Demonstration of iodine K-edge imaging by use of an energy-discrimination X-ray computed tomography system with a cadmium telluride detector

Abstract

An energy-discrimination K-edge X-ray computed tomography (CT) system is useful for increasing the contrast resolution of a target region by utilizing contrast media. The CT system has a cadmium telluride (CdTe) detector, and a projection curve is obtained by linear scanning with use of the CdTe detector in conjunction with an X-stage. An object is rotated by a rotation step angle with use of a turntable between the linear scans. Thus, CT is carried out by repetition of the linear scanning and the rotation of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced with use of charge-sensitive and shaping amplifiers. Both the photon energy and the energy width are selected by use of a multi-channel analyzer, and the number of photons is counted by a counter card. For performing energy discrimination, a low-dose-rate X-ray generator for photon counting was developed; the maximum tube voltage and the minimum tube current were 110 kV and 1.0 microA, respectively. In energy-discrimination CT, the tube voltage and the current were 60 kV and 20.0 microA, respectively, and the X-ray intensity was 0.735 microGy/s at 1.0 m from the source and with a tube voltage of 60 kV. Demonstration of enhanced iodine K-edge X-ray CT was carried out by selection of photons with energies just beyond the iodine K-edge energy of 33.2 keV.

Dual-, Multi-, and Mono-Energy CT & Iodine: Basic Concepts and Clinical Applications

“…The relation between iodine (Z = 53) and its K-edge has been investigated [17,18] and is set at 33 keV. The Iodine K-edge characteristics may be exploited in dual-energy and also low-kVp mono-energetic CT protocols [19][20][21][22][23][24][25].…”

Sparsity-regularized image reconstruction of decomposed K-edge data in spectral CT

“…These advancements are likely to benefit numerous preclinical and clinical imaging applications. For example, K-edge CT has been investigated as a modality to image contrast agents such as iodine (Abudurexiti, Kameda, Sato, Abderyim, Enomoto, Watanabe, Hitomi, Tanaka, Mori, Kawai, Takahashi, Sato, Ogawa & Onagawa 2010, He, Wei, Cong & Wang 2012), gadolinium (Feuerlein, Roessl, Proksa, Martens, Klass, Jeltsch, Rasche, Brambs, Hoffmann & Schlomka 2008), bismuth (Pan, Roessl, Schlomka, Shelton, Senpan, Scott, Allen, Zhang, Hu, Gaffney, Choi, Rasche, Wickline, Proksa & Lanza 2010), and gold (Cormode, Roessl, Thran, Skajaa, Gordon, Schlomka, Fuster, Fisher, Mulder, Proksa & Fayad 2010). Ytterbium was recently discussed as a contrast agent for conventional CT (Liu, Ai, Liu, Yuan, He & Lu 2012) in general and K-edge imaging (Pan, Schirra, Senpan, Schmieder, Stacy, Roessl, Thran, Wickline, Proska & Lanza 2012).…”

Dual-energy x-ray computed tomography system using an LSO-MPPC detector

“…Using this CdTe detector, we have developed photon-counting energy-dispersive computed tomography (ED-CT) system [1][2][3][4] to perform K-edge imaging using iodine (I) and gadolinium (Gd) contrast media. In the ED-CT system, an oscillation type linear CdTe scanner is used to obtain projection data of an object.…”