Radiological Physics and Technology最新文献

Scatter and beam hardening effect corrections in pelvic region cone beam CT images using a convolutional neural network.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-04-04 DOI: 10.1007/s12194-025-00896-0

Soya Yagi, Keisuke Usui, Koichi Ogawa

{"title":"Scatter and beam hardening effect corrections in pelvic region cone beam CT images using a convolutional neural network.","authors":"Soya Yagi, Keisuke Usui, Koichi Ogawa","doi":"10.1007/s12194-025-00896-0","DOIUrl":"https://doi.org/10.1007/s12194-025-00896-0","url":null,"abstract":"The aim of this study is to remove scattered photons and beam hardening effect in cone beam CT (CBCT) images and make an image available for treatment planning. To remove scattered photons and beam hardening effect, a convolutional neural network (CNN) was used, and trained with distorted projection data including scattered photons and beam hardening effect and supervised projection data calculated with monochromatic X-rays. The number of training projection data was 17,280 with data augmentation and that of test projection data was 540. The performance of the CNN was investigated in terms of the number of photons in the projection data used in the training of the network. Projection data of pelvic CBCT images (32 cases) were calculated with a Monte Carlo simulation with six different count levels ranging from 0.5 to 3 million counts/pixel. For the evaluation of corrected images, the peak signal-to-noise ratio (PSNR), the structural similarity index measure (SSIM), and the sum of absolute difference (SAD) were used. The results of simulations showed that the CNN could effectively remove scattered photons and beam hardening effect, and the PSNR, the SSIM, and the SAD significantly improved. It was also found that the number of photons in the training projection data was important in correction accuracy. Furthermore, a CNN model trained with projection data with a sufficient number of photons could yield good performance even though a small number of photons were used in the input projection data.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143781444","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

Enhanced urethral identification for radiotherapy planning using fat-suppressed 3D T2-weighted magnetic resonance imaging.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-04-01 DOI: 10.1007/s12194-025-00903-4

Yutaka Kato, Takayoshi Nakaya, Kuniyasu Okudaira, Yumiko Noguchi, Mariko Kawamura, Shunichi Ishihara, Shinji Naganawa

引用次数: 0

Impact of iso-dose levels on pre-treatment quality assurance in volumetric modulated arc therapy.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-04-01 DOI: 10.1007/s12194-025-00902-5

Sumanta Manna, Sanjib Gayen, Sonal Varshney

{"title":"Impact of iso-dose levels on pre-treatment quality assurance in volumetric modulated arc therapy.","authors":"Sumanta Manna, Sanjib Gayen, Sonal Varshney","doi":"10.1007/s12194-025-00902-5","DOIUrl":"https://doi.org/10.1007/s12194-025-00902-5","url":null,"abstract":"The current standard of modern radiotherapy pre-treatment evaluation of dose distributions measured using gamma pass percentage is the predominant metric for Patient-Specific Quality Assurance (PSQA). The aim of the study was to analyze the impact of the different dose levels for three different gamma criteria in various anatomical sites. Retrospectively selected 120 VMAT plans of the brain, head and neck, thorax, and pelvic sites were considered for this study. Quality assurance plans were created and measurements were done using PTW Octavius 4D phantom. Three different gamma criteria were used to evaluate different dose levels' volume gamma passing rates. The maximum gamma passing rate for all dose levels except 100% with a 3%/3 mm criterion was observed for the pelvis site. A significant variation in dose levels was observed with the 3%/2 mm gamma criteria for head and neck sites, particularly above the 85% dose level compared to other anatomical sites. Using 2%/2 mm gamma criteria, there was a rapid fall in the gamma passing rate and all the dose levels showed a significant variation among different sites. This study demonstrated significant variations in gamma passing rates across anatomical sites and dose levels, emphasizing the importance of tailored QA protocols. The findings underscore the need for site-specific action limits and highlight the sensitivity of stricter gamma criteria for detecting errors in complex treatment plans.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143765298","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

Development of estimation method for T₁ and T₂ values using the relaxivity of contrast agent and coagulant for a magnetic resonance imaging phantom. 利用造影剂和凝固剂的弛豫性开发磁共振成像模型的 T1 和 T2 值估算方法。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-23 DOI: 10.1007/s12194-025-00900-7

Hiroki Okada, Norikazu Koori, Hatsune Shimizu, Shohei Yamamoto, Tetsuya Komatsuzaki, Hiraku Fuse, Kota Sasaki, Shin Miyakawa, Kenji Yasue, Masato Takahashi

{"title":"Development of estimation method for T1 and T2 values using the relaxivity of contrast agent and coagulant for a magnetic resonance imaging phantom.","authors":"Hiroki Okada, Norikazu Koori, Hatsune Shimizu, Shohei Yamamoto, Tetsuya Komatsuzaki, Hiraku Fuse, Kota Sasaki, Shin Miyakawa, Kenji Yasue, Masato Takahashi","doi":"10.1007/s12194-025-00900-7","DOIUrl":"https://doi.org/10.1007/s12194-025-00900-7","url":null,"abstract":"The T1 and T2 values of magnetic resonance imaging phantoms used by researchers should be equivalent to those of the target tissue. However, this is difficult to achieve because of variations in the phantoms depending on the type and concentration of contrast agents and coagulants. The aim of this study was to elucidate the utility of a determination equation derived using the relaxivity of the contrast agent and coagulant. We prepared phantoms using 0.05-10 mmol L-1 contrast agent (Gadovist®; Bayer Yakuhin, Ltd., Osaka, Japan) and 0.1-5.0 wt% agar (agar, powder [010-15815]; Fujifilm Wako Pure Chemical Corporation, Osaka, Japan) and measured their T1 and T2 values. Determination equations for T1 and T2 values were derived using the relaxivity calculated from the T1 and T2 values of the contrast agent and coagulant. Subsequently, the determined values were compared with the measured values. The error rate of the determined T1 and T2 values were 7.66 ± 6.60% and 5.66 ± 4.05%, respectively, with correlation coefficients of 0.996 and 0.999. These results indicate that this method enables easy and highly accurate estimation of T1 and T2 values in MRI phantoms.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143693880","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

Risk factors for motion artifacts in fast spin-echo T2-weighted imaging of the prostate magnetic resonance imaging: a retrospective study. 前列腺磁共振成像快速自旋回波 T2 加权成像中出现运动伪影的风险因素：一项回顾性研究。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-21 DOI: 10.1007/s12194-025-00897-z

Takuya Kobata, Tatsuya Yamasaki, Hiroki Katayama, Masatoshi Morimoto, Yukito Maeda, Takashi Norikane, Yuka Yamamoto, Yoshihiro Nishiyama

{"title":"Risk factors for motion artifacts in fast spin-echo T2-weighted imaging of the prostate magnetic resonance imaging: a retrospective study.","authors":"Takuya Kobata, Tatsuya Yamasaki, Hiroki Katayama, Masatoshi Morimoto, Yukito Maeda, Takashi Norikane, Yuka Yamamoto, Yoshihiro Nishiyama","doi":"10.1007/s12194-025-00897-z","DOIUrl":"https://doi.org/10.1007/s12194-025-00897-z","url":null,"abstract":"Prostate cancer diagnosis using fast spin-echo (FSE) T2-weight imaging (T2WI) suffers from motion artifacts (T2-MA). We aimed to investigate the risk factors associated with T2-MA. We retrospectively analyzed the basic patient information and localizer images of 168 patients who underwent prostate magnetic resonance imaging at our institution between April 2019 and December 2021. FSE T2WI image quality was classified into Poor, Acceptable, and Excellent groups based on T2-MA severity. Between-group differences were analyzed using the Kruskal-Wallis test, and multinomial logistic regression was used to calculate adjusted odds ratios (ORs) for T2-MA. The bladder area of the Acceptable group was significantly larger than that of the Poor group (P = 0.010). The rectal area was significantly larger in the Poor group than in the Excellent group (P = 0.013). Larger rectal and bladder areas in the localizer image were significant risk factors for severe (OR: 1.136) and mild (OR: 1.032) T2-MA, respectively.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143674738","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 study of differences in absorbed dose estimates by images used in dosimetry of Lu-177-DOTATATE therapy.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-20 DOI: 10.1007/s12194-025-00898-y

Yui Masaki, Yasuo Yamashita, Takuro Isoda, Toyoyuki Kato, Shingo Baba

{"title":"A study of differences in absorbed dose estimates by images used in dosimetry of Lu-177-DOTATATE therapy.","authors":"Yui Masaki, Yasuo Yamashita, Takuro Isoda, Toyoyuki Kato, Shingo Baba","doi":"10.1007/s12194-025-00898-y","DOIUrl":"https://doi.org/10.1007/s12194-025-00898-y","url":null,"abstract":"In Lu-177-labeled peptide receptor radionuclide therapy, dosimetry has recently gained importance for assessing side effects and treatment responses. However, no standard method has been established yet. In this retrospective study, we compared the kidney-absorbed doses of 24 treatments with Lu-177-DOTATATE using three methods: a planar method using only planar images, a hybrid method using planar and SPECT/CT images, and a SPECT/CT method using only SPECT/CT images. In the Planar method, the ROI was defined from 2D whole-body planar images and calculated using the MIRD method. In the Hybrid method, the VOI was defined from CT images and the VOIs were placed in the 2D planar image as ROIs, which were calculated using the MIRD method. For the SPECT/CT method, the VOI was defined from CT images and the mean absorbed dose was estimated on a voxel basis. The absorbed dose estimated with the Planar method (15.2 ± 5.81 Gy) was significantly higher than the estimates with the other two methods (Hybrid: 2.93 ± 1.33 Gy, SPECT/CT: 3.81 ± 0.93 Gy) (p < 0.05). The Hybrid and SPECT/CT methods exhibited the strongest correlation. The Planar method demonstrated the highest variability in estimated values. The use of 2D planar images alone tended to overestimate the absorbed dose compared to the other methods, depending on the definition of the ROIs and the characteristics of the analysis software. This suggests that a combined approach using SPECT/CT and planar images is preferable for dosimetry.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143671386","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

Effectiveness of radiation protection educational material during angiography using visualization of scattered radiation by augmented reality technique.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-19 DOI: 10.1007/s12194-025-00899-x

Koki Noguchi, Toshioh Fujibuchi, Donghee Han

{"title":"Effectiveness of radiation protection educational material during angiography using visualization of scattered radiation by augmented reality technique.","authors":"Koki Noguchi, Toshioh Fujibuchi, Donghee Han","doi":"10.1007/s12194-025-00899-x","DOIUrl":"https://doi.org/10.1007/s12194-025-00899-x","url":null,"abstract":"In medical settings, radiation exposure among radiation workers is a significant concern, and understanding radiation protection is crucial. We developed and evaluated radiation protection educational materials using an augmented reality application for visualizing scatter radiation. The evaluation included a true/false quiz, a questionnaire based on the ARCS (Attention, Relevance, Confidence, and Satisfaction) model, and open-ended responses. The correct response rates for the true/false quiz were 65.5% and 72.4% for two questions regarding the effect of C-arm angle changes on scatter radiation distribution. The correct response rate for all other questions was 100%. Understanding how changes in C-arm angles specifically affect angiographic procedures proved more challenging than other topics. The ARCS model evaluation of learning motivation revealed average scores of 4.15 for Attention, 3.91 for Relevance, 3.93 for Confidence, and 4.28 for Satisfaction in the scale 5.00.These results suggest that the developed materials are effective in enhancing motivation. However, open-ended responses identified areas for improvement in the application's usability, particularly regarding ease of operation. While the materials successfully enhance motivation, further refinements are needed to address the variation in correct response rates across different scenarios and the usability challenges of the application.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143664868","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

Semantic segmentation for individual thigh skeletal muscles of athletes on magnetic resonance images.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-19 DOI: 10.1007/s12194-025-00901-6

Jun Kasahara, Hiroki Ozaki, Takeo Matsubayashi, Hideyuki Takahashi, Ryohei Nakayama

{"title":"Semantic segmentation for individual thigh skeletal muscles of athletes on magnetic resonance images.","authors":"Jun Kasahara, Hiroki Ozaki, Takeo Matsubayashi, Hideyuki Takahashi, Ryohei Nakayama","doi":"10.1007/s12194-025-00901-6","DOIUrl":"https://doi.org/10.1007/s12194-025-00901-6","url":null,"abstract":"The skeletal muscles that athletes should train vary depending on their discipline and position. Therefore, individual skeletal muscle cross-sectional area assessment is important in the development of training strategies. To measure the cross-sectional area of skeletal muscle, manual segmentation of each muscle is performed using magnetic resonance (MR) imaging. This task is time-consuming and requires significant effort. Additionally, interobserver variability can sometimes be problematic. The purpose of this study was to develop an automated computerized method for semantic segmentation of individual thigh skeletal muscles from MR images of athletes. Our database consisted of 697 images from the thighs of 697 elite athletes. The images were randomly divided into a training dataset (70%), a validation dataset (10%), and a test dataset (20%). A label image was generated for each image by manually annotating 15 object classes: 12 different skeletal muscles, fat, bones, and vessels and nerves. Using the validation dataset, DeepLab v3+ was chosen from three different semantic segmentation models as a base model for segmenting individual thigh skeletal muscles. The feature extractor in DeepLab v3+ was also optimized to ResNet50. The mean Jaccard index and Dice index for the proposed method were 0.853 and 0.916, respectively, which were significantly higher than those from conventional DeepLab v3+ (Jaccard index: 0.810, p < .001; Dice index: 0.887, p < .001). The proposed method achieved a mean area error for 15 objective classes of 3.12%, useful in the assessment of skeletal muscle cross-sectional area from MR images.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143664871","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 multiple regression model for peak skin dose using principal component analysis in interventional radiology.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-16 DOI: 10.1007/s12194-025-00893-3

Noriyuki Kuga, Katsutoshi Shirieda, Yumi Hirabara, Yusuke Kurogi, Ryohei Fujisaki, Lue Sun, Koichi Morota, Takashi Moritake, Hajime Ohta

{"title":"A multiple regression model for peak skin dose using principal component analysis in interventional radiology.","authors":"Noriyuki Kuga, Katsutoshi Shirieda, Yumi Hirabara, Yusuke Kurogi, Ryohei Fujisaki, Lue Sun, Koichi Morota, Takashi Moritake, Hajime Ohta","doi":"10.1007/s12194-025-00893-3","DOIUrl":"https://doi.org/10.1007/s12194-025-00893-3","url":null,"abstract":"This study addresses the growing concerns of increased radiation doses to patients resulting from the increased complexity of interventional radiology procedures. Despite the importance of dose management, few facilities use dosimetry systems to measure and control patient radiation doses. To aid in patient exposure control, this research aimed to predict the peak skin dose (PSD) using dose parameters from digital imaging and communication in medicine-radiation dose structured reports. The study focused on air kerma (Ka,r) and air kerma area product (KAP) values categorized into fixed dose (radiography and fluoroscopy) and motion dose (rotational digital subtraction angiography) for frontal and lateral biplane devices. Using single and multiple regression analysis, model equations for PSD were developed based on data from a radio-photoluminescence glass dosimeter and five dose parameters. Principal component analysis (PCA) was applied to consolidate the data, and multiple regression models were created using principal component scores. The results showed that rotational digital subtraction angiography had a minimal impact on PSD, whereas the Ka,r value demonstrated higher accuracy in predicting PSD than KAP. The inclusion of PCA in the multiple regression model further improved accuracy, with a root mean squared error of 226, confirming that PCA-enhanced models are more effective in predicting PSD.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143639648","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 multi-institutional survey on technical variations in total body irradiation in Japan.

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-14 DOI: 10.1007/s12194-025-00894-2

Masayasu Kitagawa, Ryoichi Notake, Ryuta Nakahara, Shogo Hatanaka, Tatsunori Saho, Kengo Matsuda

{"title":"A multi-institutional survey on technical variations in total body irradiation in Japan.","authors":"Masayasu Kitagawa, Ryoichi Notake, Ryuta Nakahara, Shogo Hatanaka, Tatsunori Saho, Kengo Matsuda","doi":"10.1007/s12194-025-00894-2","DOIUrl":"https://doi.org/10.1007/s12194-025-00894-2","url":null,"abstract":"This study aimed to survey technical variations in total body irradiation (TBI) across Japan. A web-based questionnaire investigating technical aspects (irradiation method, in vivo dosimetry, organ shielding, and boluses) of TBI was distributed via the authors' acquaintances in each region of Japan using snowball sampling, and 73 institutions responded. The data were collected from January to April 2024. Three institutions used two distinct irradiation methods, yielding 76 reported techniques. The reported irradiation techniques included long source-to-surface distance (SSD) techniques, which involve using a large field and extended distance; helical intensity-modulated radiation therapy (IMRT) using specialized equipment (e.g., TomoTherapy), moving couch techniques, and volumetric modulated arc therapy (VMAT) using a standard C-arm linac, with responses totaling 60 (79%), 10 (13%), 4 (5%), and 2 (3%), respectively. All institutions performing IMRT-based (helical IMRT and VMAT) TBI used computed tomography simulation with the patient in the supine position and utilized a 6 MV photon beam. Conversely, the long SSD technique exhibited significant variation; while 47 institutions treated patients exclusively in the supine position, others reported using the prone and lateral positions. Furthermore, the photon beam energies varied, with 10 MV (41 responses), 6 MV (20 responses), and 4 MV (1 response) reported. Notably, 17 institutions using long SSD techniques did not perform in vivo dosimetry and 32 did not use boluses. The differences in the methods used to shield the organs were also reported. These variations highlight the need for standardization of in vivo dosimetry, dose homogeneity strategies, and organ-shielding in TBI.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630883","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