Broken? Diagnosing Summertime Breaks and Bumps
● By Sandy Kauten
What kind of scans involve radiation and what don't?
There are four main kinds of medical scans in common use today: X-rays, CT scans, MRIs and ultrasound. X-rays and CT scans – sometimes called “CAT scans” – use small amounts of radiation to form an image. MRIs use magnetic fields and ultrasound uses sound waves; neither of these involves radiation.
Tell us about x-rays
X-rays are the most common kind of imaging process used with children. Your doctor may want an x-ray taken to check a possible broken ankle, for example, or a chest x-ray to check the lungs for pneumonia.
The amount of ionizing radiation involved in a single x-ray is very tiny. You and your child will be exposed to about the same small amount of radiation – from natural cosmic rays – while flying on a commercial airliner from Eugene to Denver as from a single x-ray.
Let's move on to CT scans. Do they involve more exposure?
They do. A CT scan is made up of many separate x-ray images, which are then combined by a computer to make a three-dimensional image. Depending on the part of your body being scanned, you get from 100 to several hundred times as much radiation exposure from a CT scan as from a regular x-ray.
As a result, physicians use CT scans far less frequently for any patients, but especially for children.
It's still not a huge amount. A low amount of radiation occurs naturally on Earth from a variety of sources. A single CT scan involves about as much radiation as we are exposed to naturally in the course of two or three years while living in Eugene.
Sometimes the benefits from a scan clearly outweigh the slight risk of radiation exposure. We may use a CT scan, for example, to see whether a child with abdominal pain has acute appendicitis requiring immediate surgery, or to diagnose bleeding in the brain, another urgent condition. In those cases a CT scan may show that surgery – which has its own risks – isn't necessary. At Oregon Imaging, we use equipment that can reduce exposure by about 70%.
So it's a matter of balancing risks
Exactly. There are risks involved with anything. Sometimes the risk of not having a scan is far greater than any conceivable risk from radiation. The important thing is that parents and guardians of children have a right to know exactly what is happening when a child has a scan of any kind. If you're not told, you should ask.
– Dr. Erik Young is a radiologist at Oregon Imaging Centers, which provides a full range of imaging services, including MRIs, low-dose CT, PET/CT, ultrasound, digital x-ray and fluoroscopy and digital mammography. He is one of 16 specialized radiologists providing services from OIC locations at University District and RiverBend Pavilion.