Biomedical Imaging and Radiotherapy:

Breast Cancer Detection Technology

An Alternative to Invasive Biopsies

In collaboration with others in the medical community, SSI scientists are developing a non-invasive IR imaging technology for breast imaging as an adjunct to the standard X-ray mammogram to reduce the number of unnecessary invasive biopsies. Parties interested in this technology or possible collaborative development in this area should contact Matt Braunstein at matt(at)spectral.com or tel. (781) 273-4770.

An Urgent Need

Physicians are in need of new diagnostic modalities for breast cancer. The non-specific nature of the X-ray mammogram has caused an over-reliance on breast biopsies. Over 80% of biopsies are negative, resulting in about 1 million unnecessary invasive biopsies per year in the U.S. alone. In addition to unnecessary pain, exposure to infection, disfigurement, hematomas, and trauma, biopsy effects can mask later carcinomas. Therefore there is an urgent need for non-invasive diagnostic imaging devices which allow further analysis in the case of an ambiguous mammogram.

SSI's Approach

In recent years, considerable research has focused on tissue imaging with non-ionizing, near-infrared (NIR) light. NIR light penetrates deeply into tissue, and chromophores such as hemoglobin show characteristic NIR absorption spectra. This has led to many useful advances to provide routine non-invasive measurement of oxygenation state and blood flow in tissue, such as the pulse oximeter. However, the basic problem with using light rather than X-rays to detect cancer is that light photons are highly scattered in tissue. This effect leads to images with poor resolution and contrast, and has resulted in a general clinical failure of NIR techniques for medical imaging in the U.S.

Our approach to this problem is to use a safe, tumor-specific contrast agent (dye) to generate characteristic optical signals from the tumor. With the proper computer processing, this allows the tumor, which has accumulated the dye, to be detected and imaged. This new information will help resolve ambiguous X-ray mammograms, and reduce the need for invasive biopsies. The figure below shows examples of NIR images of in-vitro tissue samples in which the contrast agent has been injected deep into the tissue. The characteristic absorption of the dye at a particular NIR wavelength enables effective removal of the background tissue inhomogeneities and greatly enhances the contrast. Details of a data processing method are described in a recent paper.

Experimental set up and NIR imagesExperimental set up (left) and NIR images (right) of in vitro tissue sample. "ICG" denotes contrast agent injection site.