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Berkeley Engineers: Changing Our World

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Boris Rubinsky (left) and David Otten hard at work. After graduating, Otten served as a postdoctoral researcher in Rubinsky's laboratory. (courtesy the researchers)

A doctor in a remote village is conducting a highly-advanced minimally invasive surgical procedure on a patient with a cancerous tumor. Fortunately, the doctor is not doing the surgery "blind." A display beside the operating table depicts a computer-generated real-time view inside the patient's body. The miraculous part is that the machine generating those images is located thousands of miles away.

This is the vision of the Distributed Network Imaging project, an effort led by bioengineering professor Boris Rubinsky, who is also a researcher with the Center for Information Technology Research in the Interest of Society (CITRIS). Rubinsky and his collaborators aim to use existing telecommunications technology to extend the reach of revolutionary medicine into rural areas and developing regions.

"Imaging has become a core part of medicine, but the majority of the devices are still incredibly expensive," says David Otten, a recent PhD graduate from the Department of Mechanical Engineering, where Rubinsky is also a professor. The third collaborator on the project is Gary Onik, medical director of surgical imaging at Florida Hospital .

Medical imaging systems, such as magnetic resonance imaging (MRI) and ultrasound scanners, convert data collected by sensors near the body into an image of what's inside. Depending on the technology, imaging systems now cost anywhere from tens of thousands of dollars to millions. In some systems--ultrasound or electrical impedance tomography (EIT), for example--the sensing components often account for just a small fraction of that price. The big money, Otten explains, goes into the computing power needed to translate the raw data into an accurate and detailed 3D image.

To test their Distributed Network Imaging concept, the researchers conducted cryosurgery on a liver sample. The long tube delivers supercold temperatures to the tissue sample while electrical impedance tomography (EIT) produces images of the frozen regions. (courtesy the researchers)

"Our aim is to separate the components of what's usually a stand-alone machine and move them to where they make the most economic sense," Otten says.

This concept, called Distributed Network Imaging, calls for the inexpensive data collection hardware to be installed at the remote site where the actual surgery will take place. As the patient's raw data is generated, it's instantly digitized and transmitted via existing communication conduits--telephone lines, satellite links, or wireless networks, for example--to a state-of-the-art image reconstruction server located in an urban hospital or university.

"There's no reason why you need all that computational power in a single place where it's sitting completely unused for the majority of its life," Otten says. "The idea is to have a centralized server that's taking in raw data from around the world, reconstructing the images, and sending them back out over the network where they can be displayed at the remote sites."

Photographs taken during the cryosurgical procedure are shown above the corresponding EIT images generated through Distributed Network Imaging. The growing circle is the ice ball which radiates out from the cryoprobe and disappears when thawing occurs.(courtesy the researchers)

The first Distributed Network Imaging experiments were based on electrical impedance tomography (EIT), an imaging technology that constructs 3D visualizations based on the electrical resistivity of the tissue under study. The data is painlessly gathered through an array of inexpensive electrodes placed on the body. EIT, Rubinsky says, is perfectly suited for cryosurgery, a minimally invasive surgical technique he and Onik helped pioneer in which a tiny tubular probe into the body kills cancer cells with blasts of intense cold. Real-time imaging helps surgeons guide the tube to the tumor site and monitor the freezing to ensure that the tumor is completely engulfed by ice.

"Cryosurgery is a low-cost medical treatment commonly used in developing countries, so you also need low-cost imaging," Otten says.

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As a proof-of-concept, the researchers used EIT to image an in vitro cryosurgery procedure on a liver over a modem link. Otten, Onik, and Rubinsky published a scientific paper on the study in the April issue of the journal Technology in Cancer Treatment & Research. Eventually, they hope to explore the feasibility of Distributed Network Imaging for ultrasound scans and other minimally invasive surgery applications beyond cryosurgery. Low-cost imaging could also be useful for diagnostic applications without requiring patients to travel long distances to hospitals.

"We believe that the distributed network concept will eventually provide diagnostic and treatment of cancer and genetic diseases to parts of the world population that were not exposed to advanced medical technology in the past," Rubinsky says.

Boris Rubinsky's home page

"Open Sesame for Cells" by David Pescovitz (Lab Notes, September 2002)

"Freezing cancer cells leaves them more susceptible to attack by anti-cancer drug, new study finds" by Sara Yang (UC Berkeley Media Relations)

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