Despite improved DQEs of recently commercialized flat- panel detectors, two problems intrinsic to projection x-ray imaging with area detectors remain and degrade the low contrast performance: (1) low photon fluences at the detector in heavily attenuated regions, and (2) lack of efficient methods to reject scattered radiation. The expectation that these problems would be resolved or become less important through improved DQEs is somewhat illusive. One major benefit with digital detectors is the prospect of digital image processing and analysis. However, this benefit is hard to realize due to the low signal-to-noise ratios in heavily attenuated regions where image processing often finds most use. To resolve the above mentioned problems, we propose to construct and investigate a scanning equalization digital radiography (SEDR) system using an aSi:H and CsI:Tl based flat-panel detector. Slit scanning imaging with regionally adjustable beam width will be used to achieve effective scatter rejection and exposure equalization. A pre-exposure image will be used to compute the necessary beam width modulations for the scan, eliminating the need for using a radiation detector array. A novel image readout scheme will be used to provide electronic aft-collimation to achieve scatter rejection without attenuating primary x-rays and without using a heavy, bulky aft-collimator. A re-scaling technique will be implemented to convert equalized digital chest images into images with the appearance of conventional chest images but with enhanced contrast and equalized SNRs. To evaluate the proposed technique, we will measure and characterize the performance of the proposed SEDR system. We will study and demonstrate image quality improvements with phantom images. We will also conduct a comprehensive 350 patient ROC study to compare the scanning equalization DR chest images with regular DR images with and without digital image enhancement processing. The proposed system is expected to improve the low contrast performance of digital chest images by: (1) more effectively rejecting scattered radiation without attenuating primary x-rays, (2) increasing x-ray fluences in heavily attenuated regions to improve SNRs and reduce impact of scattered radiation there, (3) providing high quality image data with improved contrast-to-noise ratios and equalized SNRs for further digital image processing and analysis without suffering excessive noise limitations in heavily attenuated regions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB000117-02
Application #
6623554
Study Section
Special Emphasis Panel (ZRG1-SRB (33))
Program Officer
Haller, John W
Project Start
2002-06-01
Project End
2006-03-31
Budget Start
2003-04-01
Budget End
2004-03-31
Support Year
2
Fiscal Year
2003
Total Cost
$476,186
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Radiation-Diagnostic/Oncology
Type
Other Domestic Higher Education
DUNS #
800772139
City
Houston
State
TX
Country
United States
Zip Code
77030
Lai, Chao-Jen; Zhong, Yuncheng; Yi, Ying et al. (2015) Radiation doses in volume-of-interest breast computed tomography--A Monte Carlo simulation study. Med Phys 42:3063-75
Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng et al. (2015) A dual-view digital tomosynthesis imaging technique for improved chest imaging. Med Phys 42:5238-51
Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen et al. (2013) Cone beam breast CT with a high pitch (75 ?m), thick (500 ?m) scintillator CMOS flat panel detector: visibility of simulated microcalcifications. Med Phys 40:101915
Liu, Xinming; Lai, Chao-Jen; Whitman, Gary J et al. (2011) Effects of exposure equalization on image signal-to-noise ratios in digital mammography: a simulation study with an anthropomorphic breast phantom. Med Phys 38:6489-501
Shen, Youtao; Yi, Ying; Zhong, Yuncheng et al. (2011) High resolution dual detector volume-of-interest cone beam breast CT--Demonstration with a bench top system. Med Phys 38:6429-42
Liu, Xinming; Shaw, Chris C; Lai, Chao-Jen et al. (2011) Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging. Med Phys 38:23-33
Liu, Xinming; Lai, Chao-Jen; Chen, Lingyun et al. (2009) Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience. Phys Med Biol 54:6959-78
Lai, Chao-Jen; Chen, Lingyun; Zhang, Huojun et al. (2009) Reduction in x-ray scatter and radiation dose for volume-of-interest (VOI) cone-beam breast CT--a phantom study. Phys Med Biol 54:6691-709
Chen, Lingyun; Shen, Youtao; Lai, Chao-Jen et al. (2009) Dual resolution cone beam breast CT: a feasibility study. Med Phys 36:4007-14
Lai, Chao-Jen; Shaw, Chris C; Geiser, William et al. (2008) Comparison of slot scanning digital mammography system with full-field digital mammography system. Med Phys 35:2339-46

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