The focal spot size in an x-ray tube affects the resolution of the image that can be produced and penumbra size also effect Blurring due to this factor is determined by the relative sizes of the penumbra and the radiographic image . A smaller focal spot size allows for higher resolution images because it produces a more finely focused x-ray beam. However, using a smaller focal spot size also requires more precise alignment of the x-ray tube and the detector, and it can lead to increased patient dose if not used properly.
