Abstract: A medical diagnostic system utilizing the principles of nuclear medicine is disclosed. The system includes a gantry having a detector support section supported by a carriage section located on a rail system for movement along a linear path. A nuclear detector is supported on a pair of weighted arms pivotally mounted on the detector support system about an axis perpendicular to the rail system. The detector is itself pivotally mounted near an end of the weighted arm pair for tilting rotation about an axis parallel to the arm pivot axis. Mechanism is provided for rotating the weighted arms additionally about an axis parallel to the rail system, in order to accomplish orbital motion of the detector. All three of these rotational movements are power actuated. A stationary pedestal and cantilevered patient support table is located between the rails of the rail system, with the patient table extending longitudinally with respect to the rails.