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Radioactive Tracers.
Radioactive tracers can be used in both medicine and industry.
How are Radioactive Tracers used in Medicine?
How can Internal Bleeding be Detected?
A radioisotope can
be injected into someone's blood to
detect internal bleeding.
Internal bleeding can occur inside
the body
when blood is being lost from a damaged
vein
although it may not be obvious where the bleeding is happening.
The method used to detect the bleeding
is the same as
that used in industry to find a leak from an underground pipe.
How can the Thyroid Gland be Monitored?
Radioactive iodine-131 can be
used
to see if
the thyroid gland in the
neck is working properly.
Iodine is
present in small amounts in the body and up to ¼ of
the total
amount of iodine can be stored in the thyroid
gland.
The amount of iodine entering the gland can be seen by
detecting
the radioactivity emitted from the
radioactive iodine.
Which Radioisotopes
can be used as Medical Tracers?
A radioisotope which is
used inside the body must be a
beta emitter
or a gamma
emitter because both of these can
penetrate body tissue
and be detected outside of the body.
A medical
tracer must have a short half-life because this will
minimize the harm done to the
cells of the body. For example,
iodine-131 (above) is a beta
emitter with a
half-life of 8
days.
An alpha
emitter cannot be used because the alpha
particles
cannot penetrate the
body
tissue and would not be detected.
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