System considerations in CCD‐based x‐ray imaging for digital chest radiography and digital mammography

Hejazi, Shahram; Trauernicht, David P.

doi:10.1118/1.598072

Cited by 51 publications

(42 citation statements)

References 27 publications

(22 reference statements)

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“…The optical coupling efficiency is defined by the fiber optic numerical aperture, fiber optic core transmittance, Fresnel reflection, and fill factor (Hejazi andTrauernicht 1997, Jain et al 2011) with details described elsewhere (Zhao et al 2015b). The impact of optical coupling efficiency on performance metrics is independent of x-ray tube angulation.…”

Section: Three-dimensional Cascaded System Analysismentioning

confidence: 99%

Three-dimensional cascaded system analysis of a 50µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

et al. 2017

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Abstract. High-resolution, low-noise x-ray detectors based on the complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been developed and proposed for digital breast tomosynthesis (DBT). In this study, we evaluated the three-dimensional (3D) imaging performance of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). The two-dimensional (2D) angle-dependent modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) were experimentally characterized and modeled using the cascaded system analysis at oblique incident angles up to 30°. The cascaded system model was extended to the 3D spatial frequency space in combination with the filtered back-projection (FBP) reconstruction method to calculate the 3D and in-plane MTF, NNPS and DQE parameters. The results demonstrate that the beam obliquity blurs the 2D MTF and DQE in the high spatial frequency range. However, this effect can be eliminated after FBP image reconstruction. In addition, impacts of the image acquisition geometry and detector parameters were evaluated using the 3D cascaded system analysis for DBT. The result shows that a wider projection angle range (e.g. ±30°) improves the low spatial frequency (below 5 mm -1 ) performance of the CMOS APS detector. In addition, to maintain a high spatial resolution for DBT, a focal spot size of smaller than 0.3 mm should be used.Theoretical analysis suggests that a pixelated scintillator in combination with the 50 μm pixel pitch CMOS APS detector could further improve the 3D image resolution. Finally, the 3D imaging performance of the CMOS APS and an indirect amorphous silicon (a-Si:H) thin-film A c c e p t e d M a n u s c r i p t transistor (TFT) passive pixel sensor (PPS) detector was simulated and compared.Keywords: CMOS active pixel sensor, x-ray detector, digital breast tomosynthesis, three-dimensional, cascaded system analysis, pixelated scintillator, detective quantum efficiency IntroductionHigh performance x-ray detectors based on the complementary metal-oxide-semiconductor ( Up to now, most studies focus on CMOS APS detector evaluation by measuring the one-dimensional (1D) or 2D modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE) using a single x-ray projection at the zero-degree incident angle (perpendicular to the detector). Nevertheless, since DBT is a quasi-three-dimensional (3D) imaging technology, the DBT image quality is influenced by the system geometry and reconstruction algorithms (Sechopoulos 2013a(Sechopoulos , 2013b. Therefore, the 3D imaging performance should be evaluated for the CMOS APS detectors. However, it is difficult to empirically investigate the 3D image quality. To deal with this issue, the 3D cascaded system analysis for CMOS APS detectors was developed and is presented in this study.Cascaded system analysis can accurately model the signal and noise propagation and blurring within ...

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Section: Three-dimensional Cascaded System Analysismentioning

confidence: 99%

Three-dimensional cascaded system analysis of a 50µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

et al. 2017

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“…The potential for utilizing charge-coupled device ͑CCD͒-based detectors for small-field digital mammography has been previously investigated. [19][20][21] It was found that the CCD detector could provide a spatial resolution closer to that of screen film mammography. Therefore, the CCD detector may help improve the detection and visualization of small MCs in CBCT.…”

Section: Introductionmentioning

confidence: 99%

Dual resolution cone beam breast CT: A feasibility study

et al. 2009

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Purpose: In this study, the authors investigated the feasibility of a dual resolution volume-ofinterest ͑VOI͒ cone beam breast CT technique and compared two implementation approaches in terms of dose saving and scatter reduction. Methods: With this technique, a lead VOI mask with an opening is inserted between the x-ray source and the breast to deliver x-ray exposure to the VOI while blocking x rays outside the VOI. A CCD detector is used to collect the high resolution projection data of the VOI. Low resolution cone beam CT ͑CBCT͒ images of the entire breast, acquired with a flat panel ͑FP͒ detector, were used to calculate the projection data outside the VOI with the ray-tracing reprojection method. The Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the dual resolution 3D images. Breast phantoms with 180 m and smaller microcalcifications ͑MCs͒ were imaged with both FP and FP-CCD dual resolution CBCT systems, respectively. Two approaches of implementing the dual resolution technique, breast-centered approach and VOI-centered approach, were investigated and evaluated for dose saving and scatter reduction with Monte Carlo simulation using a GEANT4 package. Results:The results showed that the breast-centered approach saved more breast absorbed dose than did VOI-centered approach with similar scatter reduction. The MCs in fatty breast phantom, which were invisible with FP CBCT scan, became visible with the FP-CCD dual resolution CBCT scan. Conclusions:These results indicate potential improvement of the image quality inside the VOI with reduced breast dose both inside and outside the VOI.

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“…A novel liquid crystal (LC)-based radiation detector, which combines a LC light valve with a phosphor screen, has been reported earlier [3][4][5]. The light valve has a simple structure consisting of a photoconductor layer and a LC layer.…”

Section: Introductionmentioning

confidence: 99%

Radiation detector based on liquid crystal light valve for large-area imaging applications

Kang

Park²,

Cha

et al. 2007

Nuclear Instruments and Methods in Physics Research Section A:

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System considerations in CCD‐based x‐ray imaging for digital chest radiography and digital mammography

Cited by 51 publications

References 27 publications

Three-dimensional cascaded system analysis of a 50µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

Three-dimensional cascaded system analysis of a 50µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

Dual resolution cone beam breast CT: A feasibility study

Radiation detector based on liquid crystal light valve for large-area imaging applications

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