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| Publications [#65239] of Michael R. Zalutsky
Papers Published
- Jaszczak, R.J. and Jianying Li and Huili Wang and Zalutsky, M.R. and Coleman, R.E., Pinhole collimation for ultra-high-resolution, small-field-of-view SPECT,
Phys. Med. Biol. (UK), vol. 39 no. 3
(1994),
pp. 425 - 37, Snowbird, UT, USA [010]
(last updated on 2007/04/15)
Abstract:
The authors evaluated small-field-of-view ultra-high-resolution pinhole collimation for a rotating-camera SPECT system that could be used to image small laboratory animals. Pinhole collimation offers distinct advantages over conventional parallel-hole collimation when used to image small objects. Since geometric sensitivity increases markedly for points close to the pinhole, small-diameter and high-magnification pinhole geometries may be useful for selected imaging tasks when used with large-field-of-view scintillation cameras. The use of large magnifications can minimize the loss of system resolution caused by the intrinsic resolution of the scintillation camera. A pinhole collimator has been designed and built that can be mounted on one of the scintillation cameras of a triple-head SPECT system. 3 Pinhole inserts with approximate aperture diameters of 0.6, 1.2 and 2.0 mm have been built and can be mounted individually on the collimator housing. When a ramp filter is used with a 3D filtered backprojection (FBP) algorithm, the 3 apertures have in-plane SPECT spatial resolutions (FWHM) at 4 cm of 1.5, 1.9 and 2.8 mm, respectively. In-air point source sensitivities at 4 cm from the apertures are 0.9, 2.6 and 5.7 counts s-1 μCi-1 (24, 70 and 154 counts s-1 MBq-1) for the 0.6, 1.2 and 2.0 mm apertures, respectively. In vitro image quality was evaluated with a micro-cold-rod phantom and a micro-Defrise phantom using both the 3D FBP algorithm and a 3D maximum likelihood-expectation maximization algorithm. In vivo image quality was evaluated using 2 (315 and 325 g) rats. Ultra-high-resolution pinhole SPECT is an inexpensive and simple approach for imaging small animals that can be used with existing rotating-camera SPECT systems
Keywords:
biological techniques and instruments;computerised tomography;laboratory apparatus and techniques;radioisotope scanning and imaging;
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