⁹⁰Y-DOTA-biotin consists of a

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

substance (

yttrium-90 Yttrium-90 () is a radioactive isotope of yttrium. Yttrium-90 has found a wide range of uses in radiation therapy to treat some forms of cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the ...

) complexed by a

chelating agent Chelation () is a type of bonding of ions and their molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These l ...

(

DOTA ''Dota'' is a series of strategy video games. The series began in 2003 with the release of ''Defense of the Ancients'' (''DotA''), a fan-developed multiplayer online battle arena (MOBA) custom map for the video game ''Warcraft III: Reign of Ch ...

), which in turn is attached to the vitamin

biotin Biotin (also known as vitamin B7 or vitamin H) is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. ...

via a chemical linker. It is used experimentally in pretargeted

radioimmunotherapy Radioimmunotherapy (RIT) uses an antibody labeled with a radionuclide to deliver cytotoxic radiation to a target cell. It is a form of unsealed source radiotherapy. In cancer therapy, an antibody with specificity for a tumor-associated antigen ...

. Animal studies have been conducted as well as clinical studies in humans. In pretargeted radioimmunotherapy, two or three medications are applied in succession. At first, an antibody-drug conjugate is administered, which consists of a

monoclonal antibody A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodie ...

designed to target the tumour, and a chemical marker which in the case of DOTA-biotin therapy is one of the proteins

avidin Avidin is a tetrameric biotin-binding protein produced in the oviducts of birds, reptiles and amphibians and deposited in the whites of their eggs. Dimeric members of the avidin family are also found in some bacteria. In chicken egg white, a ...

and

streptavidin Streptavidin is a 52 Atomic mass unit, kDa protein (tetramer) purified from the bacterium ''Streptomyces avidinii''. Streptavidin Homotetramer, homo-tetramers have an extraordinarily high affinity for biotin (also known as vitamin B7 or vitamin ...

. After a time of typically one or two days to let the antibody accumulate in the tumour, a clearing agent may be given to eliminate residues of antibody that are still circulating in the bloodstream; this is especially done in humans. After a further waiting time, the radiotherapy (⁹⁰Y-DOTA-biotin) is administered. Due to the high affinity of biotin to avidin and streptavidin, the radiotherapy accumulates where the antibody is, namely in the tumour, where it delivers its radioactivity. 90Y-DOTA-biotin skeletal

References

Radiopharmaceuticals DOTA (chelator) derivatives {{nuclear-med-stub