Brain navigation consists in travelling along acheter du cialis en ligne an established trajectory inside the brain anatomy in order to locate and reach a target of interest. To achieve this, neuronavigation systems provide a set of technological resources to the surgeons, allowing them to observe images from patients’ anatomy and monitor surgical instruments while performing the surgery. In this work we introduce an interactive system that uses 3D images and a high precision electromagnetic tracking device to assist the neurosurgeon during the pre-operative and intra-operative phases of minimally invasive surgical procedures. The proposal of a simple registration method called Crowning is also described. It consists in the interactive adjustment of a crown of spheres, representing the spatial locations of fiducial markers, on a tridimensional model of the patient’s head. The neuronavigator was tested on experiments with a synthetic skull model and later validated in two surgeries related to real clinical cases. These tests allowed to evaluate the navigator’s contribution to decrease planning and surgery times, eliminate manual calculations for obtaining coordinates of anatomical targets, and minimize the exposure to intra-operative ionizing radiations.