Ponder this about the radiation exposure from imaging studies:
- X-rays: These are a form of electromagnetic radiation that can penetrate your body. It can be harmless, like during an airplane flight or used beneficially in medical imaging. High amounts can cause damage to the DNA of every cell in you as well.
- A chest X-ray delivers a very small amount of radiation, typically around 0.1 millisieverts (mSv), which is comparable to about 10 days of natural background radiation, or roughly the same dose as a short airplane flight.
- An abdominal CT scan uses a continuous beam of X-rays as it rotates around you while you’re lying in that cylinder. There’s not a single “number” of X-rays, but the dose is equivalent to ~100 to 200 standard chest X-rays, or about 10 millisieverts (mSv), which is a significant dose comparable to several years of natural background radiation. The actual radiation exposure varies but is often compared to many traditional X-rays because it delivers a higher, focused dose to view detailed cross-sections of your body.
- An MRI (magnetic resonance imaging) creates detailed body images by using a powerful magnet to align water protons in your body, then hitting them with radio waves to knock them out of alignment, and finally measuring the energy they release as they snap back, with a computer translating these signals into cross-sectional slices. Different tissues release energy at different rates, allowing the computer to distinguish between fat, water, muscle, and bone to build a clear picture. IMPORTANTLY, THERE IS NO RADIATION EXPOSURE DURING MRI IMAGING.
Because CT scans are less expensive (for example $600-$1,000 abdominal CT with contrast) than an MRI ($2,000-$3,000), insurance companies require a lot of prior authorizations before they’ll agree to pay for the latter. In addition, CT scans are faster and the equipment is less expensive for a medical center to purchase. Hence, CT scans are “favorite” imaging studies in busy emergency rooms around the country.
NOTE: The new “Rapid Heart Scan” for detecting coronary artery calcium deposits does live up to its name. The new equipment completes the CT of your heart in a few seconds with radiation exposure of about ten chest x-rays. It is an excellent screening test and not at all risky.
The result of the fast turnaround, lower price, and absence of complicated ‘hoop-jumping’ for reimbursement is reflected in the final numbers:
In 2023, 93 million CT scans were performed, 58.9 million on adults, 2.5 million on children. By comparison, the radiation-free MRI is performed on half that number, 40 million annually.
A very thorough analysis of the health costs of this trend revealed some frightening data: CT scans are responsible for approximately 5% of new cancers, approximately 109,000 annually, both in adults and children. This places CT scans as a risk factor right up there with alcohol consumption, obesity, ultra-processed foods, but not as high as smoking.
The main cancers that are being documented after CT scan use: lung, colon, leukemia, breast, thyroid.
Now that you know the potential dangers of CT scans, here are a few precautionary steps:
If you’ve got an ache or a pain, begin with your primary care provider. This person, whether a physician, nurse practitioner, or chiropractor, will be least likely to begin with a high radiation imaging study. Likewise, Urgent Care Centers may have a simple x-ray unit on hand, but not a CT scan. It’s the mega-medical center emergency rooms where, after waiting eight hours to see “anybody,” you’ll be lateralled to a CT cylinder to get your kishkes fried.
If your doctor suggests a CT scan, put both hands up in defense. Question the necessity, and question why an MRI might not be just as effective.
If the answer is “cost” or “a fast report,” the freestanding MRI centers are a fraction of the cost of the major medical center (often by thousands of dollars if you pay cash), with a radiologist’s report usually within 24 hours. Just Google “MRI Best Price Chicago”.
You can read the full article about the CT risks, which appeared in JAMA, here, but maybe you’d rather do some last minute Christmas shopping.
Be well,
David Edelberg, MD