Amol Pednekar and Ioannis Kakadiaris. Department of Computer Science, University of Houston. I. Introduction. Virtual reality (VR) has revolutionized many ...
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Proceedings of the 18th Annual Houston Conference on Biomedical Engineering Research, page 159, Houston, TX, February 10-12, 2000
MODELING, VISUALIZATION AND INTERACTION IN SURGERY SIMULATION
Amol Pednekar and Ioannis Kakadiaris Department of Computer Science, University of Houston I. Introduction
endow the geometric models with physical properties and we apply the laws of physics. With today’s increasing computational power the community is exploring developments in physics-based deformable model techniques for modeling soft tissue. Organs can be visualized as either surface or volumetric models. Visual realism is added to plain geometrical models by texture mapping. As in all VR systems, the various data are presented to the user/surgeon through a number of visual displays, the user navigates through the data and interacts with them. As a result of this interaction, the user receives feedback that could be multimodal (visual, force, tactile and auditory) depending on the task.
Virtual reality (VR) has revolutionized many scientific disciplines by providing novel methods to visualize complex data structures and moreover by providing means to manipulate this data in real-time in a natural way. Among the most promising fields for the application of VR systems are engineering, education, entertainment, military simulations and medicine. In this paper, we review the applications of VR in surgery simulation. For other reviews of VR in medicine and in health care in general the reader is directed to [1], [2], [4], [5].
II. Review
Existing VR applications in surgery simulation can be broadly classified in two categories: a) education and training, and b) pre-operative planning [3]. Surgeons require extensive training and experience to execute an operation successfully and safely. Presently, surgical manipulative skills are learned mainly by observing an expert surgeon, practicing skills on animals, cadavers, or inanimate trainers, and supervised practice during human operations. High expenses associated with these training methods limit the number of times each surgeon can practice the technique. With VR-based systems surgeons are able to: navigate through the anatomy, practice established procedures, practice new procedures, learn how to use new surgical tools, and assess their progress. In particular, surgeons can practice and experience surgical techniques and procedures on greater variety of pathologies and complications, they can repeat and replay these procedures, and students will have objective evaluation and benchmarking of their performance, without putting the patient at any risk. A VR-based educational system that includes multi-sensory feedback similar to the one the surgeons will meet in real cases, will allow a procedure optimizations without any danger for the patients. Similarly, in pre-operative planning the aim is to study patient data before surgery and to plan the best way to carry out that surgery. The requirements for the pre-operative planning systems are: a) the (multimodal) data from the specific patient are available, b) the data are accurate, and c) the model can be build as fast and as automatically as possible. Currently, there is a number of VR-based surgery simulators as summarized in [3]. The main components of all these systems are: modeling, simulation, visualization, display, interaction and feedback. The first step is the acquisition of accurate data, in order to be able to realistically reconstruct the organ under consideration. For the VR systems that are geared toward education, the organ models are obtained through databases of generic models (e.g., the Visible Human Project). For the VR systems that are geared towards patient specific procedures (e.g., diagnosis, planning) the models are being build from patient data. To simulate the response of organs to surgical actions, we
III. What is missing?
Our review reveals that further research is needed in the all the components of the systems: modeling; simulation; visualization; display,interaction and feedback. In particular in modeling, there is need for better methods for registering multi-modal data and automating the segmentation of the patient specific data. In simulation, better models for the behavior and the characteristic of the tissues are needed along with progress in computing realistic information in real time. Also, there is a need for modeling the physiological response of tissues and blood flow. In visualization, current limitations on rendering speed poses limitations on the size and therefore the fidelity of anatomical models. In display technology, displays with higher resolution and better tuned to human perception will help the process. Further developments are needed in the areas of interaction devices along with (remote) force, tactile, auditory and olfactory feedback. The absence of olfaction is a serious limitation of current training and telepresence systems. Possible effects from long term use of these systems need to be studied further along with what type of design metaphors will enhance the surgeon’s performance in VR. Finally, the sociological implications of the new technologies (e.g., how is this technology going to be perceived by the doctors) need to be studied methodically.
References [1] T. Emerson, J. Prothero, and S. Weghorst. Medicine and virtual reality: A guide to the literature. Technical report, Human Interface Technology Laboratory, Univ. of Washington, 1994. [2] J. Moline. Virtual reality for health care: a survey. http://nii.nist.gov/pubs/vr-medicine.htm. [3] Amol Pednekar and Ioannis Kakadiaris. Imaging, visualization and interaction in surgery simulation. Technical Report 99-01, Department of Computer Science, University of Houston, Houston, TX, December 1999. [4] R. M. Satava and S. B. Jones. Current and future applications of virtual reality for medicine. Proceedings of the IEEE, 86:484–489, March 1998. [5] K. G. Vosburgh and G. Burdea. Tutorial: VR in medicine. In Virtual Reality '99, Houston, TX, March 13-17 1999. IEEE Computer Society.
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