Traditionally, the enormous variety of topics related to isotopes, both radioactive and stable, were presented at meetings and published in scientific journals associated with diverse scientific disciplines including chemistry, biomedical sciences, medicine, nuclear physics, nuclear technology, and industrial applications. The makers and users of isotopes had no international forum representing their specific needs to present achievements and exchange ideas related to their common interest: the preparation and application of isotopes.
The first meetings focused specifically on isotope applications were held in the 1950s under the banner of Advances in Tracers Methodology. These meetings brought together manufacturers of labeled compounds and nuclear instrumentation. In the 1960s, isotope-focused conferences continued in Europe through the EURATOM Symposia, which contributed significantly to the advancement of synthesis, analysis, purification, and application of isotopically labeled compounds.
Following another hiatus, the successful Kansas City International Symposia on the Synthesis, Analysis and Applications of Isotope-Labeled Compounds in 1982 and 1985 demonstrated the need for a permanent international organization. In response, the International Isotope Society (IIS) was incorporated in 1986 in New Jersey, USA, as an independent, non-profit international scientific organization.
Since its founding, IIS has served as the premier international forum for scientists engaged in isotope chemistry, radiochemistry, stable isotope applications, radiopharmaceutical sciences, tracer methodology, and related disciplines. Through international symposia, regional chapter meetings, awards programs, educational activities, and scientific publications, IIS has continually advanced the science and application of isotopes worldwide. The Journal of Labelled Compounds and Radiopharmaceuticals (JLCR) remains the official journal of the Society.
International Isotope Symposium Timeline
| Symposium | Year | Location |
| 1st | 1982 | Kansas City, Missouri, USA |
| 2nd | 1985 | Kansas City, Missouri, USA |
| 3rd | 1988 | Innsbruck, Austria |
| 4th | 1991 | Toronto, Canada |
| 5th | 1994 | Strasbourg, France |
| 6th | 1997 | Philadelphia, Pennsylvania, USA |
| 7th | 2000 | Dresden, Germany |
| 8th | 2003 | Boston, Massachusetts, USA |
| 9th | 2006 | Edinburgh, United Kingdom |
| 10th | 2009 | Chicago, Illinois, USA |
| 11th | 2012 | Heidelberg, Germany |
| 12th | 2015 | Princeton, New Jersey, USA |
| 13th | 2018 | Prague, Czech Republic |
| 14th | 2022 | Raleigh, North Carolina, USA |
| 15th | 2025 | Gothenburg, Sweden |
| 16th | 2028 | Boston, Massachusetts, USA (planned) |
Regional Chapters and Scientific Community Growth
Over the last two decades, IIS has expanded from a symposium-based organization into a global scientific network supported by active regional chapters and scientific communities in North America, Europe, the United Kingdom, China, and other regions. These chapters provide year-round opportunities for scientific exchange, networking, professional development, and collaboration among isotope scientists from academia, industry, government laboratories, and contract research organizations.
Recent Chapter Activities
| Year | Meeting | Location |
| 2025 | IIS China Chapter Meeting | Jiangyin, China |
| 2026 | IIS China Chapter Meeting | Shanghai, China |
| 2026 | 35th IIS North American Chapter Meeting | Morristown, New Jersey, USA |
| 2026 | IIS UK Group 32nd Annual Symposium | Cambridge, United Kingdom |
| 2026 | 28th IIS European Division Workshop | Bad Soden, Germany |
Continuing Evolution of IIS
The Society continues to evolve while maintaining its founding principles of scientific excellence, international collaboration, independence, and volunteer leadership. Recent initiatives have included modernization of the IIS website and communications infrastructure, expansion of social media outreach, strengthening of chapter activities, enhancement of scientific awards and recognition programs, and increased engagement in emerging fields such as radiopharmaceuticals, molecular imaging, PET chemistry, and radioligand therapeutics.
Today, IIS remains a truly international organization dedicated to advancing isotope science and technology for the benefit of chemistry, medicine, pharmaceutical research, agriculture, industry, and society. Through the dedication of its volunteer members and leadership, the Society continues to connect generations of isotope scientists and foster innovation across the global scientific community.
Looking ahead, IIS is preparing for the 16th International Isotope Symposium in Boston, Massachusetts, USA, in 2028, continuing a tradition that began more than four decades ago and ensuring that the Society remains at the forefront of isotope science for years to come.
