This paper presents a method for compensating the rotation error between the virtual and real endscopic images in a flexible neuroendoscopic surgery navigation system. Recently, electromagnetic tracker sensor is used in the flexible neuroen-doscopic surgery navigation system to track the tip of the endoscope camera in order to generate the navigation information such as virtual endoscope images corresponding to the endoscope views. However, due to the operation of surgery tools, the sensor will be rotated frequently during the surgery. Therefore, the virtual images become greatly different from the real endoscopic views. In this paper, we propose a method to overcome this problem using epipolar geometry. The epipoles of real (virtual) endoscope image pairs which are captured (generated) at different positions are estimated, and the rotation error between real endoscope and virtual endoscope is estimated by comparing the epipoles on the real image and corresponding virtual image. We implemented the proposed method in a navigation system for flexible neuroendoscopic surgery and performed a phantom test. The result showed the proposed method was efficient for compensating the rotation error between the virtual and real endscopic images in a flexible neuroendoscopic surgery system.

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In Japan, many people have treated/untreated carious teeth. The carious treatment often requires long time including time to visit. On the other hand, the drilling operation for the treatment requires very high accuracy despite the freehand work by a dentist. If the operation could be automated, short-time treatment and high accuracy drilling could be realized. However, it is difficult to diagnose how much the caries should be removed. Its diagnosis depends on the dentist's experience or sense. To solve this problem, we have focused on the vibration induced by drilling. The vibration commonly relates to properties of the material. In this paper, we have confirmed its relation by the measurement and also confirmed that cause of drilling vibration is the elastic wave. Based on this fact, we have indicated the possibility to estimate the properties of a material under drilling and shown the effectiveness of determination based on drilling vibration by the experiment.

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Neurosurgical motion base is a 8 DOF robotic arm for positioning a surgical tool. In this paper, its overview, kinematics, prototype implementation, mechanical evaluation and clinical set-up test using a patient phantom model are described. The neurosurgical motion base is developed as a mount-type surgical robot on a conventional surgical head frame, therefore, it is possible to realize a quick installation. In our concept, the neurosurgical motion base holds and positions a cutting-edge surgical tool including a sensor feedback suction tool and a 3D endoscope. In the neurosurgical motion base, a 4 DOF active mechanism is introduced for precise positioning of a surgical tool, and a 4 DOF passive mechanism is introduced for adjusting the robot position on the head frame. By introducing a new 3 DOF parallel mechanism into the active part of neurosurgical motion base, high rigidity and accuracy can be realized, and also it is possible to locate all actuators on the base part for a capability of sterilization. From mechanical evaluations, it was revealed that accuracy and rigidity of the developed robot were 0.04 mm and 6.5 N/mm respectively. In addition, by an installation test on a patient phantom model, a feasibility of the developed robot was positively shown.

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Catheter based operations are increasingly being used as a minimally invasive surgery method. In endovascular coil embolization, two surgeons generally fill an aneurysm with embolization coils by the collaborative manipulation of a microcatheter and a coil delivery wire. Currently, medical robot systems are being developed to assist advanced minimally invasive surgery procedures and to overcome the shortage of medical specialists. In this study, a new surgery system that can be operated by only one surgeon is developed. This system consists of a foot switch controlled delivery wire driving unit, a wire insertion force sensor unified Y-connector, and an audio insertion force feedback speaker. Basic verification for this system was conducted using a silicone dummy aneurysm. The results confirmed that the delivery of the wire at a constant velocity by the wire delivery system is an effective method for coil delivery, and that only one surgeon can perform the same coil embolization procedure. In this paper we demonstrate the above said system features and the verification results of this system by conducting a coil embolization using a silicone dummy aneurysm.

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