Half life of radionuclides

Hi, I’m struggling to answer why a short half life would lead to a lower background ratio? The question is referring to iodine 123 and why a thirteen hour half life would limit delayed imaging and compromise target/background ratio. Any help would be extremely appreciated! ^-^

It'd probably help if you showed us the question and gave us a bit of context.

shorter half life means higher radiation flux for a short time

I don't know if delayed imaging is medical jargon or the question is literally asking why you shouldn't leave your I-123 hanging around over the weekend before using it (it decays by 1/2 every 13 hours)

Hi thanks for the response there’s not much in terms of context .-.

Yeah its just because the shorter half life means the activity falls off in less time... So if you don't use it quickly it'll have such low activity you wouldn't be able to tell the I-123 from background radiation.