What is Focal plane tomography?

In radiography, focal plane tomography is tomography 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 by the Italian radiologist Alessandro Vallebona as a means of reducing the problem of superimposition of structures which is inherent to projectional radiography.