A simple test phantom for checking X-ray tube voltage

A simple and inexpensive test tool is described, for checking kV-consistency both in fluoroscopic and radiographic modes. It is designed primarily for routine checking to recognise changes in effective kV. A plexiglass body with boreholes in which copper discs of different thicknesses are inserted is depicted on a film or the TV screen via the image intensifier. Due to the very different absorption properties of copper and plexiglass the relative transparency of the copper discs changes markedly when the tube voltage is varied. The copper step-associated with a reference number-having transparency equal to the surrounding plastic can be used as a good index for tube kilovoltage. The accuracy of the visual assessment is about +-2 kV at 60 kV. (author)