INFOBOX Magnetic marker monitoring (MMM) is a non-invasive and radiation-free imaging tool for the investigation of the behavior (e.g., transit, disintegration, drug release) of solid oral dosage forms such as tablets, capsules, or single pellets in the GI tract. It is based on the labelling of dosage forms as a magnetic dipole using ferromagnetic materials, as well as measurement of the dipole field distribution using arrays of magnetic field sensors.