Role of Computer Aided Diagnosis (CAD) in the detection of pulmonary nodules on 64 row multi detector computed tomography.

Aims And Objectives: To determine the overall performance of an existing CAD algorithm with thin-section computed tomography (CT) in the detection of pulmonary nodules and to evaluate detection sensitivity at a varying range of nodule density, size, and location.

Materials And Methods: A cross-sectional prospective study was conducted on 20 patients with 322 suspected nodules who underwent diagnostic chest imaging using 64-row multi-detector CT. The examinations were evaluated on reconstructed images of 1.

FDK-Type Algorithms with No Backprojection Weight for Circular and Helical Scan CT.

We develop two Feldkamp-type reconstruction algorithms with no backprojection weight for circular and helical trajectory with planar detector geometry. Advances in solid-state electronic detector technologies lend importance to CT systems with the equispaced linear array, the planar (flat panel) detectors, and the corresponding algorithms. We derive two exact Hilbert filtered backprojection (FBP) reconstruction algorithms with no backprojection weight for 2D fan-beam equispace linear array detector geometry (complement of the equi-angular curved array detector).

Image reconstruction with laterally truncated projections in helical cone-beam CT: linear prediction based projection completion techniques.

Lateral or transaxial truncation of cone-beam data can occur either due to the field of view limitation of the scanning apparatus or in region-of-interest tomography. In this paper, we suggest two new methods to handle lateral truncation in helical scan CT. It is seen that reconstruction with laterally truncated projection data, assuming it to be complete, gives severe artifacts which even penetrates into the field of view.

Estimation of missing data using windowed linear prediction in laterally truncated projections in cone-beam CT.

In this paper, we address the reconstruction problem from laterally truncated helical cone-beam projections. The reconstruction problem from lateral truncation, though similar to that of interior radon problem, is slightly different from it as well as the local (lambda) tomography and pseudo-local tomography in the sense that we aim to reconstruct the entire object being scanned from a region-of-interest (ROI) scan data. The method proposed in this paper is a projection data completion approach followed by the use of any standard accurate FBP type reconstruction algorithm.

Extractive spectrophotometric determination of Cobalt(II) in synthetic and pharmaceutical samples using Cyanex 923.

Cyanex 923 has been proposed as a sensitive analytical reagent for the direct extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a blue-colored complex with Cyanex 923 in the organic phase. The maximum absorbance of the complex is measured at 635 nm.

Detection of edges from projections.

In a number of applications of computerized tomography, the ultimate goal is to detect and characterize objects within a cross section. Detection of edges of different contrast regions yields the required information. The problem of detecting edges from projection data is addressed.

Vector-extrapolated fast maximum likelihood estimation algorithms for emission tomography.

A new class of fast maximum-likelihood estimation (MLE) algorithms for emission computed tomography (ECT) is developed. In these cyclic iterative algorithms, vector extrapolation techniques are integrated with the iterations in gradient-based MLE algorithms, with the objective of accelerating the convergence of the base iterations. This results in a substantial reduction in the effective number of base iterations required for obtaining an emission density estimate of specified quality.