Imaging systems, methods, and computer readable mediums are provided. Image detectors are installed in a gantry to detect image information related to a subject. If obstructions are detected related to the field of view of an image detector, a system matrix can be updated accordingly. Thus, upon image reconstruction, artifacts related to obstructions can be minimized or altogether eliminated. This system can be a Nuclear Medicine (NM) imaging system to acquire Single Photon Emission Computed Tomography (SPECT) image information.