Diagram of the apparatus. The computer is programmed to control a shutter in the CCD camera that determines the exposure time. Absorptive material is placed at the bottom of the cell containing the object to absorb ultrasound with the objective of making the acoustic radiation pressure unidirectional.
(a) Phase contrast image of an ex vivo murine liver taken with the small field of view CCD camera. (b) Ultrasound modulated phase contrast image of the same liver. The direction of propagation of the ultrasound is from top to bottom. The images were acquired with an exposure time of 180 s, with the x-ray tube operating 90 kV at a power of 10 W. The source-to-object distance was 0.2 m and the source to image distance was 2.4 m giving a magnification of 13.
Third column: phase contrast image (e) and ultrasonically modulated phase contrast image (f) of a combined tumor and cyst phantom, both in the path of the -radiation. The ultrasound is directed from top to bottom in (b) and (d) and from left to right in (f). The cyst phantom is 5 mm in diameter; the tumor is 3 mm in diameter. The images were acquired with the x-ray tube operating for 30 s at 90 kV and 10 W. The source-to-object and source to image distances was 1.3 m giving a magnification of 2.
(a) X-ray phase contrast image of octafluoropropane bubbles cast in agarose. The tube voltage, power, and the distance parameters for the x-ray images are identical to those given in the caption to Fig. 2, except that the exposure time was 30 s. Inset: CCD camera signal in arbitrary units vs distance for the outlined portion of the image. The data are summed over 80 pixels in the vertical direction. The baseline is taken as the average value of the CCD signal.
(a) X-ray phase contrast image and (b) ultrasonically modulated phase contrast image of a murine skin tumor with a horizontal dimension of approximately . The exposure and distance parameters for the x-ray image are identical to those given in the caption of Fig. 2.
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