An annular cylindrical multihole collimator for a radioisotope camera made by forming a plurality of closed annular radio-opaque plates which may be all corrugated plates or may be half corrugated and half flat, each having at least one collimator segment section and junction, and stacking a number of...http://www.google.com/patents/US5270549?utm_source=gb-gplus-sharePatent US5270549 - Annular cylindrical multihole collimator for a radioisotope camera and method of making same
