An apparatus and method is disclosed for use in medical imaging including a collimator having an array of positive apertures and an array of negative apertures formed thereon. A housed collimator directed at a detector to essentially eliminate all gamma radiation except that which enters the apertures...http://www.google.co.uk/patents/US6580939?utm_source=gb-gplus-sharePatent US6580939 - Method and system for reducing background artifacts from uniformly redundant array collimators in single photon emission computed tomography
