1. A method for regulating a therapeutic beam directed at an object, the method comprising: displaying at least one multidimensional image data record encompassing at least one target area of the object; determining a treatment beam dosage directed at the at least one target area; recording and optionally visualizing an isoline or isosurface dependent on the treatment beam dosage in the at least one multidimensional image data record; automatically adjusting the isoline or isosurface such that the isoline or isosurface approximates a contour of the at least one target area as closely as possible or corresponds to the contour; adjusting the isoline or isosurface based on a user input via a slider of a user interface; and regulating the treatment beam dosage by evaluation of the adjusted isoline or isosurface, wherein the automatically adjusting comprises minimizing a cost function that expresses a distance between the isoline or isosurface and the contour of the at least one target area.