Prof. Dean Chapman, Biological, Chemical, and Physical Sciences

Screening mammography has proven to be an effective procedure for the detection of early breast cancer. However, a significant fraction of cancer escapes detection due to dense glandular tissue that obscures the underlying pathology. Diffraction Enhanced x-ray Imaging (DEI) is a new imaging modality that has the potential to dramatically change mammography and radiography in general. This is a method of imaging that utilizes single energy x-rays from a synchrotron source and has produced images of test objects and tissue whose contrast and information content far exceeds conventional techniques. Work with human breast cancer specimens suggests that DEI images include information regarding specific physical characteristics of the lesion including border detail and associated features that are not detected by conventional imaging.

An example of an image obtained with the DEI technique is shown below. The object imaged is the American College of Radiology test object. This object is routinely imaged and graded as part of the FDA validation of a conventional mammography system. The test object has features that simulate tumors in breast tissue, namely, masses, small calcifications, and fibrils. The location and identification of these features is shown in a. An image taken of this object with a conventional mammography system is shown in b. Approximately one-half of the features are visible. An image acquired using the DEI technique with the same dose exposure is shown in c. Note that all of the features are now visible, along with some manufacturing defects as well as the scotch tape used to hold the test object to a Lucite holder. The increased visibility of these features arises from the ability of the DEI technique to obtain x-ray refraction and scatter-rejection contrast.

This technique was developed using a synchrotron x-ray source. The high intensity, collimation, and tunability available using synchrotron sources make them ideal environments in which new imaging technologies, such as DEI, can be developed. An obvious drawback is then translating this technology to more conventional x-ray sources in a laboratory or clinical environment. The DEI technique delivers x-ray exposures to tissue and phantoms which is similar to that delivered by conventional x-ray mammography units. The difficulty arises in generating the highly collimated - monoenergetic imaging beam. Work is underway to develop x-ray optics and techniques which will allow the use of more conventional sources of x-rays.

The long-term goal of this program is to develop a clinical based DEI system for mammography. We are in the process of identifying the optimal DEI parameters for improved visualization of lesions of the breast and to use these parameters to develop a conceptual design of a clinical DEI system.

This work involves researchers from the Illinois Institute of Technology, University of North Carolina, North Carolina State University, and Brookhaven National Laboratory. The work has been carried out at the National Synchrotron Light Source at Brookhaven and the Advanced Photon Source at Argonne National Laboratory. The work is supported by the US Army Breast Cancer Program, Department of Energy, and the State of Illinois Higher Education Cooperative Agreement.