A dual-head gamma camera imaging system comprises a master ring gear and a slave ring rotatable about a longitudinal axis. The master ring gear is rotatably supported by a gantry. The slave ring is rotatably supported by the master ring gear and concentric with the master ring gear, such that the master ring gear and the slave ring can be rotated independently about s longitudinal axis. A first detector is supported by a first cantilever support member mounted to the master ring gear. A second detector head is supported by a second cantilever support member mounted to the slave ring. The angular displacement between the detector heads can be varied by providing relative rotation between the master ring gear and the slave ring. The rotation can be accomplished by using the weight of one of the detector heads to hold that detector head stationary while rotating the other detector head using a motor. The imaging system also includes a mechanism for rotating a detector head about an axis perpendicular to its imaging surface to increase the field of view along the longitudinal axis. The detector is mounted to an inner support ring which is rotatably coupled to and concentric with an outer support ring. The outer support ring is mounted to at least one ring gear.