Why does detector pixel size limit digital image spatial resolution?

Why does detector pixel size limit digital image spatial resolution?

• A. Pixel size determines exposure time.
• B. Pixel size sets the sampling grid; smaller pixels improve sampling resolution but system blur and focal spot geometry also limit true resolution.
• C. Pixel size controls patient dose.
• D. Pixel size only affects color.

Answer: (B)

Digital image spatial resolution depends on two things: how finely the image is sampled by the detector and how much the imaging system blurs detail. The detector’s pixel size determines the spacing of the sampling grid. Smaller pixels mean more sampling points across the image, which can capture finer features and improve sampling resolution. But you can’t realize that potential if the system itself smears details. The finite size of the X-ray focal spot (and related geometric unsharpness) plus other blur sources like scintillator spread and detector diffusion limit how sharp the final image can be. When blur is larger than the spacing between samples, the true resolution is governed by that blur rather than by how small the pixels are. So pixel size sets the sampling framework, while the actual, observable resolution is ultimately limited by system blur and focal spot geometry.

Digital image spatial resolution depends on two things: how finely the image is sampled by the detector and how much the imaging system blurs detail. The detector’s pixel size determines the spacing of the sampling grid. Smaller pixels mean more sampling points across the image, which can capture finer features and improve sampling resolution. But you can’t realize that potential if the system itself smears details. The finite size of the X-ray focal spot (and related geometric unsharpness) plus other blur sources like scintillator spread and detector diffusion limit how sharp the final image can be. When blur is larger than the spacing between samples, the true resolution is governed by that blur rather than by how small the pixels are. So pixel size sets the sampling framework, while the actual, observable resolution is ultimately limited by system blur and focal spot geometry.