What is the average interval between helium top-ups for MRI machines in Health New Zealand's public hospital system, and what is the longest period any individual MRI machine can operate before requiring added helium?

Answer

I am advised that helium is added to Health New Zealand MRIs at the time of servicing. The frequency of servicing differs according to the age and model of equipment; in general, it ranges from approximately six to twelve months. I am further advised there is no other need for regular helium top ups, although unscheduled replacement of helium may be required from time to time as result of an ad hoc event.