Brother MFC 8220
When I updated from 10.14.2 to 10.14.3, the scanner function on this Brother product stopped working.
Of course, Brother says this is an Apple problem and not a Brother problem.
Is there any work around?
iMac Pro
Please read Printer and scanner drivers for Mac - Apple Support, and pay attention to its comment "This list is no longer updated." That particular model does not appear in its list of devices.
That printer's specifications do not indicate support for any macOS version later than OS X 10.8 "Mountain Lion". That's quite old.
Workarounds include installing Mountain Lion (or other macOS version for which that printer still works) on another disk or partition and booting from it, for the sole purpose of being able to continue to use its scanner features.
Or, Revert to a previous OS X version using Time Machine.
Please read Set up a scanner to use with Mac but it is unlikely to be applicable to a device as old as that one.