Methods and apparatuses for generating irradiation plans are provided. The method includes determining a size of a focal spot in an area, determining locations of focal spots in the area to which ultrasounds are to be sequentially irradiated based on the size of the focal spot, such that each of the locations of the focal spots is farthest from locations of focal spots in the area to which ultrasounds have been previously-irradiated, determining durations and intensities of ultrasound irradiations based on the size of the focal spot and the locations of the focal spots, and generating the irradiation plan for irradiating ultrasound based on the size of the focal spot, the locations of the focal spots, and the durations and the intensities of the ultrasound irradiations.
