IRRADIATION TREATMENT PLANNING BASED ON TARGET COVERAGE REDUCTION

A computer-implemented medical method of irradiation treatment planning is provided. Therein, an initial coverage volume (118) for a planning target volume (116), which is to be irradiated in an irradiation treatment with a prescribed dose, is provided. Further, at least one constraint (106, 110) indicative of an allowed dose for an organ at risk (120) is provided. Applying an initial irradiation treatment plan, an organ dose deposited in at least a partial volume of the organ at risk (120) is calculated. Based on comparing the organ dose to the at least one constraint (106, 110), an amount of violation is determined. Taking into account the determined amount of violation, a reduction coverage volume is calculated for the planning target volume (116) and a virtual planning object (122) is generated based on changing a volume of the organ at risk (120), such that an overlap region (124) of the virtual planning object (122) and the planning target volume (116) corresponds to the reduction coverage volume. By removing at least a part of the overlap region (124) from the planning target volume (116), an optimized planning target volume (132) is generated.