US Patent 4,748,328
United States Patent and Trademark Office
University of Iowa Research Foundation (Iowa City, IA, US)
A single photon emission computed tomograph comprising a detector ring and a rotatable collimator assembly disposed within the detector ring. The rotatable collimator assembly comprises four collimator quadrants, and each of the four collimator quadrants comprises a plurality of collimator modules with their axes assembled in parallel. Each of the modules contains a plurality of inwardly directed channels focused to a single point on its own axis with a long focal length. The focal length of each of the collimator modules is individually and flexibly chosen to suit a particular imaging task. The four collimator quadrants are installed in the rotatable collimator assembly at a slightly different angular offset so as to achieve fine data sampling.
Chang, Wei; Kirchner, Peter; and Rezai, Karim Single photon emission computed tomograph using focused modular collimators. US Patent 4,748,328 filed July 10, 1986 and issued May 31, 1988. https://ir.uiowa.edu/patents/58