Safety and efficacy of radiopharmaceuticals are elements of great importance in nuclear medicine. Since the first meeting in 1965 in Oak Ridge with the title Radiopharmaceuticals tremendous developments have taken place. In 1965 the whole technetium-99m area was just in its very beginning. Safety and efficacy of the non-radioactive pharmaceuticals have attracted great attention during the last 10 years and so have similar aspects of radiopharmaceuticals during the later years. Regulatory agencies are extending their work also to the preparation of radiopharmaceuticals at hospitals and to requirements for registration of radiopharmaceuticals. In a fast developing field there might be tendencies to confrontation between interests and there have certainly been some tendencies to put undue restrictions on the use of radio­ pharmaceuticals due to the lack of understanding between the industry and the regulatory authorities and between regulatory authorities and hospitals. Much of this may have been due to lack of information and certainly is due to the lack of fundamental scientific knowledge in many radiopharmaceutical aspects. A fast and safe introduction of new radio­ pharmaceuticals and the proper handling of these requires a lot of development work, but also an understanding of how general principles from the non-radioactive drug field may be sensibly transformed into the radiopharmaceutical area. It may even require compromises between requirements for safety in different areas such as radiation protection and pharmaceutical aspects.