Systems and methods for planar imaging with detectors having moving heads are provided. One system includes a gantry having an opening therethrough, a patient table movable through the opening of the gantry along an examination axis, and a plurality of detector units mounted to the gantry and aligned in a row transverse to the examination axis. The plurality of detector units are spaced apart from each other, wherein the spacing forms gaps between adjacent detector units. The plurality of detector units are configured to acquire Single Photon Emission Computed Tomography (SPECT) data. The system further includes a controller configured to control movement of the patient table and the plurality of detector units to acquire two-dimensional (2D) SPECT data, wherein the plurality of detector units remain in a fixed relative orientation with respect to each other when acquiring the 2D SPECT data and move together to acquire the 2D SPECT data.