After the discovery of radiation at the very end of the 19th Century, we spent the following century finding all kinds of ways to harness its power: from agriculture to the atomic bomb and everything in between – radio communication, dating fossils, microwaves, nuclear energy.
Here at the beginning of the 21st Century, radiation continues to play a growing role in medicine.
Got a first-aid kit stowed away in your bathroom or kitchen somewhere? The gauze and bandages were sterilized with radiation.
If you’ve ever had an x-ray, of course, you’ve experienced another medical use of radiation.
Nowadays all kinds of complex scans are possible, allowing doctors and technicians to see what’s wrong with you from the inside out. Computed Tomography (CT or CAT) scans take multiple x-rays from different directions to assemble a 3-dimensional picture of whatever might be structurally wrong with your bones, organs or muscles. Nuclear medicine is part of this growing field of molecular imaging. Small amounts of radioactive materials – as in PET scans – can be injected into us (or swallowed or inhaled) so that special scanners can trace their path in our body and highlight the course of various diseases and disorders.
Perhaps you’ve wondered about the safety precautions of those procedures? That heavy apron? When they asked if you might be pregnant? How the medical personnel left the room during the scan?
Our innards can now be made to glow in the dark.
And so we now have a host of questions it’s time to answer:
- Is all this exposure to radiation causing its own health problems?
- Who weighs the pros and cons of deciding whether the benefit of a scan is worth the costs?
- And speaking of costs, what role is all this scanning playing in our ever-increasing costs of health care?
CT Scans Are Not Noninvasive
Just because instruments aren’t entering your body doesn’t mean these scans are noninvasive. CT scans deliver between 50 and 200 times more radiation than a conventional X-ray.
A renowned 2004 study determined “The radiation dose from a full-body CT scan is comparable to the [low] doses received by some of the atomic-bomb survivors from Hiroshima and Nagasaki, where there is clear evidence of an increased lifetime risk of dying from cancer. ” The risk is small but measurable.
A public health researcher’s book on cancer reminds us that a CT scan to the head of a baby gives the equivalent radiology dose of between 200 and 4,000 chest X-rays. The American College of Radiology now cautions against its use in children, who are more sensitive to radiation than adults.
If you get just one of these in your life, need you worry? Probably not. According to the FDA , an average CT examination (with an effective dose of 10 millisieverts of radiation) may be associated with an increase in the possibility of fatal cancer of approximately 1 chance in 2000. Compare this to the natural incidence of fatal cancer in the U.S. population: about 1 chance in 5.
But radiation accumulates over time; one CT scan won’t kill you but many CT scans might. While CT scans account for just 13% of all diagnostic radiology procedures, they are estimated to be responsible for more than 70% of the collective radiation dose delivered to patients. The availability of CT scans in malls and the false-positives they can lead to means that more and more people are getting them unnecessarily and the overall public health risk is growing.
CT Scan Use is Growing
Unfortunately, Americans are getting more radiation, not less, in recent decades. CT scans alone soared from 20 million in 1995 to 63 million in 2005. As a result of this trend, our average radiation dose has nearly doubled since 1980.
So why is the use of scanning growing?
For good reasons:
- Thanks to improvements in CT technology it can now be used to diagnose an increasing number of problems. What is driving the increase in CT scans is its growing use in screening adults for chronic disease:
- Virtual colonoscopies for those with colon disease and at-risk for colon cancer
- Lung screening for current and former smokers
- Whole-body screening – available to people without any symptoms on an elective basis
- Part of this increase is also due to doctors’ preference for such scans in order to detect heart disease – the nation’s number 1 killer – over the traditional method of angiography, in which a catheter is inserted into the blood vessels. Nuclear scans are more accurate and are 10 times less likely to cause complications like heart attack or stroke.
…and for bad:
- It is difficult – for ethical reasons – to set up experiments to measure the lifetime risk of repeated radiation exposure and its accumulation in our bodies. It takes 20 to 50 years after exposure to radiation to see its full effects. So the evidence has been long in coming and we’ve proceeded down this path without waiting for it – reveling in all that we could do with CT scans and thinking less about whether we should.
- In the typical “arms race” among hospitals and medical groups to capture a portion of the health care market, more and more providers purchase these scanners to attract customers – uh, I mean patients – to their facilities.
- Hospitals and doctors practices need to make back the cost of purchasing the equipment ($1 to $2 million each). It’s also tempting to use these scanners as a money generator against growing health costs in other areas of operation. A test can pull in $500 to $1,000 apiece in revenue.
- “Defensive medicine:” Fear of lawsuits and of the surging costs of malpractice insurance also reportedly push doctors to do things like ordering a scan for your headache just to make sure that migraine isn’t a tumor, however unlikely that is.
- Because CT scans are fast – less than 1 second – using them in children to diagnose problems like appendicitis eliminates the need to anesthetize them during the diagnosis (which has its own risks and costs) in order to get them to hold still. This is why using scans for pediatric diagnosis has been a huge driver of the overall upwards trend. But sonograms can be just as easy and effective and are safer.
The result? As many as 20 million adults and 1 million children in the U.S. receive unnecessary computed tomography (CT) scans each year.