disease acute radiation syndrome A serious human disease that occurs when the entire body (or a large portion of it) is exposed to a high dose of penetrating radiation—typically more than 1 Gray (Gy)—over a short period (minutes to hours).Key features: Prodromal Phase (hours to days): Nausea, vomiting, diarrhoea, fatigue. Latent Phase (hours to weeks): Apparent improvement or absence of symptoms. Manifest Illness Phase: Depending on dose, damage to rapidly dividing cells leads to one or more syndromes: Hematopoietic syndrome (1–10 Gy): Bone marrow failure, infection, bleeding. Gastrointestinal syndrome (5–20 Gy): Severe GI tract damage, fluid loss, sepsis. Neurovascular syndrome (≥20 Gy): Neurological impairment, confusion, convulsions; usually fatal within days. Recovery or Death: If dose is survivable and supportive care is provided, recovery can occur over weeks to months; higher doses carry a poor prognosis. acute radiation sickness, ARS Dainiak, N., & Albanese, J. (2022). Medical management of acute radiation syndrome. Journal of radiological protection : official journal of the Society for Radiological Protection, 42(3), 10.1088/1361-6498/ac7d18. https://doi.org/10.1088/1361-6498/ac7d18. https://www.icrpaedia.org/Acute_radiation_syndrome