i. Seaman Family MR Research Centre

The construction of the Seaman Family Magnetic Resonance Research Centre was made possible in 1997 through a grant from Alberta Infrastructure. The Centre subsequently received private donations, through the Partners in Health Campaign. This Campaign was a joint fundraising effort between the Calgary Health Region, the University of Calgary, Faculty of Medicine, and the Calgary Community. In 1999, the two research programs within the Centre received a Canada Foundation for Innovation award. This funding allowed establishment of the 1.5 Tesla intraoperative MRI initiative, which later provided a platform for the development of MR compatible robotics.

The Centre is committed to the development of new medical imaging technologies that improve the understanding, diagnoses, monitoring and treatment of diseases. It is strategically located adjacent to the University of Calgary, Faculty of Medicine and the Foothills Medical Centre, the major acute care teaching hospital in Southern Alberta. This location allows close interaction between medical physicists, biomedical engineers, computer scientists, neuroscientists and physicians. The Centre is part of the Hotchkiss Brain Institute at the University of Calgary, and has pioneered research in the clinical application of MR technology to surgery, and various neurological disorders including stroke and multiple sclerosis.  

ii. NeuroArm

NeuroArm was developed over the past six years by Garnette Sutherland, Professor of Neurosurgery, University of Calgary and Calgary Health Region, and his group, in collaboration with MacDonald Dettwiler and Associates (MDA). The project was funded by the Canada Foundation for Innovation and other federal and provincial agencies (see below). Close collaboration between MDA space robotic engineers, who built the Canadarm and Dexter, and University of Calgary physicians, nurses and scientists were essential for the design and development of neuroArm. Official launch of the project was on April 17 2007 and captivated large media attention worldwide. 

NeuroArm is a MRI-compatible image-guided computer-assisted device specifically designed for neurosurgery. It performs both microsurgery and biopsy-stereotaxy applications. The system includes a workstation, a system control cabinet, and two remote manipulators mounted on a mobile base. For biopsy-stereotaxy, either the left or right arm is transferred to an extension board that attaches to the OR table and the procedure is able to be performed inside the MRI bore.  

NeuroArm includes two MR compatible manipulators with end-effectors that interface with microsurgical tools. It includes filters to eliminate unwanted tremors. End-effectors are equipped with three-dimensional (3D) force-sensor, providing the sense of touch. The surgeon seated at the workstation controls the robot using force feedback hand controllers. The workstation recreates the sight and sensation of microsurgery by displaying the surgical site and 3D MRI displays, with superimposed tools.  

NeuroArm enables remote manipulation of surgical tools from a control room adjacent to the surgical suite. It was designed to function within the environment of a 1.5 Tesla intraoperative MRI system. As neuroArm is MR-compatible, stereotaxy can be performed inside the bore of the magnet with near real-time image guidance. NeuroArm possesses the dexterity to perform microsurgery, outside of the MRI system. Telerobotic operations both inside and outside the magnet are performed using specialized tool sets based on standard neurosurgical instruments, adapted to the end effectors. Using these, neuroArm is able to cut and manipulate soft tissue, dissect tissue planes, suture, biopsy, electrocauterize, aspirate and irrigate. NeuroArm is 3 feet tall and 2 feet wide, but it can be adjusted to fit any table height. The robot weighs 500 pounds and has two ambidextrous arms. It sits on castors and can be easily rolled in and out of position. It has a fail-safe braking mechanism that secures it to the floor preventing any movement.

iii. Engineering of neuroArm

The system includes a workstation, a system control cabinet, and two remote slave-manipulators on a moveable base platform. The anthropomorphic arms have 7 degrees of freedom, are MR compatible and designed to hold a variety of surgical tools. The arms are manufactured of titanium, PEEK™ and Delrin^®. MR compatibility ensures that the performance is not affected by the magnetic field or gradients, and that the manipulators do not significantly degrade image quality. The speed and payload requirements were determined based on the maximum amount of time allowable to perform a tool exchange with the heaviest tool expected. Quantitatively, this was defined as being capable of accelerating to 200mm/s during tool exchange with a 500g payload.

The end effector is designed to hold a variety of tools within a standardized interface, and allows for two separate operator controlled manipulations: tool roll and tool actuation. The mechanical design allows for rapid tool exchange, minimizing chances of tool damage and enables draping to ensure sterility. Tool exchange can be semi-automated for transfer of control between system and surgeon in seconds, thereby maintaining the seamless rhythm of surgery. This can be predetermined during surgical planning by recording a motion that can later be activated. The design also enhances safety through tool-free manual extraction of the surgical instruments in the event of system failure. The end effector dual locking mechanism locks in the tool when contacting structures of various consistencies. 

The mobile base serves as the positioning mechanism for the manipulator arms, the registration arm, and field camera. For stereotaxy, the base is used to transfer one of the manipulators to the extension board. Once the manipulator has been placed on the extension board and the patient registered, the base is removed from the surgical area. As a heavy base is required to create a stable platform, and the motors are relatively small, a counter-balance mechanism similar to elevator design, limits the power required to adjust the height. Counter weights are positioned low in the base to lower the centre of gravity, further enhancing the stability. 

The workstation is the interface by which the operator controls motion of the manipulators. The workstation components were chosen not only to recreate the sight, sound and touch of surgery, but also to facilitate the integration of surgeons with advanced imaging and computer-assisted surgical devices. The workstation is comprised of two video monitors, two touchscreen computer displays, a stereoscopic display unit and two force feedback hand controllers, all mounted on an ergonomic, height-adjustable table. The two video monitors show a field camera view, and a single channel view from the surgical microscope. A touchscreen display shows 2D and 3D MR images that can be fully manipulated and used for surgical planning and localization of the pathology. Another touchscreen provides a virtual view of the manipulators and enables control and monitoring of the system modes and status. Two high-definition cameras, mounted on the surgical microscope transmit a stereoscopic image to the surgeon. The stereoscopic display unit is structurally similar to the oculars of a standard microscope, but uses two miniature full colour XGA monitors providing the surgical view to the remote operator with depth perception.

Two PHANTOM^Ò haptic hand controllers are equipped with a stylus that allows six degrees of freedom position and orientation control over the tool in the manipulator. The stylus has an index finger manipulated lever for precise actuation of any type of tool, including microscissors, bipolar forceps, suction device and needle holders. A button located under the thumb, enables and disables the slave manipulator. In addition to the virtual and real-time video on the workstation, the operator has two way audio communication with each member of the OR staff. A microphone positioned adjacent to the surgical field provides the surgeon with the acoustics of surgical dissection.  

iv. Integration with surgery

NeuroArm is a robotic system for stereotaxy and microsurgery. As a stereotactic device, it assists in biopsy or device implant inside an MRI system. NeuroArm was developed along with its own registration system. Through the interplay of software and hardware, the robot is able to orient itself relative to the patient, to the MRI unit, and to the resulting MRI image. The surgeon is able to watch in real time the status of the lesion within the patient and the biopsy tool. Therefore, the surgeon is able to confirm that a biopsy was taken from within the lesion, thereby enhancing the success rate of stereotactic biopsy procedures. As a microsurgical devise, it offers the ability to perform surgery with greater precision and eliminates tremor. The desktop is adjustable to accommodate the surgeon’s desire to either sit or stand during the procedure.

Two specially designed hand controllers allow the surgeon to control the left and right robotic arms. These controllers are equipped with a sense of touch. Not only can the surgeon differentiate bone from soft tissue, but the surgeon can enhance his/her sense of touch so as to ‘feel’ a small artery. This feature is accessed through the robot status touch screen at the control center. Additionally the surgeon can set the calibration such that a 1cm displacement of the hand controller can result in a 1 mm movement of the surgical tool. This allows the surgeon to use more gross movements while performing very fine procedures. 

The surgeon controls the manipulators within the surgical corridor. Automated motion for tool exchange is selected by the surgeon through hand controller buttons, with activation allowed only once the instrument has been moved outside a specified radius from the surgical site, as defined during registration. Safety-critical software actions such as turning on power, or enabling arm motion, always require an additional hardware action as confirmation. The motion algorithms employ collision detection of the virtual scene to detect potential collisions between the manipulators and operative site obstacles. The surgeon is able to define a virtual geometrical region, which includes the surgical corridor and anatomical structures to be avoided. When the surgeon reaches this pre-defined boundary, force feedback is relayed to the surgeon’s hand- creating no-go zones.

Local RF shielding was used in the development of the iMRI system and includes a copper mesh-impregnated plexiglass plate at one end of the magnet, and a transparent plexiglass dome covering the patient. Wave guides allow fluid and gas lines to penetrate the shielding. NeuroArm is electrically coupled to the main system controller, located outside the OR. A filtered penetration panel is used to connect cables from the system controller, to cables inside the MR imaging environment. The cables are shielded to prevent RF interference, and the penetration panel is filtered to inhibit RF from transferring between the outside environment into the imaging space.

v. Development of bi-modal superparamagnetic nanoparticles for cell-specific imaging of glioma

In collaboration with investigators from research institutes across the country, neuroArm investigators are developing targeted contrasts agents based on superparamagnetic nanoparticles, for MR and fluorescent imaging. This collaborative initiative has obtained, in 2005, 5 years funding through a CIHR team grant in nanomedicine and regenerative medicine. Molecular imaging offers the possibility of translating advances in nanotechnology, antibody engineering, proteomics, biochemistry and imaging into clinical practice, allowing in vivo detection of unique biological markers at the cellular level. It uses specific probes to identify genes, proteins or enzymes of interest. The ability to interrogate tissue at the cellular level would improve diagnosis and follow-up of cancer patients. For such project to be successful, the active collaboration within a multidisciplinary team of researchers which span the spectrum of biomedical research is necessary.

The application of molecular sensing technologies to CNS neoplasms would ensure earlier and more accurate diagnosis, guide individualized therapies and improve monitoring of the patient’s response to treatment. As we still rely on tumor size to determine a patient’s response to therapy (a variable that does not necessarily correlate with survival), molecular imaging techniques would improve monitoring of treatment by providing specific information on cellular changes. In vivo results would help evaluate the importance of certain proteins/cellular components to tumor development, providing new directions for genetic studies or gene therapy.

While nanoparticles can be used in a passive way for glioma imaging, their specificity can be increased by conjugating them to an antibody that targets tumor-specific proteins. Superparamagnetic nanoparticles will be designed and produced by Dr. Teodor Veres’s group (INRS and Industrial Materials Institute, Boucherville, Quebec). Bi-modal nanoparticles will be used as both MR contrast agent as well as near infrared imaging particles. Such compounds will be important for tumor diagnosis and for guiding surgery with intraoperative MRI. Additionally, the near infrared signal should also aid in the identification of neoplastic cells during surgery. To make these nanoparticles specific, they will be conjugated with single-domain antibodies (produced by Dr. Roger MacKenzie’s group, University of Guelph, Ontario and Institute for Biological Sciences, Ottawa) directed to glioma-specific markers identified by Dr. Danica Stanimirovic’s group.

The specificity, potential toxicity and sensitivity of the contrast agent will be determined using controlled in vitro assays, performed by Dr. Maureen O’Connor-McCourt’s group (McGill University and Biotechnology Research Institute, Montreal). Glioma animal models developed by Drs. Stanimirovic and Abedelnasser Abulrob (University of Ottawa and Institute for Biological Sciences) will be used for quantitative and qualitative evaluation of the nanoparticles and to determine potential concentration-related toxicity effects. MR imaging will be carried out at the University of Calgary/Institute for Biodiagnostics with a small bore high field (9.4T) MRI system under the direction of Dr. Boguslaw Tomanek. The nanoparticles will be clinically used as a contrast agent for glioma patients using the intraoperative 3T MRI system (operational at the Seaman Centre in November 2008) for imaging prior to, during and following surgery. These clinical trials will be directed by Dr. Garnette Sutherland’s group. The joint use of molecular imaging technologies, combined with neuroArm and the intraoperative MRI is represents the most advanced diagnostic and robotic technologies.

Calgary Health Region www.calgaryhealthregion.ca
IMRIS www.imris.com
Leica www.leica.com
MDA www.mdacorporation.com
NRC www.nrc-cnrc.gc.ca
University of Calgary www.ucalgary.ca
UTI www.uti.ca

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CFI 450
CFI 8766
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