Authors: Naruomi Yasuda Yoko Ishikawa Yoshie Kodera
Publish Date: 2007/02/27
Volume: 1, Issue: 6, Pages: 311-320
Abstract
MDCT enables thinslice and highspeed scanning compared with conventional singledetector row CT SDCT However MDCT uses increased volume scanning with a simultaneous increase in the radiation dose to patients Recently we proposed a fluctuation reduction method using highspatialfrequency data sampling however the edge response in the processed image decreased In this research we investigate the edge response behavior in the highspatialfrequency sampling and propose a method for improving the edge response To verify this method a large water phantom that consists of five resinous rods and a small phantom with a similitude rate of 05 which is topologically similar to the former large phantom were scanned and projection data sampling using highspatialfrequency was simulated Thereafter reconstructed images were obtained by averaging the highspatialfrequency sampling data edge gradients of profiles were calculated and the increased rate of the gradient values were evaluatedThis method increased the image noise slightly and provided higher gradient values with the same image matrix size as the conventional scans could be obtained without special image processing In this phantom study in order to simulate the highspatialfrequency sampling a large phantom was scanned and the fluctuation of transmitted Xrays was increased thereby increasing the noiseA phantom study of projection data sampling by highspatialfrequency sampling was simulated in the x and ydirection by scanning two phantoms and the improvement in the edge response by this method produced 25–97 improvement using doublespatialfrequency sampling If lownoise or highsensitivity detector is developed this method may be more effective
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