Acceptance Testing of Diagnostic 5M-Pixels LCD Flat Panel Displays based on the AAPM TG18 Protocol

Abstract

In June 2005, YUMC (Yonsei University Medical Center, Seoul, Korea) Severance Hospital upgraded a full-PACS system (GE Medical Systems, USA) by adding twenty (5 M pixels) and twenty-five (3 M pixels) flat panel liquid crystal displays (LCD) for diagnostic interpretation purposes. Here we report upon the quantitative acceptance testing of the twenty flat panel LCD devices of 5 mega pixels (Totoku Electric Co., Ltd., Japan) for reflection, luminance response, luminance spatial and angular dependencies, resolution, noise, veiling glare, and display chromaticity based on AAPM on-line report No. 03. The tools used included a telescopic photometer, which was used as a colorimeter, illuminance meter, light sources for reflection assessment, light-blocking devices, and digital TG18 test patterns. For selected 8 flat panel displays, mean diffuse reflection coefficient (Rd) was 0.0188 ± 0.0016 cd/m2 per lux. In the luminance response test, luminance ratio (LR), maximum luminance difference (ΔLmax), and deviation of contrast response (Cont. of GSDF) were 550 ± 100, 2.0 ± 1.9%, and 5.84 ± 1.77%, respectively. In the luminance uniformity test, maximum luminance deviation (Non-unif.) was 14.3±5.5% for the 10% luminance of the TG18-UNL10 test pattern. In the resolution test with luminance measurement method, percent luminance (ΔL) at the center was 0.94± 0.64%. In all cases of noise testing, rectangular target in every square in the three quadrants was visible and all 15 targets except the smallest one in the every corner pattern and the center pattern. The glare ratio (GR) was 12344 ± 1994. The color uniformity, Δ(u′,v′), was 0.0025 ± 0.0008. All test results are in-line with the criteria recommended by AAPM TG18 report and are thus fully acceptable for diagnostic image interpretation. As a result, the acceptance testing schedule described provides not only an acceptance standard but also guidelines for quality control, optimized viewing conditions, and a means for determining the upgrading time of LCD display devices for diagnostic interpretation.