What to Know About Radiation Therapy Risks to Others

What to Know About Radiation Therapy Risks to Others

Reviewed by Jasper Clinical Board

Last updated 5/24/21

External beam radiation

This procedure (also called external beam therapy) uses high-energy beams of radiation to destroy cancer cells. The energy beams may be made of x-rays, gamma rays, or protons, but they all have one thing in common: When the procedure is over, there’s no more radiation.
In other words, if you’re receiving external beam therapy, you’re not radioactive in the slightest. You can interact with people around you—including children, pets, and pregnant women—without posing any danger to them. 
Receiving this therapy is a bit like being under a high-powered flashlight. You can’t carry the rays of light with you or release them onto other people later. As soon as the device is turned off, there’s no more light.

Internal radiation

The second kind of radiotherapy treatment for cancer is called internal radiation therapy or brachytherapy. Generally speaking, it involves placing a radioactive implant in your body. This implant—a pellet, ribbon, capsule, wire, or “seed,”—is put next to the tumor. As it decays, it slowly releases radiation to destroy cancer cells and shrink the growth. 
If you get a temporary implant, it will be removed after each appointment. But if your implant is permanent you will, in fact, carry radiation with you. (That’s how it works!) But don’t worry—your healthcare team will work closely with you to make sure others stay safe.
Depending on the type of implant you receive, you may need to make adjustments in the days or weeks after receiving an implant. For instance, you may need to stay a safe distance away from children and pregnant women, or avoid spooning with your partner overnight. For some temporary implants, you may also need to stay in the hospital and observe certain precautions with visitors. 
Again, the lifestyle changes you need to make will depend entirely on the type of cancer you have and how it’s being treated. Work closely with your healthcare team to figure out how to keep your loved ones safe.

Systemic radiation

The final type of radiotherapy is called systemic radiation. It involves swallowing or injecting a radioactive medication that circulates through your body to kill cancer cells. This procedure does make your body radioactive for several days, until you fully excrete all of the medication. In this time window, you’ll have to take special precautions to avoid exposing anyone to radiation.
For instance, if you receive radioactive iodine treatment for thyroid cancer, you won’t be able to take public transportation home, as this may pose a risk to others. Your body fluids and waste (like sweat, saliva, urine, and stool) will also be radioactive, so you should not expose other people to them for several days after the treatment. When you urinate, it’s important to not get any urine outside of the toilet. That means sitting down to relieve your bladder (even if you normally stand), and cleaning up any splashes using rubber gloves and paper towels.
Remember, this is just one example! Different types of systemic radiation therapy will require different measures to protect the people around you. The good news is that the most intense precautions—like the ones we describe above—are typically only necessary for a few days after you receive treatment. As always, work closely with your healthcare team to keep your loved ones safe and get the most from your treatment.

The content on this website is intended to provide the best possible information for you, but should not be considered—or used as a substitute for—medical advice. If you have questions about your diagnosis or treatment, please contact your health care provider(s). For questions or comments about this content, please email us at