Radiation Injury



  • Radiation in this chapter refers to ionizing radiation
  • Alpha (α) – helium nucleus; does not penetrate skin
  • Beta (β) – electron; penetrates tissue a few cm
  • Gamma (γ) – photon; penetrates body
  • Neutron – very penetrating; not detected by Geiger counter, but neutron emitters also emit γ radiation
  • Radioisotope/radionuclide – chemical element that emits radiation from its nucleus:
    • Radioactivity cannot be destroyed, only relocated or shielded
    • Being radioactive does not change element's other chemical and physical properties, such as heavy metal toxicity
  • Exposure/irradiation – patient has been in presence of ionizing radiation:
    • Whole body or only certain areas may be exposed
  • Contamination – radioactive material where it is not desired:
    • Internal – within body (e.g., lung)
    • External – outside body (skin, hair, clothing)
  • Dose – amount of radiation energy absorbed by tissue:
    • Units and conversions:
      • 1 gray (Gy) = 100 rad
      • 1 sievert (Sv) = 100 rem
    • For β and γ radiation:
      • 1 Gy = 1 Sv = 100 rad = 100 rem

Contact regional or federal authorities for guidance if radiation incident is suspected

Pediatric Considerations
  • Children are more sensitive to radiation injury
  • Potassium iodide is most protective for children and should be given promptly if contamination with radioactive iodine (I-131) is suspected

Pregnancy Considerations
  • Developing fetus is very sensitive to radiation
  • Pregnant staff should not care for radioactively contaminated patients


  • Ionizing radiation leads to cellular injury
  • Damage to blood vessels leads to endarteritis and loss of tissue blood supply
  • Higher rates of cell division within an organ make it more sensitive to radiation:
    • Bone marrow and GI tract are very sensitive
    • Muscle and nerve are less sensitive
  • Acute radiation syndrome (ARS) occurs in stages following whole-body exposure:
    • Prodromal: Acute radiation injury leads to acute inflammation (0–48 hr)
    • Latent: If the acute phase of injury is survived, inflammation and symptoms subside (0–2 wk)
    • Manifest illness: At higher radiation doses, organ failure then develops
    • Recovery or death (usually from infection) follows
  • Sources of radiation include medical devices, therapeutics, nuclear weapons, and industry

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