Cancers are infamous for making a comeback even after a surgery. So in a bid to reduce the rate of cancer re-occurrence, scientists have invented a new imaging system that makes the tumor light up' when a hand-held laser is directed at them. This system can make it easier for surgeons to weed out any cancerous tissue during a surgery.
Aaron Mohs, Ph.D., assistant professor of regenerative medicine at Wake Forest Baptist Medical Center and a co-inventor of the system said that in such a surgery, the goal of a surgeon is to not only remove the tumor, but also enough surrounding tissue so that no malignant tissue is left behind. But, there is no means which can tell them that they have removed enough of it. The goal in building this system is to provide better real-time information to guide the surgery.
The details about the discovery were published online in IEEE Transactions on Biomedical Engineering (TBME). In this system a fluorescent dye that localizes in tumors with a real-time imaging system is used and it allows the surgeon to simply view a screen to distinguish between normal tissue and the “lighted” malignant tissue.
During their research on both mice and dogs, the scientists found that the fluorescent dye accumulated at higher levels in tumors than in the surrounding tissue. This helped the system to detect a distinct boundary between normal and malignant tissue. Since, canine tumors are in many ways similar to human tumors, it is very likely that this system would work on human tumors as well. The scientists are working to further develop the system so that it can be safely used in human patients as well.
At present, cancer surgeons scan tumors prior to surgery with magnetic resonance imaging and other systems. However, there is no technology that can enable them to scan the tumor during surgery. Mohs remarked that this has long been an unmet clinical need. Even the pathology techniques that examine tumor tissue during surgery can take up to 20 minutes. The focus of such examination is the tissue that is removed during surgery and not the tissue that remains in the body.
Mohs was awarded a $1.37 million research grant from the National Institute of Biomedical Imaging and Bioengineering for a project to optimize the system and to test it in rodents.
In their report, the authors noted that the ideal system should be such that finds tumor boundaries with high sensitivity, have minimal impact on operative time and surgical technique, present findings in an intuitive manner and avoid the use of ionizing radiation or a specialized imaging environment, such as MRI machines.
The system, invented by Mohs, Michael C. Mancini at Spectropath Inc., and Shuming Nie with Emory University and Georgia Institute of Technology, meets the needs to a large extent. It combines two types of imaging with a surgeon-controlled laser can be directed at any area of interest and an imaging system with three cameras that sits above the surgical field. The images recorded by both systems are processed to display a composite image.
With the help of this system, a surgeon can scan the tumor before a surgery to determine the boundaries following which the tumor can be surgically removed. The area can then be re-scanned to assess for any remaining malignant tissue. In case some diseased tissue is found, it can be surgically removed, and the process would be repeated until no diseased tissue is detected by the system.
In the prototype system indocyanine green dye was used by the scientists as the source of fluorescence. They also noted that for future studies higher performance fluorescent dyes can be used and nanoparticles that can be targeted to specific tumors.