Molecular nuclear medicine: from genotype to phenotype via chemotype.

Molecular nuclear medicine can image in vivo biochemistry. Studies with receptor-based radiopharmaceuticals provide windows to the biochemical processes of proteins as they carry out instructions from genetic coding. The patient's genotype determines this biochemical expression of phenotype. Radiotracer studies that visualize in vivo biochemistry provide a glimpse at a patient's "chemotype." Molecular nuclear medicine enables us to connect genotype to phenotype via chemotype. Diagnostic medicine will move past the point of grouping patients according to clinical signs and symptoms. More and more, diseases will be viewed as biochemical processes rather than the clinical manifestations of those processes. Today, there are examples of molecular nuclear medicine studies that affect medical decision-making.