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Search Results (377)

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Keywords = X-ray tube

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21 pages, 9010 KiB  
Article
Dual-Branch Deep Learning with Dynamic Stage Detection for CT Tube Life Prediction
by Zhu Chen, Yuedan Liu, Zhibin Qin, Haojie Li, Siyuan Xie, Litian Fan, Qilin Liu and Jin Huang
Sensors 2025, 25(15), 4790; https://doi.org/10.3390/s25154790 - 4 Aug 2025
Viewed by 184
Abstract
CT scanners are essential tools in modern medical imaging. Sudden failures of their X-ray tubes can lead to equipment downtime, affecting healthcare services and patient diagnosis. However, existing prediction methods based on a single model struggle to adapt to the multi-stage variation characteristics [...] Read more.
CT scanners are essential tools in modern medical imaging. Sudden failures of their X-ray tubes can lead to equipment downtime, affecting healthcare services and patient diagnosis. However, existing prediction methods based on a single model struggle to adapt to the multi-stage variation characteristics of tube lifespan and have limited modeling capabilities for temporal features. To address these issues, this paper proposes an intelligent prediction architecture for CT tubes’ remaining useful life based on a dual-branch neural network. This architecture consists of two specialized branches: a residual self-attention BiLSTM (RSA-BiLSTM) and a multi-layer dilation temporal convolutional network (D-TCN). The RSA-BiLSTM branch extracts multi-scale features and also enhances the long-term dependency modeling capability for temporal data. The D-TCN branch captures multi-scale temporal features through multi-layer dilated convolutions, effectively handling non-linear changes in the degradation phase. Furthermore, a dynamic phase detector is applied to integrate the prediction results from both branches. In terms of optimization strategy, a dynamically weighted triplet mixed loss function is designed to adjust the weight ratios of different prediction tasks, effectively solving the problems of sample imbalance and uneven prediction accuracy. Experimental results using leave-one-out cross-validation (LOOCV) on six different CT tube datasets show that the proposed method achieved significant advantages over five comparison models, with an average MSE of 2.92, MAE of 0.46, and R2 of 0.77. The LOOCV strategy ensures robust evaluation by testing each tube dataset independently while training on the remaining five, providing reliable generalization assessment across different CT equipment. Ablation experiments further confirmed that the collaborative design of multiple components is significant for improving the accuracy of X-ray tubes remaining life prediction. Full article
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13 pages, 1471 KiB  
Article
Effect of X-Ray Tube Angulations and Digital Sensor Alignments on Profile Angle Distortion of CAD-CAM Abutments: A Pilot Radiographic Study
by Chang-Hun Choi, Seungwon Back and Sunjai Kim
Bioengineering 2025, 12(7), 772; https://doi.org/10.3390/bioengineering12070772 - 17 Jul 2025
Viewed by 388
Abstract
Purpose: This pilot study aimed to evaluate how deviations in X-ray tube head angulation and digital sensor alignment affect the radiographic measurement of the profile angle in CAD-CAM abutments. Materials and Methods: A mandibular model was used with five implant positions (central, buccal, [...] Read more.
Purpose: This pilot study aimed to evaluate how deviations in X-ray tube head angulation and digital sensor alignment affect the radiographic measurement of the profile angle in CAD-CAM abutments. Materials and Methods: A mandibular model was used with five implant positions (central, buccal, and lingual offsets). Custom CAD-CAM abutments were designed with identical bucco-lingual direction contours and varying mesio-distal asymmetry for the corresponding implant positions. Periapical radiographs were acquired under controlled conditions by systematically varying vertical tube angulation, horizontal tube angulation, and horizontal sensor rotation from 0° to 20° in 5° increments for each parameter. Profile angles, interthread distances, and proximal overlaps were measured and compared with baseline STL data. Results: Profile angle measurements were significantly affected by both X-ray tube and sensor deviations. Horizontal tube angulation produced the greatest profile angle distortion, particularly in buccally positioned implants. Vertical x-ray tube angulations beyond 15° led to progressive underestimation of profile angles, while horizontal tube head rotation introduced asymmetric mesial–distal variation. Sensor rotation also caused marked interthread elongation, in some cases exceeding 100%, despite vertical projection being maintained. Profile angle deviations greater than 5° occurred in multiple conditions. Conclusions: X-ray tube angulation and sensor alignment influence the reliability of profile angle measurements. Radiographs with > 10% interthread elongation or crown overlap may be inaccurate and warrant re-acquisition. Special attention is needed when imaging buccally positioned implants. Full article
(This article belongs to the Section Biomedical Engineering and Biomaterials)
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10 pages, 2486 KiB  
Article
Performance of Miniature Carbon Nanotube Field Emission Pressure Sensor for X-Ray Source Applications
by Huizi Zhou, Wenguang Peng, Weijun Huang, Nini Ye and Changkun Dong
Micromachines 2025, 16(7), 817; https://doi.org/10.3390/mi16070817 - 17 Jul 2025
Viewed by 360
Abstract
There is a lack of an effective approach to measure vacuum conditions inside sealed vacuum electronic devices (VEDs) and other small-space vacuum instruments. In this study, the application performance of an innovative low-pressure gas sensor based on the emission enhancements of multi-walled carbon [...] Read more.
There is a lack of an effective approach to measure vacuum conditions inside sealed vacuum electronic devices (VEDs) and other small-space vacuum instruments. In this study, the application performance of an innovative low-pressure gas sensor based on the emission enhancements of multi-walled carbon nanotube (MWCNT) field emitters was investigated, and the in situ vacuum performance of X-ray tubes was studied for the advantages of miniature dimension and having low power consumption, extremely low outgassing, and low thermal disturbance compared to conventional ionization gauges. The MWCNT emitters with high crystallinity presented good pressure sensing performance for nitrogen, hydrogen, and an air mixture in the range of 10−7 to 10−3 Pa. The miniature MWCNT sensor is able to work and remain stable with high-temperature baking, important for VED applications. The sensor monitored the in situ pressures of the sealed X-ray tubes successfully with high-power operations and a long-term storage of over two years. The investigation showed that the vacuum of the sealed X-ray tube is typical at a low 10−4 Pa level, and pre-sealing degassing treatments are able to make the X-ray tube work under high vacuum levels with less outgassing and keep a stable high vacuum for a long period of time. Full article
(This article belongs to the Section D:Materials and Processing)
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10 pages, 370 KiB  
Article
Predictors and Potential Clinical Implications of Residual Postoperative Pleural Space After Uniportal-Vats Lobectomy
by Maria Letizia Vita, Antonio Giulio Napolitano, Adriana Nocera, Claudia Leoni, Arianna Gallo, Khrystyna Kuzmych, Leonardo Petracca-Ciavarella, Maria Teresa Congedo, Elisa Meacci, Filippo Lococo, Stefano Margaritora and Dania Nachira
J. Clin. Med. 2025, 14(14), 4988; https://doi.org/10.3390/jcm14144988 - 15 Jul 2025
Viewed by 266
Abstract
Objectives: Residual postoperative pleural space (RPPS) is a common event after pulmonary lobectomy. Uniportal video-assisted thoracoscopic surgery (VATS) lobectomy has been associated with a higher incidence of RPPS. This study aims to evaluate the incidence, the predictors, and potential clinical implications of RPPS [...] Read more.
Objectives: Residual postoperative pleural space (RPPS) is a common event after pulmonary lobectomy. Uniportal video-assisted thoracoscopic surgery (VATS) lobectomy has been associated with a higher incidence of RPPS. This study aims to evaluate the incidence, the predictors, and potential clinical implications of RPPS following Uniportal VATS lobectomy. Methods: Patients who underwent Uniportal VATS lobectomy, without any previous neoadjuvant treatment, from June 2016 to March 2020, were retrospectively analyzed. RPPS was assessed using the last chest X-Ray prior to discharge and measured by Collins method (%). Results: Among 492 patients who underwent Uniportal VATS lobectomy, 325 (66.1%) developed RPPS. The mean RPPS volume measured by the Collins method was 15.46 ± 8.59% (vs. Collins = 4.2% in no-PRPS). An RPPS > 10.5% of Collins was significantly associated with a higher risk of postoperative air leak (AUC: 0.69, sensitivity: 69%, specificity: 54%, p < 0.001). Multivariable analysis identified the following predictors of RPPS > 10.5%: right-sided surgery (p < 0.001), upper lobectomy (p = 0.01), and prolonged air leak (p = 0.003). Patients with RPPS had a higher risk of only radiologically visible postoperative subcutaneous emphysema on the final chest X-ray (p = 0.041) and were more frequently discharged with a chest tube connected to a Heimlich valve (p < 0.001). Within 90 days post-discharge, 24 (4.9%) patients were readmitted due to increased RPPS (1.4%, requiring drainage in 5 cases [1%]), progression of subcutaneous emphysema (1.6%), and pleural effusion (1.8%, requiring drainage in 6 cases [1.2%]). However, RPPS was not associated with an increased overall risk of postoperative complications (p = 0.31) or 90-day readmission (p = 0.43). Conclusions: RPPS is a common occurrence following Uniportal VATS lobectomy but is not associated with clinically significant complications. The current study findings identified BMI, active smoking, right-sided surgery, and prolonged air leak as significant predictors of RPPS. Full article
(This article belongs to the Section General Surgery)
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20 pages, 3209 KiB  
Article
Experimental Evaluation of GAGG:Ce Crystalline Scintillator Properties Under X-Ray Radiation
by Anastasios Dimitrakopoulos, Christos Michail, Ioannis Valais, George Fountos, Ioannis Kandarakis and Nektarios Kalyvas
Crystals 2025, 15(7), 590; https://doi.org/10.3390/cryst15070590 - 23 Jun 2025
Viewed by 595
Abstract
The scope of this study was to evaluate the response of Ce-doped gadolinium aluminum gallium garnet (GAGG:Ce) crystalline scintillator under medical X-ray irradiation for medical imaging applications. A 10 × 10 × 10 mm3 crystal was irradiated at X-ray tube voltages ranging [...] Read more.
The scope of this study was to evaluate the response of Ce-doped gadolinium aluminum gallium garnet (GAGG:Ce) crystalline scintillator under medical X-ray irradiation for medical imaging applications. A 10 × 10 × 10 mm3 crystal was irradiated at X-ray tube voltages ranging from 50 kVp to 150 kVp. The crystal’s compatibility with several commercially available optical photon detectors was evaluated using the spectral matching factor (SMF) along with the absolute efficiency (AE) and the effective efficiency (EE). In addition, the energy-absorption efficiency (EAE), the quantum-detection efficiency (QDE) as well as the zero-frequency detective quantum detection efficiency DQE(0) were determined. The crystal demonstrated satisfactory AE values as high as 26.3 E.U. (where 1 E.U. = 1 μW∙m−2/(mR∙s−1)) at 150 kVp, similar, or in some cases, even superior to other cerium-doped scintillator materials. It also exhibits adequate DQE(0) performance ranging from 0.99 to 0.95 across all the examined X-ray tube voltages. Moreover, it showed high spectral compatibility with commonly used photoreceptors in modern day such as complementary metal–oxide–semiconductors (CMOS) and charge-coupled-devices (CCD) with SMF values of 0.95 for CCD with broadband anti-reflection coating and 0.99 for hybrid CMOS blue. The aforementioned properties of this scintillator material were indicative of its superior efficiency in the examined medical energy range, compared to other commonly used scintillators. Full article
(This article belongs to the Special Issue Exploring New Materials for the Transition to Sustainable Energy)
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27 pages, 19294 KiB  
Article
Classifying X-Ray Tube Malfunctions: AI-Powered CT Predictive Maintenance System
by Ladislav Pomšár, Maryna Tsvietaieva, Maros Krupáš and Iveta Zolotová
Appl. Sci. 2025, 15(12), 6547; https://doi.org/10.3390/app15126547 - 10 Jun 2025
Viewed by 604
Abstract
Computed tomography scans are among the most used medical imaging modalities. With increased popularity and usage, the need for maintenance also increases. In this work, the problem is tackled using machine learning methods to create a predictive maintenance system for the classification of [...] Read more.
Computed tomography scans are among the most used medical imaging modalities. With increased popularity and usage, the need for maintenance also increases. In this work, the problem is tackled using machine learning methods to create a predictive maintenance system for the classification of faulty X-ray tubes. Data for 137 different CT machines were collected, with 128 deemed to fulfil the quality criteria of the study. Of these, 66 have had X-ray tubes subsequently replaced. Afterwards, auto-regressive model coefficients and wavelet coefficients, as standard features in the area, are extracted. For classification, a set of different classical machine learning approaches is used alongside two different architectures of neural networks—1D VGG-style CNN and LSTM RNN. In total, seven different machine learning models are investigated. The best-performing model proved to be an LSTM trained on trimmed and normalised input data, with an accuracy of 87% and a recall of 100% for the faulty class. The developed model has the potential to maximise the uptime of CT machines and help mitigate the adverse effects of machine breakdowns. Full article
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10 pages, 2971 KiB  
Article
Photoelectrochemical Biosensor Based on 1D In2O3 Tube Decorated with 2D ZnIn2S4 Nanosheets for Sensitive PSA Detection
by Huihui Shi, Jianjian Xu and Yanhu Wang
Nanomaterials 2025, 15(11), 855; https://doi.org/10.3390/nano15110855 - 3 Jun 2025
Viewed by 444
Abstract
In photoelectrochemical (PEC) biosensing, efficient electron-hole separation is crucial to obtain preferred photocurrent response and analytical performance; thus, constructing developed heterointerfaces with high carrier transfer efficiency is an effective method for sensitive evaluation of analytes. Herein, a 1D ZnIn2S4 nanosheet-decorated [...] Read more.
In photoelectrochemical (PEC) biosensing, efficient electron-hole separation is crucial to obtain preferred photocurrent response and analytical performance; thus, constructing developed heterointerfaces with high carrier transfer efficiency is an effective method for sensitive evaluation of analytes. Herein, a 1D ZnIn2S4 nanosheet-decorated 2D In2O3 tube was developed to integrate with a prostate antigen (PSA)-sensitive aptamer for sensitive PSA antigen detection. 1D In2O3 tubes were first prepared by two-step hydrothermal and annealing methods, followed by the in-situ growth of ZnIn2S4 nanosheets. Morphology, optical properties, structure, and PEC performance of prepared In2O3-ZnIn2S4 were characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectrophotometry, X-ray diffraction, X-ray photoelectron spectroscopy, and an electrochemical workstation. Benefiting from the photoelectric effect and specific 1D/2D hierarchical structure, In2O3-ZnIn2S4 displayed enhanced optical absorption and photocarrier separation, thus a superior photoelectrochemical response. Proposed bioassay protocol possessed a linear range from 0.001 to 50 ng/mL and a detection limit at 0.00037 ng/mL. In addition, this biosensor exhibited satisfactory anti-interface ability and stability, which also could be extended to other quantitative platforms for detecting other proteins. Full article
(This article belongs to the Special Issue Trends in Electrochemical Nanosensing)
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13 pages, 3526 KiB  
Article
Development of a Sustainable Bone Regeneration Material Using Apatite Paste Derived from Eggshell Waste
by Masatsugu Hirota, Chihiro Mochizuki, Toshitsugu Sakurai, Hiroyuki Mishima, Chikahiro Ohkubo and Takatsugu Yamamoto
J. Funct. Biomater. 2025, 16(6), 201; https://doi.org/10.3390/jfb16060201 - 1 Jun 2025
Viewed by 744
Abstract
Apatite pastes derived from eggshell waste (BAp) were implanted onto the calvarial bone of rats, and bone formation was evaluated using X-ray μ-computed tomography (CT) and histological evaluation. BAp was mixed with distilled water to prepare a paste. Monoclinic hydroxyapatite of mineral resources [...] Read more.
Apatite pastes derived from eggshell waste (BAp) were implanted onto the calvarial bone of rats, and bone formation was evaluated using X-ray μ-computed tomography (CT) and histological evaluation. BAp was mixed with distilled water to prepare a paste. Monoclinic hydroxyapatite of mineral resources (HAp) was used as a control. A 5 mm diameter PTFE (polytetrafluoroethylene) tube was filled with apatite pastes and implanted in the calvarial bone of 9-week-old Sprague Dawley rats for 8 weeks. A larger radiopaque area, similar to that of native bone, was observed in the BAp paste-implanted specimens than that of HAp paste. The bone mineral density (BMD) value of the BAp paste was significantly higher than that of the HAp paste (p < 0.05). In the histological evaluation, new bone formation was noticed from the calvarial side for both apatite specimens, and HAp remained in the PTFE unlike BAp. The bone mass (BM) value of the BAp paste was significantly higher than that of the HAp paste (p < 0.05). SEM and XRD analyses revealed that BAp was microcrystalline and poorly crystalline. The promotion of new bone formation may contribute to the crystallinity and Mg content of BAp. BAp was found to be useful as a bone regeneration material. Full article
(This article belongs to the Section Bone Biomaterials)
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20 pages, 3777 KiB  
Article
Impact of Patient Size and Positioning on Radiation Dose in Multiphase Liver CT Examinations
by Sandra Modlińska, Michał Azierski, Natalia Denisiewicz, Adam Mitręga, Michał Bielówka, Michał Janik, Marcin Rojek and Jakub Kufel
Appl. Sci. 2025, 15(11), 5815; https://doi.org/10.3390/app15115815 - 22 May 2025
Viewed by 506
Abstract
Investigating the correlation between patient dimensions (Body Mass Index (BMI), weight, height) and radiation dose, the study also assesses the impact of the isocenter on dosage and X-ray tube. This retrospective study analyzed 258 consecutive three-phase liver CT exams (135 women, 123 men) [...] Read more.
Investigating the correlation between patient dimensions (Body Mass Index (BMI), weight, height) and radiation dose, the study also assesses the impact of the isocenter on dosage and X-ray tube. This retrospective study analyzed 258 consecutive three-phase liver CT exams (135 women, 123 men) performed on a Siemens SOMATOM Definition Edge scanner between January 3 and December 15, 2023. BMI, weight, height, maximum abdominal width (from topograms), and vertical isocenter status were extracted using the Dose&Care system and Horos software. BMI strongly correlated with total DLP in abdomen-plus-pelvis scans (r = 0.70) and moderately in abdomen-only scans (r = 0.54). Liver-phase DLP correlations were weaker (r = 0.44 and r = 0.28, respectively). Abdominal width showed similar associations with total DLP (r = 0.67 and r = 0.64) and liver-phase DLP (r = 0.41 and 0.37). Vertical mis-centering did not significantly affect total DLP (p = 0.174 and p = 0.705) or tube load. Patient size—not minor deviations from the isocenter—is the principal driver of radiation dose in multiphase liver CT. Automated, size-adapted protocols and restriction of scan range to clinically essential regions can preserve image quality while minimizing unnecessary radiation in routine practice. Full article
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13 pages, 786 KiB  
Article
Standardization of Lung CT Number Using COPD Gene2 Phantom Under Various Scanning Protocols
by Hoondong Song, Hanjoo Jang and Jongduk Baek
Sensors 2025, 25(9), 2906; https://doi.org/10.3390/s25092906 - 4 May 2025
Viewed by 494
Abstract
Lung computed tomography (CT) images are widely used to diagnose chronic obstructive pulmonary disease (COPD) by evaluating signs of lung tissue destruction. Accurate diagnosis requires standardizing the CT numbers in lung CT images to distinguish between normal and damaged tissue. The CT number [...] Read more.
Lung computed tomography (CT) images are widely used to diagnose chronic obstructive pulmonary disease (COPD) by evaluating signs of lung tissue destruction. Accurate diagnosis requires standardizing the CT numbers in lung CT images to distinguish between normal and damaged tissue. The CT number standardization method proposed by Chen-Mayer et al., which uses the linearity of Martinez’s formula, showed promising results in phantom studies. However, our findings reveal that the CT number of water varies significantly, depending on scanning conditions and the characteristics of its container, making it an unreliable reference for lung CT number standardization. To enhance the standardization method, we modified the approach to exclude water and used only solid foams from the COPD gene2 phantom as references. To evaluate the proposed method, we collected 234 CT images of the COPD gene2 phantom from 8 different CT scanners and assessed performance by analyzing CT number standard deviations and variations. The modification resulted in improved reliability and consistency in CT number standardization. Additionally, for a detailed analysis, we segmented the dataset based on CT dose index (CTDI), X-ray tube potential, and reconstruction algorithms to examine the impact of different scanning protocols on standardization performance. Full article
(This article belongs to the Section Biomedical Sensors)
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20 pages, 9533 KiB  
Article
The Corrosion Failure Mechanism of a Peak Load Boiler in a District Heating System
by Min Ji Song, Woo Cheol Kim and Soo Yeol Lee
Appl. Sci. 2025, 15(8), 4528; https://doi.org/10.3390/app15084528 - 19 Apr 2025
Cited by 2 | Viewed by 497
Abstract
The peak load boiler (PLB) is a heat production facility that uses SA178 Gr. A and SA516 Gr. 70 low-carbon steels as tube and plate materials, respectively. Recently, failures were frequently observed near plugged tubes due to water leakage, raising concerns about corrosion [...] Read more.
The peak load boiler (PLB) is a heat production facility that uses SA178 Gr. A and SA516 Gr. 70 low-carbon steels as tube and plate materials, respectively. Recently, failures were frequently observed near plugged tubes due to water leakage, raising concerns about corrosion mechanisms and their impact on tube durability. This work investigates the corrosion failure mechanisms using a combination of endoscopy, ultrasound inspection, oxide scale analysis (X-ray diffraction), chemical analysis (ion chromatography and inductively coupled plasma mass spectrometry), and computational fluid dynamics simulations. The undamaged tube near the leaked tube exhibited oxide scale levels comparable to those directly affected. Surface examinations revealed gas-side pits indicative of localized corrosion, while oxide scales were predominantly composed of iron oxides formed under humid conditions and sodium compounds derived from boiler water. Analysis of the leaked water revealed its mixture with combustion gases, forming an acidic, chloride-rich environment that significantly accelerates corrosion. Computational fluid dynamics simulations demonstrated that leaked water vapor facilitated the condensation of acidic ions near affected tubes, promoting dew point corrosion. These phenomena, driven by localized condensation and chemical concentration at the dew point temperature, exacerbate material degradation, emphasizing the importance of targeted prevention strategies. Full article
(This article belongs to the Special Issue Recent Advances in Sustainable Construction Materials and Structures)
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23 pages, 2728 KiB  
Article
A Phantom-Based Study of the X-Ray Fluorescence Detectability of Iron, Copper, Zinc, and Selenium in the Human Blood of Superficial and Cutaneous Vasculature
by Mihai Raul Gherase and Vega Mahajan
Metrology 2025, 5(2), 23; https://doi.org/10.3390/metrology5020023 - 15 Apr 2025
Viewed by 1374
Abstract
Blood concentrations of essential trace elements can be used to diagnose conditions and diseases associated with excess or deficiency of these elements. Inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and graphite furnace atomic absorption spectrometry (GF-AAS) have [...] Read more.
Blood concentrations of essential trace elements can be used to diagnose conditions and diseases associated with excess or deficiency of these elements. Inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and graphite furnace atomic absorption spectrometry (GF-AAS) have been employed for such measurements, but maintenance and operation costs are high. X-ray fluorescence (XRF) detectability in cutaneous blood of iron (Fe), copper (Cu), zinc (Zn), and selenium (Se) was assessed as an alternative to ICP-MS. Three phantoms were made up of two polyoxymethylene (POM) plastic cylindrical cups of 0.6 mm and 1.0 mm thick walls and a 5.3 mm diameter POM cylindrical insert. Six aqueous solutions of Fe in 0 to 500 mg/L and Cu, Zn, and Se in 0 to 50 mg/L concentrations were poured into the phantoms to simulate X-ray attenuation of skin. Measurements using an integrated X-ray tube and polycapillary X-ray lens unit generated 24 calibration lines. Detection limit intervals in mg/L were (36–100), (14–40), (3.7–10), and (2.1–3.4) for Fe, Cu, Zn, and Se, respectively. Fe was the only element with detection limits lower than its 480 mg/L median human blood concentration. The estimated radiation dose and equivalent dose to skin were below those of common radiological procedures. Applications will require further instrumental development and finding a calibration method. Full article
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16 pages, 4949 KiB  
Article
High-Temperature Oxidation Behavior of TiN-, Cr-, and TiN–Cr PVD-Coated Zircaloy 4 Alloy at 1200 °C
by Yan-Yu Tang, Yin-Lin Chang, Wen Luo and De-Wen Tang
Materials 2025, 18(8), 1692; https://doi.org/10.3390/ma18081692 - 8 Apr 2025
Viewed by 551
Abstract
Zirconium alloys are essential materials for nuclear fuel cladding. During a loss-of-coolant accident (LOCA), zirconium alloy cladding can oxidize in high-temperature steam (>1000 °C), generating hydrogen and releasing significant heat. Without timely emergency actions, this can result in hydrogen explosions or nuclear leakage. [...] Read more.
Zirconium alloys are essential materials for nuclear fuel cladding. During a loss-of-coolant accident (LOCA), zirconium alloy cladding can oxidize in high-temperature steam (>1000 °C), generating hydrogen and releasing significant heat. Without timely emergency actions, this can result in hydrogen explosions or nuclear leakage. In this study, titanium nitride (TiN), chromium (Cr), and TiN–Cr composite coatings were deposited on the surface of Zr-4 alloy using the magnetron sputtering method. The coatings’ surface and cross-sectional morphologies were examined using scanning electron microscopy (SEM), and their phase structures were analyzed with X-ray diffraction (XRD). The mechanical properties were evaluated using scratch tests, and their resistance to high-temperature steam oxidation was tested in a tube furnace connected to a steam generator. The results showed that the TiN, Cr, and TiN–Cr coatings exhibited strong adhesion to the Zr-4 substrates, with distinct interfaces and pure phase structures. After high-temperature steam oxidation, cracks appeared on the surfaces of the TiN, Cr, and TiN–Cr coatings, likely due to differences in the thermal expansion coefficients of TiO2, Cr2O3, and residual Cr layers. These cracks created pathways for the oxidizing medium, potentially leading to the oxidation of the substrate or inner layers of the composite coatings. For the Cr and TiN–Cr coatings, despite cracking of the Cr layer and melting of the TiN layer at high temperatures, the residual Cr layer effectively restricted oxygen diffusion into the Zr-4 substrate. This study suggests that layers with low melting points, such as TiN, are unsuitable for composite coatings in high-temperature applications. However, adding a Cr layer on top of the TiN layer to form a TiN–Cr composite coating improves adhesion between the coating and the substrate. The TiN–Cr composite coating functions as an effective diffusion barrier at temperatures up to 1200 °C, comparable to a pure Cr coating. Full article
(This article belongs to the Section Thin Films and Interfaces)
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17 pages, 10962 KiB  
Article
Impact of Rectangular Collimation on Quality of Intraoral Radiographs: Findings from a Clinical Audit at a Dental Practice
by Lydia Vazquez, Anna Muresan and Cristina Zarauz
Diagnostics 2025, 15(7), 911; https://doi.org/10.3390/diagnostics15070911 - 2 Apr 2025
Viewed by 831
Abstract
Background/Objectives: Rectangular collimation (RC) reduces patient radiation exposure but is uncommonly used due to cone-cut concerns. An audit at a dental practice was conducted to analyze impact of RC on the quality of intraoral radiographs. Methods: Four X-ray tubes with RC [...] Read more.
Background/Objectives: Rectangular collimation (RC) reduces patient radiation exposure but is uncommonly used due to cone-cut concerns. An audit at a dental practice was conducted to analyze impact of RC on the quality of intraoral radiographs. Methods: Four X-ray tubes with RC were used. 360 intraoral X-rays were collected, blinded and scored to pre-set qualitative criteria: maximum 14 points for bitewing radiographs (BWs), and 13 for periapical radiographs (PAs). Quality of the X-rays was assessed. Results: We found that 48.1% were acceptable, 32.5% were unacceptable and only 19.4% were good X-rays. The loss of image quality was unrelated to RC. Three cone-cuts occurred in PAs without RC. The mean scores for PAs performed without or with RC were as follows: 9.3 ± 1.9 points and 9.6 ± 1.9 points, respectively (p = 0.166). The mean scores for BWs performed without or with RC were as follows: 8.0 ± 1.9 points and 7.1 ± 1.9 points, respectively (p < 0.001). All scores declined over time. Conclusions: This audit highlighted the need for refresher training on film-holder use and the importance of regular maintenance of dental X-ray equipment. Decline in X-ray quality over time was related to wear and tear of X-ray equipment, incorrect image contrast, and technical errors unrelated to RC. No cone-cuts occurred when using RC. Full article
(This article belongs to the Section Medical Imaging and Theranostics)
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8 pages, 1115 KiB  
Article
Evaluation of the Ideal Horizontal X-Ray Beam Angulation to Accurately Identify Two Separate Canals in Maxillary First Premolars—A Retrospective Clinical Study Using Cone-Beam Computed Tomography in an Austrian Subpopulation
by Benedikt Schneider, Luisa Klinkhamels, Wilhelm Frank, Constantin von See and Jörg Philipp Tchorz
Dent. J. 2025, 13(4), 151; https://doi.org/10.3390/dj13040151 - 30 Mar 2025
Cited by 1 | Viewed by 639
Abstract
Background/Objectives: Intraoral (IO) radiographs are critical for endodontic diagnostics, yet conventional orthoradial imaging often results in superimposition, limiting the visibility of individual root canals. Maxillary first premolars pose challenges due to their anatomical characteristics and positioning within the dental arch. This study aimed [...] Read more.
Background/Objectives: Intraoral (IO) radiographs are critical for endodontic diagnostics, yet conventional orthoradial imaging often results in superimposition, limiting the visibility of individual root canals. Maxillary first premolars pose challenges due to their anatomical characteristics and positioning within the dental arch. This study aimed to retrospectively analyze cone-beam computed tomography (CBCT) data to determine the horizontal X-ray beam angulations for maxillary first premolars at which root canals overlap and neighboring tooth superimposition occur, providing clinically relevant guidance for optimizing IO radiographic techniques. Methods: CBCT scans from 85 patients were analyzed using ImageJ software to measure the angles at which maxillary first premolar root canals overlap or become obscured by adjacent teeth. The mean angles for canal overlap and neighboring tooth superimposition were determined. Statistical analysis was performed using SPSS Version 29.0, and the level of significance was set to 5%. Results: The mean angle for root canal overlap was 93.56° (±10.08). The angles at which neighboring teeth began to superimpose were 124.38° (±9.91) for the distal contour of the canine and 63.46° (±9.38) for the mesial root contour of the second premolar. No significant differences were observed between apical and coronal measurements for root canal overlap but tapering of the roots led to significant differences in neighboring tooth superimposition (p < 0.05). Conclusions: A mesial beam shift within a calculated safe corridor (98.5–129.5°) optimizes canal separation without superimposition from adjacent teeth. For ideal visualization, a mesial angulation close to 40° is recommended. These findings support improved IO radiographic techniques while minimizing the risk of retakes in adherence to the ALARA principle. Full article
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