Design and implementation of a compact low-dose diffraction enhanced medical imaging system.

Rationale and Objectives Diffraction-enhanced imaging (DEI) is a new x-ray imaging modality that differs from conventional radiography in its use of three physical mechanisms to generate contrast. DEI is able to generate contrast from x-ray absorption, refraction, and ultra-small-angle scatter rejection (extinction) to produce high-contrast images with a much lower radiation dose compared to conventional radiography. Materials and Methods A prototype DEI system was constructed using a 1-kW tungsten x-ray tube and a single silicon monochromator and analyzer crystal. The monochromator crystal was aligned to reflect the combined Kα1 (59.32 keV) and Kα2 (57.98 keV) characteristic emission lines of tungsten using a tube voltage of 160 kV. System performance and demonstration of contrast were evaluated using a nylon monofilament refraction phantom, full-thickness breast specimens, a human thumb, and a live mouse. Results Images acquired using this system successfully demonstrated all three DEI contrast mechanisms. Flux measurements acquired using this 1-kW prototype system demonstrated that this design can be scaled to use a more powerful 60-kW x-ray tube to generate similar images with an image time of approximately 30 seconds. This single–crystal pair design can be further modified to allow for an array of crystals to reduce clinical image times to Conclusions This paper describes the design, construction, and performance of a new DEI system using a commercially available tungsten anode x-ray tube and includes the first high-quality low-dose diffraction-enhanced images of full-thickness human tissue specimens.