OPTICAL MAMMOGRAPHY FOR CHARACTERIZING INTRINSIC CONTRAST OF BREAST CANCER AND ASSESSING RESPONSE TO NEOADJUVANT CHEMOTHERAPY
Anderson, Pamela.
2016
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Abstract:
Near-infrared spectroscopy (NIRS) techniques are sensitive to absorption and scattering
properties of biological tissue. NIRS and diffuse optical imaging have been applied to
breast tissue for decades to exploit the high absorption of tumors resulting from their
increased blood content. By developing methods focused on measuring the inherent
contrast of tumors, optical imaging can ... read morebe used to identify, characterize and monitor
breast cancer. Optical images of the human breasts were collected in this work using a
spectrally broadband (650-850 nm), continuous-wave, optical mammography instrument. A
diffusion-based model was implemented to process the spectra measured through the breast
to create maps of oxy-hemoglobin, deoxy-hemoglobin, water, and lipid concentrations.
Oxygen saturation of hemoglobin was also mapped, which indicates balance between tissue
perfusion and tissue metabolic rate of oxygen. The work in this thesis details the
methods to characterize breast cancer contrast found on optical mammograms. Tumors (n =
26) exhibited increased hemoglobin and water concentrations as well as decreased lipid
concentration and oxygen saturation of hemoglobin when compared to the surrounding
healthy tissue. When considering the appropriate healthy tissue to which the tumor
region should be compared against, a procedure was developed to provide a quantitative
metric to evaluate the symmetry between a patient's right and left breast maps. The
level of bilateral symmetry observed in the oxygen saturation of hemoglobin breast maps
for healthy patients (n = 27) and patients with benign (n = 32) or malignant lesions (n
= 21) was highest for healthy patients maps, although a high degree of variability was
found. The use of optical mammography in assessing breast cancer response to neoadjuvant
chemotherapy is also demonstrated. By obtaining optical mammograms on ten patients each
time they received a chemotherapy infusion, the trends in the hemoglobin concentrations
and oxygen saturation of hemoglobin were examined throughout the duration of treatment.
The tumor pathologic response measured following surgical excision was then correlated
to the optically measured trends. It was found that for patients achieving good response
to treatment, the tumor oxygen saturation of hemoglobin experienced a significantly
larger decrease compared to the tumors in poorer responding patients. Optical
mammography has the potential to monitor patient response to treatment and guide
clinical decision making.
Thesis (Ph.D.)--Tufts University, 2016.
Submitted to the Dept. of Biomedical Engineering.
Advisor: Sergio Fantini.
Committee: Fiorenzo Omenetto, Darren Roblyer, and Roger Graham.
Keywords: Biomedical engineering, and Medical imaging.read less - ID:
- pz50h745h
- Component ID:
- tufts:21176
- To Cite:
- TARC Citation Guide EndNote
