A METHOD FOR STABILIZING TC-99M EXAMETAZIME PREPARED FROM A COMMERCIAL KIT

Technetium-99m exametazime (Tc-99m-d,l-HMPAO), prepared by the reconst itution of the Ceretec kit, is widely used in the investigation of reg ional cerebral blood flow. The radiochemical purity specification of n ot less than 80% lipophilic complex requires that the kit is used with in 30 min of reconstitution In certain circumstances this imposes rest rictions on its clinical availability. A number of approaches to exten ding the 30-min shelf life have been proposed and these are discussed. A method of stabilising the kit by the addition of 200 mug cobalt chl oride hexahydrate (COCl2.6H2O) in 2 ml of water is described. The addi tion of this solution can extend the shelf life of the reconstituted k it to at least 5 h post reconstitution.