A device and method for selectively performing single photon planar imaging, single photon emission computed tomography, and positron emission tomography which utilizes scintillation cameras (10a, 10b). The sensitivity of the scintillation cameras (10a, 10b) to gamma rays (3) of different energies is provided for by tilting or pivoting the scintillation cameras so as to change the path length encountered by gamma rays (3) as they pass through the camera crystals (11a, 11b). The principle of direct endpoint detection with the scintillation cameras (10a, 10b) is used to define annihilation event coincidence lines from which the internal activity distribution is reconstructed.
VARIABLE AXIAL APERTURE POSITRON EMISSION TOMOGRAPHY SCANNER