Calibration of radiotherapy beams using a PC-based dosimetry recording system

Routine calibration of radiotherapy treatment units involves the following steps: 1. radiation measurement under standardized conditions; 2. recording of the resultant data; 3. applying correction factors to the data which take into account the response of the calibrating instrument, the effects of the measurement geometry and the beam type, etc.; 4. scrutinizing the results for significant changes in output from previous calibrations and, if necessary, making appropriate adjustments to the machine's dosimetry system; 5. recording all calculations and sundry other relevant information including date, time, operator, temperature, and barometric pressure etc.; 6. issuing a calibration certificate which either states the machine output or attests that the dosimetry system is set within acceptable tolerances.