A scanning apparatus (110), a medical image obtaining method, and a medical image obtaining system (100) are provided. The scanning apparatus (110) comprises a gantry, a controller, a C-shaped arm, a radiation source (112), and a detector (113). The radiation source (112) and the detector (113) are arranged at both ends of the C-shaped arm. The C-shaped arm is connected to the gantry. The controller is configured to control a motion of the gantry to drive the C-shaped arm to move so as to scan a target object.