Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program

We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-µm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48×48 µm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 µm. At a shifting distance ranging from 48 to 144 µm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 µm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 µm diameter.