Radiation Exposure

What to do in a radiation emergency

Follow the CDC's advice: Get inside, stay inside, stay tuned.

1. Get inside the nearest solid building, ideally to a basement or the middle of the building, away from doors and windows. A car does not provide good protection.
2. Stay inside for at least 24 hours unless officials advise otherwise. Bring pets inside.
3. Stay tuned to local radio, TV, emergency alerts and official social media for instructions.

Decontaminate yourself

• Remove your outer layer of clothing as soon as you are inside. This can remove up to 90 percent of external radioactive material. Seal clothes in a plastic bag and leave it away from people and pets.
• Shower with soap and shampoo. Do not scrub hard or scratch the skin. Do not use conditioner, which can bind radioactive material to hair.
• If you cannot shower, wipe exposed skin with a damp cloth.
• Blow your nose and wipe your eyelids, eyelashes and ears.
• Put on clean clothes from a drawer or closet.

Potassium iodide (KI)

KI tablets protect only the thyroid gland, and only against radioactive iodine. Take KI only when public health or emergency officials tell you to. It does not protect against other types of radiation.

Sources of radiation exposure

mSv (millisievert) measures the health-relevant dose. Gy (gray) measures absorbed energy, mainly used for high doses.

Acute radiation syndrome

Acute radiation syndrome (ARS) occurs after a large dose to most of the body over a short time, usually minutes. It has phases:

1. Prodromal phase: nausea, vomiting, loss of appetite and sometimes diarrhea, starting minutes to days after exposure. The sooner and more severe the vomiting, the higher the dose.
2. Latent phase: the person may feel better for hours to weeks.
3. Manifest illness: depends on dose: - bone marrow syndrome (above about 0.7 Gy): falling blood counts, infections, bleeding, similar to bone marrow failure - gastrointestinal syndrome (above about 6 Gy): severe diarrhea, dehydration, gut damage - cardiovascular and central nervous system syndrome (above about 20 to 50 Gy): confusion, collapse, usually fatal
4. Recovery or death.

Cutaneous radiation injury

High local doses, for example from handling a lost industrial or medical source, cause radiation dermatitis: skin redness, itching, blistering, hair loss and ulcers. Symptoms can be delayed by days to weeks.

Long-term effects

• Cancer: leukemia, thyroid cancer (especially in children exposed to radioactive iodine), breast, lung and other cancers can develop years later. The extra risk at medical imaging doses is very small.
• Cataracts: the lens of the eye is sensitive to radiation.
• Heart disease after high doses, such as chest radiotherapy.
• Effects on pregnancy: high doses to the fetus, particularly at 8 to 15 weeks, can affect development. Doses from most diagnostic imaging not involving the abdomen are far below levels known to harm a fetus.

Medical treatment

• Decontamination and detection with radiation monitors
• Dose estimation: time to vomiting, blood count changes over 48 hours, and chromosome analysis
• Supportive care: fluids, anti-nausea medicines, infection prevention, antibiotics, blood transfusions
• Medicines that boost blood cell production (such as filgrastim) for bone marrow syndrome
• Treatments for internal contamination: Prussian blue (for cesium and thallium), DTPA (for plutonium, americium and curium), and KI for radioactive iodine
• Burn and wound care for skin injuries
• Stem cell transplant in rare, carefully selected cases

Radiation from medical imaging

The benefits of a needed X-ray or CT scan almost always outweigh the small risk. To minimize exposure:

• keep a record of your imaging
• ask whether a test without radiation, such as ultrasound or MRI, would answer the question
• tell staff if you are or might be pregnant
• for children, ask whether the dose has been adjusted for size

Frequently asked questions

What are the symptoms of radiation sickness?

The first symptoms are nausea, vomiting, loss of appetite and sometimes diarrhea within minutes to days of a high dose. After a temporary improvement, people may develop infections, bleeding, hair loss, severe diarrhea and skin burns, depending on the dose.

What should I do if there is a radiation emergency?

Get inside a solid building and stay in the center or basement. Remove your outer clothing and shower to remove contamination. Stay inside for at least 24 hours and follow instructions from emergency officials.

Should I take potassium iodide after radiation exposure?

Only if public health officials advise it. Potassium iodide protects the thyroid from radioactive iodine but not from other radiation. Taking it unnecessarily can cause side effects, especially in people with thyroid conditions.

Are CT scans dangerous because of radiation?

A CT scan exposes you to more radiation than an X-ray, but the added cancer risk from a single scan is very small. When a scan is needed for diagnosis, the benefit usually far outweighs the risk. Avoid unnecessary repeat scans.

Can radiation exposure cause cancer years later?

Yes. Higher doses increase the long-term risk of cancers such as leukemia and thyroid, breast and lung cancer. The risk rises with dose. At low medical imaging doses, any added risk is very small.