A new high-definition microfocal X-ray unit

A new microfocal unit is described with an operating range up to 170 kVp, 0-1 mA and a maximum output of 75-80 W. The unit comprises a lanthanum hexaboride (LaB6) cathode, a single electromagnetic lens and a stationary oil-cooled multifaced tungsten target. The use of fast rare-earth film-screen systems permits exposures of most views of the patient within 1 s. The spatial resolution within these film-screen systems is 40-30 μm diameter at magnifications of x 5-10. The tube is fixed so as to project a horizontal beam and the patient table is designed to position the patient close to the source (20-30 cm) with the film placed at a focus-film distance of 1-3m. Stereopair macroradiographs permit greater accuracy in the identification and location of radiographic features. The large magnification and resolution of macroradiographs allow direct and accurate measurement of radiographic features. (author)