Artikel
Robotic 3D ultrasound scan of the cranium for navigation of automated drilling procedures
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Veröffentlicht: | 8. August 2007 |
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Introduction: Manual drilling of a device seat in calvarial bone is needed for various implantable hearing systems. Due to the varying bone thickness, lesions of the dura ort he sigmoid sinus may be encountered. Therefore, we would like to combine the advantages of highly precise drilling of the device seat with those of 3D ultrasound navigation.
Methods: 3 formalin preserved specimen of cranial halves were scanned with a robotic ultrasound system. This consisted of the SonoPointer® (Fraunhofer TEM II) with 1 / 2.25 MHz ultrasound transducer and a special flexible delay line mounted on a Staeubli RX90 robot. The calvarial surface was first registered by an optic tracking system (NDI Polaris), and the path for the robot was lined. Throughout the entire path, the ultrasound transducer was orientated perpendicular to the bony surface by the robot.
Results: The special flexible delay line allowed maintaining optimal acoustic coupling even in areas with bony irregularities. It withstood the exerted mechanical stress. In all cases, it was possible to perform a robotic 3D ultrasound scan of the cranium. The transducer with a mid frequency of 2.25 MHz was superior to 1 MHz.
Conclusion: These pilot experiments are a proof of concept for performing robotic 3D ultrasound scan of the cranium. This enables CT free navigation solely based on ultrasound for automated drilling procedures at the cranium.
Supported by the “Deutsche Forschungsgemeinschaft” (DFG) in the special research cluster SPP 1124 “Medical Navigation and Robotics” (grant PL 136/5-1, PL 136/5-2, PL 136/6-3).