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Lab Reports

Better Brain Probe

A new probe developed at Thayer School and the Norris Cotton Cancer Center in collaboration with the University of Toronto helps surgeons better distinguish cancer from normal brain tissue during surgery. Currently, patients take an oral dose of chemical 5-aminolevulinic acid, which produces the fluorescent protein protoporphyrin IX (PpIX). Tumor cells accumulate more PpIX than normal brain tissue and “glow” when exposed to blue light. The new tool combines violet-blue and white light to allow surgeons to analyze the concentration of PpIX and four other tumor biomarkers. “Our big discovery is that we can use the probe’s reading of PpIX to measure the presence of low-grade brain tumor which otherwise does not fluoresce visually,” says Professor Keith Paulsen, who worked with neurosurgeon David Roberts, M.D., and Pablo Valdes Th’11, who is pursuing his M.D./Ph.D. In a pilot study reported in the Journal of Biomedical Optics, in 10 patients with low-grade brain cancers, identification of low-grade tumor tissue during surgery based on visual fluorescence only had an accuracy of 64 percent; diagnostic accuracy increased to 94 percent when data from the new probe were used.

Personalizing Mobile Health Devices

Medical Bracelet
MEDICAL BRACELET: Ryan Halter helped develop a wearable mHealth device with bioimpedance-based identification capabilities. Eight electrodes gauge a person’s electrical properties. Image courtesy of Cory Cornelius ’07.

Professor Ryan Halter Th’06 is part of a Dartmouth team developing personal mobile health (mHealth) devices that will allow physicians to monitor patients’ health on a more frequent basis. One wrist-strap device under development, the “Amulet,” would function as a secure communications hub for mHealth devices on a person’s body and ultimately connect the patient to an electronic medical records system. Halter is helping two Dartmouth computer scientists, Professor David Kotz ’86 and graduate student Cory Cornelius ’07, ensure that the health records of patients monitored with mHealth devices remain private and secure.

“Most people are already carrying portable phones with sophisticated computation and some type of sensor. An insulin monitor or heart rate monitor, for example, can easily wirelessly communicate with these devices, and that information can be transferred to a database and monitored by medical personnel,” says Halter. “The difficult part is if someone puts the wrong device on and their heart rate speeds up. There could be a conflict with who is actually treated.”

Halter is helping the team use bioimpedance, how tissue responds to electrical currents, as an identification tag. “A person’s bioimpedance is not unique across an entire population, but usually is within a small group, such as a family,” Halter says.

The bioimpedance method accurately identified 90 percent of 50 test subjects last spring. The research team plans to test the robustness and wearability of the identification sensors on a larger sample over a longer period of time.

Next Big Thing in Orthopedics

Professor Douglas Van Citters ’99 Th’03 ’06 and Professor John Collier ’72 Th’77 told ODT (Orthopedic Design & Technology) magazine what they believe is gaining traction—beyond hips and knees—in orthopedics. “The resurgence of the total shoulder and reverse shoulder arthroplasties” will be the next big thing in the field, according to Van Citters, in part because of advances in polymer science and a better understanding of bone biology. Collier is interested in developing cures for arthritis—starting with measuring outcomes. “It’s like heart disease,” he told ODT. “If you can change diet, you can change heart disease. I don’t know that anyone has tried to do that for arthritis yet, but it may be the case once they get in it that there are nutritional aspects, exercise aspects, physiological aspects of arthritis that you can identify so you help people out.”

For more photos, visit our Research and Innovations and Faculty and Instructors sets on Flickr.

Categories: The Great Hall, Lab Reports

Tags: alumni, engineering in medicine, faculty, innovation, research

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