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Using Near Infrared Spectroscopy to Study Static and Dynamic Hemoglobin Contrast Associated with Breast Cancer
Başlık:
Using Near Infrared Spectroscopy to Study Static and Dynamic Hemoglobin Contrast Associated with Breast Cancer
Yazar:
Krishnamurthy, Nishanth, author.
ISBN:
9780438020092
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (137 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Sergio Fantini Committee members: Shuchin Aeron; Irene Georgakoudi; Xavier Intes.
Özet:
Near-infrared spectroscopy (NIRS) of the breast exploits the inherent contrast of tumors due to increased hemoglobin absorption of light relative to healthy tissue. Optical imaging has been used to identify, characterize and monitor breast cancer non-invasively. This work first describes a new instrument for diffuse optical mammography in parallel plate geometry that operates over a broad spectral range of 600--1000 nm, features a scan time of 1--2 min, and allows for dynamic measurements at a selected region of interest. Furthermore, this new instrument is capable of depth discrimination of optical inhomogeneities embedded in the examined tissue by using multiple off-axis detection fibers.
Second, we report on an optical mammography study on eight patients with breast cancer who underwent neoadjuvant chemotherapy to identify biomarkers that indicate the patient's degree of response. We found that both the total hemoglobin concentration and hemoglobin oxygen saturation (SO2) decreased by a greater amount in responders than in non-responders during therapy. This result applied to both cancerous and healthy breasts, but the discrimination of responders and non-responders was more significant with SO2 measurements in the cancerous breast. We developed a cumulative response index that achieved 100% sensitivity and 100% specificity in characterizing response half way through chemotherapy.
Lastly, induced arterial blood pressure oscillations result in peripheral hemodynamic oscillations that provide information about local changes in blood flow and blood volume. We first report on a comparison of two protocols to induce cerebral hemodynamic oscillations, paced breathing and cyclic inflation of pneumatic thigh-cuffs. These two protocols induce systemic mean arterial pressure oscillations of similar magnitude but show varied response in the dynamics of cerebral oxy- and deoxy-hemoglobin concentrations. This variability may be due to altered physiological states under the paced breathing protocol, or anatomical differences between subjects. We then report on an initial attempt at inducing hemodynamic oscillations using pneumatic thigh-cuffs in patients undergoing neoadjuvant chemotherapy. We found that in one patient with complete data, we were unable to distinguish changes in the hemodynamics between healthy and cancerous breasts. Ultimately, a more robust measurement protocol is needed to ensure that oscillations driven by mean arterial pressure are reliably induced in the breast. To advance NIRS into clinical practice, larger studies, with standardized equipment need to be performed to establish its value for individual patients.
Notlar:
School code: 0234
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(680087.1) | 680087-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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