Fig 1.
Schematic of the optical mammography instrument.
The breast is imaged in a parallel plate, transmission geometry where source and detector fibers scan collinearly. The illumination scheme depicts the arc lamp which emits broadband, continuous wave light, filtered between 650 and 950 nm to the surface of the breast. The detected spectra are measured with a spectrograph and cooled CCD camera.
Table 1.
Patient Demographics and relevant clinical information.
Fig 2.
Absorption spectra for typical concentrations of the four main chromophores in breast tissue and the resulting total absorption coefficient.
The different shapes of each chromophore’s absorption spectrum portray why we can recover unique concentration of deoxy-hemoglobin, oxy-hemoglobin, water, and lipid.
Fig 3.
Computed μeff spectra and spherical geometry thickness recovery data.
(a) Five computed μeff spectra for different chromophore concentrations that span the range in breast tissue from the literature (each slab’s chromophore concentrations are listed below). The μeff variability is minimal around 925 nm. (b) Thickness recovered for the 4 cm chord distance in a spherical medium with the same chromophore concentrations as in Slab 1. The reference transmittance, T0(λ*), for the application of Eq. (8) is taken to be the one for a 5 cm thick infinite slab with the chromophore concentrations of Slabs 1–5, as indicated in the x axis. Chromophore concentrations of each slab are listed as ([HbO], [Hb], [water], [lipid]): Slab 1 (14uM, 7uM, 20%, 65%); Slab 2 (17uM, 11uM, 30%, 45%); Slab 3 (18uM, 10uM, 30%, 60%); Slab 4 (28uM, 12uM, 45%, 30%); Slab 5 (6uM, 4uM, 20%, 75%).
Fig 4.
Maps for a 72 year old patient who has invasive ductal carcinoma with ductal carcinoma in situ in her left breast.
(a) X-ray mammogram where two foci of cancer spanning 3.9 cm in combined maximum diameter are located in the 5 and 6 o’clock positions within the breast (shown in the red box). (b) The data discarded at the sides of the scanned breast are depicted in blue. (c) The deoxy-hemoglobin map is used to located the tumor ROI within the red rectangular area (based on the x-ray mammogram as described in the methods section) (d) The tumor rectangular box is shown in yellow and the shaded green region represents the tumor ROI, consisting of pixels with [Hb] to within 75% of the maximum [Hb] in the box. Maps of (e) total hemoglobin concentration, (f) hemoglobin saturation, (g) water percentage, and (h) lipid percentage.
Fig 5.
Optical maps of the healthy contralateral breast for the cancer patient shown in Fig. 4.
(A) The data discarded at the sides of the scanned breast are shown in blue. Maps of the (b) deoxy-hemoglobin concentration (c) total hemoglobin concentration, (d) hemoglobin saturation, (e) water percentage, and (f) lipid percentage are shown on the same color scale as the maps in Fig. 4 (C, E-H).
Fig 6.
Individual difference quantities in the average concentration of deoxy-hemoglobin, oxy-hemoglobin, total hemoglobin, hemoglobin saturation, water concentration, and lipid concentration between the tumor region and background breast tissue for all 26 cancer patients.
Each individual patient’s measurements are shown and error bars represent the standard deviation of the differences.
Table 2.
Summary of the difference parameters averaged across the 26 cancer patients.
Fig 7.
Difference quantities in the total hemoglobin concentration, water concentration, lipid concentration, and hemoglobin saturation plotted against the Nottingham histologic score.
A linear trend showing the higher Nottingham Score corresponding to an increase in the magnitude of the difference between the tumor region and background tissue for [HbT], [water], [lipid], and SO2.
Fig 8.
Optical maps of [HbT] and SO2 for a 59 year old patient with invasive ductal carcinoma in her left breast.
The black box indicates the tumor region identified based off of findings from the x-ray mammogram. The total hemoglobin concentration maps show a local increase in the region on the tumor, yet other areas of the breast also have increased [HbT]. The saturation maps portray that only in the tumor region is there a decrease in SO2.