Radiotherapy Systems, Cobalt
Definition : Radiotherapy systems that use cobalt-60 as a radiation source to produce gamma radiation at photon energies of 1.17 and/or 1.33 MeV. The source is fitted into a treatment head that contains massive shielding (about one ton) and a mechanism for exposing or hiding the source, either by rotating it away from the collimator or by rotating the collimator to shield the source. The gamma-ray beam is directed at the tumor to be treated via a set of collimators and moved during the treatment so that maximum radiation dose is delivered to the point at the center of the rotation, other parts being irradiated less. Cobalt radiotherapy systems also include a control unit and appropriate filters and collimators. Because cobalt radiation reaches its maximum dose about 0.5 cm below the skin surface, cobalt units are especially suited for treatments of the head, neck, and breast, as well as for tumors in other parts of the body located within 5 cm of the skin surface.
Entry Terms : "Radiotherapy Units, Cobalt" , "Cobalt Radiotherapy Systems" , "Cobalt Radiotherapy Units" , "Radiographic Units, Therapeutic" , "Cobalt Therapy Units"
UMDC code : 16972