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(Ionizing Radiation Exposure)


Radiation is energy that is sent out from a source. Radiation exposure happens when you’re exposed it.

It can be found in nature. It can also be manmade. Ultraviolet (UV) rays come from the sun. They can also come from microwaves used to heat food.

There are 2 types:

  • Ionizing—High frequency and can injure cells. Linked to cancer and other health problems.
  • Nonionizing—Low frequency and is not known to cause cancer. However, UV rays can.

This fact sheet focuses on the ionizing type.


Ionizing radiation can come from:

  • X-rays
  • Cancer treatment
  • Radioactivity found in the soil or in public works such as water
  • Work such as mining
  • Fallout from a nuclear accident or bomb
External Radiation Therapy for Cancer
Radiation of Tumor
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Risk Factors

Your chances of exposure are higher if you are near sources that make it.

Health problems may not happen in everyone. Having a chest x-ray does expose you to some radiation. The dose and risk for health problems is low. Other tests, like CT scans , expose you to higher doses. Health risks from CT scans, while still small, are higher than from x-rays .

The higher the exposure, the more likely there will be problems.


Cancer may take years to grow after exposure. Common types are:


Radiation sickness may cause:

  • Nausea
  • Weakness
  • Hair loss
  • Diarrhea
  • Bleeding
  • Burns
  • Loss of organ function


The doctor will ask about your symptoms and health history. You may have:

  • A physical exam
  • Blood tests
  • Stool tests
  • Urine tests

A radiation survey meter can measure the amount of radiation in your body.


If you were contaminated, you may have:

  • Materials removed
  • A bath with soap and lukewarm water
  • Your levels watched

If you have radiation sickness, care will depend on the where the damage is. You will be watched closely during care.

Radioactive iodine can be taken in by the thyroid gland. This can cause harm and lead to thyroid cancer. Potassium iodine will block the body from taking in this type.


Talk to your doctor or manager about the best ways to lower your chances of exposure. There are policies in place to help you. Ask about the risk of exposure during visits with your doctor or dentist.


Centers for Disease Control and Prevention 

Radiation Emergency Medical Management 


Canadian Nuclear Safety Commission 

Public Health Agency of Canada 


Brenner DJ. Should we be concerned about the rapid increase in CT usage? Rev Environ Health. 2010;25(1):63-68.

Colang JE, Killion JB, Vano E. Patient dose from CT: a literature review. Radiol Technol. 2007;79(1):17-26.

Frequently asked questions on potassium iodide (KI). US Food & Drug Administration website. Available at: Updated October 14, 2016. Accessed July 23, 2018.

Gross whole-body contamination. Radiation Emergency Medical Management website. Available at: Updated March 15, 2018. Accessed July 23, 2018.

How to perform a survey for radiation contamination. Radiation Emergency Medical Management website. Available at: Updated August 25, 2017. Accessed July 23, 2018.

Radiation and potassium iodide (KI). Centers for Disease Control and Prevention website. Available at: Updated October 17, 2014. Accessed July 23, 2018.

Radiation emergency medical management: choose appropriate algorithm—evaluate for contamination and/or exposure. Radiation Emergency Medical Management website. Available at: Updated March 15, 2018. Accessed July 23, 2018.

Sun and other types of radiation. American Cancer Society website. Available at: Accessed July 23, 2018.

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