We have previously performed quantitative kinetic modeling of [I-123] CNS 1261, a new SPET ligand for the MK801 intrachannel site of the NMDA receptor. We now report a bolus-infusion protocol, which eliminates the need for arterial blood sampling. Dynamic SPET scanning and venous blood sampling were performed in 7 healthy volunteers. Good agreement was obtained between kinetic and equilibrium analysis. SPET scanning with a bolus-infusion protocol is a valid method to estimate the total volume of distribution for [I-123]CNS 1261 in clinical populations. (C) 2004 Elsevier Inc. All rights reserved.