Radiation Units for final exam

Hi,

I am having trouble coming up with useful definitions for the different units. I was wondering if I could get some help when it comes to which are occupational vs patient etc. So far I think I know:

Gray: SI for patient dose

RAD : British for patient dose

Roentgen : Radiation in the air

Sievert: SI for occupational dose?

Do these sound right?

When it comes to REMS I know it stands for radiation equivalency in man. But which man? The patient or the radiographer?