@inproceedings{dayton09a, author = {Amanda L. Dayton and Scott A. Prahl}, title = {Optical Wire Guided Lumpectomy}, booktitle = {SPIE Proceedings on Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications {IX}}, year = {2009}, editor = {Israel Gannot}, pages = {71730M-1--71730M-8}, volume = {7173}, abstract = {In practice, complete removal of the tumor during a lumpectomy is difficult to accomplish. Published rates of positive margins, range from 10\% to 50\%. A spherical lumpectomy specimen with tumor directly in the middle must be obtained more frequently. The proposed optical technique may provide a practical means by which all surgeons may achieve such a resection. It has been shown that the intensity of light sources can be sinusoidally modulated and will predictably become demodulated upon propagation through a scattering medium. \\[3mm] In this work, the modulated light within the medium was collected by optical fiber(s) fixed distance(s) from the source and used to measure the optical properties of the area. The optical properties were then used to calculate the distance the light had traveled through the medium. The fiber was coupled to an 830\,nm diode laser that was modulated at 100, 200 and 300\,MHz. A handheld optical probe collected the modulated light and a network analyzer measured the phase lag. This data was used to calculate the distance the light traveled from the emitting fiber tip to the probe. An optical phantom as well as a prophylactic mastectomy specimen were used to explore the feasibility of the system. \\[3mm] The optical properties were $\mu_a$ = 0.004\,mm$^{-1}$ and $\mu_s'$ = 0.38\,mm$^{-1}$ in the phantom. The optical properties for the tissue were $\mu_a = 0.005$\,mm$^{-1}$ and $\mu_s' = 0.20$\,mm$^{-1}$. The prediction of distance from the source was within 4\,mm of the actual distance at 30\,mm in the phantom and within 3\,mm of the actual distance at 25\,mm in the tissue. The feasibility of a frequency domain system that makes measurements of local optical properties then extrapolates those optical properties to make measurements of distance with a separate probe was demonstrated.}, }