Patent ID: 6398408
Filing Date: 2002-06-04
Classification: A61B

Abstract:
In an x-ray imaging machine including an x-ray tube generating x-rays from a focal spot, said x-rays including a central axis, said machine including a detector of the x-rays defining a source image distance measured parallel to said central axis between said focal spot and said detector and including collimator blades defining a blade plane and defining a focal distance measured parallel to the central axis between the focal spot and the blade plane, apparatus for calibrating the machine comprising:a phantom positioned between the detector and the x-ray tube, said phantom comprising a first portion defining a first dimension that generates a first x-ray image on the detector, said first x-ray image defining a first projected dimension, said phantom comprising a second portion defining a second dimension that generates a second x-ray image on the detector, said second x-ray image defining a second projected dimension, said first and second portions being separated by a predetermined distance measured parallel to said central axis; and a processor responsive to the first projected dimension or the second projected dimension to calculate at least one of said focal distance and said source image distance.