Caution signTime Phases of ARS - Caveats and Comments

(See Time Phases of Acute Radiation Syndrome)

  • The tables and illustrations in this section were adapted from the IAEA document: Safety Reports Series No. 2 - Diagnosis and Treatment of Radiation Injuries, 1998.
  • This document uses clinical observations in two populations exposed to various ranges of whole body radiation: 1) healthy radiation workers and 2) citizens exposed to radiation but no physical trauma.
  • Thus, although the IAEA document presents specific clinical effects expected for each radiation dose range, actual clinical findings in the "general population" would probably be more variable and nuanced than those seen in the relatively homogeneous IAEA populations.
  • A "general population" includes persons at extremes of age (from newborns to the elderly), and persons at extremes of health (from the very healthy to the chronically and/or acutely ill). These factors will modify the expected timing and severity of adverse health effects associated with each radiation dose level. Therefore, clinicians should not expect that a specific dose or dose range will inevitably or invariably lead to the same clinical outcome in every victim.
  • The tables and illustrations in this section are intended to convey the clinical continuum of ARS, with increasing radiation dose resulting in increasingly severe clinical effects which develop over a shorter period of time.
  • To emphasize this clinical variability, the edges of the borders between the phases of ARS merge gradually, as indicated by the gradual color changes.
  • The clinical outcomes in the original IAEA tables from 1998 also do not reflect the potential efficacy of newer techniques for aggressive supportive care, which may enable salvage in some patients previously thought to be lethally irradiated.
  • The dose ranges used in the IAEA document are arbitrary. Other ranges to describe ARS effects are presented in other documents on this topic, including in the Time/Dose Effects in ARS Illustration on REMM, which is based on a NATO document1 describing radiation effects in a military population of young men.
  • Clinicians may also wish to review other classic documents about ARS that use other dose ranges to present expected ARS effects over time. 1, 2, 3
  • Clinical variability after radiation exposure may reflect
    • The population affected, e.g., young male soldiers1 only vs. a more varied "genral population" of civilians2
    • Uncertainties about the dose actually received in a mass casualty event
    • Presence/absence of prompt, sophisticated, appropriate medical care, as would be needed after a mass casualty radiation event
  • Worse clinical outcomes are generally associated with
    • Higher whole or partial body dose and higher dose rate
    • Combined injury: burn and/or trauma + radiation exposure
    • Underlying host factors, e.g., chronic medical conditions, young/old age, immunocompromise
Adapted from: Diagnosis and Treatment of Radiation Injuries (PDF - 202 KB) (IAEA Safety Reports Series No. 2, Vienna 1998)


  1. NATO Handbook on the Medical Aspects of NBC Defensive Operations AMedP-6(B), Chapter 6, General Medical Effects of Nuclear Weapons: Diagnosis, Treatment, and Prognosis, 1 February, 1996.
  2. Gusev IA, Guskova AK, Mettler FA Jr, eds.: Medical Management of Radiation Accidents, 2nd ed. Boca Raton, Fl: CRC Press, 2001.
  3. Fliedner TM, Friesecke I, Beyrer K. Medical Management of Radiation Accidents: Manual on the Acute Radiation Syndrome. (METREPOL) (PDF - 970 KB) (originally published by Oxford: British Institute of Radiology; 2001) Compendium to the main METREPOL document (PDF - 580 KB)

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