Biophotonics '09 - Tromberg

Medical imaging in thick tissues using diffuse optics

Professor Bruce J. Tromberg, Ph.D.

Laser Microbeam and Medical Program,
Beckman Laser Institute and Medical Clinic,
University of California, Irvine 92617-1475, USA

Tel. +1 949 824 4713
E-mail: bjtrombe@uci.edu
http://www.bli.uci.edu/

Abstract

Medical diagnostic techniques based on near infrared (NIR) transillumination were first introduced more than 70 years ago to detect breast cancer. Although NIR light penetrates tissue to depths of several centimeters, early methods were not successful due to the fact that these approaches were qualitative and did not account for distortions from multiple light scattering.

Recent advances in temporal- and spatial- frequency-domain “photon migration” now make it possible to separate light absorption from scattering in thick tissues. Temporal frequency-domain methods measure the phase shift and amplitude of MHz - GHz intensity-modulated waves (1), while spatial frequency-domain techniques utilize structured light patterns to form wide-field images of tissue optical properties (2). Both approaches are based on comparing measured data with radiative transport models to form images, i.e. “diffuse optical imaging (DOI)”, and acquire spectra, i.e. “diffuse optical spectroscopy (DOS)”.

This lecture reviews principles of DOI/DOS for non-invasively characterizing tissue structure and biochemical composition. Particular emphasis is placed on the development of broadband methods for quantitative measurements of NIR absorption and scattering spectra between 600-1000 nm. These data are used to determine the tissue concentration of deoxygenated hemoglobin, oxygenated hemoglobin, methemoglobin, lipid, and water, as well as the tissue “scatter power” (1). Clinical study results are shown highlighting the sensitivity of broadband DOS to breast tumor metabolism with sufficient sensitivity for cancer detection and therapeutic drug monitoring (3,4). Broadband spatial frequency-domain imaging is used in pre-clinical animal models to dynamically map intrinsic brain signals and monitor the efficacy of chemotherapeutic agents. These findings will be placed in the context of conventional imaging methods, such as MRI, in order to assess the current and future role of diffuse optics in medical imaging (5).

References

[1] Jakubowski, D, Bevilacqua, F, Merritt, S, Cerussi, A, Tromberg, BJ, Quantitative Absorption and Scattering Spectra in Thick Tissues using Broadband Diffuse Optical Spectroscopy, J. Fujimoto and D. Farkas ed., Biomedical Optical Imaging, Oxford University Press, in press.

[2] Cuccia, D, Bevilacqua, F, Durkin, AJ, Tromberg, BJ Modulated Imaging: Quantitation and Tomography of Turbid Media in the Spatial Frequency Domain, Opt. Lett. 30, 1354-1356 (2005).

[3] Cerussi, A., Shah, N., Hsiang, D., Durkin, A., Butler, J., Tromberg, BJ., In Vivo Absorption, Scattering, and Physiologic Properties of 58 Malignant Breast Tumors determined by Broadband Diffuse Optical Spectroscopy, J. Biomedical Optics 11, 044005 (2006).

[4] Cerussi, A., Hsiang, D., Shah, N., Mehta, R., Durkin, A., Butler, J., Tromberg, B.J., Predicting response to breast cancer neoadjuvant chemotherapy using diffuse optical spectroscopy. Proc Nat Acad Sci 104, 4014-9 (2007).

[5] Tromberg B, Pogue B, Paulsen K, Yodh A, Boas D, Cerussi A. Assessing the future of diffuse optical imaging technologies for breast cancer management, Med Phys. 35, 2443-51 (2008).

Slides

Medical imaging in thick tissues using diffuse optics (approx. 32 Mb)

Link to program

Session 9

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