RADICULOPATHY
RADIONUCLIDE SCANNING
radiculopathy Damage to the nerve
roots that enter or leave the
spinal cord.
Radiculopathy may be caused by
disc
prolapse,
spinal
arthritis, diabetes mellitus,
or ingestion of heavy metals such as lead.
The symptoms are severe pain and,
occasionally, loss of feeling in the area
supplied by the affected nerves, and
weakness,
paralysis,
and wasting of
muscles supplied by the nerves. If pos-
sible, the underlying cause is treated;
otherwise, symptoms may be relieved
by
analgesic drugs
,
physiotherapy
, or, in
some cases, surgery.
radioactivity The emission of alpha
particles, beta particles, and/or gamma
radiation that occurs when the nuclei of
unstable atoms spontaneously disinte-
grate. Many radioactive substances are
naturally occurring - for example, ura-
nium ores. (See also
radiation.)
radiography The use of
radiation,
such
as
X-rays
, to image parts of the body.
(See also
imaging techniques; radiology.)
radioimmunoassay A sensitive labo-
ratory technique that uses radioactive
isotopes to measure the concentration
of proteins such as hormones or anti-
bodies in blood. (See also
immunoassay.)
radioisotope scanning See
radionu-
clide scanning
.
radiology The medical speciality that
makes use of
X-rays
,
ultrasound
,
MRI
,
and
radionuclide scanning
for investiga-
tion, diagnosis, and treatment.
Radiological methods provide images
of the body in a
noninvasive
way so that
exploratory surgery is not needed. The
techniques
also enable
instruments
(such as needles and
catheters
) to be
accurately guided into different parts of
the body for diagnosis and treatment.
This is called interventional radiology.
radiolucent A term for anything that is
almost transparent to
radiation
, espe-
cially to
X-rays
and gamma radiation.
radionuclide scanning A diagnostic
technique based on detection of
radia-
tion
emitted by radioactive substances
introduced into the body. Substances
are taken up to different degrees by dif-
ferent tissues, allowing specific organs
to be studied. For example, iodine is
taken up mainly by the thyroid gland, so
by “tagging” a sample of iodine with a
radioactive marker (radionuclide), the
uptake of iodine can be monitored to
investigate the functioning of the gland.
A radionuclide is swallowed or injec-
ted into the blood and accumulates
in the target organ. It emits radiation in
the form of gamma radiation, which is
detected by a gamma camera to pro-
duce an image. Cross-sectional images
(“slices”) can be obtained using a com-
puter-controlled gamma camera that
rotates around the patient. This special-
ized form of radionuclide scanning is
known as SPECT (single photon emis-
sion computed tomography). Moving
R
RADIONUCLIDE SCANNING
Adjustable
bed
Control
panel
Gamma
camera
Monitor
displays
image
Radiographer
Gamma camera counterbalance
478
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