An image acquisition apparatus includes: a positioner controller communicatively coupled to a positioner, wherein the positioner controller is configured to generate a control signal to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support； an imaging controller configured to operate the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager； and an image processing unit configured to obtain the first plurality of two-dimensional images and arrange the two-dimensional images relative to each other to obtain a first composite image.
