Investigation of quad-energy high-rate photon counting for X-ray computed tomography using a cadmium telluride detector

Hiroshi Matsukiyo; Eiichi Sato; Yasuyuki Oda; Satoshi Yamaguchi; Yuichi Sato; Osahiko Hagiwara; Toshiyuki Enomoto; Manabu Watanabe; Shinya Kusachi

doi:10.1016/j.apradiso.2017.09.011

Investigation of quad-energy high-rate photon counting for X-ray computed tomography using a cadmium telluride detector

Appl Radiat Isot. 2017 Dec:130:54-59. doi: 10.1016/j.apradiso.2017.09.011. Epub 2017 Sep 10.

Authors

Hiroshi Matsukiyo¹, Eiichi Sato², Yasuyuki Oda³, Satoshi Yamaguchi⁴, Yuichi Sato⁵, Osahiko Hagiwara¹, Toshiyuki Enomoto¹, Manabu Watanabe¹, Shinya Kusachi¹

Affiliations

¹ Department of Surgery, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguro, Tokyo 153-8515, Japan.
² Department of Physics, Iwate Medical University, 2-1-1Nishitokuta, Yahaba, Iwate 028-3694, Japan. Electronic address: dresato@iwate-med.ac.jp.
³ Department of Physics, Iwate Medical University, 2-1-1Nishitokuta, Yahaba, Iwate 028-3694, Japan.
⁴ Department of Radiology, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023, Japan.
⁵ Central Radiation Department, Iwate Medical University Hospital, 19-1 Uchimaru, Morioka, Iwate 020-0023, Japan.

PMID: 28942329
DOI: 10.1016/j.apradiso.2017.09.011

Abstract

To obtain four kinds of tomograms at four different X-ray energy ranges simultaneously, we have constructed a quad-energy (QE) X-ray photon counter with a cadmium telluride (CdTe) detector and four sets of comparators and microcomputers (MCs). X-ray photons are detected using the CdTe detector, and the event pulses produced using amplifiers are sent to four comparators simultaneously to regulate four threshold energies of 20, 33, 50 and 65keV. Using this counter, the energy ranges are 20-33, 33-50, 50-65 and 65-100keV; the maximum energy corresponds to the tube voltage. We performed QE computed tomography (QE-CT) at a tube voltage of 100kV. Using a 0.5-mm-diam lead pinhole, four tomograms were obtained simultaneously at four energy ranges. K-edge CT using iodine and gadolinium media was carried out utilizing two energy ranges of 33-50 and 50-65keV, respectively. At a tube voltage of 100kV and a current of 60 μA, the count rate was 15.2 kilocounts per second (kcps), and the minimum count rates after penetrating objects in QE-CT were regulated to approximately 2 kcps by the tube current.

Keywords: CdTe detector; Energy-selection electronics; Penetrating-count regulation; Quad-energy CT; X-ray photon counting.