Small animal PET: aspects of performance assessment

Abstract

Dedicated small animal positron emission tomography (PET) systems are increasingly prevalent in industry (e.g. for preclinical drug development) and biological research. Such systems permit researchers to perform animal studies of a longitudinal design characterised by repeated measurements in single animals. With the advent of commercial systems, scanners have become readily available and increasingly popular. As a consequence, technical specifications are becoming more diverse, making scanner systems less broadly applicable. The investigator has, therefore, to make a decision regarding which type of scanner is most suitable for the intended experiments. This decision should be based on gantry characteristics and the physical performance. The first few steps have been taken towards standardisation of the assessment of performance characteristics of dedicated animal PET systems, though such assessment is not yet routinely implemented. In this review, we describe current methods of evaluation of physical performance parameters of small animal PET scanners. Effects of methodologically different approaches on the results are assessed. It is underscored that particular attention has to be paid to spatial resolution, sensitivity, scatter fraction and count rate performance. Differences in performance measurement methods are described with regard to commercially available systems, namely the Concorde MicroPET systems P4 and R4 and the quad-HIDAC. Lastly, consequences of differences in scanner performance parameters are rated with respect to applications of small animal PET.

Performance Evaluation of the FLEX Triumph X-PET Scanner Using the National Electrical Manufacturers Association NU-4 Standards

“…Standardization of the assessment of system performance characteristics is thus highly desired (13,14). Recently, the National Electrical Manufacturers Association (NEMA) published its NU 4-2008 standards for performance evaluation of small-animal PET scanners (15).…”

18F-FDG PET/MRI Can Be Used to Identify Injured Peripheral Nerves in a Model of Neuropathic Pain

“…To our knowledge, this study was the first to address nociception-related 18 F-FDG uptake in peripheral nerves. Metabolic imaging of peripheral nociception has been challenged by the relatively poor spatial resolution of small-animal PET, which varies from 0.7 to 1.84 mm in full width at half maximum in phantom studies (17) (the sciatic nerve is 1-2 mm thick in rats), and the difficulty in distinguishing peripheral nerves from background activity using PET alone.…”

An Imaging System to Monitor Efficacy of Adenovirus-Based Virotherapy Agents

“…With an 18 F positron emitting substitution, it is possible to determine TK substrate incorporation into cells by PET. PET is the current paradigm for sensitivity to molecular events with in vivo imaging, and animal microPET systems are now available providing greater than 1-mm resolution (Weber and Bauer, 2004). MicroPET is ideally suited to imaging molecular events in animal studies because of its sensitivity and because the animals can be repeatedly scanned to follow the course of the disease (Luker et al, 2003).…”