Emergency Central is a collection of disease, drug, and test information including 5-Minute Emergency Medicine Consult, Davis’s Drug, McGraw-Hill Medical’s Diagnosaurus®, Pocket Guide to Diagnostic Tests, and MEDLINE Journals created for emergency medicine professionals. Explore these free sample topics:
-- The first section of this topic is shown below --
- 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
- Units and conversions:
Contact regional or federal authorities for guidance if radiation incident is suspected.
- 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.
- 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.
- Skin 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.