“ANIPET” a versatile PET scanner for imaging small animals

The authors are presently constructing “ANIPET”, a new high spatial resolution PET scanner for imaging small animals. This instrument will be used to investigate new tracers and as a substitute for autoradiography. The instrument uses two pixellated BGO crystal arrays coupled to position-sensitive PMTs. Animals can be imaged in two modes. One is similar to a “whole-body” PET scan in which the detectors are stationary and the animal support couch moves longitudinally between the detectors. This mode is used for initial characterization of the bio-distribution of new tracers. In the second mode the animal support is first rotated through 90° in the horizontal plane, allowing the detectors to rotate about the animal´s head. This mode resembles a conventional 3-D PET scan using a partial detector ring. Fully reconstructed quantitative images can be obtained. Continuous motion of either the bed, or detectors (via computer-controlled translation stages), and list-mode data collection are used. The field of view is 65 mm (lateral) by 55 mm (axial). To image larger species, the detectors can be offset by up to 25 mm allowing the lateral FOV to extend to 90 mm