Infographics / Digital Radiography

Factors Limiting CR Spatial Resolution

A teaching diagram. Left: cross-sections of a thin and a thick photostimulable imaging plate. In each, the reading laser enters the top as a small spot, and stimulated light scatters and spreads laterally as it penetrates deeper into the phosphor. The thin plate gives a narrow point-spread and higher resolution but lower x-ray absorption; the thick plate gives a wide point-spread and lower resolution but higher absorption and DQE. Below, a pixel row shows sampling: the pixel pitch sets the Nyquist limit f equals one over twice the pitch, so 200 micron pixels give about 2.5 line pairs per millimetre and 100 micron pixels about 5. A bottom scale shows CR resolution about 2.5 to 5 line pairs per millimetre is lower than film-screen about 10 to 15.