(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose:
To determine spatial variations in the tissue optical properties, namely absorption (µ?) and reduced scattering coefficients (µs’), on various body parts of patients receiving TSET.
Methods:
Diffuse reflectance measurements were acquired before TSET treatment using a specially designed fiber optic-based contact probe consisting of one source fiber, coupled to an air-cooled quartz-tungsten-halogen (QTH) lamp, and 9 detection fibers spaced at distances from 1.4 to 8.7mm from the source. Measurements were made with the probe in contact with the tissue surface at multiple body locations. The reflected light was collected and imaged via a spectrograph onto a CCD, to measure radially-resolved diffuse reflectance. Background signal was measured with white light source turned off, and then subtracted from each measurement. Each tissue spectrum is divided by the spectrum obtained with the same light source and detector in an integrating sphere to account for the wavelength-dependence of the white light source power and CCD response. The diffuse reflectance spectra are fitted with a nonlinear fitting algorithm to extract the values of tissue optical properties. Absorption and reduced scattering coefficient at 650nm for 14 patients measured between February of 2018 and September of 2019, were reported.
Results:
The average (and standard deviation) absorption coefficient at 650nm for arm, leg, chest, neck, cheek, and forehead are 0.16±0.10cm?¹ (n=13), 0.16±0.06cm?¹ (n=13), 0.15±0.08cm?¹ (n=13), 0.22±0.02cm?¹ (n=3), 0.38cm?¹ (n=1) and 0.18cm?¹ (n=1), respectively. The average (and standard deviation) reduced scattering coefficient at 650nm for arm, leg, chest, neck, cheek, and forehead are 14.3±3.1cm?¹ (n=13), 15.9±3.3cm?¹ (n=13), 17.1±3.4cm?¹ (n=13), 18.2±4.5cm?¹ (n=3), 22cm?¹ (n=1) and 19.7cm?¹ (n=1), respectively.
Conclusion:
Tissue optical properties were measured on various body parts of 14 patients receiving TSET. Large intra- and inter-patient variations in µ? and µs’ at 650nm were observed.
The authors would like to acknowledge funding support from NATIONAL CANCER INSTITUTE: 1R21CA239127-01A1.
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