First Multiple Detector Positron Imaging Device - 1962

Several versions of the single pair coincidence system were built including a commercial version. It was clear that increased sensitivity was required and a Hybrid Scanner (Figure 3) was developed in the mid 60's and results published in 1968. This device used two rows of nine detectors each in coincidence with three detectors in the opposite row. The detector assembly translated in one direction so that a two dimensional image was formed. The scanner was designed specifically for brain imaging and served for that purpose in a clinical setting for nearly a decade. A unique feature of the scanner was that in addition to increased sensitivity, another form of three-dimensional image could be obtained by focusing on planes parallel to and lying between the two detector arrays. This feature proved to be a powerful addition to the scanner and permitted lesions to be imaged in two dimensions and their position to be estimated in the third dimension by selecting the plane with the sharpest image.

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Figure 3: Hybrid Positron Scanner.