Bar-detector with extended field of view for a modular SPECT system

A new detector module has been developed for a prototype system, McSPECT 11, which is being constructed for highresolution clinical brain imaging. The detector module is the building block of the cylindrical detector system of the McSPECT 11. Each detector module contains 5 NaI(Tl) bars and is backed by a glass window in an aluminum housing. Each detector module is associated with 6 PMTs to form a functional unit for position estimation. Bench-top tests performed on a sample unit demonstrated an average of 10.5% local energy resolution (ER) at 140 keV. Centroid calculations were applied in both orthogonal directions of the module for position estimation. In the longitudinal direction, a two-step centroid method yields a 1 3 cm UFOV (useful field-of-view) along the bar and an 11 cm CFOV (center FOV), with intrinsic spatial resolution of <5.5 and 3.8k0.3 mm F' WHM, respectively. In the transverse direction, the task of identifying the bar detector involved in an event is simplified, with an accuracy better than 99% when photons are incident normally.

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A Single-tube Miniature Gamma Camera

Yasillo

Mintzer²,

Aarsvold³

et al.

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference

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In certain medical gamma imaging applications, conventional cameras are too large for practical use. To address these situations, we have constructed a clinically usable miniature gamma camera for photon energies up to 160 keV. The camera has outer dimensions of 92 mm x 92 mm x 190 mm and weighs 5 kg. Included in that mass is a collimator, an internal high-voltage power supply, and all shielding. The camera also has a position-sensitive photomultiplier tube (PSPMT) coupled to an 8-mm thick NaI(Tl) crystal; this crystal/tube combination provides signals to internal processing circuits. External electronics and analog-to-digital conversion circuits are connected to a Macintosh Quadra computer where additional processing, storage, and display of the signals takes place. Because the PSPMT has non-uniform energy response that results in geometric distortion if conventional position-arithmetic calculations are used, we have implemented a maximumlikelihood position-estimation calculation that produces undistorted images. The present version of the camera has a usable field of view of 48 mm x 48 mm and an intrinsic spatial resolution of 2.4 to 3.8 mm full width at half maximum.

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Bar-detector with extended field of view for a modular SPECT system

Cited by 6 publications

References 7 publications

PET imaging using gamma cameras

PET imaging using gamma cameras

A new modular detector for a cylindrical brain SPECT system

A Single-tube Miniature Gamma Camera

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