The National Institutes of Health has awarded a five-year, $3.5 million sum to researchers at Worchester Polytechnic Institute and Albany Medical College for the development of a robotic system that can target and destroy brain tumors inside an MR system.

Designs for the solution call for it to operate within the scanner, where it will probe the brain in a minimally-invasive fashion to locate and eliminate masses using high-intensity therapeutic ultrasound under live, real-time MR guidance. Providing technology support for the project are the universities’ corporate partners, GE Global Research and Acoustic MedSystems.

"In interactions with neurosurgery colleagues, it was determined that using robotic assistance for stereotactic neurosurgery interventions would have some great benefit over manual frame-based approaches and over frame-less units based on tracking systems," Greg Fischer, associate professor of mechanical engineering and robotics engineering at WPI and director of the Automation and Interventional Medicine Laboratory, told HCB News. "Further, the use of interactively updated MRI imaging during the procedure can help account for deformation (such as brain shift) that occurs during the surgical procedure and is not addressed with traditional approaches."

We will also ensure that we are maximizing the odds that we are removing the entire tumor, while minimizing the chances of damaging non-malignant tissue.”

About 170,000 new cases of brain metastases are diagnosed annually in North America, making them one of the most common types of brain tumors. Current treatments include chemotherapy, radiation and surgery, all of which are limited in success and risk harming unaffected brain tissue. Surgery is further challenged by the fact that tumors must be present in accessible locations.

Utilizing a thin 2 mm probe, the system will drill a small hole in the skull. It will then place the probe within the tumor, adjusting the device’s orientation and power output to deliver doses of high-intensity ultrasound energy to heat and eradicate the tumors, while keeping damage to surrounding brain tissue at a minimum. The MR scanner will be able to detect the thermal emissions and use them to monitor dose delivery.

The robotic system itself will be developed by WPI’s research team, with Acoustic MedSystems designing, building and validating the needle-based therapeutic ultrasound probe, as well as software for visualizing and controlling it. The system will position and align the probe before insertion and adjust its depth and rotate it during the procedure to conform to the shape of the tumor, targeting the mass based on real-time MR scans to account for shifting of the brain during surgical preparation.

GE Global Research Center will provide thermal imaging capabilities for monitoring in real time the ablation of tissue, and providing feedback on the effects. It also will assist in integrating the robotic system with its clinical MR scanner.

To account for the power of MR magnets, the robot will not be composed of ferrous metals, but instead plastics and ceramics, equipped with piezoelectric motors and custom motion electronics to generate very low levels of electrical noise to avoid disrupting the MR imaging system. It will be able to work within the tight confines of the MR scanner and within the presence of other technology, such as anesthesia equipment, imaging coils, and patient monitoring apparatus, and will be designed in a fashion that enables any parts that come into contact with patients to be sterilized.

The system is derived from an earlier solution designed and tested by the WPI-Albany medical College team, with funding provided through an earlier five-year, $3 million award from the NIH. The current sum provided will go toward efforts to model the behavior of the ultrasound ablation system, implement thermal monitoring for real-time feedback on dose delivery, optimize and verify its effectiveness, and verify its use and safety for admission to human clinical trials.

Researchers hope to eventually expand its use into other realms, including the delivery of other ablation technologies, performance of biopsies and electrode placement, and the delivery of therapeutics such as gene therapy.

The main focus at the moment, though, is getting the solution into clinical settings and creating streamlined approaches that minimize time and setup during procedures, as well as minimize the chance of having to re-operate on patients.

"Neurosurgery procedures often require a number of steps to ensure registration between the surgical plan, the instruments, and the patient. Further, often the instrument is moved in and out of position manually a number of times during a procedure," said Fischer. "By adding robotic actuation, the room for human error and the speed of progressing through the steps can be improved. And intraoperative imaging ensures appropriate alignment, as we are directly imaging the instrument along with the patient anatomy simultaneously."

Part of development and testing of the system will be conducted at WPI’s PracticePoint R&D facility for medical cyber-physical systems, a membership-based research, development, and commercialization alliance for the advancement of healthcare technologies.