Ryan feels that his research experiences have helped pave the way toward his major goal of obtaining an M.D./Ph.D. and pursuing medical research as a career. He pursued his current research because of an interest in techniques for detecting, treating, and curing cancer. One of the perks of undertaking this project was the chance for Ryan to take apart, modify, and reassemble a very valuable instrument, as well as work with and learn from "many giants in the field." Ryan says that participating in research as an undergraduate has helped him acquire a sense of self-achievement, enriching the learning experience.

Breast cancer exists in a variety of disease states that cannot be easily characterized with current non-invasive diagnostic methods. This study presents possible methods for characterizing the disease states of breast cancer by analyzing their optical and physiological properties by frequency-domain photon migration (FDPM) techniques. A palpable breast lesion on four patients was measured using a high bandwidth (1-GHz) FDPM instrument utilizing six wavelengths spanning red and infrared light. The optical absorption (m_a) and reduced scattering (m_s^') coefficients were calculated from the frequency dependence of the photon density waves (PDW). Using the optical absorption coefficients, the (oxy-, deoxy-, and total) hemoglobin concentration and water percentage were calculated. Statistical methods were applied to compare the optical parameters of the cancerous and normal tissue in each patient. Analysis of the statistical and physiological results of all the patients reveals an observable distinction among the different disease states of breast cancer.

Bruce Tromberg College of Medicine

Pathologists routinely examine thin sections of surgically removed tissue in order to diagnose cancer. In this work, Ryan Lanning describes a new non-invasive diagnostic method, known as "photon migration," that employs near-infrared diode lasers to probe and analyze light scattered from tissues without surgical excision. This advanced technology allows us to measure the exact magnitude of light absorption and scattering (i.e. optical properties) in vivo without risk or discomfort to the patient. We show that photon migration can be taken from "bench-top to bedside" by developing a portable, state-of-the-art instrument and conducting clinical measurements on patients. These results demonstrate that tissue optical properties can be used to locate and identify physiological changes characteristic of both malignant and benign tumors in the breast. This is particularly important for young and "high risk" women who have radiographically dense tissue and typically do not benefit from conventional x-ray mammography.