Radiological Physics and Technology最新文献

{"title":"Uncertainty-aware deep learning in FDG-PET: implications for generalizability in clinical practice.","authors":"Andrea Carolina Munive Gnecco, Carlos Mario Pedraza, John Leonardo Torres Castiblanco","doi":"10.1007/s12194-026-01155-6","DOIUrl":"https://doi.org/10.1007/s12194-026-01155-6","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149197160","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":"End to end dosimetric and geometric verification of single isocenter multitarget stereotactic radiosurgery using an anthropomorphic phantom: external audit validation.","authors":"S Balasubramanian, D Anbalagan, P Thanasekar, Rashi Agrawal","doi":"10.1007/s12194-026-01153-8","DOIUrl":"https://doi.org/10.1007/s12194-026-01153-8","url":null,"abstract":"<p><p>Our study aimed to perform a comprehensive end-to-end (E2E) dosimetric and geometric evaluation of the newly commissioned Varian Edge linear accelerator (LINAC) with the HyperArc™ VMAT system for multi-target stereotactic radiosurgery (SRS) to ensure clinical accuracy and safety in the treatment of multiple brain metastases. E2E testing was conducted using the MAX-EA anthropomorphic phantom, incorporating ion chamber and film inserts. The phantom was immobilized with a Q-fix Encompass system and scanned with a 0.625 mm CT protocol. Five spherical PTVs range between (0.3-9.2 cc) were planned using Eclipse™ v18.01 with 6 MV-FFF beams and optimized via the Photon Optimizer algorithm with Acuros XB (1.25 mm grid). A HyperArc™ plan prescribing 15 Gy to each target was generated. Ionization chamber, Gafchromic EBT-XD film, portal dosimetry (EPID), and Multi-Target Winston-Lutz (W-L) tests were used to evaluate dosimetric and geometric accuracy. The measured-to-calculated dose difference was - 3.3% for the HyperArc plan. Film analysis yielded average gamma pass rates > 94.9% (2%/2 mm), > 96.5% (3%/1 mm) and > 98.68% (3%/2 mm). Portal dosimetry achieved > 96.05% average gamma pass (2%/2 mm). The W-L test all targets demonstrated localization accuracy within 0.5 mm and MPC measurements confirmed sub-millimeter isocenter accuracy within 0.29 mm. E2E evaluation of the Edge LINAC with HyperArc VMAT demonstrated submillimeter geometric precision and robust dosimetric accuracy. Also, the Results met AAPM-RSS benchmarks. While rigid phantom validation inherently idealizes real patient-specific anatomical and setup variations. These high-quality baseline results support the clinical accuracy of the treatment workflow.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149185247","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 voxel size on hand dose calculations and dose-area histogram analysis for radiopharmaceutical operators.","authors":"Yuma Matsuki, Kosuke Yamashita, Takeshi Ohno","doi":"10.1007/s12194-026-01151-w","DOIUrl":"https://doi.org/10.1007/s12194-026-01151-w","url":null,"abstract":"<p><p>This study evaluated the impact of voxel size on three-dimensional (3D) hand dose distributions and maximum dose estimates for radiopharmaceutical operators and examined the relationship between dose-area histogram (DAH) indices and the maximum mean skin dose over 1 cm² ([Formula: see text]). Dose distributions in a hand phantom during administration with a shielded syringe containing ^99mTc, ¹⁷⁷Lu, or ¹⁸F were calculated using Monte Carlo simulations. The hand phantom voxel size was varied from 1 to 5 mm, and skin-dose distributions on the finger surface were calculated using 1 mm × 1 mm × 10 μm voxels placed at a depth of 70 μm. DAHs and [Formula: see text] were evaluated for the index finger, middle finger, and thumb. With a 1 mm voxel size, the maximum dose occurred in the index and middle fingers for all radionuclides. At larger voxel sizes, dose underestimation due to the partial-volume effect was more pronounced in these fingers, where the dose gradient was steep, and the maximum-dose region shifted to the thumb at voxel sizes of 4 mm for ^99mTc and ¹⁷⁷Lu and 5 mm for ¹⁸F. Under most conditions, the minimum dose covering 0.6 cm² ([Formula: see text]) agreed with [Formula: see text] within ± 5%. These results indicate that the smallest feasible voxel size should be used for hand dose calculations, particularly for lower radionuclide energy and smaller source volume. DAH analysis may provide a simple and robust approach for estimating [Formula: see text] and assessing radiation-induced skin injury risk while accounting for the area effect.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149167174","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":"Proton boron capture therapy and neutron capture enhanced proton therapy: a critical review of investigational approaches in proton therapy.","authors":"Abdur Rahim, Hiroshi Watabe","doi":"10.1007/s12194-026-01152-9","DOIUrl":"https://doi.org/10.1007/s12194-026-01152-9","url":null,"abstract":"<p><p>Proton Boron Capture Therapy (PBCT) and Neutron Capture Enhanced Proton Therapy (NCEPT) have been proposed as investigational approaches to improve the therapeutic effectiveness of proton therapy through additional nuclear reactions within the tumor region. Both techniques aim to enhance localized energy deposition and biological damage by introducing boron or other neutron capture agents prior to proton irradiation. Following their introduction, numerous theoretical, simulation-based, experimental and microdosimetric studies have been conducted to evaluate their potential. However, the reported outcomes remain highly inconsistent, ranging from significant dose enhancement to negligible effects, making the actual therapeutic benefit of these approaches controversial. This review provides a comprehensive and critical analysis of proton therapy-based PBCT and NCEPT studies reported in the literature. Theoretical models, Monte Carlo simulations, experimental investigations, and microdosimetric evaluations are systematically examined and compared in order to provide a concise overview of the current understanding of these techniques. Particular emphasis is placed on the underlying physical mechanisms, reported dose enhancement and biological implications. Analysis of the available literature indicates that, under clinically relevant boron concentrations, both PBCT and proton therapy-based NCEPT generally produce negligible or only marginal enhancement. Even at elevated boron concentrations, most studies have reported limited enhancement, although some investigations have observed significant physical or biological effects. The primary limitations are the relatively low proton-boron reaction cross section in PBCT and the insufficient production of thermal neutrons in proton-based NCEPT. However, limited physical dose enhancement does not necessarily exclude biological effects reported experimentally, which require further microdosimetric and radiobiological investigation. Overall, the clinical applicability of these approaches remains uncertain and requires further investigation.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149149492","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":"Inter-operator agreement and temporal reproducibility of automatically and manually generated multiplanar reconstruction axial images on head CT.","authors":"Masami Tashiro, Masaki Saito, Yuta Kaneko, Takeshi Fukaya, Tokiya Yoshii, Tomoya Kamei, Hironobu Ishikawa","doi":"10.1007/s12194-026-01150-x","DOIUrl":"https://doi.org/10.1007/s12194-026-01150-x","url":null,"abstract":"<p><p>Automatic multiplanar reconstruction (Auto MPR) for head CT has mainly been evaluated for accuracy, though temporal reproducibility remains underassessed. We compared Auto MPR and manual MPR (Manual MPR) axial images, evaluating inter-operator agreement and temporal reproducibility separately, in 16 patients who underwent three non-contrast head CT scans within two weeks, each independently processed by seven technologists. After correcting in-plane translational offsets, spatial overlap of skull regions was quantified using the Dice similarity coefficient (DSC) and intersection over union (IoU). Auto MPR showed significantly higher inter-operator agreement (median DSC, 0.849 vs. 0.776; p < 0.001), whereas Manual MPR showed higher temporal reproducibility (median DSC, 0.850 vs. 0.792; p = 0.018), particularly in intracranial hemorrhage. Inter-operator agreement and temporal reproducibility represent independent quality dimensions of Auto MPR. We propose a diagnosis-dependent workflow: Auto MPR for single time-point, multi-technologist evaluations, and Manual MPR-or Auto MPR with manual verification-for longitudinal follow-up requiring precise comparison.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149138713","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":"Influence of gantry overrun angle on CTDI variability: a Monte Carlo study.","authors":"Masanao Kobayashi, Yusei Nishihara, Tomonobu Haba, Shigeki Kobayashi","doi":"10.1007/s12194-026-01149-4","DOIUrl":"https://doi.org/10.1007/s12194-026-01149-4","url":null,"abstract":"<p><p>This study used Monte Carlo simulation to evaluate the influence of the X-ray tube start-angle uncertainty and gantry rotation overrun on computed tomography dose index (CTDI) measurements during axial scanning. Polymethyl methacrylate phantoms with diameters of 16 and 32 cm were modeled, and CTDI_100,c, CTDI_100,p, and CTDI_w were calculated while varying the overrun angle from 0° to 120°. For each condition, the tube start angle varied from 0° to 359°, and the relative standard error was used to quantify the CTDI variability. When the overrun angle was 0°, the CTDI variability was negligible. However, the relative standard error increased with an increasing overrun angle, particularly at the peripheral positions and in the 32-cm phantom. These findings indicate that gantry overrun and uncertainty in the tube start angle can contribute to CTDI measurement variability and that repeated measurements may be required under conditions with large overrun angles.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149138688","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":"Correction: Photon beam energy selection for scalp dose reduction in whole-brain radiotherapy: a benchmark phantom study.","authors":"Takahiro Kato, Daiki Senzaki, Takaomi Harada, Hisashi Sato","doi":"10.1007/s12194-026-01137-8","DOIUrl":"https://doi.org/10.1007/s12194-026-01137-8","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149116376","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 placement of the bolus-tracking region of interest using U-Net-based aortic root segmentation in coronary CT angiography.","authors":"Kiyonori Shirai, Ayuka Ono, Naohiro Sakashita","doi":"10.1007/s12194-026-01104-3","DOIUrl":"https://doi.org/10.1007/s12194-026-01104-3","url":null,"abstract":"<p><p>In coronary CT angiography (CCTA), deviation of the bolus-tracking region of interest (ROI) from the aortic root (AR) during CT fluoroscopy may lead to inappropriate scan timing. This study developed and evaluated an automated ROI placement system based on the U-Net segmentation of the AR in CT fluoroscopic images. A total of 1663 CT fluoroscopic images from 57 patients who underwent CCTA were analyzed. A patient-level five-fold cross-validation was performed; in each iteration, one fold was used for testing, one for validation, and the remaining three for training. The training images were augmented by rotation. A 2D U-Net was trained to segment the AR region, and postprocessing consisted of Otsu thresholding, median filtering, and connected-component analysis. A circular ROI corresponding to 25% of the predicted AR area was placed at the centroid of the predicted AR region. Segmentation accuracy was assessed using the Dice similarity coefficient (DSC), and ROI placement accuracy was evaluated using centroid distance between the predicted and ground-truth regions and complete containment of the ROI mask within the ground-truth AR region. The median DSC was 0.957, and the median centroid distance was 0.7 mm. All automatically placed ROIs were completely contained within the ground-truth AR region. The U-Net inference time was 72.55 ± 15.72 ms per image, and the total processing time from image loading to ROI placement was 94.8 ± 14.6 ms per image. The proposed method can enable accurate, real-time, and operator-independent dynamic ROI placement for CCTA bolus tracking.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149116359","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":"Comment on \"Single-slice CT body-weight prediction with image and metadata fusion: a multi-model comparison\".","authors":"Hamed Ghaffari, Soheila Refahi, Mahsa Falahatpour","doi":"10.1007/s12194-026-01146-7","DOIUrl":"https://doi.org/10.1007/s12194-026-01146-7","url":null,"abstract":"","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149116404","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":"Inter-software variability in CT organ-dose calculation under identical scan conditions: implications for users and dose evaluation in the Japanese population.","authors":"Toshioh Fujibuchi, Donghee Han, Choirul Anam","doi":"10.1007/s12194-026-01148-5","DOIUrl":"https://doi.org/10.1007/s12194-026-01148-5","url":null,"abstract":"<p><p>Organ dose calculation software offers a convenient way to estimate organ and effective doses in computed tomography (CT) for radiation risk assessment. However, even under identical scan conditions the estimates differ among software packages, and users must understand these differences when applying the results. We quantified the magnitude and causes of inter-software differences and evaluated typical doses for the Japanese population. Three packages-NCICT, WAZA-ARI v2, and VirtualDose CT-were compared under identical conditions (120 kV, 1 s rotation, pitch 1, no tube current modulation) for head, chest, and abdomen-pelvis scans. Tube current was matched to the national median dose indices (Japan DRLs 2025), and the body size to the Japanese adult average (male 170 cm/70 kg; female 160 cm/50 kg). Excluding muscle, organ doses differed among software by up to 28% (male) and 47% (female) relative to WAZA-ARI v2. Muscle was a separate outlier: the muscle dose from the size-adjustable phantom of NCICT was about 90% lower than that from the other two packages. Scanner-dependent differences appeared only in WAZA-ARI v2 (up to 19%), and a ± 2 cm change in scan position markedly altered doses to organs at the scan boundary. Effective doses for the Japanese population were approximately 2.2 mSv (head), 9.6 mSv (chest), and 13.0 mSv (abdomen-pelvis), all within the ranges reported by UNSCEAR 2020/2021. Because all packages have been examined against measurements previously, these differences arise from phantom anatomy and size and from calculation algorithms rather than from inaccuracy; users should interpret results with awareness of this variability.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149116374","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}