[Application of pre-clinical PET imaging for drug development]

Positron emission tomography (PET) is a sophisticated method for the quantitative and noninvasive imaging of biological functions by monitoring the delivery of tracers labeled with positron emitters (1C, 'aN, '"O, and 8F). The distribution and kinetic patterns of a labeled compound in relation to the specific biomolecule in the target tissue are assumed to reflect specific biological functions in the living body. A wide variety of labeled compounds as molecular probes have been developed to measure biochemical and physiological parameters, such as blood flow, glucose and oxygen metabolism, protein synthesis, and neurotransmitter receptor functions. Recently, PET has gradually been introduced into the research field of drug development both in pre-clinical and clinical stages. In the present chapter, the applications of animal PET with small animals (rats and mice) and non-human primates in drug development in the pre-clinical stage will be discussed based on our own experiences. In the course of drug development, the pre-clinical studies with experimental animals are indispensable, and these studies are expected to provide useful information to facilitate the development of drug candidates with more efficacy and fewer adverse effects in the clinical stage with