In 2005, 72,000 women that underwent breast surgery had to have a second re-excision surgery due to incomplete removal of the cancer during the first surgery. Needing a second surgery means increased cancer recurrence, patient anxiety, complications, and cost. Currently, surgeons have no readily available, cost efficient, intraoperative instruments that ensure that the cancer has been completely excised to prevent re-excision. To improve care, surgeons are seeking real time information on the tumor margins at the site of excision. Prior intraoperative solutions (frozen section and cytology) to prevent re-excision have not been adopted because they required a pathologist in the O.R., take too long during surgery, and only examine less than 1% of the tumor margin. Our long-term objective is to develop a chemically specific and quantitative multi-channel optical assay device for intraoperative assessment of tumor margins in patients undergoing breast conserving surgery (lumpectomy). The optical device will provide non-destructive evaluation of approximately 80% of the tumor margin in the excised specimen (as opposed to 1% provided by touch prep or frozen section); require no specialized personnel or sample processing (cutting and staining); and will require considerably less time than conventional techniques. The goal of the work is to design, fabricate and evaluate a single- channel alpha version of the optical assay device that will provide point measurements, and conduct a pilot clinical study on ex vivo breast tissues to demonstrate the feasibility and effectiveness of our novel technology. The specific aims are to: (1) design and optimize a single-channel optical device using Monte Carlo simulations; (2) build an alpha prototype device based on the simulations, and (3) validate the device's performance against a standard bench- top optical system on synthetic breast tissue phantoms, and determine the sensitivity and specificity on excised human breast tissue specimens in a pilot clinical study. Concurrent with this effort, we are recruiting expertise in management, regulatory and reimbursement strategies so that we will be well positioned to bring this device to market following completion of the R&D program. This device will have significant clinical benefits including: (1) reduced repeat surgeries and hence, reduced local recurrence, (2) reduced tissue removal, which translates to cosmetically-superior lumpectomies at the time of the first surgery, (3) reduced emotional distress, (4) reduced complications due to reduced number of surgeries and shorter recovery times for the patient and (5) reduced cost for the patient and the healthcare system. Successful completion of this project will set the foundation for the development of a fast, multi-pixel optical assay system for intraoperative assessment of tumor margins in patients undergoing breast cancer surgery. The optical assay system will have significant clinical benefits including: (1) reduced re-excision rates, (2) reduced tissue removal, which translates to cosmetically-superior lumpectomies at the time of the first surgery, (3) better margin assessment leading to reduced repeat surgeries and hence, reduced local recurrence, (4) reduced emotional distress, and (5) reduced complications due to reduced number of surgeries and shorter recovery times for the patient. [unreadable] [unreadable] [unreadable]