In the Mechanics Department at the Politecnico di Milano in Italy, a team of engineers is working on the development of a telerobotic system for prostate biopsies, under the dedicated guidance of Professor Alberto Rovetta. Last January, the first encouraging testing results were presented during the seventh edition of the Medicine Meets Virtual Reality Conference in San Francisco. The programme involves the implementation of diagnostic imaging and surgical sample taking, as well as the accurate design of safety and control functions in the remotely controlled system. If the project is able to demonstrate the reliability of this telerobotics solution, medical industrial companies, which are active in the surgical field, will most likely consider to take the system into production.
Initially, the project team decided to use a conventional industrial robot and selected a SR 8438 Sankyo Scara model. The sample-taking device has a varying level of freedom. Depending on the type of biopsy, the range of degrees can change from four to six. Successful stereotaxic diagnosis for the planning of surgery requires the accurate positioning of the unit in extremely well targeted points of three-dimensional space. Therefore, preliminary tests of echographic analysis have been performed on samples of pig meat. Given the fact that the prostate organ displays no rigid structure, a combination of advanced diagnostic image tools is needed to precisely detect the lesion. The research team applied computer assisted tomography scans (CAT), magnetic resonance (MR), stereotaxic X-ray and ultrasound.
The movement of the robot should be swift and accurate with regard to the anaesthetized and immobile patient. The built-in safety system prevents the device from executing any uncontrolled action or incorrect instruction. The interface for remote manipulation has been provided with symbolic coloured signals on the screen: green for normal functioning, yellow for critical points during the intervention, and red for possible danger. The robot movements can be slowed down, interrupted or inverted at any time the situation should require an immediate intervention. A set of on/off-type sensors records each contact with the patient whereas a force sensor indicates the haptic feedback between the patient and the sample-taking device inside the body.
A personal computer is used for controlled interfacing with the environment and the installed sensors. The PC is provided with a digital I/O card, a card for image acquisition and processing, and a card for the reception of analog signals. The system applies serial lines to transmit instructions between the computer and the robot but in case of emergencies, the commands are being switched immediately via digital lines. The controlling software will run on a Windows platform. The control over the robot can be executed from a remote station through videoconferencing via an ISDN connection. Ongoing research relates to the development of software incorporating the image analysis with the calibration of the robot in the operating room as well as hardware which connects to the robot in order to obtain the required surgical function.
If this kind of biopsy procedure can be standardized in the future, physicians will be able to enhance the level of accuracy in the detection of lesions in the prostate organ. The higher the precision in sample-taking, the more reliable the diagnosis will be. In the long run, the patient will benefit from the most adequate choice of treatment which will be based on the sound judgement by the physician. Indirect and subjective diagnostic methods such as palpation will be replaced by objective and stereotaxic biopsies, performed via remotely controlled robotic systems. For more details and illustrations with regard to the telerobotic system design and the biopsy tests, performed by the team of Professor Rovetta, we refer to the prostate biopsy robot home page.