The area on the anode of an x-ray tube or the target of an accelerator that is struck by electrons and from which the resulting x rays are emitted. The shape and size of a focal spot will influence the resolution of a diagnostic image.
The area on the x-ray tube target that is bombarded with electrons to produce x-radiation.
Located on the target of the anode within an x-ray tube, there exists a petite region referred to as the focal spot. When struck by the electron stream, this focal spot emits x-rays. It is worth noting that the level of geometric definition is directly proportional to the size of the focal spot: the smaller the focal spot, the greater the precision in the resulting image.