Research on safety condition assessment methodology for single tower steel box girder suspension bridges over the sea based on improved AHP-fuzzy comprehensive evaluation.

In order to propose a reliable method for assessing the safety condition for single-tower steel box girder Suspension bridges over the sea, a condition monitoring system is established by installing sensors on the bridge structure. The system is capable of gathering monitoring data that influence the safety status of the bridge. These include cable tension, load on the main tower and pylon, bearing displacement, wind direction, wind speed, and ambient temperature and humidity. Furthermore, an improved Analytic Hierarchy Process (AHP) algorithm is developed by integrating a hybrid triangular fuzzy number logic structure. This improvement, coupled with comprehensive fuzzy evaluation methods, improves the consistency, weight determination, and security evaluation capabilities of the AHP algorithm. Finally, taking the No.2 Channel Bridge as an example and based on the data collected by the health monitoring system, the application of the safety assessment method proposed in this paper provides favorable results in evaluating the overall safety status of the bridge in practical engineering applications. This provides a basis for management decisions by bridge maintenance departments. This project confirms that the research results can provide a reliable method for assessing the security status of relevant areas.

Treatment response assessment to chemotherapy with bevacizumab for colorectal liver metastasis by contrast-enhanced ultrasound.

Background: Though contrast-enhanced ultrasound (CEUS) perfusion parameters have been approved to be potential indicators for response to chemotherapy in solid tumors, their ability in assessment of colorectal liver metastasis (CRLM) to chemotherapy with bevacizumab (Bev) has rarely been investigated. Methods: From March 2021 to May 2022, 115 consecutive CRLM patients with CEUS pre- and post-2 months' chemotherapy with Bev were prospectively enrolled. One target lesion per patient underwent CEUS quantitative analysis with SonoLiver software. Rise time, time-to-peak, mean transit time, maximal intensity (IMAX), and area under the time-intensity curve (AUC) were assessed with region of interest (ROI) selected on whole lesion, lesion periphery, and internal lesion, respectively. The reduction and ratio of post- to pre-treatment in parameters were investigated in development cohort (n=89) and validated in internal validation cohort (n=26) according to the chronological order. Results: With modified Response Evaluation Criteria in Solid Tumor as reference, 48, 14 responders and 41, 12 non-responders were included in development and validation cohort, respectively. Significantly smaller values of IMAX and AUC on ROIwhole, ROIperipheral, and ROIinternal, were observed post-treatment in development cohort (all P<0.05). In predicting treatment response, the influence of ROI selection was observed when using ∆IMAX and ∆AUC, while no influence was observed using ratios. Areas under the receiver operating characteristic curve (AUROCs) for ∆IMAX and ∆AUC on ROIperipheral were 0.939 (0.867-0.979), 0.951 (0.883-0.985), and 0.917 (0.740-0.988), 0.923 (0.748-0.990) in development and validation cohort, respectively. For ratios of IMAX and AUC, AUROCs were 0.976 (0.919-0.997), 0.938 (0.865-0.978), and 0.899 (0.717-0.982), 0.982 (0.836-1.000) in development and validation cohort, respectively. Conclusions: IMAX and AUC showed significant reductions in responders, and different analyses ROIs influence the performance of ∆IMAX and ∆AUC in response assessment. Parameters derived from ROI peripheral exhibited the most promising results in predicting treatment response.

Pericoronary adipose tissue differences among plaque types: a retrospective assessment.

PURPOSE: To assess differences in pericoronary adipose tissue (PCAT) in patients with different plaque types by using several quantitative parameters of PCAT and investigate the relationship between PCAT and different plaque types. MATERIALS AND METHODS: We retrospectively recruited 488 patients diagnosed with stable coronary artery disease (CAD) via coronary computed tomographic angiography, including 279 with calcified plaques (CP), 153 with non-calcified plaques (NCP), and 56 with mixed plaques (MP). Volume, fat attenuation index (FAI), and 10th percentile, 90th percentile, median, and minimum Hounsfield unit (HU) values of PCAT surrounding plaques were quantified. Clinical features and quantitative PCAT parameters were compared between different plaque types. RESULTS: No intergroup differences were observed for age, sex, body mass index, risk factors, and plaque location. Length and PCAT volume in the NCP group were lower than those of the CP and MP groups (P < 0.001), whereas there were no significant differences between the CP and MP groups (P > 0.05). Patients with NCP and MP had a higher FAI and 10th percentile, 90th percentile, median, and minimum HU values of PCAT than CP (P < 0.001); however these values were not significantly different between the NCP and MP groups (P > 0.05). CONCLUSION: The quantitative parameters of PCAT, as a biosensor for CAD, vary among the different plaque types.

Modeling the progression of COVID-19 deaths using Kalman Filter and AutoML.

The COVID-19 pandemic continues to have a destructive effect on the health and well-being of the global population. A vital step in the battle against it is the successful screening of infected patients, together with one of the effective screening methods being radiology examination using chest radiography. Recognition of epidemic growth patterns across temporal and social factors can improve our capability to create epidemic transmission designs, including the critical job of predicting the estimated intensity of the outbreak morbidity or mortality impact at the end. The study's primary motivation is to be able to estimate with a certain level of accuracy the number of deaths due to COVID-19, managing to model the progression of the pandemic. Predicting the number of possible deaths from COVID-19 can provide governments and decision-makers with indicators for purchasing respirators and pandemic prevention policies. Thus, this work presents itself as an essential contribution to combating the pandemic. Kalman Filter is a widely used method for tracking and navigation and filtering and time series. Designing and tuning machine learning methods are a labor- and time-intensive task that requires extensive experience. The field of automated machine learning Auto Machine Learning relies on automating this task. Auto Machine Learning tools enable novice users to create useful machine learning units, while experts can use them to free up valuable time for other tasks. This paper presents an objective method of forecasting the COVID-19 outbreak using Kalman Filter and Auto Machine Learning. We use a COVID-19 dataset of Ceará, one of the 27 federative units in Brazil. Ceará has more than 235,222 confirmed cases of COVID-19 and 8850 deaths due to the disease. The TPOT automobile model showed the best result with a 0.99 of R 2 score.

Preoperative surgical risk assessment of meningiomas: a narrative review based on MRI radiomics.

Meningiomas are one of the most common intracranial primary central nervous system tumors. Regardless of the pathological grading and histological subtypes, maximum safe resection is the recommended treatment option for meningiomas. However, considering tumor heterogeneity, surgical treatment options and prognosis often vary greatly among meningiomas. Therefore, an accurate preoperative surgical risk assessment of meningiomas is of great clinical importance as it helps develop surgical treatment strategies and improve patient prognosis. In recent years, an increasing number of studies have proved that magnetic resonance imaging (MRI) radiomics has wide application values in the diagnostic, identification, and prognostic evaluations of brain tumors. The vital importance of MRI radiomics in the surgical risk assessment of meningiomas must be apprehended and emphasized in clinical practice. This narrative review summarizes the current research status of MRI radiomics in the preoperative surgical risk assessment of meningiomas, focusing on the applications of MRI radiomics in preoperative pathological grading, assessment of surrounding tissue invasion, and evaluation of tumor consistency. We further analyze the prospects of MRI radiomics in the preoperative assessment of meningiomas angiogenesis and adhesion with surrounding tissues, while pointing out the current challenges of MRI radiomics research.

Phosphorylation of polysaccharides: A review on the synthesis and bioactivities.

Polysaccharides are macromolecules obtained from a wide range of sources and are known to have diverse biological activities. The biological activities of polysaccharides depend on their structure and physicochemical properties, including water solubility, monosaccharide composition, degree of branching, molecular structure, and molecular weight. Phosphorylation is a commonly used chemical modification method that improves the physicochemical properties of native polysaccharides, thus enhancing their biological activity, or even imparting novel biological activity. Therefore, phosphorylated polysaccharides have attracted increasing attention owing to their antioxidant, antitumor, antiviral, immunomodulatory, and hepatoprotective effects. In this review, we have discussed recent advances in the phosphorylation of polysaccharides, and the methods used for phosphorylation, structural characterization, and determination of biological activities, to provide a theoretical basis for the use of polysaccharides. The structure-activity relationship of phosphorylated polysaccharides and their use in the food and pharmaceutical industries needs to be further studied.

Value of Visceral Fat Area and Resting Energy Expenditure in Assessment of Metabolic Characteristics in Obese and Lean Nonalcoholic Fatty Liver Disease.

BACKGROUND: The high prevalence and incidence of non-alcoholic fatty liver disease (NAFLD) have become a global medical concern. Compared with obesity, metabolic abnormalities may be more critical. Currently, there is lack of relevant data for nutritional status and energy metabolic characteristics in patients with obese and lean NAFLD. METHODS: All the enrolled NAFLD patients were divided into 2 groups: the obese group (205 patients with body mass index (BMI) ≥ 25 kg/m2) and the lean group (73 patients with BMI < 25 kg/m2). Using a body composition analyzer, we analyzed their nutritional status including skeletal muscle, body fat, protein content, and visceral fat area (VFA). Energy metabolic characteristics including resting energy expenditure (REE), respiratory quotient, and oxidation rate of 3 major nutrients (carbohydrate, CHO%, fat, FAT%, and protein, PRO%) were analyzed by metabolic cart. RESULTS: The lean NAFLD patients' LDL-c and UA even increased significantly than the obese patients (P = .001 and .006, respectively). Compared with the control group, VFA and REE were significantly higher in the lean NAFLD group (P = .008, P < .001 respectively). CHO%, FAT%, and PRO% in the lean NAFLD group were 29.31 ± 7.07%, 55.59 ± 12.09%, and 15.10 ± 4.07%, respectively, and there was no significant difference compared to the control. However, compared to the obese NAFLD group, their CHO% increased, whereas FAT% decreased (both P < .001). CONCLUSION: NAFLD patients suffer from nutritional imbalances and energy metabolic abnormalities, regardless of whether they are associated with obesity. LDL, UA, VFA, and REE can be used as good evaluation indicators.

A nationwide survey on neonatal medical resources in mainland China: current status and future challenges.

BACKGROUND: With the rapid development of economy in recent two decades, neonatology has been progressing quickly in China. However, there is little knowledge about the exact developmental status of neonatal departments in China. The aim of this study was to assess resources available for care of sick newborns in mainland China. METHODS: Questionnaires were sent to the membership of the Chinese Neonatologist Association (CNA) and used to survey the scale, facilities, staff, technologies, transport systems and preterm infants' outcomes of neonatal departments (NDs) in different areas of China from June 2012 to December 2012. RESULTS: The result of this survey including a total of 117 questionnaires showed that investigated ND had a mean of 65 (median 47; range 5-450) beds, including 19.59 (median 15, range 0-100) NICU beds. The overall doctor/bed and nurse/bed ratio was 1:3.84 and 1:1.43, respectively. Lack of medical equipment was one of the main problems in most NDs surveyed, and only 26 NDs (22.2%) had more than one neonatal incubator per bed. Only 70.1, 30.6, 30.8 and 4.3% NDs carried out high-frequency ventilation, hypothermia, nitric oxide inhalation, and ECMO respectively. The capacity to provide advanced therapies increased with the size of the NDs (P < .01). A total of 81 NDs (69.2%) carried out neonatal transport, but only 70 NDs (86.4%) were equipped with transport incubators, 36 NDs (44.4%) had the ability of performing intrauterine transport of the preterm infants, and 3 NDs (3.7%) had the ability of performing air transport. The survival rate of extremely preterm infants (Gestational age less than 28w) to discharge home was 47.8% in 2011. CONCLUSION: NDs in mainland China are not well distributed and still face many problems, such as staff shortage, inadequate facilities, and imperfect transport. It is urgent to set up a classification of neonatal care to enhance the utilization rate of medical resources and improve the prognosis of critically ill infants.

Five microRNAs in serum as potential biomarkers for prostate cancer risk assessment and therapeutic intervention.

BACKGROUND: Prostate cancer (PCa) is a common malignant human tumor and one of the main causes of cancer-related deaths in men. At present, prostate-specific antigen levels are widely used to diagnose PCa in the clinic, but they are not sufficient for an accurate early diagnosis or prognosis. METHODS: To identify potential molecular markers for PCa, we used real-time PCR to measure the expression levels of various microRNAs, including miR-1825, miR-484, miR-205, miR-141, and let-7b, in the serum of 72 PCa patients and 34 healthy controls. RESULTS: miR-1825, miR-484, miR-205, miR-141, and let-7b were shown to be highly specific for PCa, suggesting that they could be used as PCa tumor screening biomarkers. miR-205 may also be used as a biomarker for indicating bone metastasis in PCa patients, miR-1825 levels may help indicate tumor-node-metastasis classification, the evaluation of treatment effects, and determining prognosis, while let-7b levels may indicate potential tumor malignancy and the hormone resistance status and could be used as a basis to adjust individual treatments for the high-risk, early diagnosis of refractory PCa. CONCLUSION: This study identified possible PCa tumor markers to more accurately predict the occurrence, progression, and prognosis of PCa, and which could be used in the development of tumor drug therapy.

Integrated assessment of differentially expressed plasma microRNAs in subtypes of nonsyndromic orofacial clefts.

BACKGROUND: Orofacial clefts include cleft lip only (CLO), cleft palate only (CPO), and cleft lip with palate (CLP). Previously, we reported the expression profile of plasma microRNAs in CLO, CPO, and CLP, respectively. However, the interaction of each subtype remains poorly investigated. METHODS: In this study, we integrated the expression profiles of plasma miRNAs in these 3 subtypes, and assessed the distinct and overlapping dysregulated miRNAs using Venn diagrams. Their respective target genes reported in the literature were further analyzed using pathway analysis. RESULTS AND CONCLUSION: The results showed that distinct or overlapping signaling pathways were involved in CLO, CPO, and CLP. The common key gene targets reflected functional relationships to the Wnt, Notch, TGF-beta, and Hedgehog signaling pathways. Further studies should examine the mechanism of the potential target genes, which may provide new avenues for future clinical prevention and therapy.

Perfluorinated compounds in surface waters of Shanghai, China: Source analysis and risk assessment.

17 perfluorinated compounds (PFCs) were systematically investigated in the surface water from principal watersheds of Shanghai, China. 10 PFCs were above the detection limit (0.08-0.28ng/L) in 39 surface water samples. The perfluorooctanoic acid (PFOA) and perfluorobutanesulfonate (PFBS) were the two dominant compounds with a median concentration 50.67ng/L and 29.84ng/L, respectively. Concentrations of perfluorooctanesulfonate (PFOS) were generally less than PFBS, which might result from the global phase-out of PFOS production and the use of PFBS as a substitute for PFOS-based products. There were three major polluted areas of PFOA along the Huangpu River. The PFOA concentration in groundwater samples collected from one of the three areas indicated that chemical industry might be the possible source. The perfluoroalkane sulfonates (PFSAs) level had a spatial trend that indicated northwest had higher concentrations than the southeast. The distribution of PFCs was not much affected by atmospheric deposition. Mass loading analysis in the surface water revealed that the Huangpu River exhibited relatively large mass loading of total PFCs of 1742.43kg/year to Yangtze River Estuary. The predominant of the PFC species was PFOA with 652.65kg/year. The current concentrations of PFOA and PFOS were at middle level comparing to other studies in China and worldwide. Risk assessment of 6 PFCs showed that there is no risk to the aquatic organisms in Shanghai. PFOS and PFBS had low risk to the avian. Furthermore, the adults living in Shanghai were at low risk to exposure to PFCs through water consumption.

The value of grip test, lysophosphatidlycholines, glycerophosphocholine, ornithine, glucuronic acid decrement in assessment of nutritional and metabolic characteristics in hepatitis B cirrhosis.

The liver is essential for the regulation of energy, protein and amino acids, as well as in other aspects of metabolism. To identify efficient indexes for evaluation of nutritional status and metabolic characteristics during different Child-Pugh stages of hepatitis B cirrhosis, 83 patients and 35 healthy individuals were enrolled in our study. We found that grip strength, triceps skinfold thickness (TSF), body fat and skeletal muscle of the patients were reduced compared to the control group (P<0.05). Ultra-high-performance liquid chromatography data combined with mass spectrometry (UPLC-MS) showed that levels of a variety of metabolites, including lysophosphatidylcholines (LysoPCs), glycerophosphocholine, ornithine and glucuronic acid were reduced in the serum of patients with hepatitis B cirrhosis (P<0.001). However, glycerophosphoserine and taurocholic acid levels were higher than in the control group (P<0.001). Moreover, grip strength was correlated with the Child-Pugh score (P<0.05). Serum albumin, total cholesterol, LDL, LysoPCs, glycerophosphocholine, ornithine, glucuronic acid, glycerophosphoserine and taurocholic acid were correlated with the Child-Pugh score (P<0.01). These findings suggested that grip strength and the above small molecular substances might be considered as sensitive and important indexes for evaluating nutritional status and metabolic characteristics of patients with hepatitis B cirrhosis, which may help assess prognosis and adjust nutritional treatment.

[Non-invasive assessment of portal hypertension in patients with liver cirrhosis using FibroScan transient elastography].

OBJECTIVE: To investigate the clinical value of FibroScan transient elastography for assessing portal hypertension in liver cirrhosis patients by determining the relationship between the liver or spleen stiffness measurement with the imaging parameters of esophageal varices, portal vein width, spleen volume, and splenic vein width. METHODS: A total of 259 patients with liver cirrhosis underwent FibroScan measurement, ultrasound, computed tomography and routine blood analyses. One-hundred-and-one of those patients also underwent endoscopy to diagnose esophageal varices. Receiver operating characteristic (ROC) curves were generated and the areas under the curves (AUCs) were calculated to assess the accuracy of the FibroScan liver and spleen stiffness measurements to predict esophageal varices. Pearson's correlation analysis was used to assess the relationship between clinical features. RESULTS: The median liver and spleen stiffness of the cirrhotic patients were 24.27 kPa and 44.64 kPa, respectively. Liver and spleen stiffness increased in conjunction with increases in Child-Pugh score. Liver stiffness was positively correlated with spleen stiffness (P less than 0.05). Liver and spleen stiffness were positively correlated with esophageal varices, portal vein width, spleen thickness, spleen volume, and splenic vein width. The correlation of spleen stiffness was higher than that of liver stiffness. Spleen stiffness was also negatively correlated with white blood cell count and platelet count. Liver and spleen stiffness also increased in conjunction with increased severity of esophageal varices. The AUC of spleen stiffness was higher than that of liver stiffness for predicting esophageal varices (0.804 vs. 0.737). The optimal cut-off level of spleen stiffness was 44.5 kPa (sensitivity: 88%; specificity: 68%). The estimated prevalence of esophageal varices was 97.87% and the optimized cut-off level of liver stiffness was 18.0 kPa. CONCLUSION: FibroScan appears to be a clinically valuable non-invasive method to assess portal hypertension in cirrhotic patients. Both liver and spleen stiffness measurements correlated with portal hypertension but the spleen stiffness measurement may be of higher clinical value.

Dosimetric comparison of Acuros XB deterministic radiation transport method with Monte Carlo and model-based convolution methods in heterogeneous media.

PURPOSE: The deterministic Acuros XB (AXB) algorithm was recently implemented in the Eclipse treatment planning system. The goal of this study was to compare AXB performance to Monte Carlo (MC) and two standard clinical convolution methods: the anisotropic analytical algorithm (AAA) and the collapsed-cone convolution (CCC) method. METHODS: Homogeneous water and multilayer slab virtual phantoms were used for this study. The multilayer slab phantom had three different materials, representing soft tissue, bone, and lung. Depth dose and lateral dose profiles from AXB v10 in Eclipse were compared to AAA v10 in Eclipse, CCC in Pinnacle3, and EGSnrc MC simulations for 6 and 18 MV photon beams with open fields for both phantoms. In order to further reveal the dosimetric differences between AXB and AAA or CCC, three-dimensional (3D) gamma index analyses were conducted in slab regions and subregions defined by AAPM Task Group 53. RESULTS: The AXB calculations were found to be closer to MC than both AAA and CCC for all the investigated plans, especially in bone and lung regions. The average differences of depth dose profiles between MC and AXB, AAA, or CCC was within 1.1, 4.4, and 2.2%, respectively, for all fields and energies. More specifically, those differences in bone region were up to 1.1, 6.4, and 1.6%; in lung region were up to 0.9, 11.6, and 4.5% for AXB, AAA, and CCC, respectively. AXB was also found to have better dose predictions than AAA and CCC at the tissue interfaces where backscatter occurs. 3D gamma index analyses (percent of dose voxels passing a 2%/2 mm criterion) showed that the dose differences between AAA and AXB are significant (under 60% passed) in the bone region for all field sizes of 6 MV and in the lung region for most of field sizes of both energies. The difference between AXB and CCC was generally small (over 90% passed) except in the lung region for 18 MV 10 x 10 cm2 fields (over 26% passed) and in the bone region for 5 x 5 and 10 x 10 cm2 fields (over 64% passed). With the criterion relaxed to 5%/2 mm, the pass rates were over 90% for both AAA and CCC relative to AXB for all energies and fields, with the exception of AAA 18 MV 2.5 x 2.5 cm2 field, which still did not pass. CONCLUSIONS: In heterogeneous media, AXB dose prediction ability appears to be comparable to MC and superior to current clinical convolution methods. The dose differences between AXB and AAA or CCC are mainly in the bone, lung, and interface regions. The spatial distributions of these differences depend on the field sizes and energies.

Radiation doses in cone-beam breast computed tomography: a Monte Carlo simulation study.

PURPOSE: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. METHODS: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. RESULTS: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms) percentage difference = 1.7%; p = 0.01), whereas those for the cylindrical phantoms were significantly lower (rms percentage difference = 7.7%; p < 0.01). Normalized MGDs were found to decrease with increasing glandularity. CONCLUSIONS: Our results indicate that it is sufficient to use homogeneous breast models derived from CBCT generated structured breast models to estimate the average dose. This investigation also shows that ellipsoidal digital phantoms of similar dimensions (diameter and height) and glandularity to actual breasts may be used to represent a real breast to estimate the average breast dose with Monte Carlo simulation. We have also successfully demonstrated the use of structured breast models to estimate the true MGDs and shown that the normalized MGDs decreased with the glandularity as previously reported by other researchers for CBBCT or mammography.

Microarray analysis of virulence gene profiles in Salmonella serovars from food/food animal environment.

INTRODUCTION: Rapid, accurate and inexpensive analysis of the disease-causing potential of foodborne pathogens is an important consideration in food safety and biodefense, particularly in developing countries. The objective of this study is to demonstrate the use of a robust and inexpensive microarray platform to assay the virulence gene profiles in Salmonella from food and/or the food animal environment, and then use ArrayTrack™ for data analysis. METHODOLOGY: The spotted array consisted of 69 selected Salmonella-specific virulence gene probes (65bp each). These probes were printed on poly-L-lysine-coated slides. Genomic DNA was digested with Sau3AI, labeled with Cy3 dye, hybridized to the gene probes, and the images were captured and analyzed by GenePix 4000B and ArrayTrack™, a free software developed by Food and Drug Administration (FDA) researchers. RESULTS: Nearly 58% of the virulence-associated genes tested were present in all Salmonella strains tested. In general, genes belonging to inv, pip, prg, sic, sip, spa or ttr families were detected in more than 90% of the isolates, while the iacP, avrA, invH, rhuM, sirA, sopB, sopE or sugR genes were detected in 40 to 80% of the isolates. The gene variability was independent of the Salmonella serotype. CONCLUSIONS: This hybridization array presents an accurate and cost-effective method for evaluating the disease-causing potential of Salmonella in outbreak investigations by targeting a selective set of Salmonella-associated virulence genes.

Dual resolution cone beam breast CT: a feasibility study.

PURPOSE: In this study, the authors investigated the feasibility of a dual resolution volume-of-interest (VOI) cone beam breast CT technique and compared two implementation approaches in terms of dose saving and scatter reduction. METHODS: With this technique, a lead VOI mask with an opening is inserted between the x-ray source and the breast to deliver x-ray exposure to the VOI while blocking x rays outside the VOI. A CCD detector is used to collect the high resolution projection data of the VOI. Low resolution cone beam CT (CBCT) images of the entire breast, acquired with a flat panel (FP) detector, were used to calculate the projection data outside the VOI with the ray-tracing reprojection method. The Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the dual resolution 3D images. Breast phantoms with 180 microm and smaller microcalcifications (MCs) were imaged with both FP and FP-CCD dual resolution CBCT systems, respectively. Two approaches of implementing the dual resolution technique, breast-centered approach and VOI-centered approach, were investigated and evaluated for dose saving and scatter reduction with Monte Carlo simulation using a GEANT4 package. RESULTS: The results showed that the breast-centered approach saved more breast absorbed dose than did VOI-centered approach with similar scatter reduction. The MCs in fatty breast phantom, which were invisible with FP CBCT scan, became visible with the FP-CCD dual resolution CBCT scan. CONCLUSIONS: These results indicate potential improvement of the image quality inside the VOI with reduced breast dose both inside and outside the VOI.

Reduction in x-ray scatter and radiation dose for volume-of-interest (VOI) cone-beam breast CT--a phantom study.

With volume-of-interest (VOI) cone-beam computed tomography (CBCT) imaging, one set of projection images are acquired with the VOI collimator at a regular or high exposure level and the second set of projection images are acquired without the collimator at a reduced exposure level. The high exposure VOI scan data inside the VOI and the low exposure full-field scan data outside the VOI are then combined together to generate composite projection images for image reconstruction. To investigate and quantify scatter reduction, dose saving and image quality improvement in VOI CBCT imaging, a flat panel detector-based bench-top experimental CBCT system was built to measure the dose, the scatter-to-primary ratio (SPR), the image contrast, noise level, the contrast-to-noise ratio (CNR) and the figure of merit (FOM) in the CBCT reconstructed images for two polycarbonate cylinders simulating the small and the large phantoms. The results showed that, compared to the full field CBCT technique, radiation doses for the VOI CBCT technique were reduced by a factor of 1.20 and 1.36 for the small and the large phantoms at the phantom center, respectively, and from 2.7 to 3.0 on the edge of the phantom, respectively. Inside the VOI, the SPRs were substantially reduced by a factor of 6.6 and 10.3 for the small and the large phantoms, the contrast signals were improved by a factor of 1.35 and 1.8, and the noise levels were increased by a factor of 1.27 and 1.6, respectively. As a result, the CNRs were improved by a factor of 1.06 and 1.13 for the small and the large phantoms and the FOM improved by a factor of 1.4 and 1.7, respectively.

Feasibility of volume-of-interest (VOI) scanning technique in cone beam breast CT--a preliminary study.

This work is to demonstrate that high quality cone beam CT images can be generated for a volume of interest (VOI) and to investigate the exposure reduction effect, dose saving, and scatter reduction with the VOI scanning technique. The VOI scanning technique involves inserting a filtering mask between the x-ray source and the breast during image acquisition. The mask has an opening to allow full x-ray exposure to be delivered to a preselected VOI and a lower, filtered exposure to the region outside the VOI. To investigate the effects of increased noise due to reduced exposure outside the VOI on the reconstructed VOI image, we directly extracted the projection data inside the VOI from the full-field projection data and added additional data to the projection outside the VOI to simulate the relative noise increase due to reduced exposure. The nonuniform reference images were simulated in an identical manner to normalize the projection images and measure the x-ray attenuation factor for the object. Regular Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the 3D images. The noise level inside the VOI was evaluated and compared with that of the full-field higher exposure image. Calcifications phantom and low contrast phantom were imaged. Dose reduction was investigated by estimating the dose distribution in a cylindrical water phantom using Monte Carlo simulation based Geant4 package. Scatter reduction at the detector input was also studied. Our results show that with the exposure level reduced by the VOI mask, the dose levels were significantly reduced both inside and outside the VOI without compromising the accuracy of image reconstruction, allowing for the VOI to be imaged with more clarity and helping to reduce the breast dose. The contrast-to-noise ratio inside the VOI was improved. The VOI images were not adversely affected by noisier projection data outside the VOI. Scatter intensities at the detector input were also shown to decrease significantly both inside and outside the VOI in the projection images, indicating potential improvement of image quality inside the VOI and contribution to dose reduction both inside and outside the VOI.