Niels Bohr's atomic model from 1913 is the basis for millions of medical scans today 100 years later. George de Hevesy and Niels Bohr developed the tracer principle in Copenhagen in the 1920s and 30érne, with the administration of a very small amount of tracer (radiopharmaceutical) initially to physiological turnover studies. In the 1950s, image formation was developed with PET and later the Gamma camera. Hevesy won the Nobel Prize in 1943 for the tracer principle.
Today, nuclear medicine is used with many different tracers for diagnosis of disease: the staging of cancer disease, evaluation of treatment effect, planning of radiation therapy and operations, diagnosis of heart and kidney function within Transplantation and Sentinel node skildvagtslymphecroscintigraphy to find dispersion from e.g. Chest. In Denmark, 130,000 nuclear medicine studies are carried out annually (2011). With modern advanced hybrid scanners, PET/CT and PET/MRI combine the two imaging principles into one scanner: PET (positron emmision tomography) with CT (computed tomography) and PET combined with MRI (magnetic resonance).
PET has been referred to as "the fastest growing medical technology ever" because the method has such a strong diagnostic performance.