[ RadSafe ] radiographic spatial resolution

[Mike]

HELLO there!

I am wondering if there is a protocol which states what spatial resolution
an analog radiographic system should have. If for example I have a spatial
resolution of 5 lp/mm isn;t this enough information that may substitute the
focal spot size?
I have read AAPM report 74 and there is no statement about spatial
resolution.

Any help will be highly appreciated.
Thanks in advance,
Manos