An apparatus for determining a distribution of a selected therapy in a target volume is provided. A three-dimensional ultrasound transducer captures volume data from the target volume. A computing device is in communication with the three-dimensional ultrasound transducer for receiving the volume data and determining the distribution of the selected therapy in the target volume along a set of planned needle trajectories using the volume data. At least one of the needle trajectories is oblique to at least one other of the planned needle trajectories.
