Molecular imaging typically uses radioactively labeled ligands to selectively visualize molecular targets at nano molar sensitivity. CT (or MRI) is routinely used for co-registration.
Within MICA molecular imaging is applied in the field of neurosciences (metabolism, perfusion, receptor kinetics, amyloid imaging), in translational oncology (metabolism, proliferation, hypoxia and cell death) and to monitor inflammatory processes (e.g. rheumatoid arthritis, colitis etc.).
Positron Emission Tomography (PET)
Positron emission tomography (PET) detects pairs of gamma rays emitted indirectly by short-living radionuclides (tracer), which are priory introduced into the body on a biologically active molecule (ligand). Three-dimensional images of tracer concentration within the body are then constructed by computer analysis which is often complemented with simultaneous CT (X-ray) or MRI data. Radionuclides used in PET scanning are typically isotopes with short half-lives such as carbon-11 (~20 min), nitrogen-13 (~10 min), oxygen-15 (~2 min), and fluorine-18 (~110 min). These radionuclides are incorporated either into endogenous compounds such as glucose, or into specific antibodies. As such PET technology can be used to trace the biologic pathway of any compound in a living animal/patient.
Single-photon emission computed tomography (SPECT) requires injection of a gamma-emitting radioisotope (tracer) into the bloodstream of the patient/animal. In contrast to radioisotopes used in PET, SPECT radio nucleotides have typically longer half-lives making them a preferred choice for linking with antibodies that require longer time intervals to achieve a steady-state binding.