
a physician) reviews the dose distribution resulting from the treatment plan in several steps and makes changes to the treatment goals in order to find the optimal dose distribution. This optimization process is usually an operator-guided procedure in which an operator (e.g. Then, an optimization process is carried out to find the treatment plan which fulfills the specified treatment goals. Such treatment goals include objectives which may specify requirements for the radiation dose delivered to certain regions of the patient, which should be fulfilled, and/or constraints for the radiation doses delivered to certain regions, which must be fulfilled. In such a procedure, the target structure and the surrounding structures to be spared are identified and treatment goals are specified. In particular, a so-called inverse planning procedure may be carried out by means of the planning system. The treatment parameters for delivering the radiation and controlling the radiation treatment device are defined in a treatment plan, which is generated in a planning system. In this respect, it is typically the goal to deliver a sufficiently high radiation dose to the target structure and to spare sensitive structures, such as organs, in the vicinity of the target structure as far as possible. In more advanced types of radiation therapy, such as so called intensity-modulated radiation therapy (IMRT), precise doses of radiation are applied to regions of the patient's body. The radiation treatment is usually delivered in plural sessions, which are also referred to as treatment fractions in the art. In external beam radiation therapy, ionizing radiation is applied to target structures, such as tumors, within patients' bodies in order to control growth of or kill cancer cells. More specifically, the invention relates to a system, a method and a computer program for generating a radiotherapy treatment plan for a patient. The invention generally relates to a planning of an external beam radiation therapy treatment of a patient.

This application is hereby incorporated by reference herein. 7, 2016, which claims the benefit of European Patent Application No.

#SBART THERAPY SERIAL#
§ 371 of International Application Serial No. National Phase application under 35 U.S.C.
