<title>Image quality in digital phase contrast imaging using a tungsten anode x-ray tube with small focal-spot size</title>

Abstract

Phase contrast x-ray imaging has been studied intensively using x-rays from synchrotron radiation and micro-focus x- ray rubes. However, these studies have revealed the difficulty of this technique's application to practical medical imaging. We have created a phase contrast imaging technique using practical x-ray tubes with small focal spot sizes. In a previous study, we identified the radiographic conditions for phase contrast magnification mammography with screen-film systems, where the edge effect due to phase contrast outweighs the geometrical unsharpness introduced by the 0.1mm-focal spot of a molybdenum-anode x-ray tube. In the present study, phase contrast images of a hand and a chest phantoms were obtained using computed radiography and a geometrical magnification of two using a tungsten-anode x- ray tube with a 0.1mm-focal spot. The digital images were printed so that objects were reproduced at their original size. Compared to conventional digital contact images obtained at the same x-ray dose, the life-sized digital phase contrast x-ray images displayed improved sharpness and resolution, and reduced grain. We describe the empirical results of digital phase contrast imaging, and discuss these performance improvements through simulation including x-ray scatter.