scholarly journals An Optimized K-Edge Signal Extraction Method for K-Edge Decomposition Imaging Using a Photon Counting Detector

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhidu Zhang ◽  
Xiaomei Zhang ◽  
Jinming Hu ◽  
Qiong Xu ◽  
Mohan Li ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Imaging System ◽  
Photon Counting ◽  
Selection Method ◽  
Photon Counting Detector ◽  
Relative Standard ◽  
Photon Counting Detectors ◽  
Spectrum Selection ◽  
Edge Decomposition

In K-edge decomposition imaging for the multienergy system with the photon counting detectors (PCDs), the energy bins significantly affect the intensity of the extracted K-edge signal. Optimized energy bins can provide a better K-edge signal to improve the quality of the decomposition images and have the potential to reduce the amount of contrast agents. In this article, we present the Gaussian spectrum selection method (GSSM) for the multienergy K-edge decomposition imaging which can extract an optimized K-edge signal by optimizing energy bins compared with the conventional theoretical attenuation selection method (TASM). GSSM decides the width and locations of the energy bins using a simple but effective model of the imaging system, which takes the degraded energy resolution of the detector and the continuous x-ray spectrum into consideration. Besides, we establish the objective function, difference of attenuation to relative standard deviation ratio (DAR), to determine the optimal energy bins which maximize the K-edge signal. The results show that GSSM gets a better K-edge signal than TASM especially at the lower concentration level of contrast agents. The new method has the potential to improve the contrast and reduce the amount of contrast agents.

scholarly journals Simulation Research of Potential Contrast Agents for X-Ray Fluorescence CT with Photon Counting Detectors

2021 ◽  
Vol 9 ◽  
Author(s):  
Luo Yan ◽  
Feng Peng ◽  
Zhao Ruge ◽  
Zhang Yi ◽  
An Kang ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Imaging System ◽  
Photon Counting ◽  
X Rays ◽  
Simulation Research ◽  
Fluorescence Efficiency ◽  
Detectable Concentration ◽  
Novel Method ◽  
Photon Counting Detectors ◽  
Imaging Conditions

XFCT is a novel method for the early cancer detection. Increasing concentration of contrast agents and incident X-rays’ energy were used to improve detecting accuracy, which greatly increased the prevalence of contrast-induced nephropathy. Therefore, this research explores the adaptive contrast agents and uses Geant4 to simulate the imaging conditions of Pt, Bi, Gd, Ru, and Au for searching the lowest detectable concentration based on the fast multi-pinhole collimated XFCT (fmpc-XFCT) imaging system and low incident energy. Several imaging parameters including pinhole radius (0.7, 0.8, and 1 mm) were adjusted, and the optimized EM-TV algorithm was used to reconstruct XFCT images. It is found that Bi element is superior to other metal elements in terms of the contrast-to-noise ratio (CNR) and fluorescence efficiency, and the lowest concentration that can be detected is 0.12% with optimal parameters.

scholarly journals Quantitative dual contrast photon-counting computed tomography for assessment of articular cartilage health

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petri Paakkari ◽  
Satu I. Inkinen ◽  
Miitu K. M. Honkanen ◽  
Mithilesh Prakash ◽  
Rubina Shaikh ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Articular Cartilage ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Photon Counting ◽  
Spectral Imaging ◽  
Ct Scanning ◽  
Photon Counting Detector ◽  
Tissue Contrast ◽  
Reference Parameters

AbstractPhoton-counting detector computed tomography (PCD-CT) is a modern spectral imaging technique utilizing photon-counting detectors (PCDs). PCDs detect individual photons and classify them into fixed energy bins, thus enabling energy selective imaging, contrary to energy integrating detectors that detects and sums the total energy from all photons during acquisition. The structure and composition of the articular cartilage cannot be detected with native CT imaging but can be assessed using contrast-enhancement. Spectral imaging allows simultaneous decomposition of multiple contrast agents, which can be used to target and highlight discrete cartilage properties. Here we report, for the first time, the use of PCD-CT to quantify a cationic iodinated CA4+ (targeting proteoglycans) and a non-ionic gadolinium-based gadoteridol (reflecting water content) contrast agents inside human osteochondral tissue (n = 53). We performed PCD-CT scanning at diffusion equilibrium and compared the results against reference data of biomechanical and optical density measurements, and Mankin scoring. PCD-CT enables simultaneous quantification of the two contrast agent concentrations inside cartilage and the results correlate with the structural and functional reference parameters. With improved soft tissue contrast and assessment of proteoglycan and water contents, PCD-CT with the dual contrast agent method is of potential use for the detection and monitoring of osteoarthritis.

scholarly journals CdTe Based Energy Resolving, X-ray Photon Counting Detector Performance Assessment: The Effects of Charge Sharing Correction Algorithm Choice

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6093
Author(s):  
Oliver L. P. Pickford Scienti ◽  
Jeffrey C. Bamber ◽  
Dimitra G. Darambara
Keyword(s):  
Detection Efficiency ◽  
Photon Counting ◽  
Charge Sharing ◽  
Correction Algorithm ◽  
Detector Performance ◽  
Photon Counting Detector ◽  
Photon Counting Detectors ◽  
The Difference ◽  
Pixel Pitch ◽  
Made In

Most modern energy resolving, photon counting detectors employ small (sub 1 mm) pixels for high spatial resolution and low per pixel count rate requirements. These small pixels can suffer from a range of charge sharing effects (CSEs) that degrade both spectral analysis and imaging metrics. A range of charge sharing correction algorithms (CSCAs) have been proposed and validated by different groups to reduce CSEs, however their performance is often compared solely to the same system when no such corrections are made. In this paper, a combination of Monte Carlo and finite element methods are used to compare six different CSCAs with the case where no CSCA is employed, with respect to four different metrics: absolute detection efficiency, photopeak detection efficiency, relative coincidence counts, and binned spectral efficiency. The performance of the various CSCAs is explored when running on systems with pixel pitches ranging from 100 µm to 600µm, in 50 µm increments, and fluxes from 106 to 108 photons mm−2 s−1 are considered. Novel mechanistic explanations for the difference in performance of the various CSCAs are proposed and supported. This work represents a subset of a larger project in which pixel pitch, thickness, flux, and CSCA are all varied systematically.

Optimization of a CZT photon counting detector for contaminant detection

2021 ◽  
Vol 16 (11) ◽  
pp. P11015
Author(s):  
J. Nguyen ◽  
P.-A. Rodesch ◽  
D. Richtsmeier ◽  
K. Iniewski ◽  
M. Bazalova-Carter
Keyword(s):  
Food Industry ◽  
Photon Counting ◽  
Conveyor Belt ◽  
Weighting Scheme ◽  
X Ray ◽  
Photon Counting Detector ◽  
Inspection Systems ◽  
Photon Counting Detectors ◽  
High Level ◽  
Packaged Food

Abstract In the food industry, X-ray inspection systems are utilized to ensure packaged food is free from physical contaminants to maintain a high level of food safety for consumers. However, one of the challenges in the food industry is detecting small, low-density contaminants from packaged food. Cadmium zinc telluride (CZT) photon counting detectors (PCDs) can potentially alleviate this problem given its multi-energy bin capabilities, high spatial resolution and ability to eliminate electronic noise, which is superior to the conventional energy integrating detector (EID). However, the image quality from a CZT PCD can be further improved by applying an optimized energy bin weighting scheme that maximizes energy bin images that provide the largest image contrast and lowest image noise. Therefore, in this work, five contaminant materials embedded in an acrylic phantom were imaged using a CZT PCD while the phantom was in constant motion to mimic food products moving on a conveyor belt. Energy bin optimization was performed by applying an image-based weighting scheme and these results showed contrast-to-noise ratio (CNR) improvements ranging between 1.02–1.91 relative to an equivalent EID acquisition.

scholarly journals Binary Complementary Filters for Compressive Raman Spectroscopy

2017 ◽  
Vol 72 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Owen G. Rehrauer ◽  
Vu C. Dinh ◽  
Bharat R. Mankani ◽  
Gregery T. Buzzard ◽  
Bradley J. Lucier ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Photon Counting ◽  
Optical Filters ◽  
Chemical Components ◽  
Digital Micromirror Device ◽  
Direct Photons ◽  
Powder Mixtures ◽  
Photon Counting Detector ◽  
Two Photon ◽  
Photon Counting Detectors

The previously described optimized binary compressive detection (OB-CD) strategy enables fast hyperspectral Raman (and fluorescence) spectroscopic analysis of systems containing two or more chemical components. However, each OB-CD filter collects only a fraction of the scattered photons and the remainder of the photons are lost. Here, we present a refinement of OB-CD, the OB-CD2 strategy, in which all of the collected Raman photons are detected using a pair of complementary binary optical filters that direct photons of different colors to two photon counting detectors. The OB-CD2 filters are generated using a new optimization algorithm described in this work and implemented using a holographic volume diffraction grating and a digital micromirror device (DMD) whose mirrors are programed to selectively direct photons of different colors either to one or the other photon-counting detector. When applied to pairs of pure liquids or two-component solid powder mixtures, the resulting OB-CD2 strategy is shown to more accurately estimate Raman scattering rates of each chemical component, when compared to the original OB-CD, thus facilitating chemical classification at speeds as fast as 3 μs per measurement and the collection of Raman images in under a second.

Multi bin energy-sensitive micro-CT using large area photon-counting detectors Timepix

2022 ◽  
Vol 17 (01) ◽  
pp. C01028
Author(s):  
J. Dudak ◽  
J. Zemlicka
Keyword(s):  
Photon Counting ◽  
Dual Energy ◽  
Urinary Stones ◽  
Dual Energy Ct ◽  
Micro Ct ◽  
Single Object ◽  
Large Area ◽  
Intravenous Contrast ◽  
Photon Counting Detector ◽  
Photon Counting Detectors

Abstract X-ray micro-CT has become a popular and widely used tool for the purposes of scientific research. Although the current state-of-the-art micro-CT is on a high technology level, it still has some known limitations. One of the relevant issues is an inability to clearly identify and quantify specific materials. The mentioned drawback can be solved by the energy-sensitive CT approach. Dual-energy CT, which is already frequently used in human medicine, offers the identification of two different materials; for example, it differentiates an intravenous contrast agent from bone or it can indicate the composition of urinary stones. Resolving a larger number of material components within a single object is beyond the capabilities of dual-energy CT. Such an approach requires a higher number of measurements using different photon energies. A possible solution for multi bin, or so-called spectral CT, is the application of photon-counting detectors. Photon counting technology offers an integrated circuitry capable of resolving the energy of incoming photons in each pixel. Therefore, it is possible to collect data in user-defined energy windows. This contribution evaluates the applicability of the large-area photon-counting detector Timepix for multi bin energy-sensitive micro-CT. It presents an experimental phantom study focused on the simultaneous K-edge-based identification and quantification of multiple contrast agents within a single object. The paper describes the collection of multiple energy bins using the Timepix detector operated in the photon counting mode, explains the data processing, and demonstrates the results obtained from an in-house implemented basis material decomposition algorithm.

Microtomography with photon counting detectors: improving the quality of tomographic reconstruction by voxel-space oversampling

2017 ◽  
Vol 12 (01) ◽  
pp. C01060-C01060 ◽  
Author(s):  
J. Dudak ◽  
J. Zemlicka ◽  
J. Karch ◽  
Z. Hermanova ◽  
J. Kvacek ◽  
...  
Keyword(s):  
Tomographic Reconstruction ◽  
Photon Counting ◽  
Photon Counting Detectors ◽  
Voxel Space
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