Special characteristics and potential for radiopharmaceuticals for positron emission tomography

The lower doses and possibilities for short-term serial studies are part of the advantage of short half-life radionuclides. Biomolecules of all sorts can be labeled with positron emitters without alteration of their biochemical and physiologic activity. By virtue of the annihiliation radiation from the positron emitter they can be located and quantitated in a small volume element of tissue. Present efforts are focused mainly on measuring metabolic rates in the brain and in the myocardium. Assessing receptor-site action in the brain and heart with labeled neuroleptics in under intensive development. Noninvasive methods that will allow us to evaluate the dynamics of such action in disease states and to quantitate the response to therapy can be expected in the near future. Protein synthesis and cell proliferation rates measured in vivo are under study. Synthetic techniqus and the development of both remotely operated and automated procedures yielding positron emitter labeled biomolecules of all sorts, including simple alcohols, sugars, amino acids, steroids, alkaloids, and a host of drugs, made possible a wholly new area in nuclear medicine. The efforts of the next several years served by increasing interest and investments in this area will demonstrate whether the great promise of the organic radiopharmaceuticals labeled with positron emitters will be realized