Impact of ambient lighting intensity and duration on the signal-to-noise ratio of images from photostimulable phosphor plates processed using DenOptix and ScanX systems.
OBJECTIVE
To evaluate the impact on photostimulable phosphor (PSP) image signal-to-noise ratio (SNR) of pre-scanning ambient lighting exposures.


METHODS
PSP imaging plates (IPs) were exposed to different radiation exposures to achieve flat field images. The exposed IPs were subjected variously to visible light of different intensities (300, 150 or 20 lux) for durations ranging from < 10 s to 120 s. They were processed using laser scanners from two systems for further comparison (DenOptix versus ScanX). Histogram analysis was performed in each case and mean pixel value and its standard deviation were used as surrogates to assess SNR. Statistical methods applied included analysis of variance with Tukey honestly significant difference test for pair wise comparisons. The a priori alpha was set at P < or = 0.05.


RESULTS
SNR decreased with increased duration and intensity of pre-scanning light exposure. Lower X-ray exposures resulted in decreased signal resulting in reduced SNR, and increased the need to reduce ambient lighting. No statistically significant differences were found comparing ScanX and DenOptix digital imaging systems in terms of SNR.


CONCLUSIONS
Reduced ambient lighting is preferred for handling IPs prior to processing in the laser scanner.
Ramamurthy
R
R
School of Dentistry, The University of Louisville, Louisville, Kentucky 40292, USA. r0rama06@gwise.louisville.edu
Canning
C F
CF
Scheetz
J P
JP
Farman
A G
AG
D016477:Artifacts; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D008027:Light; D008029:Lighting; D011829:Radiation Dosage; D019252:Radiography, Dental, Digital; D013997:Time Factors; D014963:X-Ray Intensifying Screens; D014965:X-Rays