A stationary gamma ray detector incorporating a light image intensifier is described. The light emitted from a 2 in. diameter, 3 mm thick, flat crystal is focused, by means of a special Perspex lens system, onto the photocathode of the image intensifier (also 2 in. diameter) with a 5 efficiency. Using a parallel-hole lead collimator 2 in. long and having 2 mm square holes and 0007 in. thick septa, it was found that, when using a99mTc source (140 kev), a resolution of 1 mm was obtainable, although contrast was poorer at this value, due in part to the acceptance of unwanted Compton events within the subject, collimator and crystal. Contrast at separations of the order of 2 mm and above was quite good, however.A comparison with other image amplifier systems and with the Anger camera is made, and future plans are discussed.
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