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 computed tomography" (CT), sometimes referred to as "computerized
axial tomography" (CAT). A 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 People
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.
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?
- Does a "normal"
finding guarantee good health?
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 testing.
Points to consider if you are thinking of 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.
DHHS Publication No: (FDA) 03-0001