PATTERN DESCRIPTION: This pattern provides comprehensive evaluation of display performance based on AAPM Task Group 270 recommendations. It is based on the TG18-PQC design. MAIN FEATURES: - 18 horizontal grayscale bars (0-255 in 15 gray level steps) - Multiple modulation patterns at varying frequencies and contrasts - High-contrast line pair patterns in top/bottom regions - Vertical gradient bars with modulation for uniformity assessment MODULATION PATTERNS: - Left region: Horizontal modulation at 4 frequencies (18, 12, 6, 4 pixels) - Inner columns: 8 gray level contrast - Outer columns: 2 gray level contrast - Right region: Vertical modulation at 4 frequencies (4, 6, 12, 18 pixels) - Inner columns: 8 gray level contrast - Outer columns: 2 gray level contrast LINE PAIR PATTERNS (Top/Bottom): - 6 line pair patterns at different frequencies (2, 4, 6 pixels) - High contrast (0/128 or 128/255) for resolution assessment SIDE GRADIENTS: - Full vertical gradients (0-255) with modulation strips - For uniformity and gradient linearity evaluation USAGE: For a DICOM-conformant display, all modulation patterns should be visible across all gray levels. The line pair patterns test spatial resolution, while the side gradients assess uniformity and gradient reproduction.