FDA 510(k) Premarket Notification
The FDA pathway for medical devices substantially equivalent to predicates already on the market. Most imaging capital equipment clears via 510(k), not full PMA.
How it works
Manufacturer submits documentation showing substantial equivalence to a legally marketed predicate device. FDA reviews (target 90 days); if cleared, device can be marketed. Not "approved" — "cleared." Language matters in due diligence.
Why it matters to buyers
Every system has one or more K-numbers in its regulatory history. Software upgrades + new configurations often clear via follow-on 510(k)s. Check the FDA 510(k) database (free search at FDA.gov) by manufacturer + device to understand the regulatory footprint.