Medical Imaging applications use images coming from different sources such as magnetic resonance imaging (MRI), computer tomography (CT), positron emission tomography (PET), to generate 3D data. Starting from these volumetric data, applications reconstruct 3D models of anatomical structures which could be manipulated and analyzed. In this paper we present a new approach for the visualization and interaction with volumetric datasets in a fully immersive environment. It allows to handle the reconstructed models directly within the virtual scene; in particular a technique is described for outlining the Volume Of Interest (VOI) functionality in a three-dimensional dataset for a visual interactive inspection and manipulation of the organ of interest.