Biodistribution refers to the study of how a substance, such as a drug or nanoparticle, is distributed throughout the body after administration. This research area involves tracking the movement of the substance from the site of administration, through various organs and tissues, and ultimately its elimination from the body. Biodistribution studies are important in understanding the pharmacokinetics and safety of a drug or therapeutic agent, as well as optimizing drug delivery strategies. Techniques such as imaging, spectroscopy, and mass spectrometry are commonly used in biodistribution studies.