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

Publication date: Available online 18 August 2018

Source: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Author(s): Ohla Harald, Dagassan-Berndt Dorothea, Payer Michael, Filippi Andreas, Schulze Ralf Kurt Willy, Kühl Sebastian

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, using a high-end liquid crystal display (LCD) monitor.

Study design

: An aluminium step wedge was converted into a contrast phantom by the addition of bore holes. Radiographic images of the contrast elements were presented to twenty 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 (SN) and specificity (SP) were determined to calculate areas (AZ) under receiver operating characteristic (ROC) curves and a Friedmann 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>0.05).

Conclusion

: 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.

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