Abstract: We discuss interaction tasks and interaction techniques for the planning of soft tissue operations as for example oncologic liver and lung surgery. We focus on techniques to explore the relevant structures, to integrate measurements directly in 3d visualizations and to specify resection volumes. The main contribution of this paper is the introduction of new techniques for 3d measurements and for virtual resections. For both interaction tasks, dedicated widgets have been developed for the direct-manipulative use. In contrast to surgical simulators, which are used for the education of future surgeons, we concentrate on surgeons in the clinical routine and attempt to provide them with preoperative decision-support on the basis of patient-individual data.

The selection of the interaction tasks to be supported is based on a questionaire in which 13 surgeons described their praxis of surgery planning and their requirements for computer support. All visualization and interaction techniques are integrated in a software, named SURGERYPLANNER, which exploits the results of image analysis achieved in an earlier project. With the SURGERYPLANNER the anatomical and pathological structures of individual patients are used for surgery planning.