Description:
Diffraction enhanced imaging (DEI) has been used to study the improvements in image contrast of calcifications in breast tissue. This new imaging modality has the potential to greatly improve early detection of breast cancer, primarily due to its ability to utilize contrast mechanisms in the breast, which are not possible with existing radiographic methods. Of particular interest is the comparison of the image contrast of calcifications in breast tissue obtained using DEI to those obtained using conventional radiography. The presence of calcifications in breast tissue has been connected to breast cancer, but this relationship is not well understood. The purpose of this dissertation is to study the improvements in image contrast of calcifications in healthy as well as cancerous breast tissue when using synchrotron-based DEI compared to conventional synchrotron-based methods. Image contrast is in part determined by the capabilities of the detector in the imaging system, and this relation was used to determine the effect of the limits of spatial resolution on near-pixel-sized objects, both by experiment and by computer modeling. Consistent definitions for image contrast were presented and applied to test objects, followed by application to breast tissue specimens containing calcifications. In every case, images obtained using DEI exhibited higher image contrast than the corresponding images obtained using normal radiography. The ratio of these contrast values, called the DEI gain, was consistently larger than unity, indicating that DEI does indeed utilize additional contrast mechanisms, such as refraction and scatter rejection, in addition to absorption and provides support for the development of a clinical prototype.