Final answer:
The pixel size of a cassette-based digital imaging plate can vary, but a specific CCD referred to in the reference is 300 micrometers thick and can accommodate over 21 million pixels.
Step-by-step explanation:
The pixel size of a cassette-based digital imaging plate is b thick. This thickness is less than that of an average human hair and can hold more than 21 million pixels. The 50-micrometer difference mentioned is minor and can typically be accommodated by the same detector when positioned at the proper focal distance of the lens. Image analysis software can improve the image quality, which is essential when the details of the pixels are within the range of a few micrometers, such as differentiating the size of microorganisms or resolving fine details like lettering inside a ring.