Multiangular Tomography By Computer

Any object which is not opaque to x-ray radiation may be serially sectioned in any specified orientation (for any specified section thicknesses) without destruction,by means of internal density maps derived mathematically from the data provided by a series of ordinary radiographic images. The object must be rotated through 1800 about a given axis and radiographed at equiangular increments. Digitized intensity data obtain ed from the radiographs permit numerical analysis on a computer. The internal serial-section maps are derived by means of a suitable mathematical algorithm, and then drawn on a computer-controlled oscilloscope and photographed on microfilm. The numerical values for one set of serial-section maps (in our case, corresponding to sections perpendicular to the rotation axis) can also be stored on computer tape or disk to be later used to draw internal density maps for other desired object orientations. A single radiographic series provides all the necessary information to produce serial-section maps for any and all orientations of the object.