Provided is a flat-plate PET imaging device with a window (11), comprising: a first flat plate (10) formed of a plurality of PET detectors arranged in sequence into a plate shape and provided with at least one window (11)； a second flat plate (20) formed of a plurality of PET detectors arranged in sequence into a plate shape and parallel to the first flat plate (10) and the second flat plate (20) are fixed. By arranging a window (11) on the flat-plate PET, a space is provided for other operations, such as radiotherapy, while ensuing the real-time positioning and scanning effects, thereby actually achieving real-time diagnosis as well as positioning and navigation without affecting the therapeutic procedure.
