Role of ambient light in the detection of contrast elements in digital dental radiography

Abstract

Objective: This study aimed to evaluate the effect of different ambient light levels on observer detection of small contrast differences in a contrast phantom by using a high-end liquid crystal display (LCD) monitor.

Study design: An aluminum step wedge was converted into a contrast phantom by the addition of bore holes. Radiographic images of the contrast elements were presented to 20 observers. Images were displayed in random order under different ambient light levels (0, 50, 200, and 500 lux) twice, and the observers had to determine if contrast elements were visible. Sensitivity and specificity were determined to calculate areas under receiver operating characteristic curves and Friedmann's test was applied to evaluate the influence of the ambient light level on observer performance.

Results: Mean AZ values were moderate for each ambient light level at 0.715, 0.793, 0.764, and 0.722 for 0, 50, 200, and 500 lux, respectively. The influence of the ambient light level on observer performance was not statistically significant (P > .05).

Conclusions: There was no significant influence of ambient light between 0 and 500 lux on observer ability to detect small contrast details displayed on a high-end LCD monitor.