By ecancer reporter Janet Fricker

With the development of a new tissue-imaging technique the wait for cancer biopsy results could soon be a thing of the past, reports the journal Cancer Research in its December 1 issue. Nonlinear interferometric vibrational imaging (NIVI) is a novel microscopy technique that delivers easy to read colour coded images of tissue that outline clear tumour boundaries. The study in mouse models of breast cancer showed that the new technology was more than 99 % accurate and delivered results in minutes.

In the current gold standard of stained histopathology, a small sample of suspect tissue is taken from the patient, stained and examined under the microscope, with the diagnosis based on visual interpretation of cell shape and structure by experienced pathologists. The disadvantage of the approach is that that there are delays due to waiting for stains to set in and also the fact that the approach is based on subjective interpretation.

The new NIVI technology, developed by Stephen Boppart and colleagues from the University of Illinois (Urbana, Illinois), is based on the concept that pathologic anomalies are associated with variations in the biochemical composition of cells, and that different molecules have distinctive vibrational energy states in their bonds. The rationale for use of NIVI imaging in oncology lies in the fact that cancer cells have a higher concentration of proteins, whereas healthy cells have a higher concentration of lipids.

The NIVI technology utilises two beams of light – one for a reference and one to excite the tissue and isolate the signal. The resulting image analysis yields red for cancer and blue for healthy cells, allowing for a colour map of the tumour margins.

In the current paper, the investigators showed that in a rat model of breast cancer the technology could differentiate between cancer and normal tissue sections with greater than 99 % confidence intervals and define cancer boundaries to +-100 µm with greater than 99% confidence interval using fresh unstained tissue sections. Imaging results were available in less than five minutes.

The investigators are currently working to make the approach faster, the equipment more compact and even portable, with the ultimate goal of developing new light delivery systems, such as catheters, probes or needles that can test tissue insitu without the need to remove samples.

"One can even foresee ..NIVI providing guidance in intraoperative surgical procedures such as lumpectomies in which the precise delineation of tumour margins is critical and in which ..NIVI could provide endogenous molecular differentiation to complement the real-time optical coherence tomography imaging of endogenous scattering structures," wrote the authors.

Reference

PD Chowdary, Z Jiang, EJ Chaney Molecular Histopathology by Spectrally Reconstructed Nonlinear Interferometric Vibrational Imaging Cancer Research DOI: 10.1158/0008-5472.CAN-10-1554