The Health Risks of Using CT Scans on Kids

ct scan, ct scan toddler
Getty Images/Gerhard Egger

If you're a parent of a small child, chances are you've probably encountered that frightening moment when your child endures a fall or some other injury, and you have to decide if you should take her into the ER. 

If your child hits her head but doesn't have any obvious signs of an injury like trauma, loss of consciousness, or a change in behavior, it can be difficult to determine if she needs medical intervention.

Although head injuries are incredibly scary to face as a parent, the only real way to assess for a head injury is through a CT scan. But more and more doctors are recommending that parents and medical professionals be aware of the potential risks that CT scans carry for children. If you are a parent and your child has a head injury, should you consider giving consent for a CT scan? Here's what you need to know. 

What Is a CT Scan?

It may be confusing why we say "CAT" scan when it's often spelled out with the abbreviation "CT" scan, but there is a simple explanation: "CAT" stands for computerized axial tomography, which describes the method that the scan uses to produce an image, but the terms "CT" and "CAT" scan are used interchangeably.

A CT scan is actually a more powerful version of an X-ray. Unlike typical X-rays, which look at the body from more of a "straight-on" angle, a CT uses X-rays that take picture "slices" of the body or a body area to build a whole picture.

This allows doctors to see internal injuries and structures a lot more clearly. It's also a lot more helpful for looking at soft tissues rather than bones, which means that CT scans are commonly used to diagnose brain injuries and disorders. From falls to sports injuries to accidents, CT scans can give a better look at the brain to help doctors see what's going on internally.

 

Doctors use CT scans in the brain to diagnose brain tumors or visualize injuries, bleeding, or any structural changes and infections that can occur and be difficult to see with an X-ray or routine exam. When you think about the fact that very young children especially can't exactly tell you that their head hurts or may make an exam difficult because they get cranky or tired or act out in a way that you can't determine "normal" behavior, it makes sense that a CT scan could be especially helpful in diagnosing brain injuries. 

How Can a CT Scan Be Risky to Children?

While CT scans are obviously a helpful medical diagnostic tool and they absolutely have an important role in preventing and treating injury, they are also a tool that needs to be used very cautiously because unfortunately, when used in high doses especially, they can cause cancer. 

A 2012 study in The Lancet, a British medical journal, found that when CT scans are delivered with a dose of 50 mGY, the risk of leukemia is almost tripled; doubling the dose to 60 mGY triples the risk of brain cancer. 

Those are incredibly scary numbers to hear, but the overall risk of actually getting those cancers in children is still very low. The study notes that in the 10 years after the first CT scans were used in patients younger than 10 years, only one "excess" case of leukemia and one brain tumor (per 10,000 head CT scans) are estimated to occur.

 

So while that's reassuring, it's a relatively big risk when you think about the fact that a CT scan could potentially be used for something as simple as a fall off of a bunkbed. The risk is definitely not always worth it. 

How to Tell If a Child Needs a CT Scan

With the knowledge that CT scans can carry a risk of cancer, here comes the big question: How exactly do you determine if a child needs a CT or not? An earlier Lancet study analyzed data from over 42,000 children to come up with a list of recommendations on things that doctors should consider before ordering a CT scan. The study concluded that doctors should consider the following risk factors: 

  • The child's age 
  • Consciousness
  • Change in behavior 
  • Headache
  • Vomiting

The more risk factors that a child has, the higher the risk for a traumatic brain injury, which means the more the doctor should consider ordering a CT. 

The Hard Part

The issue of CT controversy comes in when a doctor has to weigh the potential risk of cancer-causing radiation from the scan with the potential risk of not properly diagnosing an injury or other medical disorder. There has been more awareness among both doctors and parents about how dangerous CT scans can be—though research has shown doctors are still using CT scans too frequently. 

For instance, a busy hospital might not have time to try a "wait and monitor" approach on a child, so a CT scan could be ordered for a faster diagnosis. Or a doctor might not take the time to read back in a child's history and see that he or she has had several CT scans before. Or perhaps a caregiver is unaware of the child's medical history. Or a doctor may be worried about missing a potentially life-threatening diagnosis and has to make sure to order the CT scan, so there is no question about her care. Or a worried parent might demand the scan "just in case." There are many theoretical scenarios we could imagine, but the end result is all the same: CT scans are still being overused on children, and that's a problem. 

More medical experts are pushing doctors and the public to be aware of the risks, to use the lowest possible dose when a CT is appropriate, and to explore other types of diagnostic tools that could be used that are less risky and don't carry the same chance of cancer. 

The Takeaway

Although the risk is very small and any serious consequence, such as cancer, is also very small, there is a risk associated with using CT scans in children because of the radiation used in the scans. The risk is higher with more powerful rays and obviously, the risk also increases with the more CT scans a child has. To reduce the risk of harmful consequences, be willing to talk to your doctor about how necessary a CT scan is for your child. In some cases, a doctor may have to weigh the benefits and risks before making a recommendation. And ultimately, it is always up to you as a parent to give your consent for your child to have any screening test of any kind, so it's also important for you to feel empowered with your own knowledge too. CT scans are appropriate for serious head trauma and certain medical conditions, but they should be used sparingly and with serious consideration in children. 

Sources:

Pearce, Mark S et al. (2012). Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. The Lancet. 380(9840): 499 - 505. 

Kupperman, N. et al. (2009). Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. The Lancet, 374: 1160–70 Published Online September 15, 2009 DOI:10.1016/S0140- 6736(09)61558-0. 

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