Precise excision of tumors requires knowing where neoplasm ends and healthy tissue, that should be spared, begins. For many procedures it’s standard practice to repeatedly send excised samples to the pathology lab for confirmation of healthy margins. To help identify neoplasm during surgery without the back-and-forth with the lab, fluorescent dyes that concentrate within tumors have recently been introduced, and some of these are already seeing clinical use. Observing these dyes requires a specific type of illumination and camera combination that allows for only one color to be used at a time, a serious limitation. Using dyes of multiple colors that can each congregate within specific cells types, nerves, vessels, and other anatomical structures can be made to stand out in addition to the target tumor.
Now researchers at Fraunhofer Project Group for Automation in Medicine and Biotechnology (PAMB), part of Germany’s Fraunhofer Institute for Manufacturing Engineering and Automation (IPA), are reporting that they developed a multispectral fluorescence camera that can work with multiple dyes at the same time, allowing for a color coded comprehensive view of the surgical site.
From Fraunhofer’s announcement:
“The visibility of the dye to the camera depends in large part on the selection of the correct set of fluorescence filters. The filter separates the incident excitation wave- lengths from the fluorescing wavelengths so that the diseased tissue is also set apart from its surround- ings, even at very low light intensities,” says Nikolas Dimitriadis, a scientist at PAMB. The researchers and their colleague require only one camera and one set of filters for their photographs, which can present up to four dyes at the same time. Software developed in-house analyses and processes the images in seconds and presents it continuously on a monitor during surgery. The information from the fluores- cent image is superposed on the normal color image. “The operator receives significantly more accurate information. Millimeter-sized tumor remnants or metastases that a surgeon would otherwise possibly overlook are recognizable in detail on the monitor. Patients operated under fluorescent light have improved chances of survival,” says Dr. Nikolas Dimitriadis, head of the Biomedical Optics Group at PAMB.
In order to be able to employ the multispectral fluorescence camera system as adapt- ably as possible, it can be converted to other combinations of dyes. “One preparation that is already available to make tumors visible is 5-amino levulinic acid (5-ALA). Physicians employ this especially for glioblastomas – one of the most frequent malig- nant brain tumors in adults,” explains Dimitriadis. 5-ALA leads to an accumulation of a red dye in the tumor and can likewise be detected with the camera. The multispectral fluorescence imaging system should have passed testing for use with humans as soon as next year. The first clinical tests with patients suffering from glioblastomas are planned for 2014.
Flashbacks: The (Fluorescent) Future of Surgery…; First Ovarian Cancer Surgeries Performed with Fluorescent-Guidance…; Spray Painting Cancer Cells…; New Fluorescent Imaging Compound Lights Up When Inside Viable Cells…
Fraunhofer: Special camera detects tumors…
