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Uselessness of Whole Body Scanning Using Computed Tomography (CT)
I thought this was an interesting piece that I received through another list
server.
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
E-mail: jenday1@email.msn.com (H)
-----Original Message-----
From: Grissom, Mike [mailto:mikeg@slac.stanford.edu]
Sent: Friday, April 26, 2002 1:49 PM
To: 'Medhp-Sec (E-mail)'
Subject: MEDHP-SEC: US FDA Web Site Update: Whole Body Scanning Using
Computed Tomogr aphy (CT)
The following was recently provided on the Food and
Drug Administration's Web site:
----------
April 26, 2002
Whole Body Scanning Using Computed Tomography
(CT)
http://www.fda.gov/cdrh/ct/
Extract:
"Currently some medical imaging facilities are promoting
a new use of computed tomography (CT), also called
computerized axial tomography (CAT) scanning. This use
is referred to as whole-body CT scanning or whole-body
CT screening, and it is marketed as a preventive or
proactive healthcare measure to healthy individuals who
have no symptoms or suspicion of disease. At this time
the FDA knows of no data demonstrating that whole-body
CT screening is effective in detecting any particular
disease early enough for the disease to be managed,
treated, or cured and advantageously spare a person at
least some of the detriment associated with serious
illness or premature death. Any such presumed benefit
of whole-body CT screening is currently uncertain, and
such benefit may not be great enough to offset the
potential harms such screening could cause. Public
health agencies and national medical societies-the
American College of Radiology, the American College of
Cardiology, and the American Heart Association-do not
recommend CT screening.
CT is a diagnostic imaging procedure that uses x rays
to obtain cross-sectional images of the body. Since its
introduction and rapid adoption into medicine in the
mid-1970s, CT has become recognized as a valuable
medical tool for the diagnosis of disease, trauma, or
abnormality and for planning, guiding, and monitoring
therapy.
Important information regarding whole-body CT screening:
o Such screening provides uncertain benefit with
potential for some risk - The most likely outcomes
of CT screening of a healthy person with no
symptoms of illness are:
1. Normal findings or
2. Suspicious findings requiring follow-up
tests
Normal findings carry the possibility of
inaccuracy and false reassurance. For suspicious
findings, follow-up may involve simple,
non-invasive testing. It may also involve invasive
procedures associated with surgical risks of
anesthesia, bleeding, infection, scarring, or it
may entail additional radiological exams,
associated with radiation risk and the potential
risk of allergic reaction to injected contrast
material. In any case, it is unlikely that CT
screening will benefit an individual lacking signs
or symptoms of disease by detecting a serious
disease early enough to treat it and alter the
outcome significantly.
o Radiation Dose - CT screening subjects the
individual screened to radiation exposure from
x rays. The dose a patient receives during a
typical CT procedure is generally much larger than
the radiation doses associated with most
conventional x-ray imaging procedures. The
principal risk associated with the radiation dose
resulting to a person from a CT procedure is the
small possibility of developing a
radiation-induced cancer some time later in that
person's life. For a patient with a medical need,
the benefit of a diagnostic or therapeutic CT
procedure recommended by a physician normally far
exceeds the small cancer risk associated with a
CT procedure. For a person without symptoms, CT
screening is unlikely to discover serious disease,
and the potential harm to the individual may be
greater than the presumed benefit.
o Scientific Studies - There are no data
demonstrating that whole-body CT screening of
individuals without symptoms provides a greater
probability of benefit than harm. Nor is there any
scientific study known to be underway to develop
such data. Although there are several ongoing
investigational studies of the effectiveness of
using CT to screen people, the studies are focused
on high-risk groups for specific diseases (e.g.,
cigarette smokers for lung cancer). In such
studies only a limited portion of the body is
irradiated, not the whole body, and only screening
for a specific type of disease is being evaluated,
rather than screening for just anything that might
be found anywhere in the body.
o No Food and Drug Administration (FDA) Approval of
CT for Screening - Statements by CT imaging
facilities that imply FDA "approval," "clearance,"
or "certification" of CT for screening procedures
misrepresent the actual situation. FDA has never
approved or cleared or certified any CT system
specifically for use in screening (i.e., of
individuals without symptoms), because no
manufacturer has ever demonstrated to the FDA that
their CT scanner is effective for screening for
any disease or condition."
----------
The above may be viewed on the FDA Web site at URL:
http://www.fda.gov/cdrh/newpg.html
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