What happens when all the Helium runs out?

Things that stay at home dads worry about - what happens when all the Helium runs out?! Helium is a non-renewable resource vital in the cooling of medical equipment such as MRI Scanners, yet it is still used to inflate party balloons, which once popped release the gas into the atmosphere where it is 'lost'. Should the use of helium in party balloons be banned? Surely MRI Scanners are more important than Party Balloons. Does anyone out there worry/care?