The disclosed subject matter relates to a method for treatment of a patient by irradiating a tumor by means of an irradiation device. The method comprises the steps of: scanning at least a part of a body of the patient； localizing the tumor in the scan； determining a hypoxic and a normoxic region of the tumor and a micro-environment surrounding the tumor in the scan； and emitting irradiation beams in different irradiation directions that intersect in the hypoxic region while controlling an individual irradiation dose in each irradiation direction such that an accumulated irradiation dose delivered to the hypoxic region during the treatment is greater than 8 Gy and an accumulated irradiation dose delivered to the micro-environment during the treatment is, in an average over said micro-environment, less than 3 Gy. The disclosed subject matter further relates to a system configured to carry out the method.
