Do You Need a CT Scan?
23 May 2015
How many people will die from excessive radiation exposure? Today, more patients get CT scans for a variety of problems. So how can patients decrease the risk of excessive exposure?
“Consumer Reports on Health” says the number of CT scans in the U.S. in 1980 was under 3 million. Now in 2015 it’s 80 million. Experts claim that about one-third of the scans have little medical value. And the report adds that some doctors and technicians don’t take measures to reduce radiation exposure.
In the past it’s been said that the radiation threat is greatest in children. But some research now suggests that certain radiation induced cancers place adults at risk as well, more than previously realized by doctors.
So when is a CT scan a benefit or a questionable risk? Patients sometimes worry their headaches may be due to a tumour and they request a scan. But most headaches are caused by tension or migraines. Exposure to radiation would be needed only for an abnormal neurological examination, or if doctors are concerned about a diagnosis. But if this is the case, an MRI is required, not a CT scan. An MRI does not expose you to radiation and is more accurate in diagnosing brain tumors or arterial aneurysms.
What about a blow to the head? According to the National Center for Disease Control and Prevention, the number of visits for head injuries in young children has almost doubled in the past 10 years. But the American Academy of Pediatrics says one-third of CT scans done for these injuries are not needed. Experts suggest agreeing to a CT scan only if it happens after a car accident or a fall from a bike when no helmet was worn. Or if there are symptoms such as confusion, weakness, loss of consciousness, hearing or vision.
Today, back pain is one of the most common complaints seen by doctors. It can be so incapacitating that, when it strikes, patients want a speedy diagnosis and quick relief of pain. Thus many patients are sent for either an X-ray or CT scan of the back. But most back pain is due to muscle sprain that normally subsides in a few weeks. The CT scan rarely helps doctors in deciding how to treat the pain and results in useless radiation. So unless there’s loss of bladder and bowel control, muscle weakness or decreased feeling in the legs, it’s safer to let nature heal the pain.
Suppose the doctor believes abdominal pain is due to appendicitis or a kidney stone. In these cases an ultrasound will usually point to the diagnosis. But if there is still some doubt, a CT scan may be necessary.
Some doctors recommend CT colonography to detect precancerous polyps in the large bowel, rather than regular colonoscopy where a flexible lighted instrument is inserted into the colon. But this test is less accurate and again exposes patients to radiation.
In general, MRI’s are primarily used to detect soft tissue, muscle, tendon, spinal cord injuries and small lesions in the brain such as multiple sclerosis and tumours.
CT scans are used by emergency room doctors who need a speedy diagnosis. A patient could die from a hemorrhage while having an MRI which takes 45 minutes. A CT scan makes the diagnosis in 5 minutes. So they are used for severe trauma to brain, spinal cord, chest, abdominal and pelvic injuries. And if your body contains metal, a CT scan must be used rather than an MRI.
One test to avoid at all costs is a full body scan. One study reports that for every 1,250 of these scans, one person will die of cancer. Another study claims that 2 percent of all future cancers are likely to result from CT scans.
To decrease the risk of radiation ask your doctor why a CT scan is needed. Can ultrasound or an MRI provide the same result? Could a previous scan of the same area be used to avoid having a new scan? And remember, if a doctor has invested in his own CT scanner, studies show he will use it more often.
