ABSTRACT
The high spatial resolution and structural definition obtainable using magnetic resonance imaging (MRI) makes it a promising modality for imaging processes at the molecular and cellular level. This chapter provides an overview of MR physics important for molecular imaging. MRI is based on the principle of nuclear magnetic resonance. Nuclei consisting of an odd number of protons and/or neutrons have a magnetic moment. The physics of MRI require significant time to collect the data necessary for image generation. Often the time required for data acquisition is long enough to encompass several cardiac or respiratory cycles. The sensitivity of a molecular imaging probe depends upon the distribution of the probe, the strength of the probe signal, and the means of detection of the probe. Probe distribution together with probetarget affinity determines the concentration of probe at the target for detection. Safety considerations for potential molecular imaging probes include speed and mode of clearance from the blood and body compartments.
