284350 20260212105835.0 10.3390/ijms27020590 doi pmid:41596242 pmid 1422-0067 ISSN 1661-6596 ISSN DZNE-2026-00121 English 540 Schomäcker, Klaus 0000-0003-2636-0058 0 Airborne Radioiodine: A Comparative View of Chemical Forms in Medicine, Nuclear Industry, and Fallout Scenarios. Basel 2026 Molecular Diversity Preservation International article DRIVER Output Types/Journal article DataCite Journal Article journal journal PUB:(DE-HGF)16 1770812428_18491 PUB:(DE-HGF) Review Article ARTICLE BibTeX JOURNAL_ARTICLE ORCID Journal Article 0 EndNote Airborne iodine-131 plays a pivotal role in both nuclear medicine and nuclear safety due to its radiotoxicity, volatility, and affinity for the thyroid gland. Although the total exhaled activity after medical I-131 therapy is minimal, over 95% of this activity appears in volatile organic forms, which evade standard filtration and reflect metabolic pathways of iodine turnover. Our experimental work in patients and mice confirms the metabolic origin of these species, modulated by thyroidal function. In nuclear reactor environments, both under routine operation and during accidents, organic iodides such as [131I]CH3I have also been identified as major airborne components, often termed 'penetrating iodine' due to their low adsorption to conventional filters. This review compares the molecular speciation, environmental persistence, and dosimetric impact of airborne I-131 across clinical, technical, and accidental release scenarios. While routine reactor emissions yield negligible doses (<0.1 µSv/year), severe nuclear incidents like Chernobyl and Fukushima have resulted in significant thyroid exposures. Doses from these events ranged from tens of millisieverts to several Sieverts, particularly in children. We argue that a deeper understanding of chemical forms is essential for effective risk assessment, filtration technology, and emergency preparedness. Iodine-131 exemplifies the dual nature of radioactive substances: in nuclear medicine its radiotoxicity is therapeutically harnessed, whereas in industrial or reactor contexts it represents an unwanted hazard. The same physicochemical properties that enable therapeutic efficacy also determine, in the event of uncontrolled release, the range, persistence, and the potential for unwanted radiotoxic exposure in the general population. In nuclear medicine, exhaled activity after radioiodine therapy is minute but largely organically bound, reflecting enzymatic and metabolic methylation processes. During normal reactor operation, airborne iodine levels are negligible and dominated by inorganic vapors efficiently captured by filtration systems. In contrast, major accidents released large fractions of volatile iodine, primarily as elemental [131I]I2 and organically bound iodine species like [131I]CH3I. The chemical nature of these compounds defined their atmospheric lifetime, transport distance, and deposition pattern, thereby governing the thyroid dose to exposed populations. Chemical speciation is the key determinant across all scenarios. Exhaled iodine in medicine is predominantly organic; routine reactor releases are negligible; severe accidents predominantly release elemental and organic iodine that drive environmental transport and exposure. Integrating these domains shows how chemical speciation governs volatility, mobility, and bioavailability. The novelty of this review lies not in introducing new iodine chemistry, but in the systematic comparative synthesis of airborne radioiodine speciation across medical therapy, routine nuclear operation, and severe accident scenarios, identifying chemical form as the unifying determinant of volatility, environmental transport, and dose. 353 - Clinical and Health Care Research (POF4-353) G:(DE-HGF)POF4-353 POF4-353 POF IV 0 Dataset connected to CrossRef, PubMed, , Journals: pub.dzne.de airborne I-131 Other iodine speciation Other nuclear fallout Other radioiodine therapy Other routine reactor emissions Other Iodine Radioisotopes NLM Chemicals Air Pollutants, Radioactive NLM Chemicals Iodine-131 NLM Chemicals Radioactive Fallout NLM Chemicals Iodine Radioisotopes: chemistry MeSH Iodine Radioisotopes: analysis MeSH Iodine Radioisotopes: adverse effects MeSH Humans MeSH Animals MeSH Air Pollutants, Radioactive: analysis MeSH Air Pollutants, Radioactive: chemistry MeSH Air Pollutants, Radioactive: adverse effects MeSH Radioactive Fallout: analysis MeSH Nuclear Medicine MeSH Thyroid Gland: radiation effects MeSH Sudbrock, Ferdinand 1 Fischer, Thomas P:(DE-2719)9000370 2 Dietlein, Felix 0000-0002-6651-7155 3 Dietlein, Markus 0000-0003-0992-6099 4 Krapf, Philipp 5 Drzezga, Alexander P:(DE-2719)2811239 6 Last author dzne 10.3390/ijms27020590 Vol. 27, no. 2, p. 590 - PERI:(DE-600)2019364-6 2 590 International journal of molecular sciences 27 2026 1422-0067 OpenAccess http://pub.dzne.de/record/284350/files/DZNE-2026-00121.pdf OpenAccess pdfa http://pub.dzne.de/record/284350/files/DZNE-2026-00121.pdf?subformat=pdfa oai:pub.dzne.de:284350 openaire open_access VDB driver dnbdelivery Deutsches Zentrum für Neurodegenerative Erkrankungen I:(DE-588)1065079516 DZNE 6 P:(DE-2719)2811239 DE-HGF Gesundheit Neurodegenerative Diseases G:(DE-HGF)POF4-350 G:(DE-HGF)POF4-353 G:(DE-HGF)POF4 G:(DE-HGF)POF4-300 G:(DE-HGF)POF Clinical and Health Care Research 0 2026 DBCoverage StatID:(DE-HGF)0200 StatID SCOPUS 2024-12-21 DBCoverage StatID:(DE-HGF)0300 StatID Medline 2024-12-21 Creative Commons Attribution CC BY 4.0 LIC:(DE-HGF)CCBY4 HGFVOC DBCoverage StatID:(DE-HGF)0600 StatID Ebsco Academic Search 2024-12-21 DBCoverage StatID:(DE-HGF)1150 StatID Current Contents - Physical, Chemical and Earth Sciences 2024-12-21 WoS StatID:(DE-HGF)0113 StatID Science Citation Index Expanded 2024-12-21 DBCoverage StatID:(DE-HGF)0150 StatID Web of Science Core Collection 2024-12-21 OpenAccess StatID:(DE-HGF)0510 StatID Peer Review StatID:(DE-HGF)0030 StatID ASC 2024-12-21 DBCoverage StatID:(DE-HGF)0160 StatID Essential Science Indicators 2024-12-21 DBCoverage StatID:(DE-HGF)0199 StatID Clarivate Analytics Master Journal List 2024-12-21 I:(DE-2719)1011202 AG Boecker Positron Emissions Tomography (PET) 0 journal VDB UNRESTRICTED I:(DE-2719)1011202 FullTexts