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Combined Infrared Thermography, X-ray Radiography, and Computed Tomography for Ink Drying Studies
摘要： This work describes the comparison of drying behavior of ink deposited on two substrates used commonly in polymer electrolyte fuel cells (PEFCs): microporous layer (MPL) and Nafion. For the same drying conditions and ink composition, ink deposited onto the MPL dried faster and also formed cracks faster. During drying, ink deposited on the MPL had more cracks and smaller intercrack spacing compared to ink deposited on Nafion. Smaller intercrack spacing for ink on the MPL substrate is explained by the higher critical stress predicted by the model. A novel combination of infrared (IR) thermography, X-ray radiography, and computed tomography (CT) is used to characterize ink drying behavior. X-ray radiography with fast temporal resolution showed the existence of skin on the top of drying film that formed due to slow convective ink transport within the film and fast evaporative drying. From X-ray CT, detailed three-dimensional data was obtained on crack morphology within the drying film and was correlated to temperature profiles obtained with IR-thermography. The formation of a Y-crack in the film deposited on the MPL was correlated to the defect within the MPL substrate. The combination of three techniques is a unique probe to capture the temporal, thermal, and morphological evolution of drying ink.
关键词： IR thermography,fuel cells,evaporation,X-ray computed tomography,X-ray radiography,ink drying
更新于2025-09-10 09:29:36
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Evaluation of linear measurements of implant sites based on head orientation during acquisition: An ex vivo study using cone-beam computed tomography
摘要： Purpose: This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods: Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. results: Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. conclusion: Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension. (Imaging Sci Dent 2015; 45: 73-80)
关键词： Dental Implants,Dimensional Measurement Accuracy,Patient Positioning,Cone-Beam Computed Tomography
更新于2025-09-10 09:29:36
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Computed Tomography Imaging of the Coronary Arteries: State of the Art Applications and Recent Patents
摘要： Computed tomography (CT) is important for the management of many medical illnesses, including coronary artery disease (CAD). However this technique is not free from disadvantages like the exposure to ionizing radiations and to iodinated contrast agents. To overcome these problems, imaging technologies are changing rapidly. New-generation computed tomography scanners (NGCCT) may bring substantial advantages over traditional CT and other currently used imaging methods. These novel tools employ dedicated protocols to shorten imaging times and reduce radiation doses without affecting accuracy. Current CT scanners can very accurately identify severe CAD requiring intervention in most patients, but NGCCT may further benefit imaging for some “difficult” patients like obese patients, patients with high or irregular heart rates, and patients who have high coronary calcium burden or previous stents or bypass grafts. In fact in these patients traditional CT studies often produce suboptimal quality images. Our review presents the current status in the technical background of coronary nuclear tomographic imaging in the areas of clinical practice, and focuses on future developments of related patent forms.
关键词： Computed tomography,coronary artery disease,contrast nephrotoxicity,radiation dose,computed tomography coronary angiography,iodinated contrast medium
更新于2025-09-09 09:28:46
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Past and Present of Imaging Modalities Used for Prostate Cancer Diagnosis: Androgen Receptor Targeted Imaging of Prostate Cancer as a Future Modality for Early, Rapid and Efficient Diagnosis
摘要： Background: Prostate cancer is the second most prevailing cancer among men worldwide. In the most cases, prostate cancer is slowly progressing, whereas, in some cases, it is a rapidly progressing disease leading to the significantly high mortality rate. Thus, there is still demand for prostate-specific imaging in order to provide image-guided early diagnosis and for the provision of patient-specific therapy. Discussion: Besides discussing traditional diagnostic approaches, this review illustrates a perspective on prostate cancer imaging summarizing current imaging approaches with a special focus on Prostate Specific Membrane Antigen (PSMA), Bombesin (BN) and Androgen Receptor (AR) targeted imaging using Positron Emission Tomography (PET) and Single Positron Emission Computed Tomography (SPECT) based on 99mTc and other radiotracers. Here, the prostate biology is reconsidered for nuclear imaging as future modality for early, rapid and efficient diagnosis of prostate cancer. Conclusion: Future direction in prostate cancer imaging involves the development of androgen receptor based imaging using nonsteroidal antiandrogen agent for early diagnosis of prostate cancer.
关键词： single photon emission computed tomography,Prostate cancer,patient-specific therapy,radiotracer,positron-emission tomography,prostate-specific membrane antigen
更新于2025-09-09 09:28:46
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Curved periacetabular osteotomy using intraoperative real-time 3-dimensional computed tomography with a robotic C-arm system
摘要： Rationale: Curved periacetabular osteotomy (CPO) is a procedure with excellent surgical outcome that has been proposed for patients with development dysplasia of the hip (DDH). However, the surgical outcomes depend on the surgeon’s experience and pro?ciency. Patient concerns: A 38-year-old female indicated she was experiencing left hip pain while walking. Diagnoses: The patient was diagnosed with early-stage hip osteoarthritis due to DDH. Interventions: The patient underwent CPO while a 3-dimensional ?at-panel C-arm (Artis zeego; Sciemens Healthcare, Forchheim, Germany) was used to con?rm the real-time 3-dimensional computed tomography (CT) images during surgery. It was possible to con?rm the accurate osteotomy curve using CT images twice during surgery: at the time of the ischial osteotomy and the quadrilateral surface osteotomy. Outcomes: An ideal C-shaped osteotomy line was created as shown on the postoperative CT images. In addition, neither posterior column fracture nor intra-articular osteotomy was con?rmed. Lessons: The CPO using Artis zeego resulted is a satisfactory outcome, and this is the 1st report in the world to discuss the bene?ts of Artis zeego in pelvic osteotomy.
关键词： Artis zeego,curved periacetabular osteotomy,real-time 3-dimensional computed tomography
更新于2025-09-09 09:28:46
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Low-dose CT imaging of the acute abdomen using model-based iterative reconstruction: a prospective study
摘要： Objectives Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms. Materials and methods Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10–20% and 80–90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews. Results A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (p < 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m2 than those with BMI ≥ 25 kg/m2 (5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU, p < 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (p < 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (p < 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis. Conclusions Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.
关键词： Iterative reconstruction,Computed tomography,Acute abdominal imaging,Dose optimization,Radiation dose reduction
更新于2025-09-09 09:28:46
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Observing the devastating coffee berry borer (Hypothenemus hampei) inside the coffee berry using micro-computed tomography
摘要： The coffee berry borer is the most devastating insect pest of coffee throughout the world. The insect spends most of its life cycle inside the coffee berry, which makes it quite difficult to observe its behaviour. Micro-computed tomography (micro-CT) was used to observe all developmental stages of the coffee berry borer inside coffee berries (Coffea canephora). An interesting oviposition pattern involving a sequential placement of eggs starting in the periphery of the seed and moving inwards was observed. Micro-CT should be useful in elucidating unknown life history aspects of other seed-feeding bark beetles as well as of bark and ambrosia beetles in general.
关键词： micro-computed tomography,coffee berry borer,Coffea canephora,Hypothenemus hampei,oviposition pattern
更新于2025-09-09 09:28:46
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Study of Size Effect on Microstructure and Mechanical Properties of AlSi10Mg Samples Made by Selective Laser Melting
摘要： The macroscopic mechanical performance of additive manufactured structures is essential for the design and application of multiscale microlattice structure. Performance is affected by microstructure and geometrical imperfection, which are strongly influenced by the size of the struts in selective laser melting (SLM) lattice structures. In this paper, the effect of size on microstructure, geometrical imperfection, and mechanical properties was systemically studied by conducting experimental tests. A series of AlSi10Mg rod-shaped samples with various diameters were fabricated using SLM. The uniaxial tensile test results show that with the decrease in build diameter, strength and Young’s modulus of strut decreased by 30% more than the stable state. The main reasons for this degradation were investigated through microscopic observation and micro X-ray computed tomography (μ-CT). In contrast with large-sized strut, the inherent porosity (1.87%) and section geometrical deviation (3%) of ponysize strut is greater because of the effect of thermal transform and hydrogen evolution, and the grain size is 0.5 μm. The discrepancy in microstructure, geometrical imperfection, and mechanical properties induced by size effect should be considered for the design and evaluation of SLM-fabricated complex structures.
关键词： selective laser melting,size effect,microstructure,X-ray computed tomography,mechanical properties
更新于2025-09-09 09:28:46
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Reconstructing granular particles from X-ray computed tomography using the TWS machine learning tool and the level set method
摘要： X-ray computed tomography (CT) has emerged as the most prevalent technique to obtain three-dimensional morphological information of granular geomaterials. A key challenge in using the X-ray CT technique is to faithfully reconstruct particle morphology based on the discretized pixel information of CT images. In this work, a novel framework based on the machine learning technique and the level set method is proposed to segment CT images and reconstruct particles of granular geomaterials. Within this framework, a feature-based machine learning technique termed Trainable Weka Segmentation is utilized for CT image segmentation, i.e., to classify material phases and to segregate particles in contact. This is a fundamentally different approach in that it predicts segmentation results based on a trained classifier model that implicitly includes image features and regression functions. Subsequently, an edge-based level set method is applied to approach an accurate characterization of the particle shape. The proposed framework is applied to reconstruct three-dimensional realistic particle shapes of the Mojave Mars Simulant. Quantitative accuracy analysis shows that the proposed framework exhibits superior performance over the conventional watershed-based method in terms of both the pixel-based classification accuracy and the particle-based segmentation accuracy. Using the reconstructed realistic particles, the particle-size distribution is obtained and validated against experiment sieve analysis. Quantitative morphology analysis is also performed, showing promising potentials of the proposed framework in characterizing granular geomaterials.
关键词： Machine learning,Shape reconstruction,3D particle morphology,X-ray computed tomography,Level set
更新于2025-09-09 09:28:46
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Robust beam hardening artifacts reduction for computed tomography (CT) using spectrum modeling
摘要： The aim of this study was to develop a fast and accurate beam hardening correction method by modeling physical interactions between X-ray photons and materials for computed tomography (CT) imaging. The nonlinear attenuation process of the X-ray projection was modeled by reprojecting a template image with the estimated polychromatic spectrum. By adding the scaled difference of the monochromatic reprojection data and the polychromatic reprojection to the raw projection data, the raw projection data was mapped into the corresponding monochromatic projection data, which was used to reconstruct the beam hardening artifacts corrected images. The algorithm can also be implemented in image-domain which takes the uncorrected image volume as input when there is an adequate model of the spectrum. In this case, the scaled difference was reconstructed to yield a set of artifacts images which can be added directly to the uncorrected images. Numerical simulations, experimental phantom data, and animal data which were acquired on a modern diagnostic CT scanner (Discovery CT750 HD, GE Healthcare, WI, USA), and a modern C-Arm CT scanner (Artis Zee, Siemens Healthcare, Forchheim, Germany), respectively, were used to evaluate the proposed method. The results show the proposed method significantly reduced both cupping and streak artifacts, and successfully recovered the Housfield Units (HU) accuracy. Extensive studies suggest the proposed model-based method successfully corrects the beam hardening artifacts. This work is practically useful and is promising to be applied to commercial products.
关键词： Computed tomography,quantitative imaging,spectrum modeling,polychromatic forward projection,beam hardening correction
更新于2025-09-09 09:28:46