What occurs to spatial resolution as the source to image distance (SID) increases?

As the source to image distance (SID) increases, spatial resolution improves due to the reduction of geometric unsharpness. When the distance between the radiation source and the imaging receptor is greater, the X-ray beam diverges less as it travels, allowing for sharper images. This results in finer details being more clearly defined on the image, enhancing the system's ability to capture high-resolution details of the subject being imaged. The increased SID helps to minimize the effect of penumbra, which leads to a clearer delineation of structures and better spatial resolution. Thus, improving the quality of the diagnostic images.

The other options, while they may seem plausible at first glance, do not accurately reflect the relationship between SID and spatial resolution. For instance, stating that spatial resolution decreases would imply that increasing the distance somehow blurs the image, which contradicts established imaging principles. Likewise, indicating that there is no change would ignore the well-documented benefits associated with a greater SID in producing clearer images. Fluctuating spatial resolution does not happen under normal operating conditions where SID is consistently managed; rather, it leads to predictable and improved outcomes in image quality.