Focal plane tomography

In radiography, focal plane tomography is tomography (imaging a single plane, or slice, of an object) by simultaneously moving the X-ray generator and X-ray detector so as to keep a consistent exposure of only the plane of interest during image acquisition. This was the main method of obtaining tomographs in medical imaging until the late-1970s. It has since been largely replaced by more advanced imaging techniques such as CT and MRI. It remains in use today in a few specialized applications, such as for acquiring orthopantomographs of the jaw in dental radiography.

Focal plane tomography’s development began in the 1930s as a means of reducing the problem of superimposition of structures which is inherent to projectional radiography. It was invented in parallel by, among others, by the French physician Bocage, the Italian radiologist Alessandro Vallebona and the Dutch radiologist Bernard George Ziedses des Plantes.