Enhanced Magnification Angiography Using 20-µm-Focus Tungsten Tube

Abstract

A microfocus X-ray tube is useful for performing magnification radiography, and its X-ray generator (L9631, Hamamatsu Photonics) consists of a personal computer for controlling the tube voltage and current, and a main unit with a high-voltage circuit and a fixed-anode X-ray tube. The maximum tube voltage, current, and electric power were 110 kV, 800 µA, and 50 W, respectively. The focal-spot size was proportional to the electric power of the tube, and the size was approximately 20 µm with a power of 20 W. Using a 3-mm-thick aluminum filter, the X-ray intensity was 7.75 µGy/s at 1.0 m from the source with a tube voltage of 60 kV and a current of 100 µA. Because the peak photon energy was approximately 38 keV using the filter with a tube voltage of 60 kV, the bremsstrahlung X-rays were absorbed effectively by iodine-based contrast media at an iodine K-edge of 33.2 keV. Enhanced angiography was performed by fourfold magnification imaging with a computed radiography system using iodine-based microspheres 15 µm in diameter. In the angiography of nonliving animals, we observed fine blood vessels of approximately 100 µm with high contrast.