Applied principles of radiopharmaceutical use in therapy

The initial consideration in use of a radiopharmaceutical in therapy is specificity of localization. A variety of biological principles such as active transport and binding to cellular components have been utilized to achieve this localization. The next concern is to maximize radiation to the lesion while minimizing that to the remainder of the body. This means that there is a major role to be played by emissions with a short path length (such as alpha particles, weak beta particles and Auger electrons). To achieve maximal irradiation of the lesion, dissociation of the radiolabel from the tissue should be minimized; potential approaches for achieving this are reviewed. Finally, "synergistic effects" between radiation and chemical agents are discussed.