Standard X-ray imaging produces images of tissue with spatial resolution. However, the technique only provides information about tissue density, not on type. This is because X-ray imaging measures the attenuation of the X-rays transmitted; it does not take into account diffused X-rays, which can provide very specific information about tissue structure. X-ray diffraction imaging is a powerful non-invasive technique to identify and characterize different materials by their molecular signature.
CEA-Leti leverages the potential of X-ray diffraction imaging to characterize biological tissue by combining new spectrometric detectors with conventional polychromatic X-ray tubes. Researchers tried to take advantage of the diffused X-rays, especially at small angles, to distinguish tumors from healthy tissue, thereby improving diagnostics for pathologies like breast cancer. To do so, the researchers needed premium detectors capable of picking up the spectral signature of X-rays diffused in tumor tissue in a clinical setting at room temperature. They developed CdZnTe detectors that effectively measure with a high accuracy the energy of each photon received.
Recently, they succeeded using an experimental setup based on energy-resolved measurements of diffraction spectra, as well as a data processing method for computing diffraction signatures from these measurements. The system was tested using phantoms made of beef adipose and muscle tissues, which were chosen to imitate the diffraction signatures of breast tissues. The presented results showed that the nature of the tissue –adipose, muscle or a mix of adipose and muscle– can be successfully visualized for an acquisition time of 10 seconds. This test demonstrated that this technique is able to distinguish cancerous tissue from healthy tissue.
These results showed the potential of X-ray diffraction for clinical applications in breast cancer diagnosis. The next step will be to complete tests on more complicated samples –different tumors, different stages of maturity– and on human tissue.