W. S. Ng

Robotic ultrasound-guided prostate intervention device: system description and results from phantom studies.

We introduce the first robotic ultrasound‐guided prostate intervention device and evaluate its safety, accuracy and repeatability.

A 3D computer simulation to study the efficacy of transperineal versus transrectal biopsy of the prostate

Objectives This paper aims to provide an explanation for the positive findings of the improved prostate cancer detection rate by the transperineal approach when compared to the transrectal approach. The peripheral zone (PZ) is a region of the prostate with the most cancer occurrence. Hence, the ability to reach it consistently can improve the cancer detection rate significantly.Methods In a prospective study, ultrasound images taken from five patients were used to reconstruct the prostate, rectum and pubic bone with the perineal wall data obtained from the same patient. Each anatomical model virtually underwent prostate biopsy transperineally and transrectally with 10 cores biopsy each. We assessed the efficacy by calculating the volume of PZ tissue obtained from each approach.Results The overall volume of virtual core tissue taken from the PZ was 81.7% from a total volume of 100 prostate biopsy cores. Of the volume of tissue extracted transperineally, 98.5% was from the PZ compared to only 64.9% of the transrectally extracted tissue.Conclusions This is the first paper that acquires and reconstructs the virtual anatomy of the prostate, rectum and pubic bone with the perineal wall. Transperineal biopsy is superior to the transrectal method in obtaining the peripheral zone tissue. This explains the findings that the prostate cancer detection rate is higher via the transperineal approach.

A method to minimize puncturing force and organ deformation

A robotic system providing force feedback and automation for minimally invasive heart surgery H. Mayer Æ I. Nagy Æ A. Knoll Æ E.U. Schirmbeck Æ R. Bauernschmitt Robotics and Embedded Systems Lab, Technical University Munich, Germnay Department of Cardiovascular Surgery, German Heart Center Munich, Germany Abstract We have developed an experimental system for robotic heart surgery, which provides force feedback and full Cartesian control on each of the four end effectors Currently the system is used to determine the degree of automation that can be included into surgical procedures. Therefore we have included an optical system with thread recognition and we provide assistance to the surgeon via automated knot-tying.

Control and safety aspects of medical robots for treatment of diseases of the prostate

Abstract There has been much advancement in the field of minimally invasive surgery in recent years. Medical robots play an important role in these improvements. Surgeons are fast accepting the aid of robots in laparoscopic, thorascopic, endoluminal and arthroscopic interventions, to name just a few. This paper reviews the state-of-the-art of medical robots that have been and are being developed for the purpose of treating diseases of the prostate. The main objective of these robots is to manoeuvre accurately a surgical tool via the transrectal or transurethral route to perform a surgical procedure on the prostate based on ultrasound guidance. The system approaches and control methodologies of these robots are highlighted. However, the main emphasis is on the safety aspects, both hardware and software, which are discussed in detail. Many of these safety features have been incorporated in the mentioned medical robots to enhance their reliability and safety.

SU‐FF‐T‐52: A Robotic Platform for Image‐Guided Brachytherapy (IGBT)

Purpose: In image‐guidedbrachytherapy (IGBT), accurate placement of needles and radiation sources is a major challenge. In traditional prostate brachytherapy, for example, needles are introduced through fixed, parallel holes of a template where the maneuverability of the needle is extremely limited. The accuracy of needle placement and seed delivery is subject to variation with clinician technique, such as deflection force and needle rotation. We present a robotic platform for IGBT, a semi‐automated 14 degree‐of‐freedom (DOF) robotic system, designed and fabricated for performing prostate brachytherapy with radioactive seeds. Method and Materials: The IGBT system consists of two main modules: (1) a 7 DOF positioning module, and (2) a 7 DOF surgery module. The positioning module has a 2 DOF cart and a 5 DOF platform. The surgery module includes a 2 DOF ultrasound probe driver, a 3 DOF gantry robot, a 2 DOF needle inserter and a seed pusher. All motions of the surgery module are motorized. This system incorporated numerous important data and methods garnered from in‐vivo measurements during actual brachytherapy procedures. Various techniques to enhance precision of needle insertion and seed delivery have been implemented into the system, after extensive verification via phantom experiments. Three force‐torque sensors were incorporated for tracking the forces on the needle to detect pubic arch interference and to improve robot control. Rigidity and factor of safety of the mechanical structures have been analyzed using finite element method. The system has provisions for feedback of various states (position, velocity and force), which will be useful to improve needle insertion and seed delivery accuracy, consistency and efficiency. Results and Conclusion: Preliminary experimental results demonstrate highly accurate (sub‐millimeter) and consistent placement of brachytherapy needle. Extensive experiments have been conducted to evaluate performance of this prototype system for IGBT. Acknowledgment: Work supported by NIH/NCI Grant No. R01‐CA91763.

Sci-PM Fri - 05: Effects of coating on friction force during needle insertion in soft materials

Purpose: Of the three main forces, i.e. stiffness force, friction force and cutting force experienced during needle insertion in soft tissue/material, friction force contributes the major portion. Higher friction force is partly responsible for large deformation/displacement of soft tissues/organs during various medicaldiagnostic and therapeutic procedures. In this study we investigate the effectiveness of needle coating on friction force reduction. Methods and Materials: We have used three types of 18G brachytherapy needles, two of them coated with Teflon and Carbon. Then we have compared the results with standard commercial needle whose coating is unknown. Needles were inserted by a 6 DOF robotic system in soft material phantoms prepared from polyvinylchloride with 25% softener. A 6 DOF force sensor (Nano25®) was mounted on the end‐effector of the robot. To assess the friction force alone, the needle tips were passed through the phantom; only the cannulas were in contact with the material while the data were recorded. Results: We observed significant reduction, about 34% at both 5 & 100mm/s speed, in friction force on needle with Carbon coating. Some improvement was also noticed with Teflon coated needle, about 15% reduction at both 5 & 100mm/s speed. Discussions:Carbon coating is the most effective in reduction of friction force on the needle. Therefore, one of the solutions to reduce tissue/organ deformation/displacement may be coating surgical needles with Carbon. However, chemical and pathological studies are required before going for clinical trials with Carbon coated needles. Acknowledgement: Work supported by NCI grant R01 CA091763.