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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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