The PDC (Patient Dose Calibrator) is a DAP Meter calibrator which measures DAP, DAP-rate, Dose and Dose rate of installed DAP systems and solves much publicized problems relating to variation of DAP, Patient Dose system and AEC calibration and is ideally suited to aid the setting of reference doses on Fluoroscopy x-ray machines. The PDC method of calibration is significantly quicker than the traditional method, and allows a full check of the installed DAP meter calibration over a range of field sizes, shapes and beam qualities