1. A collimation system for a medical apparatus, said collimation system comprising: a collimation component comprising a laser emitting device, at least one photographing device, and a computing device, wherein the laser emitting device is configured to the emit a laser beam to irradiate on a landmark on a body surface of a patient, the at least one photographing device is configured to take a photograph of a laser irradiation spot, and the computing device is configured to obtain a position of the laser irradiation spot by performing computation on images obtained by the at least one photographing device; and a moving component provided on the medical apparatus and configured to move to a target position for performing diagnosis or treatment, wherein the medical apparatus automatically is configured to locate the moving component based on the position of the irradiation spot obtained from the computation.