A gantry system for geometrically configuring a plurality of detectors for image scanning a patient comprises a plurality of essentially planar sensor support rings forming a barrel surrounding a central scanning area. Each ring is formed by opposing upper and lower semi-elliptical array supports, and each array support is configured to support a plurality of adjustable detector assemblies. Each array support is adjustable along a longitudinal axis of the barrel, and collectively define an imaging field of view that is configurable by separately adjusting one or more of the array supports. Upper array supports are also preferably moveable in a generally perpendicular direction with respect to longitudinal axis, e.g., to optimize position of the detector assemblies with respect to a patient, to provide for easier patient entry and/or to provide for scans of claustrophobic or obese patients.