SemiSPECT: a small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays.
The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm x 2.7 cm x -0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 x 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of -180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 x 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 x 10(-4) with the energy window of +/-10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT.
Kim
Hyunki
H
College of Optical Sciences, University of Arizona, Tucson, Arizona 85724, USA. hyunki@uab.edu
Furenlid
Lars R
LR
Crawford
Michael J
MJ
Wilson
Donald W
DW
Barber
H Bradford
HB
Peterson
Todd E
TE
Hunter
William C J
WC
Liu
Zhonglin
Z
Woolfenden
James M
JM
Barrett
Harrison H
HH
D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging; D019187:Cadmium Compounds / Q000737:chemistry*; D002277:Carcinoma / Q000000981:diagnostic imaging; D004867:Equipment Design; D005720:Gamma Rays; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D051379:Mice; D019047:Phantoms, Imaging; D010781:Photography; D011859:Radiography; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013691:Tellurium / Q000737:chemistry*; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods* / Q000662:veterinary
D019187:Cadmium Compounds; D019275:Radiopharmaceuticals; D013691:Tellurium; C028337:cadmium telluride