Comparison of unmonochromatized synchrotron radiation and conventional X-rays in the imaging of mammographic phantom and human breast specimens: a preliminary result.

A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 microm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications.

Synchrotron radiation imaging of internal structures in live animals.

Ionizing radiation has long been used in medicine since the discovery of X-rays. Diagnostic imaging using synchrotron radiation has been under investigation since Rubenstein et al. reported dual-energy iodine-K-edge subtraction coronary angiography. Recently, computed tomography (CT) and magnetic resonance imaging (MRI) have provided better quality results than conventional radiology, providing important information on human internal structures. However, such techniques are unable to detect fine micron sized structures for the early diagnosis of tumors, vascular diseases and other medical objectives. Third generation synchrotron X-rays are well known for their superiority in coherence and energy tunability with respect to conventional X-rays. Consequently, new contrast mechanisms with a superior spatial resolution are becoming available. Here we present the extremely fine details of live animal internal structures using unmonochromatized synchrotron X-rays (white beam) and a simple detector system. Natural movements of the internal organs are also shown. The results indicate that this imaging technique can be applied to investigating microstructures and evaluating the function of the internal organs. Furthermore, this imaging system may be applied to humans as the next tool beyond CT and MRI.