Astatine (211At) as a therapeutic radionuclide. The plasma: Blood cell distribution in vitro

Abstract Therapy of carcinoma of the thyroid may include the use of the radionuclide 131 I, which localizes to thyroid tissue. In considering the use of another halogen, the α particle emitting radionuclide astatine, 211 At, there is also the requirement that it too can be taken up by the thyroid. However, in view of its short half-life (7.2 h) it is important that its transport in the blood is not a factor likely to render it less available. For example, retention of 211 At by red cells may retard its uptake by the thyroid. This in vitro in-vestigation of the partitioning of the 211 At between erythrocytes and plasma indicates that it is not strongly bound by the red cells in blood.