Nuclear Medicine developed rapidly in Europe, Asia, Australia, and South Africa after WWII. Progress in clinical and research innovations has been rapid in the UK, Europe, Australia, Scandinavia, Latin America, and Israel. China, Japan, and South Korea have become major contributors outpacing developments in other regions. The rapid evolution of Nuclear Medicine has been aided by the work of the United Nations, the World Health Organization (WHO), and its sister organization, the International Atomic Energy Agency (IAEA). Both have disseminated and updated knowledge of radiation applications, and effects, and accelerated progress by sponsoring important meetings. These brought together leading scientists from many countries and helped define new areas of emerging interest. During the cold war, it was one place where Russian scientists were able to communicate with colleagues in the West. Some of the countries in Europe, Japan, China Korea and Israel have led in the evaluation of new radio-labeled tracers in patients more so than elsewhere, including the United States. This is partly due to differences in regulatory practices, and reimbursement issues. Italian Universities have conducted many of the large multicenter radioimmunotherapy (RIT) trials. This is likely to increase elsewheere, given the growing need for evidence-based guidelines that require data from coordinated multi-institution trials. New findings that emerge should lead to new, improved clinicaL practices. Much of modern radioimmunology is built on fundamental work that began in Melbourne, Australia that since has extended given improved methods of molecular targeting and is likely to advance rapidly. Emerging knowledge of genetic differences between host and tumor signatures promises to have a major impact on medicine in general and nuclear medicine in particular. New cancer therapy agents are developed by industry, often as spin-offs from University-based discoveries. Fundamental instrumentation ideas historically came first from University-based research, followed by commercial development into user-friendly commercial systems. Industry has improved the user interface, and added built in computational capabilities. The major companies are in the United States, Germany, Japan, Korea, Israel, Netherlands, Scandinavia, and Hungary. Some are closely coupled to a University, for example the Milabs/Delft collaboration. China is actively entering the imaging instrumentation field as well, as instrumentation development is once again an expanding international enterprise. Recently, Wai-Hoi Wong has developed a PET TOF system that is being built in China.