A navigation system for minimally invasive CT-guided interventions.

The purpose of our project was to develop a novel navigation system for interventional radiology. Fields of application are minimally invasive percutaneous interventions performed under local anaesthesia. In order to reduce unintentional patient movements we used a patient vacuum immobilization device. Together with the vacuum fixation and a newly developed reference frame we achieved a fully automatic patient-to-image registration independent from the tracking system. The combination of the software and a novel designed needle holder allows for an adjustment of the needle within a few seconds. The complete system is adapted to the requirements of the radiologist and to the clinical work-flow. For evaluation of the navigation system we performed a phantom study with a perspex phantom and achieved an average needle positioning accuracy of less than 0.7 mm.