A proposed framework for regulatory, ethical, and legal discussions identifies six levels of autonomy for medical robotics.

Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of prostate and surrounding tissue, thus granting potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. However, the benefits cannot be readily harnessed for interventional procedures due to difficulties that surround the use of high-field (1.5T or greater) MRI. The inability to use conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intraprostatic needle placement inside closed high-field MRI scanners. MRI compatibility of the robot has been evaluated under 3T MRI using standard prostate imaging sequences and average SNR loss is limited to 5%. Needle alignment accuracy of the robot under servo pneumatic control is better than 0.94 mm rms per axis. The complete system workflow has been evaluated in phantom studies with accurate visualization and targeting of five out of five 1 cm targets. The paper explains the robot mechanism and controller design, the system integration, and presents results of preliminary evaluation of the system.

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A surgical guidance and visualization system is presented, which uniquely integrates capabilities for data analysis and on-line interventional guidance into the setting of interventional MRI. Various pre-operative scans (T1-and T2-weighted MRI, MR angiography, and functional MRI (fMRI)) are fused and automatically aligned with the operating field of the interventional MR system. Both pre-surgical and intra-operative data may be segmented to generate three-dimensional surface models of key anatomical and functional structures. Models are combined in a three-dimensional scene along with reformatted slices that are driven by a tracked surgical device. Thus, pre-operative data augments interventional imaging to expedite tissue characterization and precise localization and targeting. As the surgery progresses, and anatomical changes subsequently reduce the relevance of preoperative data, interventional data is refreshed for software navigation in true real time. The system has been applied in Index terms: neurosurgical planning; image guided surgery; image fusion; 3D visualization; interventional MRI IMAGE-GUIDED SURGERY SYSTEMS strive to enhance the surgeon's capability to utilize medical imagery to decrease the invasiveness of surgical procedures and increase their accuracy and safety. These systems can be categorized into performing one or more of the following functions: data analysis (2,3,4), surgical planning (2,3,4), surgical guidance (5,6,7,8,9,10), and surgical guidance with intra-operative updates (11,12,13,14). The systems focused on surgical guidance tend to present the surgeon with data that was gathered prior to surgery, track surgical instruments within the operating field, and render the tracked devices along with the data. For more difficult surgeries, it is beneficial to present the surgeon with not just one diagnostic scan, but with an array of information derived from fusing data sets with information on morphology, cortical function, and metabolic activity. These varied data sets are acquired in different coordinate systems and need to be aligned, or registered, to a common framework for surgical planning before that framework is in turn registered to the patient for surgical guidance. The latter registration allows the surgeon to establish a correspondence between the patient lying on the operating table and the images rendered on a nearby computer screen.The major shortcoming of image guided surgery systems is that the use of pre-surgically acquired data does not account for intra-operative changes in brain morphology. The systems with intra-operative updates have been introduced to fill that void, but they have fallen short of achieving perfect interactivity and full information disclosure to the surgeon. In particular, the benefits of interventional MRI could be amplified by focusing on five issues: image quality, imaging time, multi-modal fusion, faster localization, and three-dimensional visualization. The need for better image quality arises because some anatomical structures are difficult...