Fluorescence Tomography

Robert Holt

Molecular Therapy has the potential to improve the prognosis for difficult to treat cancer types, including glioblastoma multiform and pancreatic cancer. By targeting tumors, this non-invasive form of treatment delivers drugs directly to cancerous cells without damaging healthy tissue. Currently, this approach to molecular imaging is being tested at the Dartmouth Hitchcock Medical Center (DHMC). Through improving the accuracy and effectiveness of this new type of therapy, the Optics in Medicine Laboratory hopes to increase the survival rate for these types of cancers that, once diagnosed, are often fatal.

Robert Holt, a fourth-year graduate student in the Optics in Medicine Laboratory, is improving the fluorescence tomography imaging methods of a system that was built by the lab several years ago. Designed to image small animals, the machine is housed in the new animal-imaging suite at DHMC. While the imaging methods that the machine utilizes were developed on small animals, the lab members are hopeful that in the future these techniques can be used to increase the effectiveness of molecular therapy in humans by providing radiologist more detailed images of tumors.

Ken Tichauer

Built under the guidance of Ken Tichauer, a Dartmouth post doc and a fellow of the Canadian Institutes of Health Research (CIHR), this machine uses laser light to recover the distribution of fluorescent molecules in tissue. Currently, Holt and Tichauer are developing a method to improve image reconstruction of tracer uptake quantification, and are optimizing the placement of imaging detectors in the machine. As the two researchers develop these methods, second-year graduate student Fadi El-Ghussein updates the machine’s software so that the imaging system is able to test these new methods.

“It’s been great working with Ken and Fadi on this project. A number of the ideas that our team has incorporated into the machine came out of a paper that Ken and I drafted together. The paper explored the uptake characteristics of fluorescence tracers, and examined how best to reconstruct their uptakes of tracers,” explains Robert. “Ken motivated this study from a biological standpoint, and I worked on the mathematics of how to make it work. After Ken and I calculate an imaging method that we want to test, we tell Fadi about the idea so that he can rewrite the software that runs the system’s instrumentation. Once the software is updated, we then conduct imaging trials on small animals to see how well our methods work.”

Fadi El-Ghussein

Being a non-invasive procedure, fluorescence tomography images tumors without harming non-infected cells. For dangerous cancers located in sensitive areas—like giloma, a type of tumor that forms in the brain and spine—this type of therapy has the potential to significantly increase the survival rates of patients diagnosed with these tumors.