An original approach for small animal emission tomography: TOHR; characterisation and first evaluation

The authors propose an original method for high resolution in vivo tomography adapted to small animal models studies: TOHR (French acronym for High Resolution Tomograph). They have designed and developed a large solid angle, high resolution and high efficiency focusing collimator. It defines the focal point which is used to scan the animal and finally to create the image. The high resolution is improved by using nuclides having a two-photon decay (Xor gamma rays). The authors have built a prototype of TOHR with a 3π collimator (15 over the 20 sides of an icosahedron). The different parts of the detector as well as the isofocusing method of the different modules of the collimator are described. The performance of the detector (energy, timing and spatial resolutions, detection efficiency) is presented and compared to the results of numerical simulations. The image quality is shown using hot spots phantom. Finally, first animal images are presented