A data processing system for modelling a medical procedure, comprising: a display; an image generator (37; 43) for generating, based on patient image information about the biological tissues of a particular patient, a dynamic image of tissues, including an image of an aneurysm, for display on said display, said generating for displaying on said display the tissues representing corresponding actual biological tissues; wherein said generating based on patient image information comprises segmenting a volume of interest defined from patient-specific DICOM data of a surgical site containing an aneurysm and surrounding vessels and structures to achieve a three-dimensional model of the volume of interest with tissue-specific segmentation; a user tool generator for generating a tool model of a user tool (112; 132) for dynamically interacting with said dynamic image of tissues via manipulations provided by a user input (20; 47) for display on said display; and a user interface (20; 47) providing a tool arranged to adjust the dynamic image of tissues displayed on said display by adding or modifying features of said tissues and assign mechanical properties characteristics by coupling a mechanical model of a specific tissue to the added or modified features of said tissues to compensate for anatomical structures that are in the actual biological tissue but are missing from the dynamic image of tissues originally displayed such that the dynamic image of tissues displayed are subsequently displayed on the display with the added or modified features, wherein said tool model (112; 132) is displayed on said display dynamically interacting with said dynamic image of tissues (111; 151, 152; 161, 162) by applying real-time tissue deformation for simulating the medical procedure; and wherein said user tool includes an aneurysm clip applier for applying an aneurysm clip model arranged to dynamically interact with the image of tissues, the aneurysm clip model being assigned with mechanical properties to block a blood flow when placed at a vessel. a display; an image generator (37; 43) for generating, based on patient image information about the biological tissues of a particular patient, a dynamic image of tissues, including an image of an aneurysm, for display on said display, said generating for displaying on said display the tissues representing corresponding actual biological tissues; wherein said generating based on patient image information comprises segmenting a volume of interest defined from patient-specific DICOM data of a surgical site containing an aneurysm and surrounding vessels and structures to achieve a three-dimensional model of the volume of interest with tissue-specific segmentation; a user tool generator for generating a tool model of a user tool (112; 132) for dynamically interacting with said dynamic image of tissues via manipulations provided by a user input (20; 47) for display on said display; and a user interface (20; 47) providing a tool arranged to adjust the dynamic image of tissues displayed on said display by adding or modifying features of said tissues and assign mechanical properties characteristics by coupling a mechanical model of a specific tissue to the added or modified features of said tissues to compensate for anatomical structures that are in the actual biological tissue but are missing from the dynamic image of tissues originally displayed such that the dynamic image of tissues displayed are subsequently displayed on the display with the added or modified features, wherein said tool model (112; 132) is displayed on said display dynamically interacting with said dynamic image of tissues (111; 151, 152; 161, 162) by applying real-time tissue deformation for simulating the medical procedure; and wherein said user tool includes an aneurysm clip applier for applying an aneurysm clip model arranged to dynamically interact with the image of tissues, the aneurysm clip model being assigned with mechanical properties to block a blood flow when placed at a vessel.