Radiological Physics and Technology最新文献_第2页

Development of a patient-specific cone-beam computed tomography dose optimization model using machine learning in image-guided radiation therapy. 在图像引导放射治疗中使用机器学习的患者特异性锥束计算机断层扫描剂量优化模型的开发。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-22 DOI: 10.1007/s12194-025-00966-3

Shuta Miura

{"title":"Development of a patient-specific cone-beam computed tomography dose optimization model using machine learning in image-guided radiation therapy.","authors":"Shuta Miura","doi":"10.1007/s12194-025-00966-3","DOIUrl":"https://doi.org/10.1007/s12194-025-00966-3","url":null,"abstract":"Cone-beam computed tomography (CBCT) is commonly utilized in radiation therapy to visualize soft tissues and bone structures. This study aims to develop a machine learning model that predicts optimal, patient-specific CBCT doses that minimize radiation exposure while maintaining soft tissue image quality in prostate radiation therapy. Phantom studies evaluated the relationship between dose and two image quality metrics: image standard deviation (SD) and contrast-to-noise ratio (CNR). In a prostate-simulating phantom, CNR did not significantly decrease at doses above 40% compared to the 100% dose. Based on low-contrast resolution, this value was selected as the minimum clinical dose level. In clinical image analysis, both SD and CNR degraded with decreasing dose, consistent with the phantom findings. The structural similarity index between CBCT and planning computed tomography (CT) significantly decreased at doses below 60%, with a mean value of 0.69 at 40%. Previous studies suggest that this level may correspond to acceptable registration accuracy within the typical planning target volume margins applied in image-guided radiotherapy. A machine learning model was developed to predict CBCT doses using patient-specific metrics from planning CT scans and CBCT image quality parameters. Among the tested models, support vector regression achieved the highest accuracy, with an R2 value of 0.833 and a root mean squared error of 0.0876, and was therefore adopted for dose prediction. These results support the feasibility of patient-specific CBCT imaging protocols that reduce radiation dose while maintaining clinically acceptable image quality for soft tissue registration.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145114566","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

Measurement of shrinking immobilizing sheets for radiotherapy using a near-infrared camera. 用近红外照相机测量放射治疗用固定片的收缩。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-18 DOI: 10.1007/s12194-025-00963-6

Akito S Koganezawa, Takuya Wada, Daiki Hashimoto, Hidemasa Maekawa, Koichi Muro, Makiko Suitani, Takeo Nakashima, Teiji Nishio

{"title":"Measurement of shrinking immobilizing sheets for radiotherapy using a near-infrared camera.","authors":"Akito S Koganezawa, Takuya Wada, Daiki Hashimoto, Hidemasa Maekawa, Koichi Muro, Makiko Suitani, Takeo Nakashima, Teiji Nishio","doi":"10.1007/s12194-025-00963-6","DOIUrl":"https://doi.org/10.1007/s12194-025-00963-6","url":null,"abstract":"We aimed to develop a technique to precisely measure the shrinkage of immobilization sheets (ISs) using a three-dimensional (3D) tracking of multiple points on IS using a near-infrared camera. A thermoplastic sheet and an elastomer sheet were used in this study. The inter-marker distance (IMD) of neighboring marker pairs and the triangular area (TA) formed by neighboring three markers were analyzed as a function of time since molding each IS. Thermal distance ratio (TDR), IMD normalized to IMD after 48 h, and thermal area ratio (TAR), TA normalized to TA after 48 h, were analyzed using an exponential function. The 3D visualization of the initial shrinkage amplitude (ISA) was created for each IS. The mean ISA and the time constant (TC) in the exponential function (ISA, TC) for horizontal and vertical pairs were (0.34 <math><mo>±</mo></math> 0.06, 3.9 <math><mo>±</mo></math> 0.9) and (0.60 <math><mo>±</mo></math> 0.05, 7.6 <math><mo>±</mo></math> 0.9) for HFT and (0.13 <math><mo>±</mo></math> 0.02, 25.0 <math><mo>±</mo></math> 4.7) and (0.06 <math><mo>±</mo></math> 0.03, 4.7 <math><mo>±</mo></math> 3.5) for SF, respectively. The mean (ISA, TC) for HFT and SF were (0.76 <math><mo>±</mo></math> 0.07, 7.1 <math><mo>±</mo></math> 0.9) and (0.22 <math><mo>±</mo></math> 0.03, 17.7 <math><mo>±</mo></math> 4.2), respectively. Horizontal pairs showed smaller ISA and shorter TC than vertical pairs for HFT, while horizontal pairs showed larger ISA and longer TC than vertical pairs for SF, possibly due to different chemical characteristics of each material under the effect of mechanical force. The mean TDR and TAR are considered useful for evaluating the gross property of IS. The visualized distributions of ISA are considered useful to provide spatial information for investigating relationships between actual handlings and shrinkage of IS.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145081784","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 absorbed dose to brain in patients undergoing head and neck helical CT based on AAPM report 293. 基于AAPM报告评价头颈部螺旋CT患者脑吸收剂量293。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-17 DOI: 10.1007/s12194-025-00962-7

M S Shehu, N N Garba, R Nasiru, M Abdullahi, A Muhammad

{"title":"Evaluation of absorbed dose to brain in patients undergoing head and neck helical CT based on AAPM report 293.","authors":"M S Shehu, N N Garba, R Nasiru, M Abdullahi, A Muhammad","doi":"10.1007/s12194-025-00962-7","DOIUrl":"https://doi.org/10.1007/s12194-025-00962-7","url":null,"abstract":"This study used AAPM Report 293 to estimate absorbed doses (EADs) from head and neck CT examinations in 100 patients (ages 18-90), leveraging its superior accuracy over Report 220. The study used data from a diagnostic CT scanner of model Canon Aquilion Lightning 16-row 32-slice, between years 2022 to 2024, with IndoseCT version 20b software to extract parameters, such as volumetric CT dose index (CTDIVol), dose length product (DLP), X-ray tube current (mAs), X-ray tube voltage (kVp) and Size Specific Dose Estimation (SSDE) based on water equivalent diameter (Dw). Two IndoseCT methods were employed: Z-axis Slice Number technique for Dw and Z-axis Slice range technique for EAD. A correlation analysis using Pearson Correlation Coefficient (PCC) and Principal Component Analysis (PCA) investigated relationships between CT dose and patient size parameters. The analysis was conducted using Microsoft Excel software embedded with XLSTAT 2024 version. Results showed CTDIvol values were higher than SSDE in most age groups, except 40-59 and 70-79 years. EADs ranged from 29.21 ± 8.12 mGy for (18-30) to 33.07 ± 5.81 mGy for (≥ 30) age groups. Conversion factors (CF) were varied, with notable impact from the 70-79 age group. this study found similar trends in CTDIvol to SSDE conversion factors (CF) as past work, with a mean CF < 1 indicating slight underestimation of radiation dose (SSDE). Notably, by including the 70-79 age group, CF can be shifted from < 1 to > 1; this suggests that patient size in the 70-79 age group may require protocol optimization.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082242","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

Improved denoising scheme using three-dimensional multi-zone convolutional neural filters in dedicated breast positron emission tomography images. 基于三维多区域卷积神经滤波器的乳腺正电子发射断层图像去噪改进方案。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-15 DOI: 10.1007/s12194-025-00949-4

Masahiro Tsukijima, Atsushi Teramoto, Akihiro Kojima, Osamu Yamamuro, Kumiko Oomi, Hiroshi Fujita

{"title":"Improved denoising scheme using three-dimensional multi-zone convolutional neural filters in dedicated breast positron emission tomography images.","authors":"Masahiro Tsukijima, Atsushi Teramoto, Akihiro Kojima, Osamu Yamamuro, Kumiko Oomi, Hiroshi Fujita","doi":"10.1007/s12194-025-00949-4","DOIUrl":"https://doi.org/10.1007/s12194-025-00949-4","url":null,"abstract":"Dedicated breast positron emission tomography (dbPET) has higher spatial resolution than whole-body PET and can detect smaller lesions. Therefore, it is expected to be useful in detecting early stage breast cancer and assessing treatment efficacy. However, dbPET images suffer leading to a relative increase in noise from reduced sensitivity. In a previous study, optimized noise reduction for each region was achieved by applying multiple convolutional neural networks (CNNs). However, CNN processing was performed in a two-dimensional (2D) slice plane, which resulted in image blurring when the image was observed from multiple directions using maximum intensity projection (MIP). In this study, we aimed to further reduce noise and improve visibility by extending multiple CNNs to the three-dimensional (3D) processing and optimizing them for each region. To train the CNN, data with acquisition times of 1 and 7 min were used as the input and teacher images, respectively. Furthermore, 3D volume data were used as the input, and the system was designed to output volume data after noise reduction processing. Quantitative evaluation of the proposed multiple 3D direction-denoising filter showed better performance than that of the 2D filter. Furthermore, the visibility of the MIP images improved. In addition, the quantitative evaluation of the maximum standardized uptake value (SUVMAX) was conducted using a phantom; the results confirmed that the proposed noise reduction method ensured maintaining the reproducibility of SUVMAX. These results indicate that the proposed method is effective for noise reduction in dbPET images.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145070702","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 the usefulness of the masking on un-smoothed image method in ²⁰¹Tl myocardial perfusion SPECT. 201Tl心肌灌注SPECT非平滑图像掩模方法的有效性评价。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-10 DOI: 10.1007/s12194-025-00959-2

Ryuichi Miyajima, Ryo Ueno, Ryosuke Ichino, Satomi Teraoka, Ishikawa Yasushi, Masahiro Sonoda

引用次数: 0

Comparative dosimetric analysis of base dose and gradient-based optimization in overlapping regions of extended target volumes using an anthropomorphic phantom. 比较剂量学分析的基础剂量和梯度优化在重叠区域的扩展靶体积使用拟人化的幻影。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-06 DOI: 10.1007/s12194-025-00961-8

Dipesh, Raj Pal Singh, Manindra Bhushan

{"title":"Comparative dosimetric analysis of base dose and gradient-based optimization in overlapping regions of extended target volumes using an anthropomorphic phantom.","authors":"Dipesh, Raj Pal Singh, Manindra Bhushan","doi":"10.1007/s12194-025-00961-8","DOIUrl":"https://doi.org/10.1007/s12194-025-00961-8","url":null,"abstract":"This study compares the dosimetric performance of Base Dose Optimization (BDO) and Gradient-Based Optimization (GBO) for extended target volumes in Total Body Irradiation (TBI). The focus is on overlapping regions using the Rando Phantom. The study evaluates dose distribution, conformity, homogeneity, and sensitivity to positional deviations. The Rando Phantom was used for treatment planning with both BDO and GBO plans. Positional shifts of ± 5 mm and ± 10 mm were introduced to assess uncertainties. Dosimetric metrics included mean dose, minimum dose, maximum dose, homogeneity index (HI), and conformity index (CI). Positional deviations and their impact on dose variations were analyzed. Quality assurance was performed using OSLDs and an array detector. The BDO plan delivered higher mean doses (103.6%-108.7%) and hotspot values, with a maximum of 133.7%. In contrast, the GBO plan produced a more uniform dose distribution (99.6%-100.3%) with lower hotspots, peaking at 112%. The BDO plan achieved better uniformity (HI 0.025-0.103) and higher conformity (CI 0.938-0.981). The GBO plan showed greater variability (HI 0.143-0.253) and slightly lower conformity (CI 0.941-0.964). Positional shifts revealed that the BDO plan was highly sensitive, with overdoses of + 46.60% and underdoses of - 47.29%. The GBO plan showed smaller deviations (+ 11.62% overdose, - 11.73% underdose). Gamma analysis demonstrated higher pass rates for the GBO plan. The BDO plan excels in target coverage and conformity but is sensitive to positional shifts. The GBO plan offers better uniformity and robustness, supporting its use in complex clinical scenarios. Further refinement of both approaches could improve clinical applicability and patient outcomes.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006612","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

Classification of liver lesions based on temporal changes in hepatobiliary phase contrast on magnetic resonance imaging: a preliminary study. 基于磁共振成像肝胆相衬时间变化的肝脏病变分类：初步研究。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-05 DOI: 10.1007/s12194-025-00933-y

Yasuo Takatsu, Masafumi Nakamura, Tomoko Tateyama, Tosiaki Miyati, Satoshi Kobayashi

引用次数: 0

Margin for compensating displacement of adrenal gland metastasis and fiducial marker along with respiratory phase in real-time motion-tracking radiation therapy. 实时运动追踪放射治疗中肾上腺转移的补偿边缘及呼吸相的基准标记物。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-05 DOI: 10.1007/s12194-025-00960-9

Yuki Aoyama, Tetsuya Tomida, Susumu Nagata, Noriaki Muramatsu, Ryosei Nakada, Hideyuki Harada

{"title":"Margin for compensating displacement of adrenal gland metastasis and fiducial marker along with respiratory phase in real-time motion-tracking radiation therapy.","authors":"Yuki Aoyama, Tetsuya Tomida, Susumu Nagata, Noriaki Muramatsu, Ryosei Nakada, Hideyuki Harada","doi":"10.1007/s12194-025-00960-9","DOIUrl":"https://doi.org/10.1007/s12194-025-00960-9","url":null,"abstract":"In therapy with Synchrony® mounted on Radixact®, the fiducial marker (FM) and adrenal gland metastasis, which shift with respiratory phase, require margin compensation for high-dose prescriptions. Although compensation is critical, no studies have examined the margin to compensate for the respiratory phase shift. Therefore, we aimed to suggest the compensating margin for the FM and adrenal metastasis shift along with respiratory phase. We used images from four-dimensional computed tomography (4DCT) taken twice and gated CT taken once before therapy initiation with available contour data for FM and adrenal gland metastasis in each image. The distance between the FM and the center of the gross tumor volume (GTV) in each image of a ten-set 4DCT was defined as the correlating association, and a relative cumulative frequency distribution was created based on it. The values of the margins compensating for respiratory displacement were obtained from the relative cumulative frequency distribution in the right-left/posterior-anterior/superior-inferior (S-I) directions. In cases wherein the FM was placed inside the GTV, the margin values decreased in the S-I direction.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006617","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

Simultaneous retrospective estimation of radiation dose and elapsed time by electron paramagnetic resonance spectroscopy of di-sodium tartrate. 用电子顺磁共振谱法同时回顾性估计酒石酸二钠的辐射剂量和经过时间。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-02 DOI: 10.1007/s12194-025-00957-4

Ahmed M Maghraby

引用次数: 0

Influence of the number of images on threshold image contrast measurements with a phantom with gold disks in digital mammography. 数字乳房x线照相术中图像数目对带金盘幻像阈值图像对比度测量的影响。

IF 1.5

Radiological Physics and Technology Pub Date : 2025-09-02 DOI: 10.1007/s12194-025-00958-3

Michał Biegała, Agata Batolik

{"title":"Influence of the number of images on threshold image contrast measurements with a phantom with gold disks in digital mammography.","authors":"Michał Biegała, Agata Batolik","doi":"10.1007/s12194-025-00958-3","DOIUrl":"10.1007/s12194-025-00958-3","url":null,"abstract":"Image quality, in addition to radiation dose, is the most important physical parameter in digital mammography. Image quality should be periodically monitored using the CDMAM phantom. The aim of this study is to investigate the effect of the number of analyzed images on the result of threshold image contrast measurements using the CDMAM phantom in different versions. The images obtained using two versions of the CDMAM phantom, i.e., 3.4 and 4.0, were analyzed. The image analysis was performed and repeated 10 times for 2, 4, 6, 8, 12, 16, 24, and 32 images from a pool of 43 images, separately for each phantom. For the CDMAM 3.4 phantom, a statistical difference was demonstrated between the following groups: S2 vs S6 (p < 0.006), S6 vs S16 (p < 0.001), S6 vs S24 (p < 0.002), S6 vs S32 (p < 0.021), S8 vs S16 (p < 0.019), S8 vs S24 (p < 0.048). For the CDMAM 4.0 phantom, a statistically significant difference was demonstrated between all groups and the N2 group (p < 0.000). For the CDMAM 3.4 phantom, the most favorable number of images required for analysis cannot be clearly determined. For the CDMAM 4.0 phantom, it is recommended to perform 24 images for analysis. Particular attention should be paid when determining the threshold image contrast for a disk diameter of 0.1 mm, as this parameter is used during exposure automation control.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144973555","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