an interface system is provided for planning a surgical procedure for inserting an object into a patient along a surgical planning trajectory from an entry point on the patient to a target point within the patient . using an imaging device , a first scan of the patient is performed to generate a first image volume data set of a first area of the patient . a first sectional image of the patient is displayed on a human - readable display device associated with the imaging device . the first sectional image is based on the first image volume data set . using an operator interface device , a second planning image of the patient is defined by placing a plurality of graphical point symbols in the first sectional image of the patient displayed on the display device . the plurality of graphical point symbols define a second area of the patient to be subject of display as a second sectional image of the patient . the second sectional image of the patient is derived either directly from the first image volume data set , indirectly from the first image volume data set by interpolation , or by performing a second scan of the patient with the imaging device .