Full-Body CT Scans What You Need to Know
a technology that "takes a look" at people's insides and
promises early warnings of cancer, cardiac disease, and other abnormalities,
clinics and medical imaging facilities nationwide are touting a new
service for health-conscious people: "Whole-body CT screening." This
typically involves scanning the body from the chin to below the hips
with a form of X-ray imaging that produces cross-sectional images.
The technology used
is called "X-ray
tomography" (CT), sometimes referred to as "computerized axial tomography" (CAT).
number of different types of X-ray CT systems are
being promoted for various types of screening.
For example, "multi-slice" CT (MSCT) and "electron beam" CT
(EBCT) - also called "electron
beam tomography" (EBT) - are X-ray CT systems
that produce images rapidly and are often
promoted for screening the buildup of calcium
in arteries of the heart.
CT, MSCT and
EBCT all use X-rays to produce
images representing "slices" of the body - like the
slices of a loaf of bread. Each image slice
corresponds to a wafer-thin section which can be
viewed to reveal body structures in great detail.
CT is recognized as an invaluable
medical tool for the diagnosis of disease, trauma, or
abnormality in patients with signs or symptoms
of disease. It's also used for planning, guiding,
and monitoring therapy. What's new is that CT
is being marketed as a preventive or proactive
health care measure to healthy individuals who
have no symptoms of disease.
No Proven Benefits for Healthy
Taking preventive action, finding unsuspected
disease, uncovering problems while they are
treatableÑ these all sound great, almost too good
to be true! In fact, at this time the Food and Drug
Administration (FDA) knows of no scientific
evidence demonstrating that whole-body scanning
of individuals without symptoms provides more
benefit than harm to people being screened. The
FDA is responsible for assuring the safety and
effectiveness of such medical devices, and it
prohibits manufacturers of CT systems to promote
their use for whole-body screening of
asymptomatic people. The FDA, however, does not
regulate practitioners and they may choose to use
a device for any use they deem appropriate.
Compared to most other diagnostic X-ray procedures, CT
scans result in relatively high radiation exposure. The risks associated
with such exposure are greatly outweighed by the benefits of diagnostic
and therapeutic CT. However, for whole-body CT screening of asymptomatic
people, the benefits are questionable:
Can it effectively differentiate between healthy
people and those who have a hidden disease?
Do suspicious findings
lead to additional invasive
testing or treatments that produce additional risk with little benefit?
a "normal" finding guarantee good health?
Many people don't realize
that getting a whole body CT screening exam won't necessarily give
them the "peace of mind" they are hoping for, or the information
that would allow them to prevent a health problem. An abnormal finding,
for example, may not be a serious one, and a normal finding may be
inaccurate. CT scans, like other medical procedures, will miss some
conditions, and "false" leads can prompt further, unnecessary
Points to consider if you are
having a whole-body screening:
CT screening has not been
demonstrated to meet generally accepted criteria for an effective screening
Medical professional societies
have not endorsed CT scanning for individuals without symptoms.
CT screening of high-risk
individuals for specific diseases such as lung cancer or colon cancer
is currently being studied, but results are not yet available.
The radiation from a CT
scan may be associated with a very small increase in the possibility
of developing cancer later in a person's life.
Before having a CT screening procedure, carefully
investigate and consider the potential risks and
benefits and discuss them with your physician.