High spatial resolution technique for SPECT using a fan-beam collimator

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States)

DOI:https://doi.org/10.1109/23.256727· OSTI ID:6062229

Ichihar, T; Nambu, K; Motomura, N ^[1]

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1. TOSHIBA Nasu Works, Tochigi-ken (Japan). Nuclear Medicine Systems Engineering Dept.

The physical characteristics of the collimator cause degradation of resolution with increasing distance from the collimator surface. A new convolutional backprojection algorithm has been derived for fanbeam SPECT data without rebinding into parallel beam geometry. The projections are filtered and then backprojected into the area within an isosceles triangle whose vertex is the focal point of the fan-beam and whose base is the fan-beam collimator face, and outside of the circle whose center is located midway between the focal point and the center of rotation and whose diameter is the distance between the focal point and the center of rotation. Consequently the backprojected area is close to the collimator surface. This algorithm has been implemented on a GCA-9300A SPECT system showing good results with both phantom and patient studies. The SPECT transaxial resolution was 4.6mm FWHM (reconstructed image matrix size of 256x256) at the center of SPECT FOV using UHR (ultra-high-resolution) fan beam collimators for brain study. Clinically, Tc-99m HMPAO and Tc-99m ECD brain data were reconstructed using this algorithm. The reconstruction results were compared with MRI images of the same slice position and showed significantly improved over results obtained with standard reconstruction algorithms.

• OSTI ID: 6062229
• Journal Information: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States), Vol. 40:4 part 1; ISSN 0018-9499
• Country of Publication: United States
• Language: English

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