Acute radiation exposures in the 10-17 gy-equivalent range

This scientific review examines the 1999 Tokaimura criticality accident in Japan, focusing on the severe radiation exposure sustained by the most heavily exposed worker, the reconstruction of radiation doses, the clinical progression of acute radiation syndrome (ARS), and the limitations of intensive medical treatment following extreme exposure. The review summarizes published clinical observations, dosimetric assessments, and radiation-safety literature. It discusses neutron and gamma radiation, hematopoietic injury, gastrointestinal damage, severe cutaneous effects, multiorgan dysfunction, and the challenges of interpreting radiation-dose estimates in a highly non-uniform exposure field. Particular attention is given to the distinction between absorbed dose measured in gray (Gy), equivalent or effective dose measured in sievert (Sv), and gray-equivalent quantities (GyEq) used in some clinical reports. These quantities are not interchangeable. The review explains why the frequently repeated description of the Tokaimura case as an exposure of “17 Sv” requires careful qualification and comparison with primary medical publications. The manuscript also considers lessons for radiation emergency medicine, retrospective dosimetry, criticality safety, occupational protection, and scientific communication. It is intended for researchers, students, radiation-protection professionals, medical specialists, and readers interested in radiation accidents and acute radiation injury. This work is a narrative review based on previously published scientific and institutional sources. It does not present new experimental data or constitute individual medical advice.