Radiochemical methodology constitutes the most important base for the successful functioning of a PET group in the routine production and development of radiopharmaceuticals. Of the several hundred products which have been labelled with positron emitters during the past two decades about 35 are presently considered to be of major interest. The time for a state-of-the- art review is right, since this field has advanced over the past fifteen years to reach a level where guidelines can now be suggested. Chapters of this book deal with each of the main methodological aspects of the chemistry needed to develop an effective radiopharmaceutical, namely radionuclide production, automation and metabolite