Labelling monoclonal antibodies with yttrium-90.

Using the cyclic DTPA derivatisation procedure developed by Hnatowich, conditions have been optimised for labelling three tumour-associated monoclonal antibodies with 90Y. High labelling efficiencies (greater than 95%) at modest specific activities (1 mCi/mg) could be routinely obtained. Radiochemical stability of the radiolabelled preparations in vitro was good, but radiolysis resulted in early losses of antibody immunoreactivity.