This paper describes the design and evaluation of the second generation of a robotic system called the light puncture robot for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patient's body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The mechanical design is described in detail along with its forward and inverse kinematics. The robot can be segmented and registered fully automatically in both imaging modalities. Phantom experiments in the CT scanner and preliminary feasibility experiments in the MRI are described, showing a targeting accuracy of 3.3 ± 1.7 mm in gelatin for depths ranging from 30 to 90 mm and needle orientations of -13° to +15° about normal from the patient's skin. A detailed error analysis is discussed along with potential improvements in the system. The potential clinical advantages of the system include higher targeting accuracy for complex dual obliquity trajectories, the need for fewer images, and improved accessibility to MRI-guided interventions.

Until recently, computer-aided medical interventions (CAMI) and medical robotics have focused on rigid and nondeformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g., HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

The objective of this work was to design a compact, accurate, safe, and ease-to-use surgical robot for total knee arthroplasty. The goal of the bone-mounted robot, named Praxiteles, is to precisely position a surgical bone-cutting guide in the appropriate planes surrounding the knee, so that the surgeon can perform the cuts manually using the guide. The robot architecture is comprised of 2 motorized degrees of freedom (DOF) whose axes of rotation are arranged in parallel, and are precisely aligned to the implant cutting planes with a 2 DOF serial adjustment mechanism. An initial prototype was first developed and tested on saw bones and cadavers, and construction of a new, refined version is now well underway. A backdrivable system, with high-stiffness, high-precision static positioning capabilities and safe low-force dynamic movement is achieved using a quick-release, spring-loaded mechanical braking system integrated in a gear transmission unit at the level of the motor outputs. This paper discusses the technical challenges encountered during the development, design, and construction of the system.

LER is a compact surgical assistant robot for positioning of an endoscope and camera during minimally invasive surgery. In contrast to typical endoscope manipulators, LER is particularly compact and lightweight at 625 g and 110 mm in diameter, so that it is simple to set up and use, occupies no floor space, and does not limit access to the patient in any way. Our current prototype is fully sterilizeable by autoclave and is ready for clinical trials. It features a full motion range of 360/spl deg/ in rotation and inclination to 10/spl deg/ from the horizontal plane and is backdriveable for manual positioning. Actuation forces are limited for safety. LER may be held in place on the abdomen by adhesive strips or sutures, or attached to the sides of the table with elastic straps or clamps. We have implemented a variety of different user command interfaces for LER, including a miniature keypad, automatic optical instrument motion tracking, and voice command recognition. Experimental trajectory following results and performance parameters are given.

This paper presents a slave robot carrying an ultrasound probe for remote echographic examination. This robot is integrated in a master-slave system called robotic tele-echography (TER). The system allows an expert operator to perform a remote diagnosis from echographic data he acquires on a patient located in a distant place. The originality of this robot lies in its architecture: the cable-driven robot is lightweight and semirigid, and it is positioned on the patient body. In this paper, we describe the clinical application, the system architecture, the second implementation of the robot, and experiments performed with this prototype.

We have developed a cable-driven manipulator using pneumatic artificial muscle actuators to control the orientation and insertion depth of an endoscope during abdominal surgery. This manipulator enables a single surgeon to manipulate surgical instruments with both hands while the endoscope position is controlled to view an area of interest inside the abdomen. The surgeon may then control the endoscope by alternate methods such as voice commands, pedals, a joystick, or head movements. The advantages of our newly developed endoscope manipulator over those of commercially available robotic laparoscopic surgical systems are its low cost, simplicity, ease of setup and use, compliance, nonintrusiveness, and very small size and light weight, with the disadvantage of somewhat reduced absolute positioning accuracy. Multiple instruments may be manipulated simultaneously by the manipulators set close together. Experimental performance results of open-loop and feedback control methods are presented.

This paper describes research work motivated by an innovative medical application: computer-assisted transbronchial biopsy. This project involves the registration, with no external localization device, of a preoperative three-dimensional (3-D) computed tomography (CT) scan of the thoracic cavity (showing a tumor that requires a needle biopsy), and an intraoperative endoscopic two-dimensional (2-D) image sequence, in order to provide assistance in transbronchial puncture of the tumor. Because of the specific difficulties resulting from the data being processed, a multilevel strategy was introduced. For each analysis level, the relevant information to process and the corresponding algorithms were defined. This multilevel strategy, thus, provides the best possible accuracy. Original image processing methods were elaborated, dealing with segmentation, registration and 3-D reconstruction of the bronchoscopic images. In particular, these methods involve adapted mathematical morphology tools, a "daemon-based" registration algorithm, and a model-based shape-from-shading algorithm. This pilot study presents the application of these algorithms to recorded bronchoscopic video sequences for five patients. The preliminary results presented here demonstrate that it is possible to precisely localize the endoscopic camera within the CT data coordinate system. The computer can thus synthesize in near real-time the CT-derived virtual view that corresponds to the actual endoscopic view.

A method is presented for modeling and calibration of sensors, to reach an accuracy similar in magnitude to the resolution of the sensors. The authors focus on camera and range image calibration. They show the limitations of existing methods, and present an approach and camera calibration using mathematical B-Spline functions. This method is abbreviated as NPBS (N-Planes B-Spline). It is an extension of the two-planes method, but relies on pure mathematical modeling based on spline approximation theory. The mathematical modeling is combined with a calibration device that enables accurate data acquisition to calibrate a camera and a light plane independently. Experimental results are presented showing accuracy on the determination of a scattered plane.>

Describes a system based on the combined use of medical imaging and robot positioning used in stereotactic neurosurgery. The types of interventions performed with the help of this system require a high precision (less than 1 millimeter) of positioning with respect to the patients brain with no direct visibility of the target; they are executed through a hole in the skull of 2.3 millimeters. A typical example is the placement of a stimulating electrode in a particular nucleus of the thalamus for patients suffering from Parkinson's disease. These interventions rely on the intensive use of medical imaging to define the operative strategy. The target is defined with respect to the images. A six-axis robot whose end-effector is a linear guide automatically reaches a configuration generated such that if the surgical instrument (needle, electrode, etc.) is introduced in the guide, the surgeon reaches the target using a linear displacement of the instrument. This system is operational and is in routine clinical use.>