Ctにおけるx線エネルギー —基礎から臨床応用まで—

Abstract

In computed tomography (CT) systems, the optimal X-ray energy in imaging depends on the material composition and the subject size. Among the parameters related to the X-ray energy, we can arbitrarily change only the tube voltage. For years, the tube voltage has often been set at 120 kVp. However, since about 2000, there has been an increasing interest in reducing radiation dose, and it has led to the publication of various reports on low tube voltage. Furthermore, with the spread of dual-energy CT, virtual monochromatic X-ray images are widely used since the contrast can be adjusted by selecting the optional energy. Therefore, because of the renewed interest in X-ray energy in CT imaging, the issue of energy and imaging needs to be summarized. In this article, we describe the basics of physical characteristics of X-ray attenuation with materials and its influence on the process of CT imaging. Moreover, the relationship between X-ray energy and CT imaging is discussed for clinical applications.

Study of Low kV, Low Contrast Agent Dosage, and Low Contrast Agent Flow Rate Scan in Computed Tomography Angiography of Children's Liver

“…Tube voltage is positively correlated with X-ray energy. By reducing the tube voltage, X-ray photon energy decreases, leading to an increase in the X-ray attenuation coefficient of high-density substances and enhanced image contrast (28)(29)(30). In this experiment, 80 kV was used, bringing the X-ray energy closer to the K-layer electron binding energy (33.2 keV) of the iodine atom in the contrast agent.…”