A dual sensitivity collimator

Collimators are used to form images of gamma ray emitting sources with gamma cameras. They are made of gamma ray attenuating material such as lead or tungsten with holes which select gamma photons arriving in a small solid angle near the normal to the detector face. The spatial resolution of the resulting image depends both on the intrinsic resolution of the detector in use and on the geometry of the collimator. Its transparency (or sensitivity) is all the more small since its resolution is improved. Resolution-sensitivity antagonism is a well known problem in radio-isotopic imaging. This can lead to a prohibitive acquisition time as well to position the camera with respect to the patient as for the acquisition itself. A collimator which makes available several resolution-sensitivity pairs in only one device has been developed.