Skip to content

Radiation Exposure: Risks and Health Effects

Font Size

Topic Overview

What is radiation?

Radiation is energy that travels as a wave or particle. Some types of radiation, called ionizing radiation, can be harmful. Radioactivity is ionizing radiation that is given off by substances, such as uranium, as they decay.

About half of the ionizing radiation we're exposed to comes from nature. It's in rock, soil, and the atmosphere. The other half comes from man-made sources like medical tests and treatments and nuclear power plants.

Recommended Related to Health A-Z

Chilaiditi's Syndrome

Important It is possible that the main title of the report Chilaiditi's Syndrome is not the name you expected.

Read the Chilaiditi's Syndrome article > >

How much radiation is dangerous?

There is always a risk of damage to cells or tissue from being exposed to any amount of ionizing radiation. Over time, exposure to radiation may cause cancer and other health problems. But in most cases, the risk of getting cancer from being exposed to small amounts of radiation is small.

The chance of getting cancer varies from person to person. It depends on the source and amount of radiation exposure, the number of exposures over time, and your age at exposure. In general, the younger you are when you are exposed to radiation, the greater the risk of cancer.

For example:

  • Someone who has had many CT scans starting at a young age is more likely to get cancer later in life than someone who hasn't had any or as many of these tests. CT scans generally use more radiation than other X-ray tests. The risk of an adult getting cancer from a CT scan is less than 1 in 1,000. The risk of a child getting cancer from the same CT scan can be much higher.1
  • A child who was treated with radiation for cancer is more likely to get another cancer later in life.
  • A person who has been exposed to large amounts of radiation from a nuclear accident is more likely to get cancer than someone who has not been exposed.

Exposure to small amounts of radiation doesn't cause any symptoms. But exposure to large amounts all at once may cause radiation sickness and death.

How do different sources of radiation compare?

Some sources of radiation give off larger amounts than others. For example, when you go through a full-body airport scanner, you're exposed to very small amounts of radiation. But if you live near the site of a nuclear accident, you're exposed to large amounts of radiation.

1|2|3

WebMD Medical Reference from Healthwise

Last Updated: October 08, 2013
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Radiation Exposure: Risks and Health Effects Topics

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

disciplining a boy
Types, symptoms, causes.
psoriasis
What it looks like.
fruit drinks
Eat these to think better.
No gym workout
Moves to help control blood sugar.
acupuncture needle on shoulder
10 tips to look and feel good.
Close up of eye
12 reasons you're distracted.
Epinephrine Injection using Auto-Injector Syringe
Life-threatening triggers.
woman biting a big ice cube
Habits that wreck your teeth.
embarrassed woman
Do you feel guilty after eating?
pacemaker next to xray
Treatment options.
caregiver with parent
10 tips for daily life.
birth control pills
Which kind is right for you?

Women's Health Newsletter

Find out what women really need.