Volume 33, Issue 4 p. 997-1004
Radiation imaging physics

An analytical algorithm for skew-slit imaging geometry with nonuniform attenuation correction

Qiu Huang

Qiu Huang

Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84108

Electronic mail: [email protected]

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Gengsheng L. Zeng

Gengsheng L. Zeng

Utah Center for Advanced Imaging Research, 729 Arapeen Drive, University of Utah, Salt Lake City, UT 84108

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First published: 22 March 2006
Citations: 12

Abstract

The pinhole collimator is currently the collimator of choice in small animal single photon emission computed tomography (SPECT) imaging because it can provide high spatial resolution and reasonable sensitivity when the animal is placed very close to the pinhole. It is well known that if the collimator rotates around the object (e.g., a small animal) in a circular orbit to form a cone-beam imaging geometry with a planar trajectory, the acquired data are not sufficient for an exact artifact-free image reconstruction. In this paper a novel skew-slit collimator is mounted instead of the pinhole collimator in order to significantly reduce the image artifacts caused by the geometry. The skew-slit imaging geometry is a more generalized version of the pinhole imaging geometry. The multiple pinhole geometry can also be extended to the multiple-skew-slit geometry. An analytical algorithm for image reconstruction based on the tilted fan-beam inversion is developed with nonuniform attenuation compensation. Numerical simulation shows that the axial artifacts are evidently suppressed in the skew-slit images compared to the pinhole images and the attenuation correction is effective.