Parametric PET Imaging of 5HT2AReceptor Distribution with 18F-Setoperone in the Normal

Because of 5HT2A receptor's (5HT2AR) putative role in several neuropsychiatrie diseases, studying it in vivo is an important goal. 18F-setoperone is a well-validated and widely used PET radioligand for the study of neocortical 5HT2AR.We have previ ously developed and validated in baboons a method to generate parametric maps of the binding potential (i.e., the k3-to-k4ratio) on a pixel-by-pixel basis, based on a single-dose tracer amount dynamic 18F-setoperone PET paradigm, and with the receptor-poor cerebellum as reference structure. However, previous semiquantitative PET human studies suggested that nonspecific (NS) binding in the neocortex might not be identical to that in the cerebellum. Methods: As a first step in the development of k3:k4 parametric mapping in humans, we therefore estimated directly the NS binding of 18F-setoperone in the neocortex of four young healthy volunteers who were studied with PET both before an