The International Congress of Radiology (ICR) is a meeting of radiologists for the exchange of ideas and the harmonisation of international standards and practice, first held in 1925 in London and held at regular intervals since then. Since 1994 it has become a biennial event. Until 1953 each congress was organised by radiological society of the host country, but in that year, a formal organisation, the International Society for Radiology was set up to provide continuity between the congresses.