NOVEMBER 9, 2016

BY INES MARTINS, PHD IN NEWS.

Researchers are working to develop a new breast-friendly, radiation-free method that may replace the unpleasant mammogram currently used to detect breast cancer.

The new method, described in the study “Towards Dynamic Contrast Specific Ultrasound Tomography,” and published in Scientific Reports, uses ultrasounds to provide 3-D images of the breast, and is meant to reduce not only a woman’s discomfort during the procedure, but also the number of false-positive results seen frequently with current mammogram methods.

Currently, women are screened for breast cancer through a mammogram, where the breast is squeezed tight between two plates to generate 2D X-ray images. The method is not only physically unpleasant and one of the reasons women choose to skip screening, it also comes with the risk that the radiation used in the mammograms can contribute to the development of cancer.

In addition, mammograms generate large numbers of false-positive results. In more than two-thirds of cases where doctors find an abnormal tissue that is recommended for biopsy, it turns out that the abnormal regions are not cancer. In the meantime, women are subjected to high levels of unnecessary worrisome stress.

Researchers have been trying to develop alternatives to this method that provide more accurate results and that reduce women’s discomfort. Recently, a team at Eindhoven University of Technology has been working on a possible alternative for mammograms.

According to a press release, the new technology requires patients to lie on a table with their breast hanging freely in a bowl. Using ultrasounds, a 3-D image of the breast is generated and scanned for tumors. The researchers believe this method will generate far fewer false negative results.

The technology builds up on a patient-friendly prostate cancer detection method also developed at the Eindhoven University of Technology. The approach takes advantage of the distinct vessel architecture found in tumors and healthy tissues. Tiny micro-bubbles that can be precisely monitored with an echoscanner are injected in the prostate blood vessels, allowing doctors to precisely identify the presence and location of the tumor.

Although this method is now being tested for prostate cancer in hospitals worldwide, breast motion and size have largely limited its application in breast cancer screening.

But researchers may have developed a new variant of the echography method that is suitable to be used in breast cancer. Libertario Demi, Ruud van Sloun and Massimo Mischi developed the Dynamic Contrast Specific Ultrasound Tomography, which uses the same micro-bubbles, but under a different principle. They use the fact that bubbles vibrate in the blood at the same frequency as the sound produced by the echoscanner, and at twice that frequency — the second harmonic.

When the scanner captures that vibration, it knows where the bubbles are located. Similar to the micro-bubbles, the body tissue also generated harmonics, which limited the researchers’ observations. But the researchers found that, contrary to the body tissues, the gas bubbles delayed the second harmonic. And the more bubbles the sound-waves encountered, the bigger the delay.

This, however, can be detected only if the sound is captured on the other side, which makes the technology ideal for the breast tissue.

The researchers are now starting a collaborative effort to conduct preclinical studies with the new tool, and hope it will be included in clinical practice within 10 years, possibly in combination with other methods that will generate high-quality images that allow for highly accurate diagnoses.