A fine focus x-ray tube contains a focal spot smaller than 0.5 millimeters.

The first pass scintigraphy allows imaging of the first passage of a radiopharmaceutical through the heart or artery. After a bolus injection of the radioactive material, the first pass scintigraphy (or angiography) gives information over the cardiac circulation or blood supply in various organs.

Atomic or nuclear fission is the process of splitting a heavy nucleus into two lighter nuclei. Some nuclides split up spontaneous as a type of radioactive decay. In other elements, fission is induced through the reaction of an incident radiation with the nucleus. High energy rates are released during the fission reaction (difference between the binding energies); this energy is used to produce heat and electricity e.g. in nuclear power plants.

A fixer is a chemical solution that removes the undeveloped silver halide crystals from films. Fixer also helps to harden the gelatin containing the black metallic silver so the film may be dried more readily.

The flare phenomenon is an increased activity uptake, seen in scintigraphic procedures in the early phases of therapy or due to healing processes.