For PET radiopharmaceuticals the important prerequisite is the availability of suiatable radionuclides, mainly with short half-lives and emission of positrons. That allows imaging by registration of the gamma radiation (annihilisation) in coincidence i.e one detector registeres a signal only when an opposite one also gets one signal.
Prooduction of the radionuclides is performed by cyclotrons. Important nuclides are 15O, 13N, 11C and 18F 18 with half-lives of 2 min, 10 min, 20 min and 110 min, respectively, In subsequent radiosyntheses by use of automatic modules the compounds (radiopharmaceuticals are prepared for clinical administrations).
In contrast to the past, technical improvements allow installations of facilities for productions, radiosynthesis, and quality control in any building without special constructed buildings.