Technetium-99m's short half-life of 6 hours makes long-term storage impossible. Transport of Tc from the limited number of production sites to radiopharmacies (for manufacture of specific radiopharmaceuticals) and other end users would be complicated by the need to significantly overproduce to have sufficient remaining activity after long journeys. Instead, the longer-lived parent nuclide Mo can be supplied to radiophamacies in a generator, after its extraction from the neutron-irradiated uranium targets and its purification in dedicated processing facilities. Radiopharmacies may be hospital-based or stand-alone facilities, and in many cases will subsequently distribute Tc radiopharmaceuticals to regional nuclear medicine departments. Development in direct production of Tc, without first producing the parent Mo, precludes the use of generators; however, this is uncommon and relies on suitable production facilities close to radiopharmacies.