TITLE:
Enhanced K-Edge Radiography Using a High-Spatial-Resolution Cadmium Telluride Array Detector
AUTHORS:
Manabu Watanabe, Eiichi Sato, Yasuyuki Oda, Hodaka Moriyama, Osahiko Hagiwara, Hiroshi Matsukiyo, Toshiyuki Enomoto, Shinya Kusachi
KEYWORDS:
X-Ray Photon Counting, CdTe-Array Detector, Dual-Energy, Energy-Dispersive Radiography, I-K-Edge Radiography, Gd-K-Edge Radiography
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.3,
July
18,
2018
ABSTRACT: To confirm the imaging effect of a dual-energy (DE)
cadmium telluride (CdTe) array detector (XCounter, Actaeon) and to perform
fundamental studies on DE computed tomography, we performed enhanced K-edge radiography
using iodine (I) and gadolinium (Gd) media. DE radiography was performed using
an X-ray generator with a 0.1-mm-diam-focus tube and a 0.5-mm-thick beryllium
window, a 1.0-mm-thick aluminum filter for absorbing extremely low-energy
photons, and the CdTe array detector with pixel dimensions of 0.1 × 0.1 mm2.
Each pixel has a charge-sensitive amplifier and a dual-energy counter, and the
event pulses from the amplifier are sent to the counter to determine two
threshold energies. The tube current was a maximum value of 0.50 mA, and the
tube voltages for I- and Gd-K-edge radiograms were 60 and 80 kV, respectively.
In the I-K-edge radiography of a dog-heart phantom at an energy range of 33 - 60
keV, the muscle density increased, and fine coronary arteries were visible.
Utilizing Gd-K-edge radiography of a rabbit head phantom at an energy range of
50 - 80 keV, the muscle density increased, and fine blood vessels in the nose
were observed at high contrasts. Using the DE array detector, we confirmed the
image-contrast variations with changes in the threshold energy.