Which measurement is used to assess lateral resolution in a phantom?

Which measurement is used to assess lateral resolution in a phantom?

• A. Depth axis
• B. Lateral width of a target
• C. Elevational width
• D. Temporal resolution

Answer: (B)

Lateral resolution is about how well two features that sit side by side in the image (across the width of the image) can be distinguished. In a phantom, this is quantified by looking at how wide a target must appear along the lateral (left–right) direction to be resolved. Measuring the lateral width of a target gives a direct read on how finely the system can separate side-by-side structures; a smaller measured width means better lateral resolution because the system can distinguish thinner features along the lateral axis. The other measurements relate to different aspects: depth axis corresponds to axial resolution, which is the ability to separate targets along the beam’s travel direction; elevational width pertains to the dimension across the elevational plane (thickness in that dimension); temporal resolution deals with how quickly frames are acquired (frame rate), not with the spatial separation of targets.

Lateral resolution is about how well two features that sit side by side in the image (across the width of the image) can be distinguished. In a phantom, this is quantified by looking at how wide a target must appear along the lateral (left–right) direction to be resolved. Measuring the lateral width of a target gives a direct read on how finely the system can separate side-by-side structures; a smaller measured width means better lateral resolution because the system can distinguish thinner features along the lateral axis.

The other measurements relate to different aspects: depth axis corresponds to axial resolution, which is the ability to separate targets along the beam’s travel direction; elevational width pertains to the dimension across the elevational plane (thickness in that dimension); temporal resolution deals with how quickly frames are acquired (frame rate), not with the spatial separation of targets.