Common medical uses
of sealed radioactive sources
The sealed sources used in medical applications are usually very powerful.
Therefore, they have the potential to cause serious and life threatening
Sealed radioactive sources are used in several medical applications for
diagnosis and treatment of diseases. One of the most common uses is teletherapy,
which delivers precise doses of radiation to a well-defined area of the
Teletherapy commonly uses cobalt-60
as the source of radiation, although some older equipment may use caesium-137.
Teletherapy equipment can be used safely and effectively to kill tumours,
but to do so, it must be properly installed, calibrated, and maintained
and should only be used by skilled personnel under the supervision of
a radiation oncologist. The sources may also need to be changed regularly.
A source change can only be done by a licensed source supplier. The
preferred option to further manage disused sources is to return the
source to the supplier. If this is not possible, disused sources should
be transferred to an authorized waste management organization for
storage and for disposal.
Another common medical use of sealed radioactive sources is brachytherapy.
Unlike teletherapy, in brachytherapy the radioactive source is in direct
contact with the patient, inserted into a tumour either directly by a
surgical team or remotely using special equipment.
In order to reduce exposure risks both to patients and the medical
staff, remote loading is much more frequently used. In addition to routine
measures to reduce exposure risks to both patients and healthcare workers,
because brachytherapy sources are implanted, care must be taken to ensure
that no source is left implanted following treatment.
Depending on the manufacturers specifications, some brachytherapy sources
need to be replaced every 10 to 15 years. This necessitates not just
appropriate procedures for radiation protection during replacement and
transfer, but also appropriate procedures and facilities to dispose
of all disused brachytherapy sources permanently.