In a medical image generation method, projection data of a scanned object is acquired during rotation of a radiographic source, and a scout image of the scanned object is generated in one scanning direction using corresponding projection data in two opposite scanning directions in the projection data. The scanning direction is used to represent a relative position relationship between the radiographic source and the scanned object. Using projection data in two opposite directions to generate a scout image in one direction during rotary scanning of a radiographic source can significantly shorten the generation time of the scout image.