The invention relates to a system (100) for determining a feedback on a three-dimensional location of a pointer in a three-dimensional region of image data, the system comprising: a display unit (110) for computing a view of the three-dimensional region for displaying on a display; a pointer unit (115) for computing a two-dimensional location of the pointer on the view of the three-dimensional region, based on a pointer location input; a location unit (120) for computing a three-dimensional location in the three-dimensional region, based on a two-dimensional location on the view of the three-dimensional region; and a shadow unit (125) for determining a set of two-dimensional locations for displaying a shadow on the view of the three-dimensional region, wherein the set of two-dimensional locations for displaying the shadow comprises the two-dimensional location of the pointer on the view of the three-dimensional region, and wherein a set of three-dimensional locations, computed based on the set of two-dimensional locations for displaying the shadow, is connected. Typically, the connected set of candidate three-dimensional locations comprising the three-dimensional location of the pointer is comprised in a structure indicated by the pointer. Therefore, the determined feedback on a three-dimensional pointer location on a view of the three-dimensional region of the image data improves clarity and decreases ambiguity of indicating a 3D location on the structure.