Few patients are aware of the risks associated with medical scans. Individuals need to be aware that one CT scan can be as much as 300 times the radiation exposure of one chest x-ray, further emphasizing the importance of appropriate imaging procedures. The following questions can specifically avoid unnecessary testing and promote safety for themselves and their families.
Why do I need this test?
Ask how the scan will help make a diagnosis and how the results of the scan will affect your treatment.
Advanced medical imaging scans such as MRI (Magnetic Resonance Imaging), CT (Computerized Tomography) and PET (Positron Emission Tomography) are excellent tools in diagnosing and treating illness, but they should not replace a physical exam. Your physician’s training and experience are often all that are needed to take care of the majority of health problems, without the need for expensive scans.
Also, just because your friend or neighbor got the latest high tech scan or you saw an ad for it, does not mean that you should get one, too. Sometimes your doctor will tell you that you do not need a particular scan. Again, take the time to discuss the pros and cons of any scan with your doctor.
What are the risks and side effects?
A. Exposure to energy source.
Producing medical images involves an energy source that transmits pictures to film or computer. Radiation exposure (in CT studies), magnetic fields (in MRIs) and nuclear sources (in PET) must be considered:
- MRI is conducted with a magnetic field and is considered safe for most patients. In general, it should not be done if someone has a pacemaker or an automatic defibrillator, has had recent surgery with metallic articles put into place, has known metal fragments in the eyes or tattoos that contain metallic dyes.
- CT is conducted with ionizing radiation at higher levels than plain x-rays and is relatively safe if used when needed. Medical experts differ about how much radiation exposure leads to problems. This test should be avoided in pregnancy unless no other imaging would provide the needed information.
- PET is done with a nuclear source and is considered safe for most patients. There is also a newer machine called a PET/CT scan that adds some radiation.
B. Allergic reactions.
All of these scans might call for contrast, a sterile dye-like substance usually injected into a vein. In rare cases, contrast can cause allergic reactions that require immediate medical attention. Be sure to let your doctor know prior to your test if you have ever had such a reaction, or if you have history of diabetes or kidney problems.
C. Other testing.
Advanced imaging techniques frequently expose abnormalities that are not necessarily a health problem. However, your physician is obligated to do further testing to ensure there is not a problem. For example, while viewing a CT for someone with stomach pain, the radiologist sees something in liver or in the gland above the kidney that would never have caused a problem, but now the doctor has to do follow up studies to make sure. This causes inconvenience and extra tests – sometimes even a biopsy – and increases the cost of health care.
How much will it cost?
Is there a more cost effective alternative? The price of imaging studies varies, but CT is generally less expensive than MRI, which is less expensive than PET. There are many cases where less expensive imaging studies, such as an x-ray or ultrasound study, may provide the information your physician needs. Often, waiting for the results of blood tests or other tests such as biopsies will offset the need for imaging. Ultimately, it is a decision that should be discussed completely with your doctor.
Where should I have the tests?
Just as quality may vary at different stores, quality at medical imaging facilities also varies. Centers may differ in the age of their equipment and quality of the images.
Target points of interest/concern may include:
- Are the technicians and technologists certified/licensed?
- Do board certified radiologists read the films?
- Is the equipment up to date?
- Are proper safety measures in place for radiation and magnetic fields?
- Are you treated courteously and with consideration?
- Is it convenient?
- Ask the doctor if the recommended imaging center provides quality results.
How soon do I need it?
Most advanced imaging studies do not have to be performed immediately. You should consider is how long your health problem or condition has been present and whether you are improving or not. Take MRI of the lower back for sciatica, as an example. Most orthopedists and physicians who treat this problem agree that, unless there are complications, this problem should be treated for six to eight weeks before considering an MRI. Of course, if the imaging is needed urgently, your physician will send you to the appropriate setting at the right time.