What happens to the nominal focal spot size as the x-ray tube target decreases?

As the x-ray tube target decreases in size, the nominal focal spot size also decreases due to the geometry of the x-ray production process. The focal spot size is determined by the area on the target where the electron beam strikes and generates x-rays. When this area is smaller, the spatial resolution of the x-ray beam improves, resulting in sharper images with less blurriness. A smaller focal spot can provide better detail in the resulting images, which is particularly important in high-resolution imaging tasks.

In comparison, a larger focal spot size tends to scatter more radiation and can lead to decreased image quality. This relationship between the target size and the focal spot size is fundamental in radiographic practice, as it impacts the overall quality and diagnostic utility of the x-ray images produced.