Sense of 'Touch'
Daniell Dokko Contributed to New Haptic Feedback System for
A Johns Hopkins senior majoring in biomedical engineering has played a key role in developing a new system designed to tell doctors how much force a surgical robot is applying on suture threads and human tissue.
Supported by an undergraduate research grant from the university, Daniell Dokko, 21, of La Canada, Calif., spent last summer and the current school year working with graduate students on a way to give medical robots a rudimentary sense of "touch"and then send that information instantly to the surgeon who is controlling the machine.
The project is important because minimally invasive operations, performed with robotic assistance, can speed a patient's recovery by reducing the size of the incision and the need to move other tissue. During such operations, doctors direct a robot from a remote work station, using tiny cameras to guide the machine through delicate work. But generally these surgeons do not know how much force the robot is exerting when they direct it to tie sutures or manipulate the body.
Johns Hopkins researchers, led by Allison Okamura, assistant professor of mechanical engineering, have been looking for a method of providing such haptic feedback to surgeons, and during his junior year Dokko joined this team.
His Provost's Undergraduate Research Award enabled Dokko to remain in Baltimore last summer to work full-time in Okamura's lab. "First, I worked on adding a tiny sensor called a strain gauge to a robotic surgical tool so that we could measure the forces it exerts when it touches the body and when it ties sutures," Dokko said. "In the second phase, we looked at another important issue: Once you have the force information, how do you give it back to the surgeon, who's seated somewhere else in front of a video monitor, guiding the operation?" For this part of the project, Dokko worked with Masaya Kitagawa, a Johns Hopkins doctoral student in mechanical engineering from Osaka, Japan. "In traditional surgery, doctors control the amount of force they exert with their hands, based on their own experience," Kitagawa said. "We knew that if we could tell the surgeons how much force the robotic 'fingers' were applying, it would be more like their own hands were working inside the patient."
This knowledge can be particularly useful when robotic tools are used to tie a suture. These knots must be firm enough to hold the incision together, but the tool must not apply so much force that it breaks the sutures or injures the tissue. To get the force information to the surgeons, Dokko and Kitagawa tested several ideas. One option was an audio signal that grew louder as the force increased, but some surgeons objected because the operating room already is cluttered with the sounds of spoken commands and medical equipment.
The researchers then focused on a visual system, tucked into a corner of the video screen that a surgeon uses to guide the robot. They devised a bar graph that rises and changes color as the force increases. The surgeon also sees a dotted line that indicates the appropriate level of force for the procedure. Dokko and Kitagawa added their experimental setup to a da Vinci medical robot being used for training and research at The Johns Hopkins Hospital. Most surgeons who have tested the system have been pleased by it, the researchers said. Dokko and Kitagawa are preparing a paper about their project and hope to present it at a medical technology conference in September. Dokko, who expects to receive his undergraduate degree from Johns Hopkins in May, is still weighing graduate school options. But he said the opportunity to work on medical robotics in Okamura's haptics lab has influenced his thinking. "This is definitely something I'm interested in pursuing further," he said. "I really enjoyed having Dr. Okamura as a research supervisor. She is very accessible to both grad students and undergraduate researchers. She cares about undergraduates and the work they're doing."
He added, "I've really appreciated the chance to work in a lab here on a project that means something, something where I can see the results of my work. It's much more rewarding than just doing some repetitive task to get practice in a particular subject."
On Tuesday, April 1, Steven Knapp, university provost and senior vice president for academic affairs, will host the ninth annual Provost's Undergraduate Research Awards ceremony, which will honor the 41 winners who conducted their projects in the summer and fall of 2002. Since 1993, about 40 students each year have received PURA grants of up to $2,500 to conduct original research, some results of which have been published in professional journals. The awards, funded through a donation from the Hodson Trust, are an important part of the university's commitment to research opportunities for undergraduates.
The Johns Hopkins University is recognized as the country's first graduate research university, and has been in recent years the leader among the nation's research universities in winning federal research and development grants. The opportunity to be involved in important research is one of the distinguishing characteristics of an undergraduate education at Johns Hopkins.
The Provost's Undergraduate Research Awards program provides one of these research opportunities, open to students in each of the university's four schools with full-time undergraduates: the Krieger School of Arts and Sciences, the Whiting School of Engineering, the Peabody Conservatory and the School of Nursing.
Color photos of the researchers available; Contact Phil Sneiderman
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