Intraoperatively assessed optical properties of malignant and healthy breast tissue used to determine the optimum wavelength of contrast for optical mammography

Abstract

We use spatially resolved diffuse remittance spectroscopy (DRS) for the measurement of absorption (mu(a)) and reduced scattering (mu(s)') coefficients of normal and malignant breast tissue in vivo during surgery. Prior to these measurements, the linearity of the measurement technique was evaluated on liquid optical phantoms. In addition, the reproducibility of in-vivo tissue measurements was determined on a healthy volunteer. We present results of the in-vivo measurement of optical properties in the wavelength range from 600 to 1100 nm performed during radical mastectomy. A total of 24 patients were included in the study. Both the absorption and reduced scattering properties show large variations. Significant differences in optical properties between normal (glandular plus lipid rich tissue) and tumor tissues are present in 74% of all patients. However, in some cases the tumor showed lower values than normal tissue, and in other cases this was the other way around. Thus, a general trend in optical properties is not observed. However, the average absorption contrast of all patients as a function of wavelength reveals an optimal contrast peak at 650 nm. We believe that this relates to a difference in vascular saturation between tumor and adjacent normal tissue.

Characterization of normal breast tissue heterogeneity using time-resolved near-infrared spectroscopy

“…These papers present a variability in optical properties for different lesions. Other studies have investigated the variability in optical properties of normal breast tissue (Shah et al 2004, van Veen et al 2004a, Pogue et al 2004. Of these, only Shah et al (2004) emphasize intrasubject variations.…”

“…The absorption coefficient µ a and the reduced scattering coefficient µ s can be determined. This can be done locally, by using a probe based on a number of optical fibres to deliver and collect the light (Cubeddu et al 1999, Cerussi et al 2002, van Veen et al 2004a, or by imaging techniques such as diffuse optical tomography (Gratton et al 1993, Colak et al 1999, Hebden et al 2002, Li et al 2003, Yates et al 2005 or by scanning the source and detector fibres across the compressed breast to record a shadowgram type image analogous to x-ray mammography (Franceschini et al 1997, Grosenick et al 2003. A key concept in these optical methods is the spectral information that can be derived if several wavelengths are used.…”

Diagnostic imaging of breast cancer with LOIS: clinical feasibility

“…On the hardware side, our development efforts benefit from the progress being made in the development of laser sources that are more and more compact, powerful, and reliable and from the discovery of new piezoelectric materials that allow construction of transducers with higher sensitivity and wider bandwidth of the ultrawideband ultrasonic transducers. Beneficial research results include the discovery by the biomedical optics community that, in spite of the fact that there is significant optical heterogeneity in the normal tissue of the breast, there is always a significant (2 to 4 fold) 3,4 difference between the optical NIR absorption coefficients of normal tissue and malignant masses. This difference primarily stems from an increased blood level in malignant tumors.…”

<title>Efficient noise tolerant reconstructions in diffuse optical tomography through computation of Jacobian in wavelet domain</title>

“…The motivation for reconstructing the optical property variation is that they, and in particular the absorption coefficient variation, can be used to diagnose different metabolic-and disease states of tissue [9][10][11][12] . For this the spectral variation in absorption coefficient is converted to useful functional information such as total hemoglobin content and oxygen partial pressure, which can throw light on the onset of malignant tumours [13][14][15][16] .…”