Performance evaluation of CsI screens for X-ray imaging
CsI film has been one of the most extensively used scintillators for indirect X-ray imaging because of its needle-like micro-structure. The purpose of this paper is to investigate the imaging performance of CsI screen as a function of thickness and radiation quality. Four multilayer scintillation sc...
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| Published in | Chinese physics C Vol. 38; no. 11; pp. 39 - 44 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
01.11.2014
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1137 0254-3052 |
| DOI | 10.1088/1674-1137/38/11/116003 |
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| Summary: | CsI film has been one of the most extensively used scintillators for indirect X-ray imaging because of its needle-like micro-structure. The purpose of this paper is to investigate the imaging performance of CsI screen as a function of thickness and radiation quality. Four multilayer scintillation screens with microcolumnar CsI：T1 film （thicknesses of 50 μm, 100 μm, 200μm and 300 μm） included were prepared and coupled to an optical imaging sensor. The modulation transfer function （MTF）, normalized noise power spectrum （NNPS） and detective quantum efficiency （DQE） of these screens were evaluated based on the standard IEC 62220-1, and the results indicated that, in the medium spatial frequency range （1-6 lp/mm）, the MTF of CsI screens with the same thickness was lower when the incident X-ray photon energy was higher, possibly owing to scattering and K-fluorescence re-absorption effects. The NNPS in the higher spatial frequency range （above 8 lp/mm） is dominated by stochastic noise while the entrance surface air Kerma （ESAK） decreases. For 100 μm, 200 μm and 300 μm thick CsI screens, the DQE under RQA7 and RQA9 is lower than that under RQA3 and RQA5 due to low absorption efficiency. |
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| Bibliography: | CsI film has been one of the most extensively used scintillators for indirect X-ray imaging because of its needle-like micro-structure. The purpose of this paper is to investigate the imaging performance of CsI screen as a function of thickness and radiation quality. Four multilayer scintillation screens with microcolumnar CsI：T1 film （thicknesses of 50 μm, 100 μm, 200μm and 300 μm） included were prepared and coupled to an optical imaging sensor. The modulation transfer function （MTF）, normalized noise power spectrum （NNPS） and detective quantum efficiency （DQE） of these screens were evaluated based on the standard IEC 62220-1, and the results indicated that, in the medium spatial frequency range （1-6 lp/mm）, the MTF of CsI screens with the same thickness was lower when the incident X-ray photon energy was higher, possibly owing to scattering and K-fluorescence re-absorption effects. The NNPS in the higher spatial frequency range （above 8 lp/mm） is dominated by stochastic noise while the entrance surface air Kerma （ESAK） decreases. For 100 μm, 200 μm and 300 μm thick CsI screens, the DQE under RQA7 and RQA9 is lower than that under RQA3 and RQA5 due to low absorption efficiency. 11-5641/O4 microcolumnar CsI：T1 film, scintillation screen, DQE ZHAO Bo-Zhen, QIN Xiu-Bo, FENG Zhao-Dong, WEI Cun-Feng, CHEN Yan, WANG Bao-Yi, WEI Long（ 1 Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China; 2 Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049, China ; 3 University of Chinese Academy of Sciences, Beijing 100049, China ; 4 Chongqing Zhence Science and Technology Corporation Limited, Chongqing 400044, China） ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 1674-1137 0254-3052 |
| DOI: | 10.1088/1674-1137/38/11/116003 |