With the present Badgastein Symposium "Radioactive Isotopes in Clinical Medicine and Research" we have now had 40 years of an uninterrupted series of Badgastein meetings on nuclear medicine, since the first one took place in January 1954. We believe that this anni- versary is worth mentioning. The 21 st symposium proved again to offer a representative cross- section through the current topics of scientific interest of nuclear medicine. The general...