In this article, the author presents the introductory sketch of the field of medical applications of the virtual reality technologies.Research topics are also referred with the stress on the use of the virtualized human body, applications of three dimensional image processing, and computer guraphics.As the examples the author introduces virtualized endoscope systems, and pre-and intra-operative surgical aids.

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Although the concept of “visualization of medical information” can be applied to not only the minimally invasive surgery but also any surgical treatment, we have selected this application because either a microsurgery or our system demands the surgeon to operate with indirect view of the surgical field. In general, the role of the surgical strategy system is:(1) presurgical planning, (2) observation of surgical process during procedure and instruction about surgical guidance and estimation, (3) supporting decision making to choose alternative plan when an unexpected accident happened during the surgery, (4) supporting communication between the surgeon and the operating team, and recording of the total process of the surgery.Using such a strategy system, the surgeon and the instructors can collect and analyze the medical information and multi modal images.Such a system works, so to speak, to augment the surgeon's vision, so we call this concept “augmented reality”.

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In recent years the numbers of clinical oriented robots for neurosurgery have been developed, however, up to date, these robots haven't been used in clinical even in experimental operation yet because of many reasons. To solve the mechanical and medical problems in clinical setting, a newly designed needle insertion manipulator for neurosurgery has been developed. This manipulator, a CT image guided manipulator, is designed with following features: detachable mechanical and electrical parts for the sterilization with all axes moving step by step. In this paper, a design concept that clinical manipulators should be and its one solution are described.

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Neurosurgical navigation systems using preoperative images have a big problem in their accuracy which is caused byBrain Shift. To this problem we have developed an image modification technique using brain mechanics. In this study a method is introduced in which the intraoperative brain shape is estimated through Finite Element Method. In the process the nearest model shape to intraoperative brain surface is firstly estimated by modifying an FEM result through adjusting mechanical property, then the residual between the result and the actual shape is obtained by a virtual load on the brain surface.
The accuracy of our method is evaluated with phantom experiments.We prepare two kinds of phantom experiments for investigating the most adaptive conditions in terms with bindings, initial model parameters, etc. One is that using mathematical model whose mechanical property is elastic, and the other is that using soy bean curd whoes mechanical property is non-linear.

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We have used computer-based virtual endoscopic techniques as a novel approach to clarify the 3D surgical anatomy of the pancreas and improve preoperative surgical planning. 13 cases with mucin-producing pancreas tumors were investigated by virtual pancreatoscopy. All cystic tumors and the main pancreatic ducts were displayed by virtual endoscopy. The surfaces of the intraductal papillary adenocarcinoma were illustrated more irregularly than were benign adenomas. Virtual pancreatoscopy was useful for surgical planning of minimally invasive resection of the pancreas.
However, there were some technical problems with virtual endoscopic images. Cystic lesions next to the main pancreatic duct were displayed together with the main pancreaticduct, because thin septa between cystic lesion and the main pancreatic duct could not be generated. A septum was illustrated like pillars in some cases. Fly-path image did not always fly through the main pancreatic duct.

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