Breast Cancer Scans With Less Radiation?
(Ivanhoe Newswire)—When doctors screen for breast cancer, they usually take a CT scan of the breast to get a look at what’s going on inside. However, the concern with using CT scans is that it utilizes radiation, which can be bad for the possibly cancerous breast due to the high radiosensitivity of the breast glandular tissue. Now scientists have not only developed a way to take better scans, but also developed a way to use a radiation dose that is about 25 times lower.
The new method enables the production of 3D diagnostic computed tomography (CT) images with a spatial resolution 2-3 times higher than present hospital scanners. Synchrotron X-rays, once deployed in hospitals, will make CT scans a diagnostic tool to complement dual view mammography.
Early detection largely contributes to an improved prognosis and results in reduced breast cancer mortality. The breast cancer screening method typically used today is "dual-view digital mammography". The limitation is that it only provides two images of the breast tissue, which can explain why 10 percent to 20 percent of breast tumors are not detectable on mammograms. Mammograms can also sometimes appear abnormal, when no breast cancers are actually present.
Computed tomography (CT), an X-ray technique that allows a precise 3D visualization of the human body organs, cannot be routinely applied in breast cancer diagnosis because the risk of long-term effects in radiosensitive organs like the breast is considered too high. Recognizing these limitations, a multidisciplinary team comprised of physicists, radiologists and mathematicians from the European Synchrotron Radiation Facility ESRF (Grenoble, France), the Ludwig Maximilians University in Munich (LMU, Cluster of Excellence MAP) and the University of California at Los Angeles (UCLA), went in a new direction.
CT scans for early detection of breast cancer may now become possible thanks to the combination of three ingredients: high energy X-rays, a special detection method called "phase contrast imaging" and the use of a sophisticated novel mathematical algorithm, known as "equally sloped tomography" (EST), to reconstruct the CT images from X-ray data. Tissues are more transparent to high energy X-rays and therefore less dose is deposited.
"This new technique can open up the doors to the clinical use of computed tomography in the breast diagnosis, which would be a powerful tool to fight even better and earlier against breast cancer", Prof. Maximilian Reiser, Director of the Radiology Department of the LMU, was quoted as saying. "This result has been obtained thanks to the synergy of the expertise by researchers from very different disciplines. These high-quality X-ray CT images at high energies are the result of a 10-year effort at the ESRF," Alberto Bravin, head of the ESRF medical research laboratory who led the team in Grenoble, was quoted as saying. "After dramatically reducing the dose delivered during the examination of the breast, our next objective is to develop this technique in the early visualization of other human diseases and to work towards its clinical implementation.” Paola Coan, Professor of X-ray imaging at LMU and member of "Munich-Centre for Advanced Photonics (MAP)" who led the group from Munich, was quoted as saying.
Today, the new technology is in the research phase and will not be available to patients for some time. To be implemented in clinics, it needs an X-ray source small enough to become commonly used for breast cancer screenings. "Many research groups are actively working to develop this device and once this hurdle is cleared, the new X-ray technique is poised to make a big impact on society", Emmanuel Brun was quoted as saying.
Source: Proceedings of the National Academy of Sciences, October 2012