A team of researchers in Munich, Germany, has developed a new imaging technology using laser light to detect cancer based on molecular signatures, leading to the localization of even small cancer cell nests that surgeons might otherwise overlook during surgery. The technique has been successfully tested on nine patients with ovarian cancer.
Before the operation, the patients were injected with folic acid chemically coupled to a green fluorescent dye. Most ovarian tumors have a protein molecule on their surface that bonds with folic acid and transports it inside the cell. During surgery, the surgeon can then shine a special laser light onto the patient’s ovaries, causing the green-labeled folic acid inside the cancer cells to emit light. Healthy tissue remains dark.
The fluorescent cancer cells, however, cannot be detected by the naked eye. Three cameras, mounted on a pivoting support arm over the operating table, detect optical and fluorescent signals at multiple spectral bands and then correct for light variations due to illumination and tissue discolorations in order to provide accurate fluorescence images that can be simultaneously displayed with corresponding color images on monitors in the operating room. The surgeon can check whether all the cancer cells have been removed by inspecting for remnant fluorescence light.
The researchers want to further develop the camera system so it can be used to detect other forms of tumors during operations. Of significant importance in future developments is the ability to offer accurate fluorescence imaging so that data collected reflect true presence of disease. This is important for the clinical acceptance of the technology and its approval by regulatory agencies.
In the future, patient selection through personalized medicine approaches -- for example, by obtaining a molecular profile of the tumor of each patient -- would further enable custom-tailored surgical treatment of improved accuracy. The team is also planning to build a version for minimally invasive operations.
