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Research team develops tumor imaging system

Jan 14, 2013   |   by Elizabeth Mc Nally   |   The Dartmouth

Researchers from Dartmouth-Hitchcock Medical Center and Thayer School of Engineering have developed a quantitative imaging system to detect low-grade brain cancer cells and make tumor removal more precise, according to Thayer School professor and research group co-leader Keith Paulsen.

The technology consists of a drug, taken pre-operatively, which is broken down, processed and moved into brain tumor tissue.

During surgery, the cancerous tissue fluoresces a pink color under a blue light, allowing neurosurgeons to remove the tumor more accurately, according to DHMC neurosurgeon and research group co-leader David Roberts.

The fluorescent compound accumulates most intensely in high-grade brain tumor cells, which are not curable by surgery, according to Paulsen. Low-grade tumor cells that are potentially curable, however, accumulate a lower percentage of the compound.

Biomedical engineers are collaborating with neurosurgeons to create a quantitative system that will measure the levels of the compound needed to make low-grade tumor removal more successful. Researchers have been working on improving the drug for six years, but began focusing on the quantitative imaging system two years ago.

“We have been working with Dr. Roberts, in particular, to develop more sensitive image capabilities than the eye and record them on a monitor,” Paulsen said. “The quantitative image produced is not as sensitive or accurate as the probe [used for the high grade cancer cells], but it is much better than the human eye.”

The research builds on technology that has been used outside the U.S. for the past 10 years. Although the Federal Drug Administration has not approved this technology for use in the U.S., the FDA has given “very special permission” to Dartmouth for the study, according to Roberts.

Paulsen said the lack of FDA approval stems from data about the drug from outside of the United States and the diagnostic, rather than therapeutic, nature of the technology. “It has just fallen on the ground, where no one is pushing for it,” Paulsen said. “There is a small company now that is pushing for it, but there is not much money to be made, which is why it’s languished.”

Paulsen said that the drug is safe, and FDA approval and use in the U.S. will “just be a matter of time.”

Kolbein Kolste Kolbein Kolste

Undergraduates Sarah Pasternak ’14 and Yichuan Wang ’14 and Kolbein Kolste TH’14 have collaborated on the project.

Pasternack collected and analyzed some of the data collected toward the beginning of the experiment, she said.

Collaborating with undergraduate interns has allowed Kolste to conduct higher-level interpretation of the data, he said.

“Making phantom equipment and running experiments is very time-consuming,” Kolste said. “[The undergraduates] have done a great job putting in the time and performing quality work so I was able to take their results and do meaningful analysis.”

The research team has several implications for future study, including analyzing deeper tissue fluorescence, applying the technology to other types of tumors and exploring how the drug can be used in other settings.

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