Euromedim 2006 :1st European Conference on Molecular Imaging Technology

Initial Studies Using the RatCAP Conscious Small Animal PET Tomograph

10 May 2006, 09:00

15m

Palais du Pharo, Marseille

oral S1-S2 Small animal imaging

Speaker

Dr Craig Woody (Brookhaven National Lab)

Description

The RatCAP is a small, head mounted PET tomograph that has been designed to image the brain of a conscious rat. It will allow PET imaging studies to be carried out on laboratory rats without the use of anesthesia, which severely suppresses many of the brain functions and neurological activities that one would like to study using PET, and also prevents studying animal behavior while simultaneously acquiring PET data. The RatCAP is a complete, high performance 3D tomograph consisting of a 3.8 cm inside-diameter ring containing 12 block detectors, each of which is comprised of a 4x8 array of 2.2x2.2x5 mm3 LSO crystals read out with a matching APD array, and has a 1.8 cm axial field of view. The APDs are read out using a custom designed ASIC and FPGA time stamp module using a VME readout system. The complete detector weighs less than 200 gram and is suspended by a tether which allows limited freedom of movement of the awake animal. The first working prototype of the RatCAP has been studied using various phantoms and was determined to have a point source resolution of 2.1 mm FWHM (measured in the center of the field of view), a time resolution of 13.9 ns FWHM , and an overall sensitivity of 0.7% at an average energy threshold of 150 keV. Initial brain images of live rats have been obtained and show comparable resolution to similar images obtained with a commercial microPET R4 scanner. Initial studies have also been carried out to study stress levels in rats wearing the RatCAP, and to improve their adaptation and tolerance to the device through training and positive food reinforcement. Results on improved system performance, along with additional brain and animal behavioral studies, will be presented at the conference.