Radiopharmaceuticals labelled with positron-emitting radioisotopes

This chapter reviews the preparation of radioisotopes for biochemical and physiological studies and the principal methods for their incorporation into radiopharmaceuticals, while pointing out the problems encountered with their use and considering their medical interest in the following areas: distribution and flow of fluids, metabolic and pharmacokinetic studies. Inorganic and organic radiopharmaceuticals presently in use and most probable to be used in the future are reviewed. It is anticipated that three types of products labelled with 15O, 13N, 11C and 18F will be developed in the future. The first type includes products which trace general phenomena such as fluid movement or metabolism of sugars, fats and proteins. The compromise between physiological accuracy and imaging technology is discussed in relation to the use of 11C and 18F. The second type of product is one to measure more specific parameters such as those of molecular transport kinetics, membrane permeability, cellular pH and receptor-ligand interactions, again with particular reference to 11C and 18F. The third type of product discussed is that intended for pharmacology studies, particular reference being made to 68Ga, 82Rb. Extensive bibliography. (U.K.)