1. A method for correcting a CT scan image, the method comprising: extracting a target image including a target region to be corrected from an original CT scan image; obtaining a target projection range corresponding to the target region by orthographically projecting the target image, and correcting target projection data within the target projection range; adjusting noise of the corrected target projection data to generate noise-adjusted target projection data to improve noise consistency between target region and the rest of the CT scan image; and reconstructing a corrected CT scan image based on the noise-adjusted target projection data.