Small animal PET: aspects of performance assessment

Review articleSmall animal PET: aspects of performance assessmentSimone Weber1, Andreas Bauer21 Central Institute for Electronics, Research Center Jlich, Jlich, Germany2 Institute of Medicine, Research Center Jlich, Jlich, GermanyPublished online: 2 October 2004

Springer-Verlag 2004Abstract. 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.Eur J Nucl Med Mol Imaging (2004) 31:15451555DOI 10.1007/s00259-004-1683-xIntroductionDedicated small animal positron emission tomography

(PET) scanners are attracting increasing interest for the

purposes of preclinical drug development and experimental studies in animal models of various diseases. Extensive reviews on small animal PET research scanners

have been published [15], describing the design and

characteristics of different commercial and non-commercial systems and highlighting the potential of dedicated

small animal scanners.It is becoming increasingly clear that the users decision on which scanner to use for the intended experiments should be guided by precise knowledge of the

physical characteristics of available scanners. For human

PET scanners, the performance evaluation normally follows NEMA standards NU 2-1994 [6, 7] or NU 2-2001

[8, 9]. Scanner performance is expressed...