CoALA-SPECT: a coded aperture laboratory animal SPECT system for pre clinical imaging

S. R. Meikle, Royal Prince Alfred Hospital, Sydney
R. Wojcik, Thomas Jefferson National Accelerator Facility, Virginia, USA
A. G. Weisenberger, Thomas Jefferson National Accelerator Facility, Virginia, USA
M. F. Smith, Thomas Jefferson National Accelerator Facility, Virginia, USA
S. Majewski, Thomas Jefferson National Accelerator Facility, Virginia, USA
P. Kench, University of Sydney
S. Eberl, Royal Prince Alfred Hospital, Sydney
R. R. Fulton, Royal Prince Alfred Hospital, Sydney
M. L. Lerch, University of Wollongong
A. Rosenfeld, University of Wollongong

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This article was originally published as: Meikle, SR, Wojcik, R, Weisenberger, AG, Smith, MF, Majewski, S, Kench, P, Eberl, S, Fulton, RR, Lerch, M & Rosenfeld, AB, CoALA-SPECT: a coded aperture laboratory animal SPECT system for pre clinical imaging, 2002 IEEE Nuclear Science Symposium Conference Record, 10-16 November 2002, 2, 1061-1065. Copyright IEEE 2002.

Abstract

We have previously demonstrated the potential of multi-pinhole coded apertures when used in conjunction with compact pixelated detectors for high resolution, high sensitivity small animal SPECT. We are now constructing a prototype SPECT system with three such detectors mounted on a rotating gantry. Each detector comprises a 12 cm diameter circular array of NaI(Tl) crystals, each 1/spl times/1/spl times/5 mm/sup 3/ on a 1.25 mm pitch. Each crystal array is coupled to a Hamamatsu R3292 12.7 cm diameter PS-PMT. Signals from the three detectors are read out by a custom subtractive resistive circuit and multiplexed. Data are acquired by a National Instruments PCI-6110E board running on a Macintosh dual processor G4 computer under Kmax software control. Images are reconstructed using a 3D iterative MAP-EM algorithm based on a multi-pinhole forward and back projector. The trade-off between contrast and variance was studied by simulation for a number of multi-pinhole configurations. We also performed initial planar imaging studies on one of the detectors. Our results indicate that spatial resolution approaching 1 mm full width at half maximum (FWHM) can be achieved with a single pinhole aperture, while improved contrast and variance may result from using optimized multi-pinhole apertures.