Each year around a million women in the Netherlands undergo
mammograms for early detection of possible breast cancer. In the regular screening method the breast is squeezed tight
between two plates in order to produce one or more good X-ray photos.
Apart from being unpleasant, it is not without risk. The X-rays used can
themselves be a contributor to the onset of cancer. Moreover, it is
often unclear whether the anomaly found is malignant lesion or not.
‘A novel breast cancer screening method that identifies cancerous tumors by blood vessels structure is being developed by researchers.’
than two-thirds of the cases where something worrying can be seen on
the X-ray photos is a false-positive: after biopsies, they are not found
to be cancer. This is why science is seeking alternatives.
Researchers at TU Eindhoven are
working on a 'breast-friendly' method, without radiation, that is more
accurate and generates 3D rather than 2D images. They published their
proof of concept earlier this month in the online journal Scientific Reports
Researchers at TU Eindhoven have now cleared a major scientific
hurdle towards a new technology in which the patient lies on a table and
the breast hangs freely in a bowl. Using special echography (inaudible
sound waves) a 3D image is made of the breast. Any cancer is clearly
identifiable on the generated images; the researchers therefore expect
there to be many fewer false-positive results.
The new technology builds on the patient-friendly prostate cancer
detection method developed at TU/e whereby the doctor injects the
patient with harmless microbubbles. An echoscanner allows these bubbles
to be precisely monitored as they flow through the blood vessels of the
prostate. Since cancer growth is associated with the formation of
chaotic microvessels, the presence and location of cancer become
visible. This method works well for the prostate and this is now being
widely tested in hospitals in the Netherlands, China and, soon, Germany.
For breast cancer the method had not yet been suitable because the
breast shows excessive movement and size for accurate imaging by
Researchers Libertario Demi, Ruud van Sloun and Massimo Mischi
have now developed a variant of the echography method that is suitable
for breast investigation. The method is known as Dynamic Contrast
Specific Ultrasound Tomography. Echography with microbubbles uses the
fact that the bubbles will vibrate in the blood at the same frequency as
the sound produced by the echoscanner, as well as at twice that
frequency; the so-called second harmonic. By capturing the vibration,
you know where the bubbles are located. But body tissue also generates
harmonics, and that disturbs the observation.
For the new method the researchers are using a phenomenon that
Mischi happened upon by chance and later investigated its properties
together with Demi. They saw that the second harmonic was a little
delayed by the gas bubbles. The researchers have now developed a new
visualization method. The more bubbles are encountered by the sound on
its route, the bigger the delay compared to the original sound. By
measuring this delay, the researchers can thus localize the air bubbles
and do so without any disturbance because the harmonic generated by the
body tissue is not delayed, and is therefore discernible. This
difference, however, can only be seen if the sound is captured on the
other side. So this method is perfectly suited to organs that can be
approached from two sides, like the breast.
The researchers are currently putting together an international,
strong medical team to start performing preclinical studies. Application
in practice is certainly ten or so years away, Mischi expects.
Moreover, he forecasts that the technology that has been developed will
probably not operate on a standalone basis but in combination with other
methods, which will create a better visualization. One of the
candidates for this elastography, a variant of echography whereby the
difference in the rigidity of the tumor and healthy tissue can be used
to detect cancer.