I was curious about this so given some numbers I found on the internet, an average MRI machine has about 1700 liters of liquid helium capacity and loses 48% of

I was curious about this so given some numbers I found on the internet, an average MRI machine has about 1700 liters of liquid helium capacity and loses 48% of its helium over the course of a year. 1 liter of liquid helium expands to .74m^3 of gaseous helium at room temperature. A 16" party balloon has .042 m^3 of space, so requires .05 liters of liquid helium. So one MRI machine can hold ~30,000 balloons worth of helium and leaks about 39 balloons per day. Note: This is not to suggest helium that is used for balloons is being redirected from MRI machines. As the article states, helium is captured almost exclusively as a byproduct of natural gas mining and any excess helium not worth capturing is just vented off. Reducing demand for helium by eliminating party balloons would have no affect on the amount of helium that is released from the ground.