The accuracy of an x-ray film quality-assurance step-wedge test.

The accuracy of an aluminum step-wedge quality-assurance test for machine and processor in dental radiography was determined. The clinical radiographic density range accepted by twenty dentists was similar to eight steps of an aluminum step-wedge test object, with dentists using six or seven steps. The test used a two-step density shift to detect and separate changes in both x-ray machine and film processing before radiographic quality becomes clinically unacceptable. Measured latent image fading of test films stored for months was small and did not affect the test performance. The accuracy of the step-wedge test in detecting eighteen machine and film-processing variables was measured with a densitometer. Possible comparisons with measurements made by an accepted densitometric method used in medical radiography showed similar results. The test can be used in lieu of more costly, time-consuming tests.