Novel imaging technique to determine x-ray focal spot size of mammographic systems with microchannel plate

A microchannel plate was used to record images of mammographic x-ray focal spots on film. Different versions of this device were made to authors' specifications by fiberoptic fusing and etching techniques. Each plate consisted of an array of Pb-glass capillaries with a length of 1-2 mm and an internal diameter of 6-10 μm. This device is not yet optimized, but it has the potential of alleviating the problems with alignment and long exposures associated with pinhole cameras and slits. A significant problem affecting accuracy in size was associated with septal penetration, contributing to some blurring of the focal spot image