Document Detail

Investigation of the signal behavior at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers incorporating polycrystalline HgI2.
MedLine Citation:
PMID:  18296765     Owner:  NLM     Status:  MEDLINE    
Active matrix, flat-panel x-ray imagers based on a-Si:H thin-film transistors offer many advantages and are widely utilized in medical imaging applications. Unfortunately, the detective quantum efficiency (DQE) of conventional flat-panel imagers incorporating scintillators or a-Se photoconductors is significantly limited by their relatively modest signal-to-noise ratio, particularly in applications involving low x-ray exposures or high spatial resolution. For this reason, polycrystalline HgI2 is of considerable interest by virtue of its low effective work function, high atomic number and the possibility of large-area deposition. In this study, a detailed investigation of the properties of prototype, flat-panel arrays coated with two forms of this high-gain photoconductor are reported. Encouragingly, high x-ray sensitivity, low dark current and spatial resolution close to the theoretical limits were observed from a number of prototypes. In addition, input-quantum-limited DQE performance was measured from one of the prototypes at relatively low exposures. However, high levels of charge trapping, lag and polarization, as well as pixel-to-pixel variations in x-ray sensitivity are of concern. While the results of the current study are promising, further development will be required to realize prototypes exhibiting the characteristics necessary to allow practical implementation of this approach.
Hong Du; Larry E Antonuk; Youcef El-Mohri; Qihua Zhao; Zhong Su; Jin Yamamoto; Yi Wang
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-02-14
Journal Detail:
Title:  Physics in medicine and biology     Volume:  53     ISSN:  0031-9155     ISO Abbreviation:  Phys Med Biol     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-02-25     Completed Date:  2008-06-26     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1325-51     Citation Subset:  IM    
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MeSH Terms
Diagnostic Imaging / instrumentation*
Iodides / chemistry*,  diagnostic use*
Linear Models
Mercury / chemistry*,  diagnostic use*
Monte Carlo Method
Sensitivity and Specificity
Grant Support
Reg. No./Substance:
0/Iodides; FXS1BY2PGL/Mercury

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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