Radiation Injury

Basics

Description

  • 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 (n): Very penetrating; not detected by Geiger counter, but neutron emitters also emit α and 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 (lung, GI tract)
      • 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
ALERT

Contact regional and 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 likely (reactor breach, nuclear detonation)

Pregnancy Considerations

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

Etiology

  • 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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