Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 6-8 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: 6-8 Gy

Acute Radiation Syndrome time phases resulting from 6-8 Gy radiation expoure Next

ARS time phases and approximate whole body dose from exposure: 6-8 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: <30 minutes after exposure
  • Percent of victims who vomit at this dose: 100%
  • Heavy
  • Onset: 1-3 hours after exposure
  • Percent of victims with diarrhea at this dose: >10% at low end; at high end of dose range ~100% of victims affected
  • Severe
  • Onset: 3-4 hours after exposure
  • Percent of victims with headache at this dose: 80%
Level of consciousness
  • May be decreased
Body temperature
  • High fever
  • Onset: < 1 hour after exposure
  • Percent of victims with fever at this dose: 100%
Medical response
  • Treatment in specialized hospital, if feasible
  • From end of prodrome through day ≤ 7
  • Usually complete hair loss
Medical response
  • Hospitalization urgently needed
  • <7 days after prodrome
  • Months
Potential clinical effects
  • Anorexia
  • Fever
  • Malaise, weakness
  • Bleeding, infection
  • Epilation: hair is lost by day 11
  • Nausea, vomiting
  • Diarrhea: common by day 6-9; more severe with increased dose from exposure
  • Disorientation
  • Hypotension
Medical response
  • For those with best prognosis, prolonged, aggressive supportive care, and possible hematopoietic stem cell transplant
  • Supportive care for all others
  • Percent of victims who die at this dose: >50% beginning at 1-2 weeks
  • Recovery will require prolonged, aggressive supportive care.
  • All victims who recover will require continued surveillance for late effects.
  • Psychological support helpful
Time to Recovery
  • Months to years
Time to Death
  • Days to weeks depending on dose and clinical complications
  • Aggressive supportive care may extend survival and salvage selected patients.