Physiological and Pathological Factors of Human Breast Disease That Can Influence Optical Diagnosis^a

Abstract

The 'normal' human female breast is a very complex organ that changes considerably during development, pregnancy and menopause. In addition, it is an excretory organ that, during lactation, discharges various metabolites and certain drugs that can be optically active. Optical diagnosis of breast cancers requires detection of differential concentrations of 1) various absorbers and scatterers or 2) native or exogenous fluorophores to distinguish cancers from surrounding 'normal' and benign breast tissues. The differential concentrations are due to the biology of the cancer cells and the host responses to the cancer growth. For most patients, the cancer will be intermixed with a complex 3-dimensional array of 'normal' breast tissue and benign breast lesions. This complexity will challenge the optical biopsy investigator but, with the recent advances in our understanding of light transport, optical diagnostic techniques and devices can be developed to complement and supplement current breast cancer screening techniques.

Sources of Absorption and Scattering Contrast for Near-Infrared Optical Mammography

“…The late decrease in THC and water correlates well with previous histologic studies showing both atrophy in well-vascularized lobular tissue and an increase in the fat-to-collagen ratio after menopause (15). This decrease is consistent with compositional analysis data showing lower blood and water content for fat versus glandular tissue (27).…”

“…Many investigators have used them to explore brain, breast, and muscle tissue, exploiting their enhanced penetrance relative to that of visible or ultraviolet radiation (1). In breast tissue, the principal NIR absorbers are assumed to be reduced hemoglobin (Hb-R), oxygenated hemoglobin (Hb-O 2 ), water (H 2 O), and lipids (15). NIR tissue spectroscopy offers a safe way to quantify these components and to view unique functional information with low-cost "point-of-care" devices.…”

Diagnosis of breast cancer using fluorescence and diffuse reflectance spectroscopy: a Monte-Carlo-model-based approach

“…Certain collagens, especially type 1 collagen, is a major constituent of the dermis and fibrous stroma of breast. 42 It was shown that in normal breast tissues the fluorescence contribution of the collagen component decreased with increasing adipose tissue content, while it increased with increasing fibro-connective and glandular tissue content (as seen in Table 2). This agrees with the fact that collagen resides primarily in the dense fibrous stroma of the breast.…”

“…This agrees with the fact that collagen resides primarily in the dense fibrous stroma of the breast. 42 Taroni et al 43 measured absorption of collagen in healthy breast tissues using time-resolved transmittance spectroscopy, and showed that less fatty tissues are characterized by higher collagen concentration. Results of our study also showed that the collagen component has statistically higher contribution to the fluorescence of malignant and fibrous/benign breast tissues, as compared with that of normal adipose tissues (p<1×10 −6 ).…”

“…In the normal breast, NADH may also increase with the increased metabolism associated with the duct proliferation and secretory activities of the breast lobules, while adipose cells have an indolent metabolism. 42 Therefore, fluorescence of adipose tissues would be expected to have lower contribution from NADH than that of fibrous/benign breast tissues. This explains the negative correlation observed between the fluorescence contribution of this component and adipose tissue content, as well as the positive correlation observed between this fluorescence component and fibroconnective and glandular tissue content in healthy breast tissues.…”