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.
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:
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.
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.
You may be exposed to more radiation than other people if you:
To understand more about radiation exposure, you may find it helpful to compare some common sources of radiation to a standard dose from a chest X-ray. A chest X-ray gives off very small amounts of radiation.
For example:
You can't avoid radiation that occurs naturally. But there are some things you can do to reduce your exposure to man-made sources.
Citations
- National Cancer Institute (2012). Radiation risks and pediatric computed tomography (CT): A guide for health care providers. Available online: http://www.cancer.gov/cancertopics/causes/radiation/radiation-risks-pediatric-CT.
Other Works Consulted
- American College of Radiology and Radiological Society of North America (2012). Patient safety: Radiation dose in X-ray and CT exams. Available online: http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_xray.
- American Nuclear Society (2011). Estimate your personal annual radiation dose. Available online: http://www.ans.org/pi/resources/dosechart/docs/dosechart.pdf.
- Catlett C, Baker Rogers JE (2011). Radiation injuries. In JE Tintinalli, ed., Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7th ed., pp. 56–61. New York: McGraw-Hill.
- Centers for Disease Control and Prevention (2006). Acute Radiation Syndrome (ARS): A Fact Sheet for the Public. Available online: http://emergency.cdc.gov/radiation/ars.asp.
- Centers for Disease Control and Prevention (2010). Airport Security Scanning and Human Health. Available online: http://www.cdc.gov/nceh/radiation/airport_scan.htm.
- Centers for Disease Control and Prevention (2011). Frequently Asked Questions About a Radiation Emergency. Available online: http://www.bt.cdc.gov/radiation/emergencyfaq.asp.
- Centers for Disease Control and Prevention (2012). Emergency preparedness and response: Potassium iodide (KI). Available online: http://emergency.cdc.gov/radiation/ki.asp.
- Environmental Protection Agency (2012). Radiation doses in perspective. Available online: http://epa.gov/radiation/understand/perspective.html.
- Environmental Protection Agency (2012). Radiation protection: Health effects. Available online: http://www.epa.gov/radiation/understand/health_effects.html.
- Environmental Protection Agency (2012). Radiation: Facts, Risks and Realities. Available online: http://www.epa.gov/radiation/docs/402-k-10-008.pdf.
- Environmental Protection Agency (2012). Radiation: Non-ionizing and ionizing. Available online: http://epa.gov/radiation/understand/index.html.
- Environmental Protection Agency (2012). RadTown USA: Airport security scanning. Available online: http://www.epa.gov/radtown/security-scan.html.
- Environmental Protection Agency (2012). RadTown USA: Basic information. Available online: http://www.epa.gov/radtown/basic.html.
- Environmental Protection Agency (2012). Sources of radiation exposure. Available online: http://epa.gov/radiation/sources/index.html.
- Mehta P, Smith-Bindman R (2011). Airport full-body screening: What is the risk? Archives of Internal Medicine. Published online March 28, 2011 (doi:10.1001/archinternmed.2011.105).
- National Cancer Institute (2012). Radiation risks and pediatric computed tomography (CT): A guide for health care providers. Available online: http://www.cancer.gov/cancertopics/causes/radiation/radiation-risks-pediatric-CT.
- Schauer DA (2009). Report No. 160—Ionizing Radiation Exposure of the Population of the United States. Bethesda, MD: National Council on Radiation Protection and Measurements.
- World Nuclear Association (2013). Nuclear radiation and health effects. Available online: http://www.world-nuclear.org/info/Safety-and-Security/Radiation-and-Health/Nuclear-Radiation-and-Health-Effects.
Current as of: February 18, 2021
Author: Healthwise Staff
Medical Review:Kathleen Romito MD - Family Medicine & Adam Husney MD - Family Medicine & R. Steven Tharratt MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
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