Back to Homepage
“Many people concerned about radiation exposure from their medical imaging scan will ask, “”Do all radiology tests use radiation?”” The short answer to that is no, not at all. A slightly longer answer to that is no, but usually if your doctor has ordered a radiology exam that does in fact use radiation, the chances are that’s the best test for you to get in order to get the information that your doctor needs as to why they ordered the study in the first place. Any radiology test that uses x-rays, gamma radiation or positron emitters exposes patients to radiation that is capable of causing radiation injury, as we’ve discussed throughout this series. Note again as we’ve discussed at length, it doesn’t mean that it will cause a significant injury or significant radiation effects. In fact, it almost always does not cause one of those things. These tests include x-rays, CT scans, fluoroscopy studies, interventional procedures, nuclear medicine, and PET scans (PET CTs). Actually all other radiology exams are 100% free of radiation.
The radiation free tests include any form of MRI, any type of ultrasound, and thermal scanning, which is a pretty rare modality. Now doctors are very cognizant of public radiation awareness and the importance of using radiation as sparingly as possible. Sometimes, just by the nature of the modality though, certain tests are often way better for answering certain questions than other modalities. For example, if you’re looking for a blockage in the arteries that bring blood to the lungs (called a pulmonary embolism), the best test for that is a contrast enhanced CT exam of the chest. No question, hands down. And all CTs use radiation to build their images. If you’re looking for a brain tumor or perhaps the cause of seizures, then the best test is a brain MRI. Now that uses zero radiation.
Looking for a blood clot in the leg, the best test is a DVT ultrasound, which inherently has zero radiation, and again, is by far the best for the job. If you’re concerned about medical radiation and your doctor has ordered an imaging study that does depend on radiation, you’re encouraged to discuss it with them and inquire if perhaps an ultrasound or an MRI could be done instead. But realize they’ve probably already thought that through and they are most likely not being patronizing or ignoring you if they insist on the CT scan or the PET scan. It just so happens to be the best test to answer the question that they have and get you the best care that they possibly can.”
