X-ray tubes are frequently used in fluoroscopy. The Infinixi-i series incorporates a backup focus function which enables a smooth change of focus even if the filament burns out owing to prolonged use. As the focus is always monitored by computer, even if the filament of a small fluoroscopy focus should burn out during an examination, it is an easy operation to switch to a large or medium radiography focus so that the examination can be safely concluded.
