New 3D Visualization Tool for Early Detection of Breast Cancer

This technology provides a three-dimensional (3D) visualization of the breast with a high spatial resolution and is extremely sensitive to alterations in the tissue, such as those generated by cancer. The technique could be used in the near future in hospitals and it may help clinicians to identify tumors with greater precision than is possible using current X-ray mammography.

Breast cancer is the most frequent form of cancer affecting women in industrialized countries, according to the World Health Organization (Geneva, Switzerland). It is widely recognized that the early detection of breast cancer is directly linked to a successful treatment of the disease. Although X-ray mammography is currently the most widely used tool in diagnostic radiology, it fails to identify approximately 10-20% of palpable breast tumors. This is because some breasts, especially in young women, are very dense. Therefore, on mammograms, glandular tissues can mask cancer lesions.

Better results are obtained using computed tomography (CT). CT imaging produces accurate 3D images of the entire breast, improving the detection of early diseases in dense breasts. However, its use in breast imaging is limited by the radiation dose delivered to a radiosensitive organ such as the breast.

A new CT technique has allowed scientists to overcome this problem. The teams from the European Synchrotron Radiation Facility (ESRF; Grenoble, France), Helsinki University Central Hospital, Turku University Central Hospital (Finland), Radiation and Nuclear Safety Authority (Helsinki, Finland), University Hospital of Grenoble (France), the European Molecular Biology Laboratory (Hamburg, Germany), and the Biomedical Experimental Station (beamline) at the ESRF have managed to visualize breast cancer with an unprecedented contrast resolution and with clinically compatible doses.

The researchers, including physicists, surgeons, radiologists, and pathologists, used the technique, called analyzer-based X-ray imaging (ABI), on an in vitro specimen at the ESRF, using a radiation dose similar to that of a mammography examination. The dose corresponded to one-quarter of that required for imaging the same sample with conventional CT scanner, and the spatial resolution of the ABI images was seven times better. For the experiment, researchers chose an especially challenging specimen: a breast invaded by a lobular carcinoma (a diffusely growing tumor), the second most common form of breast cancer, which is also very difficult to visualize in clinical mammography. In this kind of sample, the determination of the extension of the cancer frequently fails in X-ray mammograms and ultrasonographic scans of the breast.

The study's findings revealed that high-spatial-resolution ABI-CT makes visible small-size and low-contrast anatomic details that could otherwise only be seen by the microscopic study of an extracted sample of the breast tissue. "We can clearly distinguish more micro calcifications--small deposits of minerals which can indicate the presence of a cancer--than with radiography methods and improve the definition of their shapes and margins,” explained Dr. Jani Keyriläinen, main author of the article. "If we compare the images with X-ray mammograms and conventional CT images, we can confirm that this technique performs extremely well.”

Despite having evaluated only in vitro samples, the team is very optimistic that the technique will be applied in the future in clinics. "The technique does not require sophisticated and expensive synchrotron radiation facilities,” explained Dr. Alberto Bravin, scientist in charge of the biomedical beamline at the ESRF. However, "it would not be viable to use X-ray tubes, as exposure times would be too long and this would be incompatible with clinical practice.”

Scientists hope that current worldwide development of compact, highly intense X-ray sources will enable the clinical use of this technique. The Biomedical beamline at the ESRF is directly involved in one of these projects, with the role of developing synchrotron techniques for clinical application on compact sources (e.g., the tabletop X-ray-free electron laser [X-FEL] machine of the Munich Advanced Center for Photonics [MAP]).

Once the technique has been further validated and tabletop synchrotrons are on the market, the progression could be very straightforward. "With these machines it would definitely be possible to apply this technique to clinical practice,” concluded Dr. Bravin, "and, in this way, contribute actively to a more efficient detection of breast cancer.”

Related Links:
European Synchrotron Radiation Facility