Abstract/Details

Estimation of effective scatterer size and number density in near-infrared tomography


2007 2007

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Abstract (summary)

Light scattering from tissue originates from the fluctuations in intra-cellular and extra-cellular components, so it is possible that macroscopic scattering spectroscopy could be used to quantify sub-microscopic structures.

Both electron microscopy (EM) and optical phase contrast microscopy were used to study the origin of scattering from tissue. EM studies indicate that lipid-bound particle sizes appear to be distributed as a monotonic exponential function, with sub-micron structures dominating the distribution. Given assumptions about the index of refraction change, the shape of the scattering spectrum in the near infrared as measured through bulk tissue is consistent with what would be predicted by Mie theory with these particle size histograms.

The relative scattering intensity of breast tissue sections (including 10 normal & 23 abnormal) were studied by phase contrast microscopy. Results show that stroma has higher scattering than epithelium tissue, and fat has the lowest values; tumor epithelium has lower scattering than the normal epithelium; stroma associated with tumor has lower scattering than the normal stroma.

Mie theory estimation scattering spectra, was used to estimate effective particle size values, and this was applied retrospectively to normal whole breast spectra accumulated in ongoing clinical exams. The effective sizes ranged between 20 and 1400 nm, which are consistent with subcellular organelles and collagen matrix fibrils discussed previously. This estimation method was also applied to images from cancer regions, with results indicating that the effective scatterer sizes of region of interest (ROI) are pretty close to that of the background for both the cancer patients and benign patients; for the effective number density, there is a big difference between the ROI and background for the cancer patients, while for the benign patients, the value of ROI are relatively close to that of the background. Ongoing MRI-guided NIR studies indicated that the fibroglandular tissue had smaller effective scatterer size and larger effective number density than the adipose tissue.

The studies in this thesis provide an interpretive approach to estimate average morphological scatter parameters of bulk tissue, through interpretation of diffuse scattering as coming from effective Mie scatterers.

Indexing (details)


Subject
Biomedical engineering;
Optics
Classification
0541: Biomedical engineering
0752: Optics
Identifier / keyword
Applied sciences; Pure sciences; Breast cancer; Mie theory; NIR; Optics; Scattering; Tomography
Title
Estimation of effective scatterer size and number density in near-infrared tomography
Author
Wang, Xin
Number of pages
191
Publication year
2007
Degree date
2007
School code
0059
Source
DAI-B 69/10, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549855163
Advisor
Pogue, Brian W.; Paulsen, Keith D.
Committee member
Blencowe, Miles P.; LaBelle, James W.; Wax, Adam; Wells, Wendy A.
University/institution
Dartmouth College
Department
Physics and Astronomy
University location
United States -- New Hampshire
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3330650
ProQuest document ID
304860558
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304860558
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