AAPM/RSNA tutorial on equipment selection: PACS equipment overview: display systems.

Area of Science:

• Medical Imaging Technology
• Display Physics
• Radiology Informatics

Background:

• Current medical imaging display systems predominantly utilize cathode-ray tube (CRT) or active-matrix liquid crystal display (AMLCD) technologies.
• CRTs generate light via cathodoluminescence, while AMLCDs modulate light through pixel transparency.

Purpose of the Study:

• To compare the image quality aspects of CRT and AMLCD display systems in medical imaging.
• To identify the primary factors influencing spatial noise and contrast in both display types.

Main Methods:

• Analysis of luminance generation in CRT pixel displays.
• Evaluation of resolution properties in AMLCDs compared to CRTs.
• Identification of noise sources in CRTs (phosphor granularity, raster scanning) and AMLCDs (subpixel structure).
• Assessment of contrast limitations in CRTs (veiling glare, ambient reflections) and AMLCDs (reflectance, crosstalk, viewing angle variations).

Main Results:

• AMLCDs exhibit significantly better resolution properties than CRTs.
• Spatial noise in CRTs is primarily due to phosphor granularity and raster scanning.
• AMLCD noise characteristics are influenced by their subpixel structure.
• CRT contrast is mainly affected by veiling glare and ambient light reflections.
• AMLCD contrast is impacted by display reflectance, crosstalk, and off-normal viewing angles.

Conclusions:

• AMLCDs present advantages in resolution for medical imaging displays over traditional CRTs.
• Understanding the distinct noise and contrast mechanisms of each display technology is crucial for optimizing medical image display quality.