Issues regarding lower activity concentration for PET spatial resolution QA?
NEMA based PET QA protocols like TG 126 recommend a relatively high activity concentration (up to 10 mCi/ml) which isn't always feasible if tests are carried out after clinical activity has ended. However, acquisitions are done in terms of total counts, so at a first glance it doesn't seem to be much of an issue if we simply allow for longer acquisition times.
Does anyone have experience with this particular issue?