[en] The method described for use in nuclear medicine optimises a system of slit collimators in an opposite arrangement with reference to a maximum mean sensitivity for line sources over the screened layer. The program contains quality factors for the variation of the thickness of the layer and deviations from the mean efficiency. Restrictions can be assigned for both quality factors as well as for the penetration through the collimator septa. Collimators used in an auxiliary system for screening layers by means of γ-γ-coincidence scintigraphy are optimised with the aid of the program. Collimators designed by the program with a separation of 240mm have a higher sensitivity than those designed by Schmitz-Feuerhake with a separation of 180 mm. As the program only considers absorption and not scattering in material, there are deviations in the response in comparison with the computed response, dependent on the width of the energy window in the pulse height analysis. Experimental results enable one to estimate the broadening of the screened layer by scattering and to include the broadening by further optimisations. In profile scanning, scattering effects are of little importance once small energy windows are employed. The method can therefore be applied without restrictions. (author)