X-ray micro-tomography system for small-animal imaging with zoom-in imaging capability

Chun, In Kon; Cho, Myung Hye; Lee, Sang Chul; Cho, Min Hyoung; Lee, Soo Yeol

doi:10.1088/0031-9155/49/17/005

Cited by 38 publications

(25 citation statements)

References 23 publications

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“…The centers of rotation in the CT and tomosynthesis may not be necessarily the same. In the tomosynthesis scan, the center of rotation O may be moved toward the x-ray source to get higher magnification ratio of the projection data, hence, higher lateral resolution if the scanning mechanism permits such displacement of the x-ray source and detector pair as introduced in our previous works [11-13]. The magnification ratio of the projection data is determined by SDD / SOD where SDD and SOD are the source-to-detector and source-to-object distances, respectively.…”

Section: Methodsmentioning

confidence: 99%

Inter-plane artifact suppression in tomosynthesis using 3D CT image data

et al. 2011

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BackgroundDespite its superb lateral resolution, flat-panel-detector (FPD) based tomosynthesis suffers from low contrast and inter-plane artifacts caused by incomplete cancellation of the projection components stemming from outside the focal plane. The incomplete cancellation of the projection components, mostly due to the limited scan angle in the conventional tomosynthesis scan geometry, often makes the image contrast too low to differentiate the malignant tissues from the background tissues with confidence.MethodsIn this paper, we propose a new method to suppress the inter-plane artifacts in FPD-based tomosynthesis. If 3D whole volume CT images are available before the tomosynthesis scan, the CT image data can be incorporated into the tomosynthesis image reconstruction to suppress the inter-plane artifacts, hence, improving the image contrast. In the proposed technique, the projection components stemming from outside the region-of-interest (ROI) are subtracted from the measured tomosynthesis projection data to suppress the inter-plane artifacts. The projection components stemming from outside the ROI are calculated from the 3D whole volume CT images which usually have lower lateral resolution than the tomosynthesis images. The tomosynthesis images are reconstructed from the subtracted projection data which account for the x-ray attenuation through the ROI. After verifying the proposed method by simulation, we have performed both CT scan and tomosynthesis scan on a phantom and a sacrificed rat using a FPD-based micro-CT.ResultsWe have measured contrast-to-noise ratio (CNR) from the tomosynthesis images which is an indicator of the residual inter-plane artifacts on the focal-plane image. In both cases of the simulation and experimental imaging studies of the contrast evaluating phantom, CNRs have been significantly improved by the proposed method. In the rat imaging also, we have observed better visual contrast from the tomosynthesis images reconstructed by the proposed method.ConclusionsThe proposed tomosynthesis technique can improve image contrast with aids of 3D whole volume CT images. Even though local tomosynthesis needs extra 3D CT scanning, it may find clinical applications in special situations in which extra 3D CT scan is already available or allowed.

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Section: Methodsmentioning

confidence: 99%

Inter-plane artifact suppression in tomosynthesis using 3D CT image data

et al. 2011

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“…For CT scans, we have used a lab-built micro-CT system [19,20]. The micro CT system consists of a micro-focus x-ray source, a CMOS flat-panel x-ray detector (C7942, Hamamatsu, Japan) and a rotating stage between them.…”

Section: Imaging With a Micro-ctmentioning

confidence: 99%

Sparse-view CT imaging of trabecular bones: Comparison of image reconstruction methods

2011

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Purpose In longitudinal in-vivo imaging studies of trabecular bones using a micro-CT, sparse-view imaging is highly desired to reduce x-ray dose to the animals under study and to reduce the scan time. Sparse-view imaging, i.e., imaging with reduced number of views in the CT scan, may result in severe streak artifacts in the reconstructed images degrading the image quality. We compare image reconstruction methods in terms of final image quality in CT imaging of trabecular bones. Methods We have compared three image reconstruction methods, the conventional filtered backprojection method and two iterative image reconstruction methods, i.e., SIRT and TV-minimization methods, in trabecular bone imaging with sparse-view CT scans. After acquiring projection data from sparse-view scanning of a chicken bone using a micro-CT, we have calculated relative image errors and edge preservation metrics from the images reconstructed by the three different methods. Results We have observed that the TV-minimization method outperforms the other methods in trabecular bone imaging in terms of edge preservation and relative image error. Conclusions TV-minimization-based iterative image reconstruction methods may be greatly used for low-dose CT imaging of trabecular bones with reduced number of views.

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“…In zoomin micro-tomography, the missing projection data outside the FOV is estimated from the full FOV projection data as depicted in Fig.1. Once the missing projection data has been calculated from the full FOV projection data, the calculated projection data outside the FOV is augmented to the limited FOV projection data to reconstruct artifact-free images of the ROI [9,11].…”

Section: Rotating-gantry-based Micro-ctmentioning

confidence: 99%

“…However, we often have to compromise the spatial resolution of the micro-CT since high magnification is not allowed in large FOV imaging. To obtain high resolution images of a region of interest (ROI) in the animal subject, the zoom-in microtomography technique has been introduced [9]. Using the zoom-in micro-tomography technique, in vivo rat femur imaging has been successfully performed for longitudinal observation of trabecular thickness changes in Sprague-Dawley (SD) rats raised with the osteoporosis model.…”

Section: Introductionmentioning

confidence: 99%

High-resolution local imaging using a micro-CT

Lee

Cho

Choi

2008

2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro

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An x-ray micro-tomography system has been developed for in vivo small animal imaging studies. For efficient in vivo scanning, it has a rotating gantry on which the x-ray source and the flat panel x-ray detector are mounted. To reconstruct artifact-free images of a small local region inside the animal subject from the truncated projection data, the projection data from the large field of view (FOV) scan of the whole animal subject are combined with the projection data from the small FOV scan of the region of interest. For the acquisition of x-ray projection data, a 1248 1248 flat-panel x-ray detector with the pixel pitch of 100 m has been used. The developed system has the spatial resolution of 12 lp/mm when the highest magnification ratio of 5:1 is applied to the zoom-in imaging.Index Terms-micro-CT, zoom-in imaging, small animal imaging, rotating gantry, flat panel x-ray detector

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X-ray micro-tomography system for small-animal imaging with zoom-in imaging capability

Cited by 38 publications

References 23 publications

Inter-plane artifact suppression in tomosynthesis using 3D CT image data

Inter-plane artifact suppression in tomosynthesis using 3D CT image data

Sparse-view CT imaging of trabecular bones: Comparison of image reconstruction methods

High-resolution local imaging using a micro-CT

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