Optical Wire Guided Lumpectomy: Frequency Domain Measurements

摘要

In practice, complete removal of the tumor during a lumpectomy is difficu the published rates of positive margins range from 10% to 50%. A spherical lumpectomy specimen with tumor directly in the middle may improve the success rate. A light source placed within the tumor may accomplish this goal by creating a sphere surrounding the tumor that can serve as a guide for resection.rnIn an optical phantom and a prophylactic mastectomy specimen, sinusoidally modulated light within the medium was collected by optical fiber(s) at fixed distance(s) from the source and used to measure the optical properties. These 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.rnThe optical properties were μ_a = 0.004 mm~(-1) and μ'_s = 0.38 mm~(-1) in the phantom. The optical properties for the tissue were μ_a = 0.005 mm~(-1) and μ'_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 and then extrapolates those optical properties to make measurements of distance with a separate probe was demonstrated.