There are three main fields of nuclear medicine.

12.1.1 In Vitro Diagnostics

The meaning of in vitro is “measurement in a vial.” In this case, the patient does not make direct contact with the radioactive material, but the sample (blood, urine, etc.) is taken and analyzed using a radioactive component; in most cases, the concentration of a constituent will be measured. The first such procedures were developed by Yalow and Berson (1959) to measure insulin and by Ekins (1960) to measure thyroxin concentrations in blood. Rosalyn Yallow was awarded the Nobel Prize for medicine in 1977 for developing several peptide hormone RIAs. For further details, see Section 12.3.