okamoto, Noriyuki Kadoya, Nobutaka Mukumoto, Masahiko Toyota, Junichi Fukunaga, Yukio Fujita, Naoki Tohyama, Hiroshi Onishi, Mitsuhiro Nakamura

{"title":"Multi-institutional questionnaire-based survey on online adaptive radiotherapy performed using commercial systems in Japan in 2023.","authors":"Hiraku Iramina, Masato Tsuneda, Hiroyuki Okamoto, Noriyuki Kadoya, Nobutaka Mukumoto, Masahiko Toyota, Junichi Fukunaga, Yukio Fujita, Naoki Tohyama, Hiroshi Onishi, Mitsuhiro Nakamura","doi":"10.1007/s12194-024-00828-4","DOIUrl":"10.1007/s12194-024-00828-4","url":null,"abstract":"In this study, we aimed to conduct a survey on the current clinical practice of, staffing for, commissioning of, and staff training for online adaptive radiotherapy (oART) in the institutions that installed commercial oART systems in Japan, and to share the information with institutions that will implement oART systems in future. A web-based questionnaire, containing 107 questions, was distributed to nine institutions in Japan. Data were collected from November to December 2023. Three institutions each with the MRIdian (ViewRay, Oakwood Village, OH, USA), Unity (Elekta AB, Stockholm, Sweden), and Ethos (Varian Medical Systems, Palo Alto, CA, USA) systems completed the questionnaire. One institution (MRIdian) had not performed oART by the response deadline. Each institution had installed only one oART system. Hypofractionation, and moderate hypofractionation or conventional fractionation were employed in the MRIdian/Unity and Ethos systems, respectively. The elapsed time for the oART process was faster with the Ethos than with the other systems. All institutions added additional staff for oART. Commissioning periods differed among the oART systems owing to provision of beam data from the vendors. Chambers used during commissioning measurements differed among the institutions. Institutional training was provided by all nine institutions. To the best of our knowledge, this was the first survey about oART performed using commercial systems in Japan. We believe that this study will provide useful information to institutions that installed, are installing, or are planning to install oART systems.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141724712","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

Visualization of distribution in the vitreous cavity via eye drops using ultra-heavily T2-weighted sequences in MRI: a preliminary study with enucleated pig eyes. 利用磁共振成像中的超高 T2 加权序列观察滴眼液在玻璃体腔中的分布：对去核猪眼的初步研究。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1007/s12194-024-00826-6

Yutaka Kato, Kenya Yuki, Koji Nishiguchi, Shinji Naganawa

{"title":"Visualization of distribution in the vitreous cavity via eye drops using ultra-heavily T2-weighted sequences in MRI: a preliminary study with enucleated pig eyes.","authors":"Yutaka Kato, Kenya Yuki, Koji Nishiguchi, Shinji Naganawa","doi":"10.1007/s12194-024-00826-6","DOIUrl":"10.1007/s12194-024-00826-6","url":null,"abstract":"We investigated whether magnetic resonance imaging can visualize the distribution in the vitreous cavity via eye drops of ophthalmic solutions, gadolinium-based contrast agent, and 17O-water, and to clarify the usefulness of ultra-heavily T2-weighted sequences in the research of intraocular distribution. Five different solutions (V-ROHTO, TRAVATANZ, gadobutrol, H217O, and saline) were administered to excised pig eye specimens. The samples were scanned using T1 mapping, T2 mapping, 3D T2-weighted (echo times (TE): 500, 3200, and 4500 ms), a half-Fourier single-shot turbo-spin echo sequence (HASTE; TE: 440 and 3000 ms), and 3D-real inversion-recovery before eye drops administration. Subsequently, we used a plastic dropper to drop a 0.5 mL solution each, and images were obtained up to 26 h later. Temporal changes in the T1 and T2 values of the anterior chamber and vitreous cavity were compared. The other sequences were evaluated by determining temporal signal changes as signal intensity ratio (SIR) compared to \"No drop.\" The T1 and T2 values of samples treated with gadobutrol and H217O decreased over time. The SIR of samples treated with gadobutrol and H217O showed remarkable changes in the 3D T2-weighted images, whereas no remarkable temporal changes were observed in the other solutions. Longer TEs resulted in remarkable changes. We demonstrated that visualization of distribution in the vitreous cavity via eye drops could be achieved with excised pig eyes using gadobutrol and H217O, but not with ophthalmic solutions. Ultra-heavily T2-weighted sequences may be promising for the early and highly sensitive visualization of the intraocular distribution of eye drops.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11341737/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141724713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a body movement detection system to avoid re-exposure during radiography. 开发人体移动检测系统，避免射线照相过程中再次曝光。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-09-01 Epub Date: 2024-06-14 DOI: 10.1007/s12194-024-00820-y

Michihiro Eto, Tomofumi Nakawatari, Yuji Hatanaka

{"title":"Development of a body movement detection system to avoid re-exposure during radiography.","authors":"Michihiro Eto, Tomofumi Nakawatari, Yuji Hatanaka","doi":"10.1007/s12194-024-00820-y","DOIUrl":"10.1007/s12194-024-00820-y","url":null,"abstract":"During the radiographic examination of the chest and bones in hospitals, communicating and maintaining posture is difficult for some patients, and movement before or during X-ray irradiation may necessitate re-exposure owing to body wobbling movements or breathing movements. To prevent the need for re-exposure during radiography and to determine the exposure timing, a body movement detection system that considers breathing movements was developed in this study. The posture of a patient was monitored using an RGB camera. The acquired video data was analyzed to detect body movement using either an inter-frame difference method or an optical flow estimation method. The performance of the system was evaluated by detecting the body and breathing movements during positioning. Consequently, the inter-frame difference method detected 179.8-1222.2 pixels during body movements, and the optical flow estimation method confirmed that the feature points moved by 5.5-26.6 mm (4.2-20.3 pixels). When detecting breathing movements, 82-585 pixels were detected by the inter-frame difference method, and the optical flow estimation method showed that the feature points moved by 5.2 mm (2-4 pixels). Therefore, the proposed method can detect body movements during radiography to prevent re-exposure due to body wobble and breathing movements. For healthcare providers, it will lead to reduce not only concerns about patient exposure but also unnecessary radiographic workload.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141318491","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

Assessment of accuracy and repeatability of quantitative parameter mapping in MRI. 评估磁共振成像定量参数绘图的准确性和可重复性。

IF 1.7

Radiological Physics and Technology Pub Date : 2024-08-28 DOI: 10.1007/s12194-024-00836-4

Yuya Hirano, Kinya Ishizaka, Hiroyuki Sugimori, Yo Taniguchi, Tomoki Amemiya, Yoshitaka Bito, Kohsuke Kudo

引用次数: 0