Positron emission tomography (PET) has well-established strengths which are commonly exploited in human clinical research. Not least of these are its dynamic and quantitative capabilities. The recent growth in small animal PET, spurred on by technological developments and an interest in the application of imaging to the field of genomics in mice, has seen impressive improvements in image spatial resolution. The availability of commercial small animal PET scanners has meant a broadening of the user base away from PET development environments and into experimental laboratories. This paper will review these developments and assess the impact on overall data quality.