Can niobium tubes be used in medical devices? What are the advantages?

Yes.
Niobium tubes are increasingly used in medical implants (e.g. orthopedic devices) and diagnostic equipment due to their biocompatibility, non-magnetic properties and radiopacity.
Unlike stainless steel or cobalt-chromium alloys, niobium's corrosion resistance also reduces the risk of allergic reactions or long-term degradation in the body.