Influence of hole shape on collimator performance.

The imaging properties of triangular and hexagonal hole shapes were compared for low energy scintillation camera collimators. The response of both hole shapes was calculated using a ray-tracing computer program, corresponding collimators were constructed and their performance was evaluated by measuring line spread functions and imaging bar patterns. The triangular hole shape was found to give better results above a spatial frequency of 1-5 cycles cm-1, below that frequency the hexagonal hole shape is superior. The differences, however, are small and the superior performance of the hexagonal hole collimator at clinically significant spatial frequencies is barely visible in bar pattern images.