METHOD AND APPARATUS FOR X-RAY OR .gamma.-RAY 3-D TOMOGRAPHY USING A FAN BEAM

摘要

Application for PatentofDouglas P. BoydforMETHOD AND APPARATUS FOR X-RAY OR .gamma.-RAY3-D TOMOGRAPHY USING A FAN BEAMABSTRACT OF THE DISCLOSUREA fan-shaped beam of penetrating radiation, such as X-ray ory-ray radiation, is directed through a slice of the body to beanalyzed to a position sensitive detector for deriving a shadow-graph of transmission or absorption of the penetrating radiationby the body. A number of such shadowgraphs are obtained fordifferent angles of rotation of the fan-shaped beam relativeto the center of the slice being analyzed. The detected fanbeam shadowgraph data is reordered into shadowgraph data corres-ponding to sets of parallel paths of radiation through the body.The reordered parallel paths shadowgraph data is then convolutedin accordance with a 3-D reconstruction method of convolution ina computer to derive a 3-D reconstructed tomograph of the bodyunder analysis. In a preferred embodiment, the position sensitivedetector comprises a multiwire detector wherein the wires arearrayed parallel to the direction of the divergent penetratingrays to be detected. A focused grid collimator is interposed be-tween the body and the position sensitive detector for collimatingthe penetrating rays to be detected. The source of penetratingradiation is preferably a monochromatic source.