The German MEDARPA consortium, consisting of five technology and three clinical end user partners, has created the VR/AR navigation system to solve the surgeon's limited viewing field of the patient, an ever recurring problem in medical interventions. The MEDARPA workstation provides spatial registration tools to restore the missing visual information without obstructing the physician with complicated technical devices or constructions. As such the surgeon can "look into" the patient during the operation, without having to take away his eyes from him. The information is provided on a freely positionable, half-transparent display, the so-called "virtual window" and can be used by the surgeon whenever he needs it.
The MEDARPA system can be used, among other applications, in minimally invasive heart surgery, pneumology and radio-oncology. In brachytherapy, for instance, irradiation-pillows must be advanced as close as possible to the patient's tumour to minimize the damage of the healthy cells surrounding the tumour. After a preceding CT-based three-dimensional planning of the brachytherapy treatment, the irradiation is performed with a small radio-active source, inserted into the irradiation probe by a computer-controlled afterloading device, right into the tumour itself. Within the tumour, a very high irradiation dose can be achieved while the surrounding structures as well as the skin is being preserved.
The MEDARPA AR display is used during the intervention but also in post-implentation-planning procedures to compare the post-planning results with the actual probe situation and the isodose processes in the planning CT. In this way it is possible to exactly determine the position, to create a complete view as well as to control the graphic-interactive access of the surgical instruments. The application of augmented reality allows to overlay the real view on the patient with the computer-generated images.
In addition to his experience with human anatomy and his good memory of the previously gathered patient data, the surgeon now can rely on the interactive visualization capabilities provided by the AR semi-transparent display. The lack of spatial reference between the a priori captured data and the position of the patient during the intervention no longer exists. This is of great value in biopsy procedures. The surgeon no longer needs to inject the puncture needle "blindly" with only an accurate planning and his experience at hand to support him while still running the risk of damaging healthy tissue. The AR workstation prevents the physician from injuring an embryo during an amniocentesis, from violating nerve cells in the spinal cord during a lumbar puncture and from paralyzing the patient by accident. And then we did not even mention the punctures in the brain area where important areas could be harmed without the use of a savvy navigation tool.
The MEDARPA consortium particularly has addressed the medical area in developing the VR/AR navigation system but the innovative technology can also be easily adapted to other application domains, in which the user has little or no opportunity to carry additional devices with him, such as for example in the service and maintenance area.
The MEDARPA partners are the Fraunhofer-Institut für Graphische Datenverarbeitung and the Zentrum für Graphische Datenverarbeitung e.V., both hosted in Darmstadt, as well as MedCom GmbH; the Gesellschaft für Medizintechnik mbH in Weiterstadt; and the Medical Innovative Technology GmbH in Bochum. The three hospital partners are the Klinikum der Johann Wolfgang von Goethe Universität Frankfurt am Main; the Klinikum Nürnberg; and the Klinikum Offenbach. More information is available at the Web site of the MEDARPA project.