What people don’t know about
CT Scans
CT scans (computed tomography is a form of x-ray) can be life-saving when diagnosing colon cancer, brain tumours, internal bleeding, blood clots, broken bones and other problems. But what many people don’t realize is the greater the number of CT scans, the greater the risk of developing cancer.
Studies suggest that about 2 percent of all cancers are caused by CT Scans. The U.S. National Cancer Institute in Bethesda, Maryland, claims that 14,000 additional malignancies a year are due to CT scans of the abdomen and pelvis, 4100 due to chest scans and 2,700 from diagnosing blockages in coronary arteries.
To find out how much people know about CT scans, researchers interviewed 235 patients who were scheduled for a non-emergency CT scan. It’s shocking that one-third did not understand that their body was being exposed to radiation. Those that were aware grossly underestimated the exposure. Researchers then asked what the patients were thinking about before the procedure was done. The majority replied they were more concerned about getting their parking tickets validated than possible radiation effects, This was not a very encouraging survey.
The brutal fact is that a lung CT scan exposes patients to the same amount of radiation as 100 X-rays of the lungs. An abdominal CT scan provides the same radiation as 500 chest X-rays!
Remember that CT scans are the biggest source of radiation of all imaging technologies. And every year about 10 percent of North Americans are scanned.
CT scans are valuable and necessary to diagnose disease. But when about 80 million are done annually in the U.S. some of these are of questionable value. For instance, of CT scans ordered because of a headache, only 2 percent found a treatable condition.
The message is clear. If a doctor orders a CT scan, ask if it’s absolutely necessary. And if so, could an MRI or ultrasound which does not subject patients to radiation, provide the same result. Studies show that doctors do not put enough emphasis on the risk and benefits of CT scans and other tests that expose patients to radiation.
Caution with radiation for early disease detection
Remember there are radiation tests and there are radiation tests. For example, some doctors believe that it’s prudent to search for early disease in coronary arteries. Consequently, an increasing number of CT angiography scans are being done to detect calcification, one indication of trouble, in these vessels. But these CT scans are not a single exposure to radiation. Rather, they require 64 exposures. This is 200 times the radiation received from a standard X-ray of the chest. Few patients are aware of this huge difference in radiation exposure.
Dental X-Rays
Less is Better
Is a bite-wing X-ray necessary at every visit? Are full mouth X -rays needed? A report published in the journal, Cancer, offers a reason to hesitate.
Dr. Elizabeth Claus at Yale University reports that those who have frequent dental x-rays have an increased risk of developing a brain tumour called meningioma. Just two percent are malignant, but 30 percent of the benign ones grow and can kill in five years.
What concerns Dr. Klaus is that more children today are getting braces to straighten teeth and are being subjected to increased numbers of X-rays during the process. She acknowledges new X-ray machines produce lesser amounts of radiation and the risk of brain tumours is small. But no one knows how much this level of radiation will effect the future health of these children.
She concludes by saying that in general, there is little reason for x-ray when patients have no symptoms.
Radiation is like an elephant.
It never forgets.
Every roentgen you receive including dental, bone and other x-rays is added to the overall amount.
Remember, if you’re patient most aches and pains get better with time. And never say to your doctor, “Can’t you take an x-ray?” This is the same as waving a red flag in front of a bull. You will get one.
Beware of defensive x-rays. Even if a doctor believes the ankle isn’t broken, often an x-ray is ordered anyway for fear of being sued for missing the diagnosis. Tell your doctor you don’t want a defensive film done and be willing to assume responsibility.
Find a dentist who uses good judgment in taking x-rays. We all need x-rays now and then. But get a second opinion if full mouth films are ordered every year. Remember that procedures such as fluoroscopy and CT scans result in much larger doses of radiation than single ones.
The Health Department should provide everyone with a radiation card so dosage can be documented each time an x-ray is done. If radiologists don’t know the exact dose they must find out. Surely this is the least patients can expect.
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