by ecancer reporter Janet Fricker

Introducing Edge Illumination X-ray Phase-Contrast Imaging (EIXPCI) techniques for breast cancer detection could result in X-ray reductions for mammography, reports a European collaborative study in “Physics in Medicine and Biology”.

Currently, there is much debate regarding the pros and cons of breast cancer mammography, with acknowledged screening drawbacks including risks of inducing secondary cancers through exposure to radiation.

“Being able to substantially reduce this exposure would significantly change the boundary conditions, arguably shifting the balance towards the benefits,” write the authors, led by Paul Diemoz, from University College, London.

X-ray phase contrast imaging (XPCI) generates contrast based on refraction and interference, rather than attenuation delivering two significant implications for diagnostic radiology.

First, features considered X-ray invisible can be detected, and the visibility of all image details enhanced.

Second, the generation of image contrast does not require X-rays to be absorbed in the sample, allowing images to be acquired at much higher energies than conventional radiology, offering the potential to achieve significant reductions in radiation doses.

The current collaboration between researchers from UCL, the European Synchrotron Radiation Facility, France, and Ludwig Maximilians University, Germany, aimed to further reduce radiation exposure through adding Edge Illumination technology (EI) to XPCI technolog.

EI offers additional features to reduce radiation including placing the main optical element before the sample to protect it from unwanted dose delivery and the detector containing a low-absorbing graphite substance.

In the study, investigators tested their approach using 2 and 4cm thick tissue samples removed during routine mastectomies from two women.

Results showed that the mean glandular dose received with EIXPCI was 0.12 mGy, representing an order of magnitude smaller than clinical mammograms, where the typical dose is 1-1.5 mGy.

Furthermore, when EI-XPCI images were compared with those acquired from conventional mammography, tissue features (such as collagen strands and glandular tissue) were equally discernible.

Previous studies have shown that EI-XPCI technology is compatible with commercial X-ray tubes, allowing for translation to future clinical applications.

The next goal, say the investigators, will be to develop a compact set-up that can be used clinically.
Demonstration of the ability to reduce dose in mammography, they add, could trigger similar research in other diagnostic radiology areas, such as Computed Tomography.

Reference
Diemoz P, Bravin A, Sztrokay-Gaul A, et al. A method for high-energy, low-dose mammography using edge illumination x-ray phase contrast imaging. Physics in Medicine & Biology 2016, 61: 8750-61