Filter interlocks on Grenz-ray units, A potential Hazard

Abstract

I should like to draw your attention to a near failure of a filter interlock circuit, on a low-energy X-ray unit, which could have resulted in a patient overdose. The unit concerned, a typical Grenz-ray unit, operates at to 50 kV in 10 kV steps. Five filters are stored in slots on the control console. To operate the unit a filter has to be removed from its storage slot and clipped into position at the end of the X-ray tube head where it actuates a microswitch.