[3] Some synthetic radioisotopes are extracted from spent nuclear reactor fuel rods, which contain various fission products.
Gamma cameras and other similar detectors are highly efficient, and the tracer compounds are generally very effective at concentrating at the areas of interest, so the total amounts of radioactive material needed are very small.
The metastable nuclear isomer technetium-99m is a gamma-ray emitter widely used for medical diagnostics because it has a short half-life of 6 hours, but can be easily made in the hospital using a technetium-99m generator.
Weekly global demand for the parent isotope molybdenum-99 was 440 TBq (12,000 Ci) in 2010, overwhelmingly provided by fission of uranium-235.
[8] Several radioisotopes and compounds are used for medical treatment, usually by bringing the radioactive isotope to a high concentration in the body near a particular organ.