PURPOSE. The purpose of this thesis is to investigate the possibility of implementing a prototype of a steerable needle in a medical procedure. Therefore the two main research questions are: “Can the intended user perform a steering motion with the steerable needle and reach the target area following a straight and curved trajectory?” and “Does the tip of the cannula maintain its position after the instrument change with a biopsy needle for a straight and curved trajectory?”. METHODS. Two studies were conducted to answer these research questions. A user study was designed and performed to test the steering properties of the steerable needle for a straight and curved trajectory. A second controlled study with automated insertions was designed and performed to investigate the cannula tip displacement after the instrument change. RESULTS. The results of both studies show that steering towards a specific target is highly achievable with the steerable needle for insertions with a straight and curved trajectory. Results also show a high success-rate, a low time consumption for the instrument change, and a high satisfactory level on the manual handling of the steerable needle by the interventional radiologists. The results of the second study show that the cannula tip maintains its position after the instrument change for a straight trajectory, and the cannula tip only displaces 1.4 mm back over a deflection of ±25 mm after the instrument change for a curved trajectory. CONCLUSION. Reaching the target with a steering motion is achievable with the steerable needle and only a small displacement of the cannula tip is seen after the instrument change for a maximum imposed curved trajectory. These results answer the main questions concerning the effectivity of the steerable needle and are promising for future implementation of this prototype in a real medical procedure, containing real patients, and real liver tissue. KEY WORDS. liver disease – liver biopsy – radiofrequency ablation – steerable needle – polyvinyl alcohol