This book provides information on the production and processing of four important long lived parent radionuclides, 68Ge, 82Sr, 90Sr and 188W, used for the preparation of generators for nuclear medicine applications such as positron emission tomography and therapy. It includes descriptions of the production routes for and process chemistry of the selected parent radionuclides, including relevant separation approaches. Information on use of the generator system and on physical and chemical characteristics is also provided.