tube life

Expected useful life of an X-ray tube, typically measured in scans, mA·s, or hours depending on modality.

Why it matters to buyers: Single biggest replacement cost on CT, interventional, and (sometimes) fluoro. Check tube hours / scan count on every refurb purchase.

Why it matters to engineers: mA·s is the best wear proxy on CT. Anode bearing noise is the end-of-life warning before arcing.