The present application discloses a method for detecting an abnormity in an optical path or measuring and adjusting of a dynamic balance of a gantry in a CT system, comprising performing, by a gantry controlled by a controller, a test scan along an optical path of the CT system, the optical path being a path along which rays pass from a ray source to a detector. The method further comprises obtaining, by a processor, data relating to the test scan, and based on the data relating to the test scan. The method further comprises determining, by the processor, a status characteristic index of the optical path or an amount of dynamic imbalance of the gantry. The method further comprises analyzing, by the processor, a result of the status characteristic index; determining, by the processor, whether the optical path is abnormal, or determining whether a dynamic balance of the gantry satisfies a requirement based on a result of the analysis of the amount of dynamic imbalance.