Simultaneous /sup 125/I SPECT imaging of small animals with pinhole and parallel collimation

Abstract

A rotating cylindrical gantry apparatus holding a pair of Hamamatsu R3292 position sensitive photomultiplier tubes (PSPMTs), each of which can include either a parallelhole collimator or a pinhole collimator, has been used to gather planar images and single photon emission computer tomography (SPECT) data of an entire mouse. In addition, in a number of experiments a magnified view of a specific organ was obtained with pinhole collimation. The scintillators used were pixelated NaI(Tl) or CsI(Tl) with pixels 1 x 1 x 3 mm and were air coupled to the PSPMTs. The active area of each detector was a circle about 110 mm in diameter. The parallel hole detector had an intrinsic resolution in planar images of 2 mm and the pinhole collimator was used in a magnification which yielded 1 mm spatial resolution. A rigid, lightweight Lexan tube is used to contain a heated mouse bed formed in a semi-cylindrical shape. Warmed, humidified air as well as gas anesthetic can be introduced and exhausted via the tube. The arrangement facilitates accurate centering and positioning of the SPECT cameras to the animal. The simultaneous acquisition of whole body data and a magnified image of the gut and pancreas within the animal has been applied in a study of 125 I tagged insulin in hyperglycemic and normal mice. In a study of the effectiveness of KI blocking on uptake of iodine in a mouse thyroid, images a phantom of the thyroid and submaxillary glands were of considerable interest. 0-7803-8257

Performance Evaluation of a Dedicated Camera Suitable for Dynamic Radiopharmaceuticals Evaluation in Small Animals

“…The next step will be to evaluate the system's performance in small animal imaging, using a 1 mm pinhole collimator, mainly for the magnification of small organs [19], [23]. The end goal of the collaboration is the development of a full SPECT/CT system based on designs that have been presented [24].…”

A small-animal imaging system capable of multipinhole circular/helical SPECT and parallel-hole SPECT

“…Its transparency allows easy positioning and visual monitoring of the animal. The tube can also serve a dual purpose of keeping the animal in stable condition with introduction of humidified, warmed air from one end and preventing contamination of the environment by exhaust of gases from the other end via a tube leading to a filtered exhaust system [31]. …”