Neuroreceptor Imaging in Psychiatry: Theory and Applications

The ability of single photon emisssion computed tomography (SPECT) and positron emission tomography (PET) to image specific biomolecules in the living brain provides a unique tool for clinical researchers. Given this, it is not surprising that the use of neuroreceptor imaging techniques has become more widespread over the past decade. These tools are currently being used to study neurological and psychiatric disorders and to inform early-stage drug development. The accurate derivation of receptor parameters from PET or SPECT brain activity data involves model-based methodology. These models take into account the various sources comprising the total activity observed in the brain and fluctuations in the relative contributions from these sources over the time course of the scan. The goal of this chapter is to first present the theory underlying these models providing the reader with a conceptual framework for understanding this technique. Subsequently, we will discuss the specific methods used to generate the outcome measures from neuroreceptor studies in detail. Finally, the application of neuroreceptor imaging to the study of specific psychiatric illnesses will be reviewed.