A method of irradiating a target tissue in a patient comprising positioning the patient on a patient support system so that the target tissue in the patient is within irradiating distance of at least one source of a beam of radiation and moving the patient support system relative to the at least one source of a beam of radiation and, coordinately with movement of the patient support system, rotating the at least one source of radiation relative to the target tissue, which comprises and/or is adjacent to a non-target tissue, so that the center of rotation of the beam of radiation is placed at one or more desired locations within the target tissue, while simultaneously and/or sequentially irradiating the target tissue; a collimator; a method of making such a collimator; a system for irradiating a target tissue in a patient; and a method of planning irradiation of a target tissue in a patient.