Patent Number: 052280691
Section: claims

1. A computerized tomographic (CT) scanner comprising: a patient holding means,  a gantry,  means for mounting an X-ray source on said gantry on one side of said patient holding means,  means for mounting a partial ring of discrete X-ray detectors on the other side of said patient holding means,  holding a patient,  mounting an X-ray source on one side of said patient,  mounting an X-ray detector means on the other side of said patient,  simultaneously rotating the X-ray source and said X-ray detector means about the patient more than 180.degree. per rotation in a rotate-rotate mode, and  selectively detecting either X-rays that have simultaneously traversed two juxtaposed planar sections in said patient or X-rays that have traversed a single planar section in said patient. 2. The CT scanner of claim 1 wherein said partial ring of a second row of said two rows being juxtaposed to the first row in the Z direction with both the first row and the second row of detectors extending in the X direction and being defined by the limits of the fan beam. 3. The CT scanner of claim 1 wherein the partial ring of the the second row is angularly smaller than the limits of the fan beam. 4. The CT scanner of claim 1 including shielding means for preventing interaction between said juxtaposed rows of detectors said shielding means being in the order of no more than 0.1 mm thick. 5. A method of selectively obtaining computerized tomographic (CT) image data from either a single slice in the patient or from two contiguous slices in the patient, said method comprising the steps of: 6. The method of claim 5 including selectively shifting said detector means relative to said X-ray source in the Z direction; where X, Y and Z are directions in a Cartesian coordinate system with Y being the direction between the X-ray source and the detector means, Z being the longitudinal direction of the patient and with X being the direction of rotation and Z being normal to both the X and the Y directions. 7. The method of claim 6 including the step of shifting the detector means in the Z direction relative to the X-ray source so that only X-rays from the X-ray source that pass through only a single slice of the patient are detected. 8. The method of claim 6 including the step of shifting the detector means in the Z direction relative to the X-ray source so that X-rays from the X-ray source that pass through two contiguous slices are detected.