Active-matrix flat-panel imagers (AMFPIs) have undergone extensive research and development since their initial conception approximately 14 years ago. As a result of these efforts, this x-ray imaging technology is presently being introduced to a wide variety of clinical environments. While diagnostic AMFPIs offer definite benefits over older conventional devices, present indirect and direct AMFPI technologies suffer from inherent limitations that severely restrict their performance under the low-exposure conditions commonly encountered in fluoroscopy. ? ? Specifically, existing AMFPI devices suffer from a relatively large additive noise compared to the gain of the system. Research leading up to this proposal has specifically identified two innovative strategies that have shown particular promise for eliminating these limitations. Consequently, the question to be examined in the proposed research is: """"""""Is it feasible, through the development and incorporation of specific fundamental innovations to imager design, to develop large area, advanced technology, fluoroscopic AMFPIs with performance levels matching or exceeding those of x-ray image intensifiers under all conditions, and capable of high radiographic imaging performance?"""""""" To address that question, this grant application proposes an ambitious, focused program of research to quantitatively investigate the two strategies: one involving in-pixel amplification circuits coupled to a continuous photodiode structure for indirect detection of the incident radiation; and the other involving a high-gain photoconductive converter material (mercuric iodide) for direct detection. Through the iterative development of a series of small and large area prototype imagers incorporating these innovations, the effectiveness of the strategies will be quantitatively examined over the relevant imaging conditions. The successful conclusion of this research will facilitate the creation of one of more highly advanced x-ray imaging technologies allowing the realization of higher performance AMFPI systems. Such systems would offer spatial resolution and detective quantum efficiency (DQE) performance superior to existing XRIIs and DQE performance superior to existing film-screen and computed radiography systems under all clinical conditions. The development of technologies exhibiting such performance levels could have a profound impact on digital radiology.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB000558-12
Application #
6775698
Study Section
Diagnostic Imaging Study Section (DMG)
Program Officer
Wolbarst, Anthony B
Project Start
2002-08-01
Project End
2007-07-31
Budget Start
2004-08-01
Budget End
2007-07-31
Support Year
12
Fiscal Year
2004
Total Cost
$1,100,280
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Koniczek, Martin; Antonuk, Larry E; El-Mohri, Youcef et al. (2017) Theoretical investigation of the noise performance of active pixel imaging arrays based on polycrystalline silicon thin film transistors. Med Phys 44:3491-3503
Liang, Albert K; Koniczek, Martin; Antonuk, Larry E et al. (2016) Performance of in-pixel circuits for photon counting arrays (PCAs) based on polycrystalline silicon TFTs. Phys Med Biol 61:1968-85
El-Mohri, Youcef; Antonuk, Larry E; Koniczek, Martin et al. (2009) Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors. Med Phys 36:3340-55
Antonuk, Larry E; Zhao, Qihua; El-Mohri, Youcef et al. (2009) An investigation of signal performance enhancements achieved through innovative pixel design across several generations of indirect detection, active matrix, flat-panel arrays. Med Phys 36:3322-39
Du, Hong; Antonuk, Larry E; El-Mohri, Youcef et al. (2008) Investigation of the signal behavior at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers incorporating polycrystalline HgI2. Phys Med Biol 53:1325-51
Antonuk, L E; Koniczek, M; McDonald, J et al. (2008) Noise Characterization of Polycrystalline Silicon Thin Film Transistors for X-ray Imagers Based on Active Pixel Architectures. Mater Res Soc Symp Proc 1066:457-462
Su, Zhong; Antonuk, Larry E; El-Mohri, Youcef et al. (2005) Systematic investigation of the signal properties of polycrystalline HgI2 detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions. Phys Med Biol 50:2907-28