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Proceedings Paper

Novel direct conversion imaging detector without selenium or semiconductor conversion layer
Author(s): Denny L. Lee; Andrew Maidment; Ali Kassaee; Lei Dong; Taoran Li; Trevor Vent; Heather Petroccia; Peyton Irmen; Irina Malajovich; Kang Heo; Dooho Kim; Hyunsuk Jang
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Paper Abstract

It has been reported and discussed that electrical current can be produced when an insulating material interacts with ionizing radiation. We have found that high-resolution images can be obtained from insulating materials if this current is guided by an electric field to the pixels of a TFT array. The charge production efficiency of insulators is much smaller than that of photoconductor materials such as selenium, silicon, or other conventional semiconductors. Nevertheless, when the intensity of the ionizing radiation is sufficiently high, a charge sensitive TFT imaging array with only dielectric material can produce high MTF images with contrast resolution proportional to the intensity of the radiation. The function of the dielectric in this new detector may be similar to that of an ionization chamber. Without the semiconductor charge generating material, the dielectric imaging detector does not exhibit charge generation fatigue or charge generation saturation. Prototype detectors have been tested using diagnostic x-ray beams with energy ranging from 25 kVp to 150 kVp, and therapeutic 2.5MV, 6MV, 10MV, and 15MV photon beams (with and without an electron built-up layer), electron beams, broad area proton beams, and proton pencil beams in the energy range of 150 MeV. High spatial resolution images up to the Nyquist frequency have been demonstrated. The physics, structure, and the imaging properties as well as the potential application of this detector will be presented and discussed.

Paper Details

Date Published: 1 March 2019
PDF: 8 pages
Proc. SPIE 10948, Medical Imaging 2019: Physics of Medical Imaging, 1094818 (1 March 2019); doi: 10.1117/12.2512127
Show Author Affiliations
Denny L. Lee, Direct X Ray Digital Imaging Technology LLC (United States)
Univ. of Pennsylvania (United States)
Vieworks Co., Ltd. (Korea, Republic of)
Andrew Maidment, Univ. of Pennsylvania (United States)
Ali Kassaee, Univ. of Pennsylvania (United States)
Lei Dong, Univ. of Pennsylvania (United States)
Taoran Li, Univ. of Pennsylvania (United States)
Trevor Vent, Univ. of Pennsylvania (United States)
Heather Petroccia, Univ. of Pennsylvania (United States)
Peyton Irmen, Univ. of Pennsylvania (United States)
Irina Malajovich, Univ. of Pennsylvania (United States)
Kang Heo, Vieworks Co., Ltd. (Korea, Republic of)
Dooho Kim, Vieworks Co., Ltd. (Korea, Republic of)
Hyunsuk Jang, Vieworks Co., Ltd. (Korea, Republic of)

Published in SPIE Proceedings Vol. 10948:
Medical Imaging 2019: Physics of Medical Imaging
Taly Gilat Schmidt; Guang-Hong Chen; Hilde Bosmans, Editor(s)

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