C70 Cyclotron Arronax in Nantes, France for the production of therapeutic radionuclides such as 67Cu, or 211At (Courtesy Arronax/IBA)
Radiopharmaceuticals are molecules combining two specific activities. These molecules contain a conventional chemical structure, called the vector, to which a radioactive atom is attached. The vector has the property to target in a unique way a molecular entity that is present only on one tissue, one cell or one organ and surely tumor is the best example. The radioactive atom may emit rays or particles. Depending on the type of emitted radiation, this atom will either play the role of imaging agent emitting a signal from target-bound tissue or of a therapeutic agent by destroying the neighbor cells, in fact the ones to which it is connected to.
Gamma emitters vectors that targets tumors allow to image cancer and its dissemination in the body (tumor and metastases imaging). The same agent linked to a radionuclide that will emit beta or alpha radiation will destroy these tumors and metastases. The effectiveness of the treatment is obviously depending on the quality of the vector (specificity), the choice of the radionuclide, but also on the right calculated dose. Millions of combinations are possible and only recently, the biological rules have been understood to better select vectors, while at the same time, the ideal radionuclides can be manufactured under pharmaceutical quality standards. Nuclear Medicine is ready to become in the near future a very efficient tool in cancer treatment.
