Radiation Safety

An x-ray creates black-and-white pictures of the inside of the body. Your care team may use x-rays to help diagnose and monitor injuries or illnesses.

X-rays use a very small amount of radiation. It is about the same as a few days of the natural background radiation your child normally gets from their environment. This is safe for most people. But it is important not to have too many x-rays. Your care team will only order x-rays when necessary.  

A CT (computed tomography) scan or CAT scan uses computers and x-rays. The scan uses several x-rays taken from a machine that rotates around the body. A computer combines the images to create detailed, 3D images. CT scans often focus on a certain area of the body, such as the head, chest, or abdomen. 

CT scans use more radiation than x-rays. But, since CT scans are more detailed than x-rays, they are sometimes the safest and fastest way to get the answers needed.

Fluoroscopy is a type of x-ray that makes real-time images and allows your care team to see how parts of the body move and function. It often involves a special dye or contrast liquid that is swallowed or injected to show organs or structures. The x-rays create a live video showing movement inside the body. 

Examples of tests that use fluoroscopy include a barium enema, upper GI series, and VCUG. Fluoroscopy can also be used to help place feeding tubes, central lines, and other medical devices. The radiation dose for these tests is small, but it can be more than a traditional x-ray.

A nuclear medicine scan, such as a PET scan, MIBG scan, or bone scan, uses a radioactive substance to show organs and tissues inside the body. To take these pictures, the medical team injects a small amount of this substance (called a tracer) into your child's IV. For a short time, this substance gives off gamma rays. These rays can be seen and recorded by a nuclear medicine camera.

• PET scans (positron emission tomography) take pictures of the inside of the body by measuring the level of glucose (sugar) in cells. A form of glucose with a small amount of radioactive material is used as a tracer. The tracer lets off a small amount of energy in areas where the cells are more active than normal. This light is captured in pictures taken by a special camera in the PET scan machine. 
• MIBG scans are imaging tests that use a lower dose of a radioactive tracer to take pictures of neuroblastoma and other neuroendocrine tumors. An MIBG scan usually takes place over 2 days. First, patients get an infusion by IV that includes a liquid called metaiodobenzylguanidine (MIBG) combined with a small amount of radioactive iodine. The next day, a special camera takes pictures to show where the tracer was absorbed by tumor cells.   

After a nuclear medicine scan, the radioactive substance will leave your child’s body within hours to a week or longer. The time it takes to leave the body depends on the type of substance used and the type of test performed. The scan is not harmful to your child.  

This therapy uses beams of radiation, either x-rays or protons, to shrink tumors and kill cancer cells. Radiation targets cancer but may damage nearby healthy tissue. The medical team designs treatments to protect as much healthy tissue as possible.

Proton beam radiation therapy is a type of external beam radiation therapy. In proton beam radiation therapy, the amount of energy and how deep it goes into the tumor can be tailored to match each tumor’s size and shape. The radiation can stop at the tumor site.  Proton beam radiation therapy allows the care team to aim high doses of radiation at tumors with less damage to nearby healthy cells.

Brachytherapy is a type of internal radiation therapy. It uses a tiny radioactive source (sometimes called a seed) placed inside the body to kill tumor cells. It is most often used for treating certain sarcomas and retinoblastoma.

With brachytherapy, the risk from radiation is generally low, because the radioactive material is placed inside or near the tumor. This limits exposure to the rest of the body.

MIBG therapy is a type of radiation treatment used to treat neuroblastoma and other neuroendocrine tumors. MIBG stands for metaiodobenzylguanidine. It is a liquid absorbed by neuroendocrine tumor cells. MIBG is combined with I-131 radioactive iodine that targets and kills cancer cells. The MIBG medicine is given into a vein by infusion.

After the infusion, your child will be in the hospital for several days. They will stay in a special MIBG treatment room built to reduce radiation exposure to surrounding rooms in the hospital. Caregivers will stay in a parent room next to the patient room. It is important to follow all radiation safety instructions after MIBG therapy.

Short-term side effects of MIBG therapy include nausea, tiredness, and low blood counts (your child may need blood transfusions). Rare, long-term problems include thyroid issues, fertility problems, or other cancers later in life. 

Even when you return home, your child may give off small amounts of radiation. Follow the safety precautions given by your care team, such as limiting close contact with others, not sharing personal items, double-flushing toilets, and washing laundry separately. Your care team will let you know when it is safe for your child to be around others, return to school, and do usual activities. This usually happens after about 7 days.  

The radiation dose depends on the disease being treated, its location in the body, and the goals of treatment. Your care team plans radiation therapy to deliver the most effective dose that can safely be received. Radiation can cause side effects or lead to health problems that develop later (late effects). Talk to your care team about the potential risks and radiation safety plans based on your child’s specific treatment plan.