Title :
Improvement of image quality by tilted fan beam data acquisition in a helical scan X-ray CT
Author :
Ogawa, K. ; Yamada, Y. ; Uno, T.
Author_Institution :
Dept. of Electron. Inf., Hosei Univ., Tokyo, Japan
Abstract :
The helical scan X-ray CT is useful for high speed acquisition of three dimensional image data. In image reconstruction from helical scan data, a set of sequential data is used and the data are interpolated to produce projection data which reconstruct an image of a given cross section. This interpolation sometimes causes artifacts in the reconstructed image. We propose a new data acquisition method which minimizes the effect of scanning slice position in the axial direction. The proposed method inclines an X-ray detector array in the direction of rotation. The tilted angle is defined as arctan(θL/2Rπtanθ), where L is the moving distance of a table per rotation and R is the radius of rotation of the X-ray source. The angle θ is the orthogonal projection of the half of a fan angle onto the parallel beam projection plane. Simulation results showed that our method eliminated the low frequency distortion and improved the spatial resolution in the axial direction
Keywords :
computerised tomography; data acquisition; image reconstruction; interpolation; medical image processing; X-ray detector; X-ray source; helical scan X-ray CT; image quality; image reconstruction; interpolation; projection data; scanning slice position; sequential data; spatial resolution; tilted angle; tilted fan beam data acquisition; Computed tomography; Data acquisition; Frequency; Image quality; Image reconstruction; Interpolation; Sensor arrays; Spatial resolution; X-ray detectors; X-ray imaging;
Conference_Titel :
Nuclear Science Symposium, 1996. Conference Record., 1996 IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3534-1
DOI :
10.1109/NSSMIC.1996.591720