Measurement of X-ray tube accelerating potential by differential beam filtration

Indirect determination of X-ray generator kilovoltage (kV) using the ratio of differentially filtered beam measurements has been known for 20 years. Measurement of generator potentials used for diagnostic computed tomography (CT), conventional X-ray, and mammography typically requires filter cassettes or special instruments in the X-ray beam; the resulting readings are usually accurate within /spl plusmn/2%. A related technique, free of many theoretical and practical restrictions, provides simplified generator potential measurements with significantly improved accuracy. Curve fitting provides a simple relationship predicting generator kV from a measured filter response ratio. Routine use has established that this technique is robust, reliable, repeatable, and more accurate than most working standards.