Program Information
Comparison of the External Luminance Meter Performance as a Part of Diagnostic Monitor QC
A Ruuge*, Y Erdi , Memorial Sloan Kettering Cancer Center, New York, NY
Presentations
WE-RAM1-GePD-IT-2 (Wednesday, August 2, 2017) 9:30 AM - 10:00 AM Room: Imaging ePoster Theater
Purpose: This work evaluates the agreement between luminance measurements performed by the external photometers as a part of the annual quality control measurements of the primary diagnostic monitors (PDM).
Methods: Ten PDMs (Barco) were included in the analysis. Four external photometers (RaySafe Solo Light, RaySafe Xi, Konica–Minolta CA-210 and Konica-Minolta CS-100A) were used to measure the luminance values. All PDMs were equipped with the manufacturer’s built-in photometer (Barco I-Guard). These monitors were located at radiology reading rooms and connected to the BarcoMediCalQA web service for manual and automatic quality control measurements. TG-18 LN test patterns were used to verify the DICOM Grayscale Standard Display Function (GSDF) conformance and to evaluate the PDM performance. For each TG-18 LN test pattern, measured luminance values by four external photometers were plotted against the values measured by the built-in photometer.
Results: An agreement was demonstrated between all tested photometers for the majority of tested digital driving levels (15 out of 18). For luminance levels below 3 cd/m2, the largest disagreement was observed for Konica-Minolta CS-100A, which was up to 125% between the external and internal photometer. For luminance values above 3 cd/m² the largest disagreement was 12.7%. For the internally calibrated luminance value (400 cd/m²), the external photometers showed a measurement value between 367.9 and 390.4 cd/m². The lowest level was measured with Konica-Minolta CS-100A and the highest value was measured with the RaySafe Solo.
Conclusion: Photometer CS-100A demonstrated the largest disagreement for the measured luminance values. This is because CS-100A measures luminance at a distance and other photometers perform “puck-on-screen” measurements. This work shows that luminance measurements made with on-screen detectors have smaller variations (< 3.8%) in luminance measurements.
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