For maximum image quality, the focal spot size in radiography should be?

For maximum image quality in radiography, the focal spot size should be as small as feasible. A smaller focal spot reduces the geometric unsharpness of the image, leading to increased detail and clarity. This is particularly important when imaging structures that require high resolution, such as small bones or delicate anatomical details.

The principle behind this is that when the focal spot is smaller, the x-ray beam emanates from a more concentrated point, which creates sharper and more defined images. In contrast, larger focal spots can produce images with more blur and less precision because they increase the amount of beam divergence, which can lead to a loss of detail.

While it is true that certain x-ray machines may have specific focal spot sizes optimized for particular types of imaging, the overarching goal remains to minimize focal spot size to enhance image quality, wherever feasible. Therefore, the choice of "as small as feasible" directly aligns with the objective of producing high-quality radiographic images.