An original emission tomograph for in vivo brain imaging of small animals

The principle of a new tomograph (TOHR) dedicated for small volume analysis with very high resolution is presented. The authors use uncorrelated multi-photon (X- or gamma rays) radioisotopes and a large solid angle focusing collimator to produce tomographic images without a reconstruction algorithm. With this device, detection efficiency and resolution are independent and submillimeter resolution can be achieved. A feasibility study shows that collimators made with a stack of chemically etched plates can achieve the predicted performances of TOHR. The authors discuss its potential in rat brain tomography by simulating a realistic neuropharmacological experiment using a 1.4 mm resolution prototype of the TOHR under development