The GENAT4/GAMOS Monte Carlo (MC) plug-in is now available for free download. The Optics in Medicine Laboratory has also released a user’s manual for the software, example simulation files, and a MATLAB file of the program.

The technique developed by Glaser and his Dartmouth colleagues has been verified through a series of experiments using a clinical linac from Varian Medical Systems. The first step in the process is to fill a water tank with tap water and dissolve the fluorophore (quinine sulphate) to a concentration of 1.0 g/l. Then, a standard commercial CMOS camera is positioned at a given distance from the water tank, perpendicular to the incident beam, and focused to the beam’s isocentre.

When the beam is turned on, a 2D projection image is captured using a 10 s exposure time, and an equivalent image with the beam off is recorded and subtracted to isolate the Cerenkov-excited fluorescence for direct correlation to the deposited dose.

“Each image is immediately downloaded from the camera to a computer and can be viewed in real time,” explained Glaser. “Our experiments in this proof-of-concept study show that the strength of the fluorescence signal equates near-linearly to the dose imparted in the water. We believe this is the first demonstration of using Cerenkov light to indirectly determine the spatial distribution of a charged particle’s energy deposition within a medium.”

For more on Glaser’s research, read the article on medicalphysicsweb.com.

Kristian’s projects are in the field of biomedical technologies, and his research project is part of a larger Dartmouth initiative titled “Fluorescence guided neurosurgery.”  Sexton’s work explores the use of fluorescence to help surgeons and medical practitioners differentiate between diseased and healthy tissue. In medicine, fluorescence is used to identify healthy and cancerous tissue during surgical procedures.

To read the full post, visit the Machine Shop’s blog.

Over a decade ago, a group of German doctors discovered that if a patient is given an oral dose of a 5-aminolevulinic acid solution before brain surgery, a chemical reaction will cause certain cells, including cancer cells, to appear fluorescent, allowing them to identify tumors for removal during surgery.

But it was Dartmouth engineering professor Keith Paulsen and his team, along with doctors from the Ontario Cancer Institute in Toronto, who took even more of the guesswork out of fluorescence-guided brain surgery by creating a fiber optic probe that when placed on early-stage, low-grade tumors detects fluorescence not visible to the naked eye.

For more, read the full article published by the Thayer School of Engineering on 2/4/2013.

Researchers from Dartmouth-Hitchcock Medical Center and the 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.

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.

To learn more about this collaborative research project, read Elizabeth Mc Nally’s article in The Dartmouth. 

In the segment, graduate student Kolbein Kolste explains how the imaging technique that he developed with PhD/MD candidate Pablo Valdes, Dr. David Roberts, and the directors of the Optics in Medicine Lab work in practice. The research project is being funded by a grant from the National Science Foundation, and the optical probe is being developed through a research collaboration with the University of Michigan.

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To learn more about this research collaboration, visit the press release published on the WCAX website.

A semi-transparent CT view of one a study participant’s heel and ankle. The horizontal line overlays indicate where scientists will set the microwave imaging planes.

Microwave imaging has been shown reliable in detecting breast tumors

One area we are exploring is microwave technology: the same basic technology used in microwave ovens can be used to create an image of breast tissue. By sending very low levels (1,000 times less than a cell phone) of microwave energy through tissue, researchers can form a three-dimensional image. These images capture the dielectric properties — electrical conductivity and permittivity (electrical resistance) — of the tissue, which translates into detecting anomalies, such as tumors or other aberrations.

Paul Meaney, a professor at Dartmouth’s Thayer School of Engineering, has been working on microwave engineering for more than 15 years, primarily with Keith Paulsen, the co-director of the CIR, and also the Robert A. Pritzker Professor of Biomedical Engineering at Dartmouth’s Thayer School of Engineering; professor of radiology at the Geisel School of Medicine at Dartmouth; and director of the Dartmouth Advanced Imaging Center at Dartmouth-Hitchcock Medical Center.

For full article, please visit Focus by the Norris Cotton Cancer Center (NCCC).