Xiao Yongshun

Material discrimination study of dual-energy imaging using photon counting detector

Photon counting detectors with electronic spectrum splitting, such as cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detectors have been widely used in x-ray imaging. We research the feasibility of material discrimination using dual energy imaging with CZT photon counting detector. The initial x-ray spectrum is from the X-ray tube with a voltage of 160 kVp, and the x-ray spectrum is calculated by Monte-Carlo method. A linear CZT detector with 32 pixels was used and an experiment with different materials was conducted. For each scanned object, three images under different photon energies are obtained simultaneously. We chose two of them for dual-energy imaging. A method of material discrimination is presented, using transmission data in different energy regions, we can calculate the atomic number of them. The results show its feasibility and possible of material discrimination using this kind of energy resolving detector. Compared with the typical dual-energy imaging system, this method can achieve higher precision. Using dual-energy imaging method, photon counting detectors can be used in explosive detection and luggage screening, which is proved to be effective.

Expected Value Correction-Based Computed Tomography for Airplane Engine

Airplane engine is one of the most important parts in the plane, and the rotating parts are the key parts of the engine. In order to monitor the real-time statue of the rotating parts of the engine, a novel in situ airplane engine computed tomography system which takes advantage of the objects’ self-rotation has been proposed. Some featured artifacts exist due to the existence of static parts of the engine, causing difficulties in reconstructing the object. In this paper, these artifacts are introduced and discussed, a novel method based on expected value correction is put forward to eliminate them, and numerical experiments are taken to verify the effects of the method.