Abstract: A novel method is set out of preparation of radioactive diagnostic radiopharmaceutical in a stable, shippable, lyophilized form by an apparatus designed to rapidly flash freeze and dehydrate a radiopharmaceutical composition to minimize auto radiolysis. The method proposes rapid cooling and removal of ambient vapor, and then ultra cold removal when the potential of explosive liquid oxygen is eliminated. The radioactive diagnostic radiopharmaceutical requires no further cold or refrigerated storage, including with respect to shipping, subsequent to stabilization. The preferred composition can be reconstituted “on site” by the addition of a suitable diluent to bring the radiopharmaceutical complex into solution at a desired concentration.