Relationships between radiotracer properties and image quality in molecular imaging of the brain with positron emission tomography.
In molecular imaging of the brain, many factors affect the reliability of the quantitative information that can be derived from the imaging process. This article discusses factors impacting on the imaging quality that are related to the radiotracer per se. Following a brief summary of key concepts in receptor quantification, a number of these factors are discussed, including selectivity, affinity, delivery, and lipophilicity. Concepts discussed in the theoretical section are then illustrated, by reviewing a recent comparative evaluation of four agents developed to label the serotonin transporter ([(11)C]ADAM, [(11)C]DASB, [(11)C]DAPA, and [(11)C]AFM). Specifically, the relationship between affinity and lipophilicity, measured in vitro, and several scanning parameters are investigated. These include peripherical metabolism, brain uptake, required scanning time, nonspecific binding, and binding potential. It is shown that, within a given structural family, affinity and lipophilicity are associated with scan outcome in a relatively predictable manner.
Laruelle
Marc
M
Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. ml393@columbia.edu
Slifstein
Mark
M
Huang
Yiyun
Y
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D050356:Lipid Metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010215:Papio; D011869:Radioligand Assay; D019275:Radiopharmaceuticals; D050486:Serotonin Plasma Membrane Transport Proteins; D014055:Tomography, Emission-Computed / Q000379:methods* / Q000592:standards
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D019275:Radiopharmaceuticals; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins