"A new surgical tool that uses light to make sure surgeons removing cancerous tumors got it all was found to correlate well with traditional pathologists diagnoses in a clinical study showing that the tool could soon enable reliable realtime guidance for surgeons. The interdisciplinary research team led by Stephen Boppart a University of Illinois professor of electrical and computer engineering and of bioengineering performed the study on  patients with breast cancers at the Carle Foundation Hospital in Urbana Illinois. The results appear in the journal Cancer Research. One difficult but crucial determination for surgeons and tissue pathologists is figuring out where a tumor ends. A solid tumor may be easily identifiable but the tissue around the main body of the tumor known as the margin may contain cancerous cells as well. Because of this excess tissue surrounding the tumor is typically removed but the question lingers of whether any cancer cells remain to reemerge later as tumors. In almost all solidtumor surgeries theres a question of margins said Dr. Boppart who also is a medical doctor. Typically surgeons will remove the tissue mass that contains the tumor and will send it to the lab. The pathologist will process section and stain the tissue then examine the thin sections on microscope slides. They look at the structure of the cells and other features of the tissue. The diagnosis is made based on subjective interpretation and often other pathologists are consulted. This is what we call the gold standard for diagnosis. The new device is a handheld probe based on a technology called optical coherence tomography OCT that uses light to image tissue in real time. Cancer cells and normal tissue scatter light differently because they have different microstructural and molecular features Boppart said so OCT gives physicians a way to quantitatively measure the cellular feature of a tumor. Surgeons can pass the OCT wand over a section of tissue and see a video on a screen with no special chemical stains or lengthy tissue processing required. In many cases you cant tell the difference between cancer cells and normal tissue with the naked eye but with OCT theyre very different said Boppart who also is affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. In the clinical study surgeons treated patients according to the standard surgical procedure but OCT data were collected from the margin of the tumor cavity and the margin of the removed tissue mass during surgery so that the results could be compared later. The study found that the OCT device analysis identified the differences between normal and cancerous tissue with  percent sensitivity and  percent specificity. They also found that the way that OCT spotted cancer in the removed tissue was closely correlated with the results from the postoperative pathology reports which often came days later. For the first time this study demonstrates the use of OCT for imaging tumor margins within the tumor cavity in the patient during surgery Boppart said. It is likely better to check to see if any residual tumor cells might be left behind rather than checking the tissue mass that was taken out. Then the surgeon can intervene immediately. The researchers will continue clinical studies with the OCT device looking at other types of solidstate tumors. Diagnostic Photonics a startup company Boppart cofounded that also collaborated on the study is commercializing the OCT probe technology for broader use. Ultimately new technological innovations like this in medicine and surgery are going to improve our health care and save lives. Thats when this work will be most rewarding Boppart said.  The National Institutes of Health supported this work. Editors notes Editors note To reach Stephen Boppart call  email boppartillinois.edu mailtoboppartillinois.edu. The paper Realtime imaging of the resection bed using a handheld probe to reduce incidence of microscopic positive margins in cancer surgery is available online at httpcancerres.aacrjournals.orgcontent.full."