Comparison Of Planar Research Articles

99mTc-DMSA renal cortical scanning: a comparison of planar, SPECT, and SPECT/CT imaging for the detection of renal cortical scarring

BackgroundThe best way to assess renal cortical scarring is planar scintigraphy with 99mTc-dimercaptosuccinic acid (DMSA), while the value of single-photon emission computed tomography/computed tomography (SPECT/CT) is not well validated. The aim of the present study was to assess the value of planar, SPECT, and SPECT/CT scanning using 99mTc-DMSA in detecting renal cortical scarring.MethodsPatients with clinically suspected renal cortical scar were included in this prospective cohort. 99mTc-DMSA Planar images were obtained approximately 3–4 h after intravenous injection (IV) of 185 MBq of the tracer. SPECT/CT scans were obtained immediately after the planar ones. An expert nuclear medicine doctor who was unaware of the patient's clinical history or any previous imaging results analyzed the images. Each kidney was given a score of 0 for no obvious defects, 1 for equivocal lesions, 2 for a single defect, 3 for several defects, and 4 for non-visualized/non-functioning kidney (in CT images). The results of each method were then compared to each other.ResultsOne hundred eighty-six kidneys from ninety-three individuals were eligible for assessment. Planar scans detected 21 kidneys with equivocal lesions, 5 with single and 7 with multiple defects. SPECT scans detected 17 kidneys with single and 40 with multiple defects, while SPECT/CT scans revealed 5 with single and 11 with multiple defects. Only 5 of the 17 kidneys with single defects diagnosed by SPECT imaging had a scar in the SPECT/CT scans, whereas the remaining 12 had a solitary cortical cyst in the CT images. Only 11 of 40 kidneys with multiple defects on SPECT were shown to have a scar in the corresponding SPECT/CT images, whereas the rest matched to either hydro-nephrotic changes or multiple cortical cysts. Four kidneys with multiple defects on the SPECT/CT images were normal in the planar readings, were ascribed to an increase in renal background activity and a reduction in renal function.ConclusionsIn cases with suspected renal cortical scar, 99mTc-DMSA SPECT/CT scanning outperformed both planar and SPECT imaging by reducing the number of false-positive SPECT readings and false-negative planar readings.

Comparison of Planar and Tubular Flow Field Plates for Proton Exchange Membrane Fuel Cells (PEMFCs) through Simulation

The proton exchange membrane fuel cell (PEMFC) is an excellent clean energy alternative to current non-renewable energy sources. Bipolar plates (BPPs) are a key component of these PEMFCs and are directly responsible for their performance. Much research has been invested in channel design, materials characterization, and interfacial phenomenon of BPPs but not much attention has been paid to the architecture of the plate itself. Traditional BPPs are created in a planar form, but recent research efforts have revealed a novel tubular design that performs equally as well if not better than conventional plates. This study will experiment with three different channel designs for both planar and tubular plate configurations. The finite element ANSYS software will be used to determine and visualize velocity and pressure distributions of fluid flow through the BPP channels. Results from this study will validate whether the tubular configuration is superior to the planar form as well as which channel design is most appropriate for either configuration.

Comparison of Planar and Tubular Flow Field Plates for Proton Exchange Membrane Fuel Cells (PEMFCs) through Simulation

Proton exchange membrane fuel cells are excellent clean energy alternatives to current non-renewable energy sources. Bipolar plates are a key component of these fuel cells and directly responsible for their performance. Traditional bipolar plates are created in a planar form, but recent research has revealed a novel tubular design that performs similarly to conventional plates. This study compares traditional planar designs with tubular ones. The finite element ANSYS software was used to determine and visualize velocity and pressure distributions of fluid flow through the bipolar plate channels.

Comparison of planar, PET and well-counter measurements of total tumor radioactivity in a mouse xenograft model

IntroductionQuantitative small animal radionuclide imaging studies are often carried out with the intention of estimating the total radioactivity content of various tissues such as the radioactivity content of mouse xenograft tumors exposed to putative diagnostic or therapeutic agents. We show that for at least one specific application, positron projection imaging (PPI) and PET yield comparable estimates of absolute total tumor activity and that both of these estimates are highly correlated with direct well-counting of these same tumors. These findings further suggest that in this particular application, PPI is a far more efficient data acquisition and processing methodology than PET. MethodsForty-one athymic mice were implanted with PC3 human prostate cancer cells transfected with prostate-specific membrane antigen (PSMA (+)) and one additional animal (for a total of 42) with a control blank vector (PSMA (−)). All animals were injected with [18F] DCFPyl, a ligand for PSMA, and imaged for total tumor radioactivity with PET and PPI. The tumors were then removed, assayed by well counting for total radioactivity and the values between these methods intercompared. ResultsPET, PPI and well-counter estimates of total tumor radioactivity were highly correlated (R2>0.98) with regression line slopes near unity (0.95<slope≤1.02) and intercepts near zero (−0.001MBq≤intercept ≤0.004MBq). ConclusionTotal mouse xenograft tumor radioactivity can be measured with PET or PPI with an accuracy comparable to well counting if certain experimental and pharmacokinetic conditions are met. In this particular application, PPI is significantly more efficient than PET in making these measurements.

Characterization and Comparison of Planar and Trench Silicon Carbide (SiC) Power MOSFETs

This paper presents a comprehensive evaluation and experimental comparison of silicon carbide power MOSFETs through double pulse test. First, a universal hardware platform is designed and developed to test power semiconductor devices with various device packages and measuring requirements. Using the developed platform, the static characteristics and switching performance of the two types of SiC MOSFETs (one planar and one trench type) are evaluated under different case temperatures from 25 oC to 175 oC. Based on the evaluation data, a comparison of both SiC MOSFETs is conducted in terms of their on-state resistance, switching loss, and temperature dependent behavior. It is found that the latest trench SiC MOSFETs present similar switching loss while much lower conduction loss compared to existing commercial planar SiC MOSFETs. Moreover, the trench devices show a nearly temperature independent switching loss, which is beneficial to suppress the potential thermal runaway issue under high temperature continuous operation.

Characterization and Comparison of Planar and Trench Silicon Carbide (SiC) Power MOSFETs

This paper presents a comprehensive evaluation and experimental comparison of silicon carbide power MOSFETs through double pulse test. First, a universal hardware platform is designed and developed to test power semiconductor devices with various device packages and measuring requirements. Using the developed platform, the static characteristics and switching performance of the two types of SiC MOSFETs (one planar and one trench type) are evaluated under different case temperatures from 25 oC to 175 oC. Based on the evaluation data, a comparison of both SiC MOSFETs is conducted in terms of their on-state resistance, switching loss, and temperature dependent behavior. It is found that the latest trench SiC MOSFETs present similar switching loss while much lower conduction loss compared to existing commercial planar SiC MOSFETs. Moreover, the trench devices show a nearly temperature independent switching loss, which is beneficial to suppress the potential thermal runaway issue under high temperature continuous operation.

PO-0874: Pre-treatment QA for IMRT: comparison of planar and helical diode arrays and 3D patient dose reconstruction

PO-0874: Pre-treatment QA for IMRT: comparison of planar and helical diode arrays and 3D patient dose reconstruction

Classical Density Functional Study on Interfacial Structure and Differential Capacitance of Ionic Liquids near Charged Surfaces

We have implemented a generic coarse-grained model for the aromatic ionic liquid [CnMIM+][Tf2N-]. Various lengths for the alkyl chain on the cation define a homologous series, whose electric properties are expected to vary in a systematic way. Within the framework of a classical density functional theory, the interfacial structures of members of this series are compared over a range of surface charge densities, alkyl chain lengths, and surface geometries. The differential capacitance of the electric double layer, formed by ionic liquids against a charged electrode, is calculated as a function of the surface electric potential. A comparison of planar, cylindrical, and spherical surfaces confirms that the differential capacitance increases and varies less with surface potential as the surface curvature increases. Our results are in qualitative agreement with recent atomistic simulations. (Less)

Design and Performance Comparison of Planar and Linear Antenna Array Using ADS

Design and Performance Comparison of Planar and Linear Antenna Array Using ADS

A multi-center study for comparison of planar versus tomographic pulmonary ventilation/perfusion imaging for the diagnosis of pulmonary embolism

Objective To compare between one-day planar and tomographic pulmonary V/Q imaging for the diagnosis of PE using ROC analysis.Methods From September 2010 to October 2011,272 patients suspected or confirmed of acute/sub-acute PE with Wells scores ≥ 2 or blood D-Dimer values ＞500 μg/L were recruited into this study.Patients' data were collected from six hospitals in Beijing.All patients were followed clinically for at least six months after V/Q imaging.Based on the criteria of prospective investigation of pulmonary embolism diagnosis (PIOPED) study Ⅱ,the diagnosis by planar pulmonary V/Q scans was categorized as high-probability (definite PE),moderate or low probability (suspected PE),and very low probability or normal lung perfusion (no PE).The diagnosis by SPECT V/Q scans was also classified as definite PE,suspected PE and no PE.The final diagnosis was decided by doctors in consensus based on the results of multiple imaging modalities,laboratory tests,clinical data and a six-month follow-up.Kappa test was used to analyze the concordance between planar and tomographic V/Q scans.The difference between the two methods was tested using x2 test.ROC analysis was used to determine the AUCs.Z test was used to calculate the statistical significance of the difference between the AUCs.Results The uncertain diagnosis rate was 1.8％ (5/272) for V/Q SPECT and 9.2％ (25/272) for planar imaging.The diagnostic values for SPECT and planar V/Q scans were respectively:Se 83.6％ (117/140) and 78.3％ (101/129)(x2=1.217,P＞0.05); Sp89.8％(114/127) and 94.9％(112/118) (x2 =2.269,P＞0.05); PPV 90.0％ (117/130) and 94.4％ (101/107) ; NPV 83.2％ (114/137) and 80.0％ (112/140) ; Ac 86.5％ (231/267) and 86.2％ (213/247).There were no significant differences in Se and Sp between the two methods.The concordance between the two methods was 84.9％ (231/272,Kappa =0.727,P ＜ 0.05).The AUC (95％ CI) was 0.891 (0.848-0.933) and 0.865 (0.819-0.911) for SPECT and planar V/Q,respectively (Z =2.65 and 2.03,both P ＜ 0.05).Conclusion Pulmonary V/Q imaging using tomographic techniques combined with ROC analysis may significantly improve the diagnostic accuracy of PE when compared with the conventional planar technique. Key words: Pulmonary embolism ; Radionuclide imaging; Tomography, emission-computed,single-photon; Technetium ; MAA

Identifying Children with Vesicoureteral Reflux: A Comparison of 2 Approaches

Various screening approaches have been proposed to identify the subgroup of children with urinary tract infection who have vesicoureteral reflux. However, few studies have compared the sensitivity of screening approaches in a representative population of young children. We compared the sensitivities of the top-down ((99m)technetium dimercaptosuccinic acid renal scan to screen) and biomarker based (C-reactive protein level at presentation) approaches in identifying children with vesicoureteral reflux. We calculated the sensitivity of the 2 screening approaches in detecting vesicoureteral reflux and subsequently high grade (III or greater) vesicoureteral reflux in children. The top-down and C-reactive protein based approaches missed 33% and 29% of cases of high grade vesicoureteral reflux, respectively. The sensitivity of the top-down approach for detecting high grade vesicoureteral reflux was lower than previously reported. Further study of novel methods to identify children at risk for renal scarring is warranted.

Comparison of Planar and 3‐D Interdigitated Electrodes as Electrochemical Impedance Biosensors

AbstractIt has been reported that the introduction of a dielectric barrier between adjacent digits of an interdigitated electrode array can improve the sensitivity of the array as an electrochemical impedance biosensor. Here we present an in‐depth analysis of the impedance in planar interdigitated electrodes and 3‐D interdigitated electrodes (with dielectric barriers). The analysis indicates that the planar geometry not only provides lower impedance but also a higher change impedance as a result of molecular immobilization on the electrode array surface.

Matrix models and parquet approximation

This paper examines the comparison of planar and planar parquet approximation in the zero-dimensional hermitian matrix models. We discuss how the parquet approximation reproduces the results of a planar approach to matrix model φ4, multitrace model, two-matrix model and the Goldstone matrix model.

A comparison of planar, laser-induced fluorescence, and high-sensitivity interferometry techniques for gas-puff nozzle density measurements

The distribution of argon gas injected by a 12-cm-diameter triple-shell nozzle was characterized using both planar, laser-induced fluorescence (PLIF) and high-sensitivity interferometry. PLIF is used to measure the density distribution at a given time by detecting fluorescence from an acetone tracer added to the gas. Interferometry involves making time-dependent, line-integrated gas density measurements at a series of chordal locations that are then Abel inverted to obtain the gas density distribution. Measurements were made on nominally identical nozzles later used for gas-puff Z-pinch experiments on the Saturn pulsed-power generator. Significant differences in the mass distributions obtained by the two techniques are presented and discussed, along with the strengths and weaknesses of each method.

99mTc white-cell imaging in inflammatory bowel disease: a comparison of planar vs SPECT

99mTc white-cell imaging in inflammatory bowel disease: a comparison of planar vs SPECT

A high resolution photoemission study of surface core-level shifts in clean and oxygen-covered Ir(2 1 0) surfaces

High resolution soft X-ray photoemission electron spectroscopy (SXPS), using synchrotron radiation, is employed to investigate 4f core-level features of four differently-prepared Ir(2 1 0) surfaces: clean planar, oxygen-covered planar, oxygen-induced faceted, and clean faceted surfaces. Surface and bulk peak identifications are supported by measurements at different photon energies (thus probing different electron escape depths) and variable emission angles. Iridium 4f 7/2 photoemission spectra are fitted with Doniach–Sunjic lineshapes. The surface components are identified with core levels positioned at lower binding energies than the bulk components, in contrast to previous reports of binding energy inversion on Ir(1 0 0) (1×1) and (5×1) surfaces. For clean planar Ir(2 1 0) three surface Ir 4f 7/2 features are observed with core-level shifts of −765, −529, and −281 meV, with respect to the bulk; these are associated with the first, second and third layers of atoms, respectively, for atomically rough Ir(2 1 0). Adsorption of oxygen onto the planar Ir(2 1 0) surface is found to cause a suppression and shift of the surface features to higher binding energies. Annealing at T≥600 K in oxygen produces a faceted surface as verified by low energy electron diffraction (LEED). A comparison of planar and faceted oxygen-covered surfaces reveals minor differences in the normal emission SXPS spectra, while grazing emission spectra exhibit differences. The SXPS spectrum of the clean, faceted Ir(2 1 0) exhibits small differences in comparison to the clean planar case, with surface features having binding energy shifts of −710, −450, and −230 meV.

Comparison of planar and network K-functions in traffic accident analysis

The network and planar K-function methods are applied to traffic accident data to illustrate the risk of false positive detection associated with the use of a statistic designed for a planar space to analyze a network-constrained phenomenon. We also demonstrate the benefits of using a method specifically designed for a network space. The results clearly indicate that the planar K-function analysis is problematic since it entails a significant chance of over-detecting clustered patterns. Analyses are implemented based on Monte Carlo simulation and applied to 1997 traffic accident data in the Buffalo, NY area.

214. 高純度ゲルマニウム半導体検出器を用いた X 線スペクトル測定 : その 2 プレーナ型およびクローズドエンド同軸型検出器の比較(放射線管理 被曝線量・測定器)

214. 高純度ゲルマニウム半導体検出器を用いた X 線スペクトル測定 : その 2 プレーナ型およびクローズドエンド同軸型検出器の比較(放射線管理 被曝線量・測定器)

Comparison of planar and SPECT 99Tcm-DMSA scintigraphy for the detection of renal cortical defects in children

Renal cortical scintigraphy with 99Tcm-dimercaptosuccinic acid is an excellent imaging modality for the detection of renal cortical defects in children presenting with vesicoureteric reflux and urinary tract infections. Single photon emission computed tomography (SPECT) has proven increased sensitivity over planar scintigraphy for lesion detection in the heart, liver and brain. However, its role in the evaluation of renal cortical defects compared to planar scintigraphy has not been fully assessed. We wished to determine whether SPECT increases the sensitivity for detecting renal cortical defects in children compared to high-resolution planar scintigraphy. Forty-one children (90 renal units) with underlying vesicoureteric reflux and/or recently treated urinary tract infection (UTI) were evaluated. There was no statistically significant difference in the number of defects detected between a single-head SPECT system and high-resolution planar scintigraphy, 24 and 20, respectively (P = 0.54). There were four defects detected by SPECT not reported by planar scintigraphy; two of these were only seen retrospectively on planar scintigraphy. There were two children with renal cortical defects detected by SPECT and not by planar scintigraphy. All defects defected by planar scintigraphy were detected by SPECT. It is concluded that although the risk of missing renal cortical defects is low when using high-resolution, three-view planar scintigraphy, SPECT should be employed whenever feasible. Single photon emission computed tomography detected renal cortical defects in children not diagnosed by planar scintigraphy and hence patient management may be altered.

Fully elliptic incompressible flow calculations on regular grid

References *Mack, L. M., Stability Theory and the Problem of Supersonic Boundary-Layer Transition, AIAA Journal, Vol. 13, No. 3, 1975, pp. 278-298. Mack, L. M., Layer Linear Stability Theory, AGARD Kept. 709, June 1984. Potter, J. L., Review of the Influence of Cooled Walls on Boundary Layer Transition, AIAA Journal, Vol. 18, No. 1980, pp. 1010-1012. Sanator, R. J., DeCarlo, J. P., and Torrillo, D. T., Boundary Layer Transition Data for a Cold-Wall Slender Cone, AIAA Journal, Vol. 3, No. 4, 1965, pp. 758-760. Stetson, K. F., and Rushton, G. H., Shock Tunnel Investigation of Boundary Layer Transition at M = 5.5, AIAA Journal, Vol. 5, No. 5, 1967, pp. 899-906. Mateer, G. G., Effects of Wall Cooling and Angle of Attack on Boundary-Layer Transition on Sharp Cones at Moo = 7.4, NASA TD D-6908, Aug. 1972. Stetson, K. F., Kimmel, R. L., Thompson, E. R., Donaldson, J. C., and Siler, L. G., A Comparison of Planar and Conical Boundary Layer Stability and Transition at a Mach Number of 8, AIAA Paper 91-1639, June 1991. Kendall, J. M., Wind Tunnel Experiments Relating to Supersonic and Hypersonic Boundary Layer Transition, AIAA Journal, Vol. 13, No. 3, 1975, pp. 290-299. Demetriades, A., New Experiments on Hypersonic Boundary Layer Stability Including Wall Temperature Effects, Proceedings of the Heat Transfer and Fluid Mechanics Institute, edited by C. T. Crowe and W. L. Grosshandler, Stanford Univ. Press, Stanford, CA, 1978, pp. 39-54.