A non-linear programming method for optimizing parallel-hole collimator design.

Abstract

A new method for optimizing the design of multi-aperture parallel-hole collimators for the gamma scintillation camera is presented. The method takes into account the frequency spectrum of a plane source object distribution as well as the energy of the radiation. A frequency dependent statistical figure of merit is calculated and combined with a weighted object distribution frequency spectrum to obtain an objective function which, when maximized, yields the optimum collimator design according to the chosen criteria. The optimization is performed by means of a sequential pattern search technique. The results show a positive correlation between te objective function and an experimental performance index evaluated for existing collimators. The optimal designs obtained by maximizing the objective function, under the assumption of no scatter within the source, exhibit somewhat higher sensitivity and lower resolution than the commercial low energy collimators tested. It is concluded that much of the resolution capability of very high resolution collimators is unused because of the limitation imposed by the intrinsic resolution of the detector assembly.