Which factor does NOT affect spatial resolution in imaging?

Spatial resolution in imaging refers to the ability to distinguish small objects that are close together in a captured image. It is largely influenced by several physical and technical factors involved in the imaging process.

Focal spot size is crucial because a smaller focal spot can produce a sharper image, thereby enhancing spatial resolution. Postprocessing techniques can also affect how the final image appears, potentially enhancing the details seen in images, which can contribute to better perceived resolution; hence, they are relevant to spatial resolution.

Patient motion is another significant factor impacting spatial resolution. If the patient moves during the imaging process, blurring can occur, making it difficult to clearly delineate structures within the image.

Dynamic range, however, refers to the range of exposure values that an imaging system can accurately capture and display, rather than its ability to resolve fine details. While it influences the overall image quality and the ability to detect varying signal intensities, it does not directly affect the spatial resolution. Therefore, this characteristic does not play a role in the clarity of details between closely spaced objects and is why it is the correct choice for the answer.