Strategies in Synthesizing Short-Lived Radiopharmaceuticals for Positron Emission Tomography

Abstract

Positron Emission Tomography (PET) is one of the most exciting medical imaging modalities and it provides quantitative three dimensional images of specific biochemical, physiological and pathophysiological processes in living organs like brain, heart, liver, pancreas etc¹. PET uses radiopharmaceuticals that are labeled with short-lived isotopes. The majority of these short-lived radioisotopes are elements of the chemical compounds of biological systems (¹¹C., ¹³N, ¹⁵O, etc.). ¹⁸F is used to substitute a hydrogen atom of an organic molecule of interest with the assumption that the biological activity is not significantly altered. Over the years PET has proved to be an effective diagnostic modality and the demand for clinical PET has increased considerably. Clinical utility of PET has been useful for the evaluation of myocardial viability and for the differentiation of radiation necrosis from tumor recurrence²,³,⁴. Evaluation of brain disorders such as epilepsy, Parkinson’s disease, Alzheimer’s disease, Stroke etc. can be achieved by measuring the regional brain function⁵,⁶,⁷. Therefore, synthesis of the radiopharmaceuticals labeled with positron emitting radioisotopes is the key to the success of this state of the art diagnostic modality.