METHODS & MATERIAL
Off-the-shelf gesture-based user interface technology (e. g., Leap Motion) is utilized to develop a new human-computer interface for 3D image post-processing, allowing to:

1. define position and orientation of oblique MPR (multiplanar reformations) and sliding-thin-slab MIP (maximum intensity projections)
2. define viewing angle and position for VRT (volume rendering technique) and MIP
3. control other commonly used (2D) functions like zoom & pan and "windowing"

with simple hand movements.

RESULTS
The presented natural, "deviceless" user interface provides more degrees of freedom than conventional input devices. However, it lacks accuracy for certain tasks, and is prone to cause fatigue. It works well in combination with a conventional input device like a normal keyboard and when used with simple gestures, e. g., an extended hand that can be reliably detected.

CONCLUSIONS
Compared to conventional input devices (mouse, keyboard, trackball, touchscreen), a gesture-based natural user interface

1. is not a suitable substitute with regard to (2D) routine tasks
2. can be a valuable addition with regard to advanced 3D imaging tasks