Molecular imaging techniques directly or indirectly monitor and record the spatiotemporal distribution of molecular or cellular processes for biochemical, biologic, diagnostic, or therapeutic applications (Thakur ML, Lentle BC; J Nucl Med. 2005 46(9):11N-13N, 42N).
In 2007, the SNM molecular imaging center of excellence recommended an expanded definition. Molecular imaging is the visualization, characterization, and measurement of biological processes at the molecular and cellular levels in humans and other living systems. Molecular imaging typically consists of 2- or 3-dimensional imaging as well as quantification over time. The techniques used include radiotracer imaging/nuclear medicine, MR imaging, MR spectroscopy, optical imaging, ultrasound, and others (Mankoff DA; JNM 48(6)18N, 2007).