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One-pot bottom-up fabrication of biocompatible PEGylated WS2 nanoparticles for CT-guided photothermal therapy of tumors in?vivo
摘要： Background: Tungsten disulfide (WS2), which enjoyed a good potential to be a promising clinical theranostic agent for cancer treatment, is still subject to the tedious synthesis procedure. Methods: Here, we reported a one-pot 'bottom-up' hydrothermal strategy for the fabrication of PEGylated WS2 nanoparticles (NPs). The WS2-PEG nanoparticles were characterized systematically. The CT imaging and photothermal therapy against tumor as well as biosafety in vitro and in vivo were also investigated. Results: The obtained WS2-PEG NPs enjoyed obvious merits of good solubility and favorable photothermal performance. WS2-PEG NPs exhibited desirable photothermal ablation ability against cancer cells and cancer cell-bearing mice in vitro and in vivo. MTT assay and histological analysis demonstrated the low cytotoxicity and biotoxicity of WS2-PEG NPs, providing a valid biosafety guarantee for the coming biomedical applications. In addition, thanks to the obvious X-ray attenuation of W atom, the WS2-PEG NPs can also be served as a favorable contrast agent for CT imaging of tumors. Conclusion: WS2-PEG NPs has enjoyed a good potential to be a promising clinical CT-guided photothermal therapeutic agent against cancers.
关键词： Photothermal therapy,Computed tomography,WS2,Tumor,Nanoparticles
更新于2025-11-14 17:03:37
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Image quality optimization using a narrow vertical detector dental cone-beam CT
摘要： Objectives: To determine the optimised kV setting for a narrow detector cone-beam CT (CBCT) unit. Methods: Clinical (CL) and quantitative (QUANT) evaluations of image quality were performed using an anthropomorphic phantom. Technical (TECH) evaluation was performed with a polymethyl methacrylate phantom. Images were obtained using a PaX-i3D Green CBCT (Vatech, Hwaseong, Korea) device, with a large 21x19 and a medium 12x9 cm field of view, and high-dose (HD– ranging from 85 to 110 kV) and low-dose (LD– ranging from 75 to 95 kV) protocols, totalling four groups (21x19 cm HD, 21x19 cm LD, 12x9 cm HD, 12x9 cm LD). The radiation dose within each group was fixed by adapting the mA according to a predetermined dose-area product. For CL evaluation, three observers assessed images based on overall quality, sharpness, contrast, artefacts, and noise. For QUANT evaluation, mean grey value shift, % increase of standard deviation (SD), % of beam-hardening and contrast-to-noise ratio (CNR) were calculated. For TECH evaluation, segmentation accuracy, CNR, metal artefact SD, metal object area, and sharpness were measured. Representative parameters were chosen for CL, QUANT and TECH evaluations to determine the optimal kV based on biplot graphs. kV values of the same protocol were compared by bootstrapping approach. The ones that had statistical differences with the best kV were considered as worse quality. Results: Overall, kV values within the same group showed similar quality (p>0.05), except for 110 kV in 21x19 cm HD and 85 kV in 12x9 cm HD of CL score; also 85, 90 kV in 21x19 cm HD and 75, 80 kV in 21x19 cm LD of QUANT score which were worse (p<0.05). Conclusion: At a constant dose, low and high kV protocols yield acceptable image quality for a narrow-detector CBCT unit.
关键词： Image Quality,Computed-assisted image analysis,Phantoms,Imaging,Optimization,Cone-beam computed tomography
更新于2025-09-23 15:23:52
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Positron emission tomography/computed tomography outperforms MRI in the diagnosis of local recurrence and residue of nasopharyngeal carcinoma: An update evidence from 44 studies
摘要： Studies on nasopharyngeal carcinoma (NPC) in five electronic databases were systematically searched online from the inception to June 5, 2018. Quality of the included studies was assessed using the updated Quality Assessment of Diagnostic Accuracy Studies 2. Data of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the 95% confidence intervals were pooled using a bivariate random‐effect model. Forty‐four studies with 61 groups of data and totally 3369 patients were included in the qualitative and quantitative synthesis analysis. The overall estimated sensitivity and specificity of positron emission tomography/computed tomography/magnetic resonance imaging (PET‐CT/MRI) for local recurrent/residual NPC were 0.90 and 0.85, respectively. The pooled area under the curve of (AUC) of PET‐CT/MRI in the summary receiver operator characteristic curve was 0.94. Subgroup analysis showed MRI vs PET‐CT had lower sensitivity (0.83 vs 0.92) and specificity (0.78 vs 0.89). The AUCs of MRI and PET‐CT were 0.87 and 0.96, respectively. No‐cross of 95% CI was found in MRI vs PET/CT (0.87‐0.90 vs 0.94‐0.98). Meta‐regression showed PET/CT vs MRI was a potential source of heterogeneity. PET/CT and MRI both showed quite high overall ability in diagnosing local recurrent/residual NPC, but the subgroup analysis indicated PET‐CT was superior over MRI in diagnosis of local recurrence and residue of NPC after radiotherapy. The examination methods affected the heterogeneity within studies.
关键词： specificity,positron emission tomography/computed tomography,sensitivity,magnetic resonance imaging,recurrence/residue,nasopharyngeal carcinoma
更新于2025-09-23 15:23:52
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A novel alignment procedure to assess calcified coronary plaques in histopathology, post-mortem computed tomography angiography and optical coherence tomography
摘要： Purpose: Improve mapping and registration of longitudinal view on histopathology vessels in a three-dimensional alignment procedure for postmortem quantitative coronary plaque analyses. This new procedure is applied and results shown using calcified coronary plaque analyses within post-mortem computed tomography angiography (PMCTA), optical coherence tomography (OCT) and the gold standard of histopathology. Results: In total, 338 annotated histopathology images were included, 166 PMCTA transversal images and 285 OCT images were aligned in the comparison. The results from the comparison using the alignment procedure showed overall that the calcified plaques seem to be overestimated by PMCTA and underestimated by OCT. Conclusions: The 3D fusion approach, aligning the images of PMCTA, OCT and histopathology as gold standard allowed for a slice-based comparison of the different modalities. The results showed that PMCTA overestimates the calcified plaques while OCT underestimates these, compared to histopathology.
关键词： Alignment,Calcified coronary plaques,Histopathology,Optical coherence tomography,Postmortem-computed tomography angiography
更新于2025-09-23 15:23:52
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Initial evaluation of <scp>PET</scp> / <scp>CT</scp> with <sup>18</sup> F‐ <scp>FSU</scp> ‐880 targeting prostate‐specific membrane antigen in prostate cancer patients
摘要： This first-in-man study was carried out to evaluate the safety, whole-body distribution, dose estimation, and lesion accumulation of 18F-FSU-880, a newly developed probe targeting prostate-specific membrane antigen. Six prostate cancer patients with known metastatic lesions underwent serial whole-body PET/computed tomography (CT) with 18F-FSU-880. Blood and urine were analyzed before and after PET/CT. Accumulation of 18F-FSU-880 in organs and metastatic lesions in serial PET images were evaluated by measuring the standardized uptake values. From the biodistribution data, the organ doses and whole-body effective dose were calculated using OLINDA/EXM software. 18F-FSU-880 PET/CT could be carried out without significant adverse effects. High physiological uptake was observed in the salivary/lachrymal glands and kidneys. The effective dose was calculated to be 0.921 × 10?2 mSv/MBq. Known metastatic lesions were clearly visualized with high image contrast that increased with time, except in 1 patient, whose bone metastases were well-controlled and inactive. The PET/CT with 18F-FSU-880 could be carried out safely and could clearly visualize active metastatic lesions. The present results warrant further clinical studies with a larger number of cases to verify the clinical utility of 18F-FSU-880 PET/CT in the management of prostate cancer patients.
关键词： dosimetry,prostate cancer,prostate-specific membrane antigen,positron emission tomography/computed tomography,fluorine-18
更新于2025-09-23 15:23:52
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[SPIE Image Processing - Houston, United States (2018.2.10-2018.2.15)] Medical Imaging 2018: Image Processing - Deep learning for biomarker regression: application to osteoporosis and emphysema on chest CT scans
摘要： Introduction: Biomarker computation using deep-learning often relies on a two-step process, where the deep learning algorithm segments the region of interest and then the biomarker is measured. We propose an alternative paradigm, where the biomarker is estimated directly using a regression network. We showcase this image-to-biomarker paradigm using two biomarkers: the estimation of bone mineral density (BMD) and the estimation of lung percentage of emphysema from CT scans. Materials and methods: We use a large database of 9,925 CT scans to train, validate and test the network for which reference standard BMD and percentage emphysema have been already computed. First, the 3D dataset is reduced to a set of canonical 2D slices where the organ of interest is visible (either spine for BMD or lungs for emphysema). This data reduction is performed using an automatic object detector. Second, The regression neural network is composed of three convolutional layers, followed by a fully connected and an output layer. The network is optimized using a momentum optimizer with an exponential decay rate, using the root mean squared error as cost function. Results: The Pearson correlation coefficients obtained against the reference standards are r = 0.940 (p < 0.00001) and r = 0.976 (p < 0.00001) for BMD and percentage emphysema respectively. Conclusions: The deep-learning regression architecture can learn biomarkers from images directly, without indicating the structures of interest. This approach simplifies the development of biomarker extraction algorithms. The proposed data reduction based on object detectors conveys enough information to compute the biomarkers of interest.
关键词： regression,deep learning,bone mineral density,computed tomography,emphysema
更新于2025-09-23 15:23:52
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Effect of Object Position in Cone Beam Computed Tomography Field of View for Detection of Root Fractures in Teeth with Intra-Canal Posts
摘要： Background: Vertical root fracture (VRF) is a common problem in endodontically treated teeth. Due to its poor prognosis, a reliable technique must be used to make an accurate diagnosis. Cone beam computed tomography (CBCT) has been recently introduced for maxillofacial imaging. Despite the high diagnostic value of this method, metal artifacts resulting from intra-canal posts still make the detection of VRFs challenging. Objectives: This study aimed to assess the effect of object position in the field of view (FOV) of CBCT on detection of VRFs in teeth with intra-canal posts. Materials and Methods: The crowns of 60 extracted premolar teeth were cut at the level of cementoenamel junction (CEJ). Root canals were filled with gutta-percha and filling of the coronal 2/3 of the root canals was subsequently removed to fabricate intra-canal cast posts. The teeth were randomly divided into two groups of 30. Fracture was induced in group one using an Instron machine. Group two was considered as the control group with no fracture. All teeth were then randomly positioned and scanned in five different positions starting at the center of the FOV as well as right, left anterior and posterior relative to the center (3, 9, 12, and 6 O’clock) via the New Tom VGI CBCT unit. Two observers evaluated images for VRFs. Sensitivity and specificity of fracture diagnosis in each position was calculated in comparison with the gold standard. Wilcoxon test was used for data analysis. Results: Considering deterministic and probabilistic diagnostic parameters, probabilistic sensitivity was similar in all positions; but probabilistic specificity of the center position (65.1%) was significantly higher than that of 6 and 12 O’clock positions. Considering the deterministic diagnostic parameters, the overall sensitivity and specificity values decreased in all positions in FOV, but sensitivity of the center position of FOV was significantly higher than that of other positions; specificity was significantly higher at the 3 O’clock position (58.5%). Conclusion: Concerning the positions in FOV, the center position is suitable for detection of VRF in teeth with intra-canal posts due to significantly higher sensitivity at this position. The 3 O’clock position would be suitable for assessment of intact teeth without fractures due to significantly higher specificity at this position.
关键词： Post and Core Technique,Position,Tooth Fracture,Cone-Beam Computed Tomography
更新于2025-09-23 15:23:52
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Development of Animation Projector System and Usefulness in Pediatric Head CT; 小児頭部 CT のためのアニメーション投影システムの考案;
摘要： The restlessness of young children often causes motion artifacts on CT images. We devised a new animation projector system (CT Theater) that enables a child to view an animation during a pediatric head CT examination. The purpose of this study is to assess the usefulness on a children of a video viewed during a head CT scan. Children of 3–10 years old who underwent head CT (SOMATOM Definition Flash, SOMATOM Force; Siemens) were analyzed for a period from 6 months before, to 6 months after, introduction of the projector system (before: n=46, after: n=29). Mobile projector (MP-CL1; Sony) connected with tablet device (iPad; Apple) was put on the CT table near the child’s head. An animation was projected onto the child’s line of sight inside the gantry. The animation is projected onto the line of sight of the child such that the projector moves with the child on the table. The number of requests for use made by children was 28/29 (96.6%). The presence of images without motion artifacts decreased significantly after introduction (before/after introduction: 84.8% vs 100%, p=0.03). The overall examination success rate tended to increase after introduction (84.8% vs 92.9%, p=0.26). The overall examination time was significantly reduced (92.4±42.4 s vs 65.1±47.3 s, p<0.001). We developed an animation projector system that shortened examination time and decreased motion artifacts in pediatric head CT.
关键词： motion artifact,pediatric,computed tomography,distraction,mobile projector
更新于2025-09-23 15:23:52
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Evaluation of patient effective dose in a PET/CT test
摘要： The positron emission tomography (PET)/computed tomography (CT) technique generates high doses in patients because two radiodiagnostic modalities are used in a single examination. In this study, the absorbed and effective doses generated by CT scans and by the incorporation of radiopharmaceutical solution were evaluated in 19 organs. It was found that 78.2% of the effective dose in PET/CT examinations comes from the CT scan. With an activity of 3.33 MBq/kg, 18F-FDG contributes 21.8% of the final effective dose.
关键词： Patient dosimetry,PET/CT,Computed tomography
更新于2025-09-23 15:23:52
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Value of a smartphone-compatible thermal imaging camera in the detection of peroneal artery perforators: Comparative study with computed tomography angiography
摘要： Background: The aim of this study was to investigate the value of a smartphone-compatible thermal imaging camera in the mapping of the peroneal artery perforators. Methods: Twelve consecutive patients scheduled for fibular flap reconstruction were enrolled. The lower limbs were first studied using smartphone-based dynamic infrared thermography (DIRT). During the rewarming, the hotspots were marked, small rubber markers were taped to the registered sites, and then the patients were sent for a CT scan. The diagnostic performance of smartphone-based DIRT was evaluated by comparing the DIRT findings with CT angiography and intraoperative findings. Results: DIRT detected 42 of the 57 dominant perforators in 24 limbs and resulted in a sensitivity of 73.7% and a positive predictive value of 65.6%. Conclusions: The sensitivity and positive predictive value of the smartphone-based DIRT are low. Currently, it should be used as an adjunctive tool together with the established imaging techniques.
关键词： thermography,fibular flap,perforator mapping,peroneal artery perforator flap,computed tomography angiography
更新于2025-09-23 15:23:52