1. Apparatus for use with a gamma camera for permitting first the identification of an anatomical area of interest and then the study of the identified area without requiring movement of either the camera or the identified area, comprising a first high resolution collimator section for identifying an area of interest, a second high sensitivity collimator section for study of the identified area, the first and second collimator sections joined to each other at one end, means located between the camera and the area of interest for permitting communication of the camera with the area of interest, including means for receiving the joined first and second collimator sections and for permitting sliding movement of the joined sections to permit positioning of either the first or the second collimator section between the camera and the area of interest thereby allowing first the identification of the area of interest and then the study of the identified area without requiring movement of either the camera or the identified area.