What effect does a decrease in x-ray tube target angle have on the focal spot?

A decrease in the x-ray tube target angle results in a smaller focal spot size. This occurs because a steeper angle at the target reduces the effective area from which x-rays are emitted. Consequently, the x-rays are concentrated over a smaller surface area, leading to improved image sharpness and detail.

Smaller focal spots enhance the spatial resolution in radiographic images, making it easier to visualize fine details within the structures being imaged. This is particularly advantageous in applications such as mammography or other forms of imaging that benefit from high levels of detail. Thus, a decrease in target angle directly correlates with a decrease in the size of the focal spot.