Evaluation of Slice Shield Collimators for Multi-Layer Positron Emission Computed Tomographs

Evaluation of slice shield collimators is carried out using theoretical event rate formulas. This approach permits calculation of system performance in terms of sensitivity, scatter fraction, and high-counting rate characteristics. Electronics counting efficiency is also taken into account. A rational approach to optimal design is presented along with design examples. Effectiveness of collimator replacement is suggested. A system using sub-collimator with relatively small detector ring radius is proposed. It achieves a level of performance similar to that of a conventional collimator system with large ring radius.