Reducing Risks from Sources in Medical Uses

 

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 injuries.

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 body.

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.



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Teletherapy Unit — 500 TBq cobalt-60 (IAEA)

An example of brachytherapy is a radium applicator once used for insertion into a patient's nasal passageways to shrink the lymphoid tissues.
The small monel metal capsule on the right end of the applicator would contain approximately
1.8 GBq (50 millicuries) of radium-226.

Photo Credits and
Copyright 1999:
Oak Ridge Associated Universities

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 


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