Patent Number: 043485910
Section: claims

1. A straight bore flat field masking collimator for multiple detector imaging gamma cameras comprising: (A) an open generally cylindrical radiation shield, having a camera end and an aperture end, the greatest inner dimension thereof being substantially between two and five inches, and  (B) a radiation shielding portion at the camera end of said cylindrical radiation shield for mounting to a gamma camera and for masking off the greater portion of the gamma camera's multiple detectors.  (A) a generally cylindrical radiation shield having a camera end and an aperture end, the greatest inner dimension thereof being substantially between two and five inches, said shield being a solid cylinder of radiation shielding material having a plurality of channels, and  (B) a radiation shielding portion at the camera end of said cylindrical radiation shield for mounting to a gamma camera and for masking off the greater portion of the gamma camera's multiple detectors. 2. The collimator of claim 1 wherein said radiation shielding portion comprises an upstanding open sleeve-like radiation shield having a camera end and an aperture end, the maximum inside dimension of said aperture end being equal to or greater than three inches, means at the camera end of said sleeve-like radiation shield for attachment to a gamma camera, and means at the aperture end for mounting said cylindrical radiation shield. 3. The collimator defined in claim 2 wherein said sleeve-like radiation shield is frustoconical. 4. The collimator defined in claim 1 wherein the walls of said generally cylindrical radiation shield are thicker at the camera end thereof than at the aperture end thereof. 5. The collimator of claim 1 wherein said radiation shield is substantially a right circular cylinder. 6. The collimator of claim 1 wherein the length of said cylindrical radiation shield is substantially greater than its inner diameter. 7. The collimator of claims 1, 5, or 6 wherein said radiation shielding portion is a substantially flat flange at the camera end of said cylindrical radiation shield. 8. A masking collimator for a multiple detector imaging gamma camera comprising: 9. The collimator of claim 8 wherein said channels are parallel. 10. The collimator of claim 8 wherein said channels are conically arranged, said channels radiating from a common point external thereto.