Page 43 - Brachytherapy
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Constancy check of callibrated
dosimeter
The constancy of the response of the calibrated dosimeter system may
be checked by periodic measurement of a long half-life source, such as
Caesium - 137 in the case of a well type chamber. It is necessary to use
a special source holder that will position the check source in a
reproducible manner, since the ionization chamber response is very
dependent on source position and orientation. This periodic
measurement also provides a good quality assurance check of the entire
measuring system.
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