Animal studies on the in vivo stability of 211At-labelled albumin particles.

The alpha-emitter astatine-211 appears as one of the most suitable representatives for radiotherapy owing to its excellent decay properties. We report the studies in mice on the stability of the astatine bond to HSA-particles. Microspheres stick fast in the lung capillaries. There is a comparatively very slow decrease of radioactivity in the lungs. The 211At-labelled microspheres appear quite stable in vivo compared with a series of other biomolecules and so give a potential possibility for using the excellent radiophysical features of 211At in endogenous therapy of malignant tumours.