Radiological Physics and Technology最新文献

{"title":"A practical method for measuring rotation angles in partial-angle CT scan by using CTDI phantoms, metal rods, and a real-time dosimeter.","authors":"Hironori Otsubo, Tomonobu Haba, Yusei Nishihara, Masanao Kobayashi, Rei Ito, Yoshiki Sunada, Tomoya Ishida, Haruki Ibamoto, Shigeki Kobayashi","doi":"10.1007/s12194-026-01060-y","DOIUrl":"https://doi.org/10.1007/s12194-026-01060-y","url":null,"abstract":"<p><p>Partial-angle computed tomography (CT), including CT fluoroscopy and C-arm cone-beam CT systems, plays an important role in image-guided interventions. In these systems, the X-ray tube rotation angle is a critical factor affecting the dose evaluation. However, scans are often performed with partial rotations of approximately 180°-240°, and reliable methods for measuring the actual rotation angle have not been established. In this study, we propose a method for measuring the rotation angle in partial-angle CT scans and improving dose evaluation accuracy by incorporating the measured angles into Monte Carlo simulations. Measurements were performed using CT fluoroscopy and angiography. A CT dose index phantom was placed on the patient table, and metal rods and a real-time dosimeter were inserted into the peripheral holes and center hole, respectively. The rotation angles were identified from the X-ray attenuation caused by the metal rods, and the dose profiles for a single scan were determined by combining measurements acquired with and without the rods. The measured rotation angles and dose profiles were incorporated into Monte Carlo simulations and then validated against measured values. The differences between the displayed and measured rotation angles were 3.4% for CT fluoroscopy and 8.1% for angiography. Compared with the conventional method, the maximum discrepancy in dose evaluation was reduced by 9.0% for CT fluoroscopy and 4.8% for angiography. The proposed method facilitates rotation angle quality assurance in partial-angle CT scans and contributes to appropriate dose management.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147843880","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":"Quality control of opportunistic multi-energy CT bone mineral density quantification.","authors":"Emily A Thompson, Megan C Jacobsen, Rachel M Barbee, Jia Sun, Cayla A Wood, Rick R Layman","doi":"10.1007/s12194-026-01059-5","DOIUrl":"https://doi.org/10.1007/s12194-026-01059-5","url":null,"abstract":"<p><strong>Background: </strong>Accurate assessment of bone mineral density (BMD) is crucial for evaluating bone loss in elderly and oncologic patients. Quantitative computed tomography (QCT) enables noninvasive quantification of patient BMD and can be performed opportunistically during routine CT examinations using either conventional or multi-energy CT (MECT). While both methods are used clinically, MECT can address limitations of conventional CT-based QCT.</p><p><strong>Purpose: </strong>This study addresses a critical gap in the literature by systematically evaluating commercially available calibration phantoms for use with MECT, assessing the impact of protocol variations, establishing a calcium-based material decomposition workflow for BMD quantification, validating phantom-derived metrics against patient data, and providing recommendations for integrating quality control (QC) into routine clinical workflows.</p><p><strong>Methods: </strong>Five CT QC phantoms containing bone-approximating materials, including calcium (Phantom A), dipotassium phosphate (Phantom B), hydroxyapatite (Phantom C), and calcium carbonate (Phantoms D and E), were evaluated by determining the dual-energy ratio (DER) of inserts. Phantoms were scanned on two identical dual-source CTs at 90/150Sn and 100/150Sn kVp with dose levels of 10 and 20 mGy. Images were reconstructed using filtered back-projection and iterative reconstruction. Phantom DERs were compared with retrospective vertebral measurements from a 10-patient cohort.</p><p><strong>Results: </strong>Phantom A provided the most suitable representation of patient data, exhibiting a DER of 1.55 [95%CI:1.54-1.57] at 100/150Sn kVp, compared with 1.44 [95%CI:1.37-1.50] in patients. kVp significantly influenced response, whereas radiation dose and reconstruction approach had minimal effect.</p><p><strong>Conclusions: </strong>Phantom selection is critical for MECT-based QCT, and calcium-based phantoms are well-suited for clinical QC and BMD quantification workflows.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147844120","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":"Automated detection of pediatric forearm fractures in X-ray images using deep learning.","authors":"Haruna Suzuki, Atsushi Teramoto, Tsuyoshi Honmoto, Ayumi Niki, Tatsuo Kono, Hiroshi Fujita","doi":"10.1007/s12194-026-01061-x","DOIUrl":"https://doi.org/10.1007/s12194-026-01061-x","url":null,"abstract":"<p><p>Children's bones are more elastic and have a thicker periosteum than those of adults, resulting in subtle, incomplete fractures. Diagnosis based on plain radiographs alone can be challenging. The shortage of pediatric radiologists compounds this difficulty, leading to a risk of missed fractures. Therefore, we considered that it might be possible to help prevent missed fractures by developing and validating an automated detection model for pediatric forearm fractures on plain radiographs using deep learning techniques (convolutional neural networks [CNNs] and Vision Transformers [ViTs]). To train and validate such a model, this study targeted the frontal and lateral views of plain radiographs from 517 patients aged 1-14 years with forearm fractures. We first performed preprocessing to focus on the forearm region in the images. Thirteen models (visual geometry group [VGG], ResNet, DenseNet, and ViT) were used to classify the presence or absence of fractures and were evaluated and compared using 5-fold cross-validation. Verification of these models showed that VGG16 exhibited the best performance. The overall result, which integrated the predictions from the frontal and lateral views, achieved a sensitivity of 0.872 ± 0.015, a specificity of 0.925 ± 0.016, a balanced accuracy of 0.898 ± 0.003, and an AUC of 0.962 ± 0.002. Furthermore, visualization of saliency maps (using gradient-weighted class activation mapping and an attention map) revealed that the model focused on the bone during prediction. Therefore, if the proposed method is used in hospitals, it could possibly support diagnosis and help reduce missed fractures.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147843918","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 added filtration and field size on operator eye lens exposure in over-table fluoroscopy: a Monte Carlo simulation study.","authors":"Takayuki Tamura, Kaito Hoashi, Yoshifumi Masumoto, Shingo Hamaoka","doi":"10.1007/s12194-026-01062-w","DOIUrl":"https://doi.org/10.1007/s12194-026-01062-w","url":null,"abstract":"<p><p>This study characterized operator eye lens exposure in over-table fluoroscopy using Monte Carlo simulation, focusing on beam quality and geometry under simulated conditions. Absorbed doses were calculated using voxel phantoms across tube voltages (75-95 kV), filtrations (Al 2.5-4.5 mm, Cu 0.0-0.5 mm), and field sizes (10-30 cm). Grid correction was applied to normalize results to detector entrance dose. Beam hardening via increased filtration significantly reduced lens doses, although the rate of dose reduction gradually diminished as Cu thickness increased. Field size reduction was the most effective strategy; a 10 cm field reduced the dose by 40-50% compared to a 30 cm field. When using Patient Entrance Reference Point (PERP) values to estimate operator lens exposure, beam quality must be considered, as the same PERP value can yield substantially different operator doses depending on filtration. Field size restriction remains the most effective measure for dose reduction.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147822092","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":"Establishment of local diagnostic reference levels for trunk computed tomography examinations at governmental hospitals in the Gaza Strip: a cross-sectional study.","authors":"Amjad Ayyad, Yasser Alajerami, Ahmed Najim, Husam H Mansour, Muhammad Khalis Abdul Karim, Fahad Alghamdi, Kinan Mokbel","doi":"10.1007/s12194-026-01053-x","DOIUrl":"https://doi.org/10.1007/s12194-026-01053-x","url":null,"abstract":"<p><p>To establish the local diagnostic reference levels (LDRLs) for trunk multi-slice CT (MSCT) examinations in the Gaza Strip, Palestine. This cross-sectional study included adult oncology patients undergoing trunk MSCT at two governmental hospitals in Gaza Strip; Al Shifa Medical Complex (SMC) and Al Aqsa Martyrs Hospital (AMH), using an adapted dose survey booklet. Data collected from July 2019 to March 2020 included patient characteristics, volumetric CT dose index (CTDI_vol) and dose length product (DLP). Descriptive, univariate and multivariate analyses identified key factors affecting radiation dose, and the coefficient of variation between scanner- and software-derived dose values was also determined. A total of 170 trunk CT examinations were analysed (57.1% SMC, 42.9% AMH). 72.94% were female; the mean age of the participants is 53.1 ± 15.8 years, and the mean body mass index was 30 ± 6.1. The estimated LDRLs for trunk CT were 13 mGy for CTDI_vol and 1010.4 mGy·cm for DLP. There was notable variation between hospitals in CTDI_vol and DLP (p < 0.001). At SMC, factors such as tube current, peak kilovoltage, scan length, pitch and BMI significantly affected dose indices. In contrast, at AMH, the main influences were tube current and scan length. CTDI_vol had a greater impact on DLP than scan length at both locations. LDRLs for trunk CT scans in the Gaza Strip were established and found to be generally comparable to international benchmarks. Notable variation in doses between hospitals indicates potential for improvement through standardising protocols, managing scan lengths and using techniques tailored to patient size.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147785246","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":"Optimal timing of the cumulative dose and factors related to acute urinary toxicity in prostate cancer treated using magnetic resonance linear accelerator.","authors":"Shohei Tanaka, Noriyoshi Takahashi, Noriyuki Kadoya, Wingyi Lee, Taichi Hoshino, Yoshiyuki Katsuta, Kazuhiro Arai, Yushan Xiao, Hisamichi Takagi, Yu Suzuki, Shinsaku Okuda, Keiichi Jingu","doi":"10.1007/s12194-026-01056-8","DOIUrl":"https://doi.org/10.1007/s12194-026-01056-8","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147785236","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":"Comparison between a T-tube and a spiralflow-tube to improve the visualization ability of the subclavian artery in CT angiography from the neck to the aortic arch.","authors":"Junichi Nakagawa, Norimi Nishiyama, Takashi Hoshino, Shota Watanabe, Isao Yamaguchi, Takanori Masuda","doi":"10.1007/s12194-026-01054-w","DOIUrl":"https://doi.org/10.1007/s12194-026-01054-w","url":null,"abstract":"<p><p>This study aimed to compare contrast media (CM) remaining in the right subclavian vein after saline flush using a conventional T-tube or a spiralflow-tube in computed tomography angiography (CTA) from the neck to the aortic arch and to evaluate the visualization ability of the right subclavian artery. A total of 71 patients who underwent CTA from the neck to the aortic arch at our institution were retrospectively included (38 in the spiralflow-tube group and 33 in the T-tube group). The volumes of CM were measured in the volume-rendered images of the right subclavian vein by setting the thresholds of 300, 500, and 1000 Hounsfield units (HU) on a three-dimensional workstation. Two reviewers evaluated the depiction of the vascular visualization of the right subclavian artery using a 5-point scale. Data are presented as median (interquartile range; Q1-Q3). The volumes of CM remaining in the right subclavian vein were significantly smaller with the spiralflow-tube group than the T-tube group at all thresholds [300 HU: 0.95 (0.33-2.08) mL vs. 3.02 (1.66-8.64) mL; 500 HU: 0.30 (0.09-0.88) mL vs. 1.60 (0.73-3.61) mL; 1000 HU: 0.07 (0.05-0.35) mL vs. 0.48 (0.18-1.28) mL; all p < 0.01]. The spiralflow-tube group showed significantly higher visualization scores for the right subclavian artery than the T-tube group [5 (4-5) vs. 4 (3-4), p < 0.01]. The saline flush using a spiralflow-tube in CTA from the neck to the aortic arch reduced CM in the right subclavian vein and improved the vascular visualization ability of the right subclavian artery.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147785179","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":"Comparison of small bowel and bladder doses between prone and supine positions in preoperative intensity-modulated radiotherapy for rectal cancer.","authors":"Takuya Hayashi, Mami Ogita, Yuki Nozawa, Masanari Minamitani, Hideomi Yamashita","doi":"10.1007/s12194-026-01051-z","DOIUrl":"https://doi.org/10.1007/s12194-026-01051-z","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147730442","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":"Effects of perfusion fixation on whole-brain structural connectivity in marmoset: a diffusion MRI analysis.","authors":"Daisuke Yoshimaru, Tomokazu Tsurugizawa, Naoya Hayashi, Kanako Muta, Shuhei Shibukawa, Hirotaka James Okano, Hideyuki Okano, Junichi Hata","doi":"10.1007/s12194-026-01036-y","DOIUrl":"https://doi.org/10.1007/s12194-026-01036-y","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147718133","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":"Effect of carbon dioxide insufflation on the delay-attenuation relationship of mesenteric veins in contrast-enhanced CT colonography.","authors":"Yoshiya Ohashi, Kohei Harada, Takeo Tanaka, Shun Hayasaka, Kizuku Ishibashi, Ryo Kasahara, Naoya Yama","doi":"10.1007/s12194-026-01052-y","DOIUrl":"https://doi.org/10.1007/s12194-026-01052-y","url":null,"abstract":"<p><p>To evaluate whether carbon dioxide (CO₂) insufflation modifies the relationship between scan delay and mesenteric venous attenuation during fixed-delay portal venous phase scans in contrast-enhanced CT colonography (CTC). This retrospective study included 170 patients (mean age, 66.6 ± 13.0 years; 72 men) who underwent contrast-enhanced abdominal CT between April 2017 and October 2021 with portal venous phase scans acquired at fixed delays of 25, 30, or 35 s after the start of arterial-phase scanning. Examinations were classified as the CO₂ insufflation group (n = 86) or the non-insufflation group (n = 84). Attenuation of the inferior and superior mesenteric veins (IMV, SMV) was measured at each delay. Associations among insufflation status, scan delay, and venous attenuation were evaluated using multivariable linear regression including a CO₂-by-delay interaction term. In the CO₂ insufflation group, IMV attenuation was highest at 25 s (283.0 ± 40.4 HU) and decreased at 30-35 s (p < 0.001), whereas in the non-insufflation group IMV attenuation was higher at 30-35 s than at 25 s (p = 0.002). SMV attenuation showed a similar directional pattern with smaller magnitude. Significant CO₂-by-delay interactions were observed for both veins (p < 0.05), indicating different delay-attenuation relationships by insufflation status. In routine fixed-delay CTC, CO₂ insufflation was associated with a modified relationship between scan delay and mesenteric venous attenuation, most prominently in the IMV. Mesenteric venous enhancement on portal venous phase scans should be interpreted in the context of insufflation status.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147677591","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}