X-ray machine calibration: a study of failure rates.

Inaccurate calibrations can seriously affect the technique chart and, ultimately, affect patient exposure and the diagnostic quality of radiographs. Texas regulations require that several quality control tests, including kV accuracy, timer accuracy, mAs linearity and reproducibility, be performed on all x-ray units. This article reports the results of those tests for radiographic x-ray machines in nonhospital facilities. Of the 161 machines tested, 30% failed one or more tests. The most commonly failed test was kV accuracy, while failure of mAs linearity was the second most frequently failed test.