TARGET TRACKING AND IRRADIATION METHOD AND DEVICE USING RADIOTHERAPY APPARATUS AND RADIOTHERAPY APPARATUS

A method for tracking and irradiating a target using a radiotherapy apparatus, a device and a radiotherapy apparatus are provided. The radiotherapy apparatus includes a first ray source, a second ray source, and at least one detector. The method includes: moving the first ray source to a first location to emit a ray beam; receiving the ray beam emitted from the first ray source at the first location and generating first image data of a target according to the received ray beam, by the detector; and adjusting the second ray source according to the first image data to make the second ray source move to the first location and an emitted ray beam pass through the target, wherein a time taken for the second ray source to move to the first location is a positive integer multiple of a preset respiratory period of a patient.