Development and validation of a simulation tool for K-edge Subtraction imaging with polychromatic spectra and X-ray photon counting detectors

Trapani, Vittorio Di; Oliva, Piernicola; Arfelli, Fulvia; Brombal, Luca; Menk, R. H.; Delogu, Pasquale

doi:10.1016/j.nima.2022.167675

Cited by 3 publications

(1 citation statement)

References 29 publications

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“…From the estimated x-ray spectrum and detector response, the energy response of the system was calculated for the threshold values, 26 and 33 keV, used in the acquisitions, as shown in figure 1 (b). The low threshold (26 keV) was chosen to exclude the cadmium fluorescence, while the high threshold (33 keV) was set to maximize the iodine’s K-edge contrast (Di Trapani et al 2023 ). Additionally, the x-ray spectrum was shaped to be symmetric and centered on the second threshold, thus ensuring nearly equal statistics in the two energy bins.…”

Section: Methodsmentioning

confidence: 99%

Edge-illumination spectral phase-contrast tomography

Brombal,

Arfelli,

Brun

et al. 2024

Phys. Med. Biol.

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Following the rapid, but independent, diffusion of X-ray spectral and phase-contrast systems, this work demonstrates the first combination of spectral and phase-contrast computed tomography (CT) obtained by using the edge-illumination technique and a CdTe small-pixel (62 μm) spectral detector. A theoretical model is introduced, starting from a standard attenuation-based spectral decomposition and leading to spectral phase-contrast material decomposition. Each step of the model is followed by quantification of accuracy and sensitivity on experimental data of a test phantom containing different solutions with known concentrations. An example of a micro CT application (20 μm voxel size) on an iodine-perfused ex-vivo murine model is reported. The work demonstrates that spectral-phase contrast combines the advantages of spectral imaging, i.e. high-Z material discrimination capability, and phase-contrast imaging, i.e. soft tissue sensitivity, yielding simultaneously mass density maps of water, calcium, and iodine with an accuracy of 1.1%, 3.5%, and 1.9% (root mean square errors), respectively. Results also show a 9-fold increase in the signal-to-noise ratio of the water channel when compared to standard spectral decomposition. The application to the murine model revealed the potential of the technique in the simultaneous 3D visualization of soft tissue, bone, and vasculature. While being implemented by using a broad spectrum (pink beam) at a synchrotron radiation facility (Elettra, Trieste, Italy), the proposed experimental setup can be readily translated to compact laboratory systems including conventional X-ray tubes.

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Section: Methodsmentioning

confidence: 99%

Edge-illumination spectral phase-contrast tomography

Brombal,

Arfelli,

Brun

et al. 2024

Phys. Med. Biol.

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Block-matching and 3D filtering algorithm in X-ray image with photon counting detector using the improved K-edge subtraction method

Kim,

Lee

2024

Nuclear Engineering and Technology

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Quantitative spectral micro-CT of a CA4+ loaded osteochondral sample with a tabletop system

Fantoni,

Brun,

Cardarelli

et al. 2024

Eur. Phys. J. Plus

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Micro-computed tomography ($$\upmu$$ μ CT) is the gold standard for nondestructive 3D imaging of biomedical samples in the centimeter scale, but it has limited effectiveness in revealing intricate soft tissue details due to the limited attenuation contrast. Radiopaque contrast agents that accumulate in the structures of interest are employed to enhance their visibility. However, the increased attenuation provided by the contrast agents does not guarantee discrimination among tissues. This issue can be solved by spectral $$\upmu$$ μ CT (S$$\upmu$$ μ CT) systems employing small-pixel chromatic photon-counting detectors. These detectors, combined with material decomposition algorithms, allow the generation of high-resolution material-specific 3D maps. This work aims to demonstrate the potential of photon-counting X-ray S$$\upmu$$ μ CT on osteochondral samples loaded with a cationic iodinated contrast agent (CA4+) at a spatial resolution below 50 $$\upmu$$ μ m, and to compare the results against a conventional $$\upmu$$ μ CT system. An osteochondral sample extracted from a bovine stifle joint was loaded with CA4+ and imaged with a novel multimodal X-ray imaging system, featuring a 62 $$\upmu$$ μ m pixel CdTe spectral detector (Pixirad1-PixieIII). After material decomposition, quantitative 3D density maps of iodine and hydroxyapatite were reconstructed. The same sample was also scanned with a commercial $$\upmu$$ μ CT scanner with matched spectrum and exposure time. SCT$$\upmu$$ μ images at a (measured) spatial resolution comparable with the commercial scanner ($$\sim$$ ∼ 45 $$\upmu$$ μ m) were obtained. Spectral images allowed for a fully automatic segmentation of cartilage and subchondral bone. The unambiguous discrimination between iodine and hydroxyapatite revealed a more realistic representation of proteoglycan distribution compared to conventional imaging.

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Development and validation of a simulation tool for K-edge Subtraction imaging with polychromatic spectra and X-ray photon counting detectors

Cited by 3 publications

References 29 publications

Edge-illumination spectral phase-contrast tomography

Edge-illumination spectral phase-contrast tomography

Block-matching and 3D filtering algorithm in X-ray image with photon counting detector using the improved K-edge subtraction method

Quantitative spectral micro-CT of a CA4+ loaded osteochondral sample with a tabletop system

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