Abstract: A control circuit configured as a multi-criteria optimizer generates a radiation therapy treatment plan. The circuit then determines a resultant dose distribution as a function of the radiation therapy treatment plan and presents, on a display, at least a part of that resultant dose distribution. The latter may comprise, for example, presenting at least one isodose line on the display. The control circuit then detects user manipulation of a user interface. By one approach, this manipulation does not include corresponding immediate movement of any part of the presented resultant dose distribution itself. In particular, the detected user manipulation does not result in dragged movement of an isodose line on the display.