Thallium-201 for medical use. Part 3: Human distribution and physical imaging properties.

Studies were undertaken to determine the biologic distribution of thallium-201 in man. The disappearance from the blood is extremely rapid and intracellular deposition is nearly immediate. The biologic half-time of thallium was measured by both the Brookhaven whole-body counter and the Donner whole-body scanner, with excellent agreement. The effective whole-body half-time of thallium-201 is about 57 hr. Concentration of activity was seen in the heart, kidneys, large bowel, and thyroid. The whole-body radiation dose is 0.21 rads/mCi.