CT scan radiation Part II
To Live Long and Age Well, it’s a good idea to avoid unnecessary radiation, and for most people, that means unnecessary CT scans. A typical CT scan results in much greater radiation exposure than a regular X-ray.
One new test, the cardiac 64-slice CT scan is used to look for blockages in the arteries of the heart, which indicate heart attack or high risk of heart attack. These scans give fantastic 3-D images, like the one below. You might see this or a CT brochure and think: I want one! But don’t be mesmerized by color and hype, because medicine is also a business, subject to market forces. 
Cardiac CT scanning is often used in cases when someone comes to the emergency room with chest pain, and the doctor wants to know if the pain is due to a blocked coronary artery or some other cause. The use of this scan has tripled in the past two years, and the cardiac CT commonly exposes the patient to the equivalent radiation as 600 regular chest X-rays. Still, this scan can give much useful information, but due to the radiation exposure, you only want it when it’s really needed and when other less risky tests aren’t adequate.
Doctors are trained to always balance the risk of any procedure or test with the benefits received (the risk: benefit ratio), but the companies that sell the equipment do their best to convince doctors that the benefits are high, and the risks low. And doctors—used to being pushed around and mistreated by insurance companies—can be seduced by the fawning attention of the medical device sales force.
Last week in the Journal of the American Medical Association (JAMA), a report was issued by a group of American and German researchers, who evaluated how much radiation patients were exposed to while undergoing the 64-slice cardiac CT scans, and they found the radiation exposure varied from center to center by a factor of six, meaning a patient at some X-ray facilities received six times the radiation dose as someone having the same test at another center.
One reason for this center-to-center difference is that several new radiation-lowering techniques are available, but some centers don’t use them. It’s still not clear yet which are the best methods to lower the dosage, but it would be good to know your facility was employing at least one of those methods.
Below are some basic questions you might ask if a CT is recommended for you or a loved one. (Of course in an emergency situation, you might not want—or be in a position—to question the necessity of the test.)
1. Could another test, one without radiation exposure such as MRI or ultrasound, be done instead of the CT? If the answer is: “The CT is better.” then you might ask: How much better? Does the difference between CT and the other test justify the radiation exposure?
2. If you have already had a CT scan of the same type and your doctor orders a repeat scan, question him/her carefully if another scan is truly necessary.
3. Explain you have read about the radiation dose from CT and you want to go to a facility that takes measures (or has a “protocol”) to diminish unnecessary radiation.
For more detailed questions, check this link.
