Radiological Physics and Technology最新文献

{"title":"Development of an anomaly detection system for Gibbs artifact identification in amyloid PET imaging.","authors":"Mitsuru Sato, Hiromitsu Daisaki, Haruyuki Watanabe, Saaya Isogai, Manami Shiga, Yasuhiko Ikari, Keisuke Tsuda, Kenji Hirata, Ukihide Tateishi, Kazuaki Mori, Makoto Hosono, Hirofumi Fujii","doi":"10.1007/s12194-025-00928-9","DOIUrl":"https://doi.org/10.1007/s12194-025-00928-9","url":null,"abstract":"<p><p>The PET Imaging Site Qualification Program for amyloid positron emission tomography (PET) in Japan includes visual evaluation of the cylinder phantom. This visual evaluation requires observation of the entire image of the phantom and confirmation of the absence of apparent artifacts. Because the evaluation is visually performed, inter-observer differences might exist among evaluators for difficult cases. Therefore, the workload of the staff who perform approval tasks must be reduced, and objective evaluation methods are needed. Thus, we attempted to develop an artificial-intelligence-based objective method for anomaly detection. Three artificial intelligence methods for anomaly detection were developed, and their accuracy was evaluated using AutoEncoder, AnoGAN, and a method combining feature extraction using AlexNet and a one-class support vector machine. In total, 10,207 normal images from 128 facilities and 594 abnormal images from eight facilities, all of which were submitted as part of application for amyloid PET certification, were used. Group five-fold cross-validation was employed for artificial intelligence training and evaluation. In addition, the performance of each artificial intelligence method was assessed using receiver operating characteristic analysis. The areas under the curve for anomaly detection using AutoEncoder, AnoGAN, and the method combining feature extraction using AlexNet and a one-class support vector machine were 0.80 ± 0.04, 0.77 ± 0.03, and 0.99 ± 0.01, respectively. Artificial intelligence effectively distinguished between normal and abnormal images with high accuracy. In the future, its practical implementation is anticipated to reduce the workload in the approval work for the Japanese site qualification program for amyloid PET.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144486552","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":"Refining cardiac segmentation from MRI volumes with CT labels for fine anatomy of the ascending aorta.","authors":"Hirohisa Oda, Mayu Wakamori, Toshiaki Akita","doi":"10.1007/s12194-025-00926-x","DOIUrl":"https://doi.org/10.1007/s12194-025-00926-x","url":null,"abstract":"<p><p>Magnetic resonance imaging (MRI) is time-consuming, posing challenges in capturing clear images of moving organs, such as cardiac structures, including complex structures such as the Valsalva sinus. This study evaluates a computed tomography (CT)-guided refinement approach for cardiac segmentation from MRI volumes, focused on preserving the detailed shape of the Valsalva sinus. Owing to the low spatial contrast around the Valsalva sinus in MRI, labels from separate computed tomography (CT) volumes are used to refine the segmentation. Deep learning techniques are employed to obtain initial segmentation from MRI volumes, followed by the detection of the ascending aorta's proximal point. This detected proximal point is then used to select the most similar label from CT volumes of other patients. Non-rigid registration is further applied to refine the segmentation. Experiments conducted on 20 MRI volumes with labels from 20 CT volumes exhibited a slight decrease in quantitative segmentation accuracy. The CT-guided method demonstrated the precision (0.908), recall (0.746), and Dice score (0.804) for the ascending aorta compared with those obtained by nnU-Net alone (0.903, 0.770, and 0.816, respectively). Although some outputs showed bulge-like structures near the Valsalva sinus, an improvement in quantitative segmentation accuracy could not be validated.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144477164","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":"Assessment of lens absorbed dose by radiological technologists during mobile X-ray radiography: a comparison between computed radiography and flat panel detector systems.","authors":"Satoe Konta, Saya Ohno, Ryota Shindo, Keisuke Yamamoto, Yoshihiro Haga, Toshiki Kato, Masahiro Sota, Yuji Kaga, Mitsuya Abe, Koichi Chida","doi":"10.1007/s12194-025-00930-1","DOIUrl":"https://doi.org/10.1007/s12194-025-00930-1","url":null,"abstract":"<p><p>Mobile X-ray radiography is crucial for imaging patients with limited mobility; however, radiological technologists (RTs) may be positioned closer to patients and thus be at risk of harmful radiation doses owing to scattered radiation. As X-ray systems transitioned from digital computed radiography (CR) to flat panel detector (FPD) systems, we studied the RTs' eye lens and neck radiation doses over 2 years. Three RTs participated in measurements using a CR system, and five RTs participated in measurements using a FPD system. We measured radiation exposure with neck dosimeters (glass badges) and lens dosimeters (DOSIRIS®). The results showed a 66% reduction in lens dose after switching from the CR system to the FPD system. Comparisons of specific RT members also revealed significantly lower doses for the FPD system than for the CR system. Two main factors contributed to this decrease: the FPD system used a virtual grid instead of a scatter removal grid, and the RTs' awareness of radiation exposure increased with experience. Although the lens dose was significantly reduced, RTs should still wear protective eyewear and equipment when frequent imaging is expected or when working close to patients.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144477162","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":"Clinical technique: evaluation of detection accuracy in surface-guided radiation therapy using CT references from different treatment planning systems.","authors":"Masahide Saito, Koji Ueda, Hikaru Nemoto, Ryota Tozuka, Yosuke Miyasaka, Yoshiko Onishi, Syuichiro Sugiyama, Yumi Sasada, Naoki Sano, Hiroshi Onishi","doi":"10.1007/s12194-025-00929-8","DOIUrl":"https://doi.org/10.1007/s12194-025-00929-8","url":null,"abstract":"<p><p>This study evaluated the detection accuracy of the VOXELAN surface-guided radiation therapy (SGRT) system using CT reference body surfaces generated by different radiation treatment planning systems (RTPSs) under their respective default CT value threshold settings. Two phantoms were used to assess 6-axis position matching accuracy with 1 mm and 2 mm slice thicknesses. Contour variations of approximately 2 mm were observed in the ventral and dorsal directions due to differing RTPSs. VOXELAN generally achieved detection accuracy within 1 mm, though some RTPS combinations showed errors exceeding 1 mm in the longitudinal and lateral directions. Slice thickness differences had minimal impact on detection accuracy. Overall, VOXELAN's detection accuracy varied slightly depending on the RTPS used but remained within approximately 1 mm. From our results, using a consistent RTPS when performing SGRT is recommended, as detection errors associated with different RTPS combinations were complex and difficult to interpret.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144477163","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":"Reduction of metal artifact from cryoprobe using tilt CT scanning with metal artifact reduction algorithms for CT-guided cryoablation.","authors":"Tomohiro Inoue, Noriyuki Umakoshi, Yusuke Matsui, Shota Tanaka, Takatsugu Yamauchi, Toshihiro Iguchi, Koji Tomita, Mayu Uka, Mitsugi Honda, Takao Hiraki","doi":"10.1007/s12194-025-00923-0","DOIUrl":"https://doi.org/10.1007/s12194-025-00923-0","url":null,"abstract":"<p><p>Computed tomography (CT) is a simple and useful method for monitoring during cryoablation; however, image quality is degraded by artifacts caused by the cryoprobe used during treatment. We evaluated the effectiveness of combining tilt scanning and single-energy metal artifact reduction (SEMAR) to improve image quality. A cryoprobe was inserted into an agar phantom, and CT scans were performed at various angles (0°, 5°, 10°, 15°, and 20°) with and without metal artifact reduction. The relative artifact index, calculated using the CT value standard deviation, was used to evaluate the intensity. The strongest tip artifacts occurred at 0°. The relative artifact index decreased with increasing tilt angles. The tilted scanning reduced artifacts extending beyond the cryoprobe tip, but SEMAR demonstrated a limited effect on artifact reduction. The tilted scanning method may be a useful approach for improving the image quality around the cryoprobe without increasing the exposure dose.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144318358","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":"Predicting perceived exertion during high-intensity exercise using quantitative MRI: insights from T2* value and muscle cross-sectional area.","authors":"Shuhei Shibukawa, Daisuke Yoshimaru, Yoshinori Hiyama, Tatsunori Saho, Takuya Ozawa, Keisuke Usui, Masami Goto, Hajime Sakamoto, Shinsuke Kyogoku, Hiroyuki Daida","doi":"10.1007/s12194-025-00927-w","DOIUrl":"https://doi.org/10.1007/s12194-025-00927-w","url":null,"abstract":"<p><p>This study aimedto investigate the relationship between MRI-derived skeletal muscle biomarkers and subjective exercise intensity, measured by the Rating of Perceived Exertion (RPE). Both T2* value and CSA showed significant time-dependent changes following exercise. The percent change (PC) in T2* immediately after exercise (T2* PC-post/pre) was most strongly associated with RPE (ρ = 0.45,p < 0.01), while CSA showed a weaker correlation. Muscle strength was not significantly associated with RPE.Random forest analysis identified T2* PC-post/pre as the most important predictor of RPE, supported by partial dependence plots showing a nonlinear increase in RPE with higher T2* value changes. T2* value changes after exercise reflect metabolic stress and serve as a more specific predictor of RPE than CSA or muscle strength. These findings highlight the potential of T2* value as a non-invasive biomarker for assessing subjective exercise intensity.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144303263","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":"Dose-volume histogram-based comparison of conventional and hypofractionated radiotherapy: lifetime attributable risk estimation in Indian breast carcinoma patients.","authors":"Amal Jose, Desh Deepak Ladia, Anju George, Abhishek Pratap Singh, Vandana Dahiya","doi":"10.1007/s12194-025-00924-z","DOIUrl":"https://doi.org/10.1007/s12194-025-00924-z","url":null,"abstract":"<p><strong>Aim: </strong>This study investigates secondary cancer risks in the contralateral breast (CB) and ipsilateral lung (IL) in postmastectomy radiotherapy (PMRT) patients treated with forward-planned intensity-modulated radiation therapy (IMRT). It is the first analysis of Dose-Volume Histogram (DVH)-based secondary cancer risks for patients undergoing forward-planned IMRT for PMRT. The objective is to compare cancer risks between conventional fractionated (CF) IMRT and hypofractionated (HF) IMRT. A retrospective analysis was conducted on 20 patients (aged 37-69 years) treated with 6 MV forward-planned IMRT. Treatment plans included CF IMRT (50 Gy in 25 fractions) and HF IMRT (42.56 Gy in 16 fractions). Organ equivalent doses (OED), excess absolute risk (EAR), lifetime attributable risk (LAR), and Relative Risk (RR) were calculated for CB and IL using Schneider non-linear mechanistic model & differential DVH. HF IMRT demonstrated a significant reduction in IL secondary cancer risk compared to CF IMRT (P = 0.0001), with LAR values decreasing from 54.9%-75.5% (CF) to 48.3%-66.5% (HF). The RR for IL cancer induction also declined from 10.16-13.6 (CF) to 9.06-12.1 (HF). In contrast, CB cancer risks exhibited minimal change, with LAR values slightly reducing from 1.08%-6.9% (CF) to 0.96%-6.1% (HF) (P = 0.52). The RR for CB remained relatively stable at 1.10-1.55 (CF) and 1.09-1.48 (HF). HF IMRT is more effective in reducing IL secondary cancer risk compared to CF IMRT, presenting it as a safer PMRT option. However, CB cancer risks remained largely unchanged, suggesting the need for further dose optimization research.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144295100","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":"Human glioblastoma (U87) cells grown in 3D culture showed a radio-resistance to X-ray and proton radiation.","authors":"Dea A Kartini, Pharewa Karoon, Yuwadee Malad, Thititip Tippayamontri, Taweap Sanghangthum, Chutima Talabnin, Chinorat Kobdaj","doi":"10.1007/s12194-025-00921-2","DOIUrl":"https://doi.org/10.1007/s12194-025-00921-2","url":null,"abstract":"<p><p>Glioblastoma multiforme is the most malignant brain tumor and is resistant to conventional radiotherapy. Proton radiotherapy utilizes accelerated proton beams to irradiate deep-seated tumors with minimum ionization in the entrance channel, thanks to its inverted dose profile. This work aims to investigate the response of human glioma (U87) cells cultured in a 3D culture after X-ray and proton irradiation. U87 cells have been cultured in 3D bio-phantom where cells were grown in Matrigel matrix inside a 96-well plate. The morphology of U87 cells in 3D culture has been observed for 48 h, and cells have grown in their natural shape. The response of cells in 3D bio-phantom was evaluated by exposing the cells to 6 MV X-ray and 70 MeV monoenergetic proton beams. Post-irradiation, the surviving cells were determined by a colony formation assay, and the survival curve of cells in 3D culture was compared with the cells grown in 2D monolayer culture. The response of cells in the 3D bio-phantom following X-ray and proton radiation demonstrated an increased survival fraction in the high-dose region than those in 2D monolayer. However, U87 cells showed more sensitivity towards proton irradiation compared to X-rays, regardless of the culture setup. Finally, we obtained the RBE <math><mmultiscripts><mrow></mrow> <mrow><mn>10</mn> <mo>%</mo></mrow> <mrow></mrow></mmultiscripts> </math> value of 1.15 for cells in 3D bio-phantom and 1.29 for cells in 2D monolayer. Therefore, U87 cells grown in our 3D culture setup demonstrate radio-resistant behavior and exhibit higher sensitivity towards proton irradiation compared to X-ray irradiation in our clonogenic assay.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144295101","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":"Quantification and comparison of the reference dose measurements using IAEA TRS-398 protocols and its revised version.","authors":"Mohammad Abdul Fatha, Sathiya Raj, Y S Pawar, Sathiyan Saminathan","doi":"10.1007/s12194-025-00925-y","DOIUrl":"https://doi.org/10.1007/s12194-025-00925-y","url":null,"abstract":"<p><p>The International Atomic Energy Agency (IAEA) released a protocol named Technical Report Series (TRS-398) to measure the absorbed dose in water for external radiotherapy beams. It provides a unified approach for using calibrated ionization chambers that are traceable to standard laboratories in determining the absorbed dose to water. The objective of the study was to compare the reference dosimetry [dose at 10 cm depth ( <math><msub><mi>D</mi> <mn>10</mn></msub> </math> )] between TRS-398 and its revised version. Reference dosimetry was performed for flattened photon beam with nominal energies of 6, 10, and 15 MV as well as flattening filter free (FFF) beam of energies 6 FFF and 10 FFF based on the guidelines of both TRS-398 and its revised version using two different ionization chambers of varying sensitive volumes such as 0.65 cm³ (FC65-G) & 0.13 cm³ (CC13) IBA ionization chambers with calibration coefficient traceable to absorbed dose to water (D_w) standards. The comparison of absorbed dose at 10 cm ( <math><msub><mi>D</mi> <mn>10</mn></msub> </math> ) depth using both protocols with FC65-G chamber shows a difference ranging from 0.40 to 0.63% in FF beams and 0.03 to 0.05% in FFF beams. For CC13 chamber, the difference ranged from -0.60 to -0.77% in FF beams and -0.40 to -0.50% in FFF beams. The differences in absorbed dose between TRS-398 old and revised protocols were evaluated and a variation of up to 0.63% in <math><msub><mi>D</mi> <mn>10</mn></msub> </math> was observed for FC65-G and -0.77% in <math><msub><mi>D</mi> <mn>10</mn></msub> </math> was observed for CC13 chamber. The use of old <math><msub><mi>k</mi> <mrow><mi>Q</mi> <mo>,</mo> <msub><mi>Q</mi> <mi>O</mi></msub> </mrow> </msub> </math> value affects the reference dose measurements, which overestimates the results by an average of 0.5%. The use of cross-calibrated chamber following the old protocol in determining the <math><msub><mi>D</mi> <mn>10</mn></msub> </math> underestimates the results by maximum of -0.77% in FF beams and -0.5% in FFF beams.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144276195","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":"PatchDSA: improving digital subtraction angiography with patch-based phase-matching in natural breathing scenarios.","authors":"Yuki Sekiguchi, Takayuki Okamoto, Tsukiho Matsuzawa, Kentaro Fujimoto, Kisako Fujiwara, Takayuki Kondo, Jun Koizumi, Hideaki Haneishi","doi":"10.1007/s12194-025-00922-1","DOIUrl":"https://doi.org/10.1007/s12194-025-00922-1","url":null,"abstract":"<p><p>Digital subtraction angiography (DSA) is used to visualize blood vessels by subtracting pre-contrast (mask) images from contrast images; sequential mask and contrast images are used to generate dynamic DSA images that allow observation of blood flow and organ movements. However, misalignment between mask and contrast images can cause motion artifacts, which not only obscure the appearance of enhanced structures but also lead to the misidentification of patterns as vascular structures. In this study, we proposed a new method for generating abdominal sequential DSA images using a patch-based phase-matching technique between mask and contrast images acquired under natural breathing conditions. Our method divides mask and contrast images into small patches and selects the mask image patch most structurally similar to each patch in the target contrast image. Furthermore, the selected mask image patch is refined by searching for the subpixel-level region that most closely matches the target contrast image patch. The proposed method was evaluated using 20 abdominal angiogram cases, and its performance was compared with an existing phase matching-based method. Our experimental results showed that the proposed method effectively reduced motion artifacts and outperformed the comparison method in all cases. We demonstrated that our method successfully identified the optimal mask image for each contrast image on a patch-by-patch basis, allowing it to suppress artifacts caused by physiological motions such as peristalsis and cardiac pulsation, thereby generating higher-quality DSA images.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144267591","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}