Small animal PET: a review of commercially available imaging systems

More than ten years ago, several research groups started to develop Positron Emission Tomography (PET) systems dedicated to animal studies. The growing interest in pre-clinical imaging studies, both in biological and medical basic research, and in pharmaceutical industry, has recently induced the world-leading manufacturers of medical image equipment to invest in this market. Some of the proposed scanner prototypes in an overhauled and/or enhanced version, turned into commercial systems, and five PET scanners dedicated to small animals (mice and rats) are today commercially available: "Explore Vista" from General Electric Healthcare (Waukesha, Wisconsin, USA), "microPET Focus" from Concorde Microsystems, Inc., (Knoxville, Tennessee, USA), "quad-HIDAC" from Oxford Positron Systems Ltd. (Weston-on-the-Green, Oxfordshire, UK), "Mosaic" from Philips Medical Systems (Milpitas, California, USA) and "Yap- PET" from I.S.E. Srl (Migliarino Pisano, Pisa, Italy). This paper reviews the commercially available systems describing each tomograph in terms of gantry geometry, detector material, detector size and configuration, and reporting the parameters (field of view, spatial resolution, and sensitivity) characterizing the imaging capability. A critical discussion on some aspects related to the use of these systems is reported.