Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 4-6 Gy
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Dose Range in gray (Gy)
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Data adapted from:
Diagnosis and Treatment of Radiation Injuries
(PDF - 202 KB)
(IAEA Safety Reports Series No. 2, Vienna 1998)

Timeline: 4-6 Gy

Acute Radiation Syndrome time phases resulting from 4-6 Gy radiation expoure Next

ARS time phases and approximate whole body dose from exposure: 4-6 Gy

Manifest Illness
Prodromal Latent Manifest Illness (Critical Phase) Recovery or Death
bar chart of subsyndrome severity of hematopoietic, gastrointestinal, and neurovascular subsyndromes
bar chart legend
  • Onset: <1 hour after exposure
  • Percent of victims who vomit at this dose: 100%
  • Mild at low end and moderate at high end of dose range
  • Onset: 3-8 hours after exposure
  • Percent of victims with diarrhea: <10% at low end; percentage increases at high end of dose range to ~10%
  • Moderate
  • Onset: 4-24 hours after exposure
  • Percent of victims with headache at this dose: 50%
Level of consciousness
  • Unaffected
Body temperature
  • Fever
  • Onset: 1-2 hours after exposure
  • Percent of victims with fever at this dose: 80-100%
Medical response
  • Treatment in specialized hospital, if feasible
  • From end of prodrome through day 8-18
  • Moderate to complete hair loss
Medical response
  • Hospitalization usually necessary
  • 8-18 days after prodrome
  • Weeks to months
Possible clinical effects
  • Anorexia
  • Fever
  • Malaise, weakness
  • Bleeding, infection
  • Epilation: hair is lost by day 11-21
  • Nausea, vomiting
  • Diarrhea: more severe at higher end of dose range with fluid and electrolyte loss
Medical response
  • Aggressive supportive care
  • Percent of victims who die at this dose: 20-70% beginning at 4-8 weeks
  • Recovery will require aggressive supportive care
  • All victims require continued surveillance for late effects
  • Psychological support helpful
Time to recovery
  • Months to years