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 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.

Erratum: Bayesian deconvolution as a method for the spectroscopy of X-rays with highly pixelated photon counting detectors

2012 ◽  
Vol 7 (08) ◽  
pp. E08001-E08001
Author(s):  
P Sievers ◽  
T Weber ◽  
T Michel ◽  
J Klammer ◽  
L Büermann ◽  
...  
Keyword(s):  
Photon Counting ◽  
X Rays ◽  
Photon Counting Detectors

Bayesian deconvolution as a method for the spectroscopy of X-rays with highly pixelated photon counting detectors

2012 ◽  
Vol 7 (03) ◽  
pp. P03003-P03003 ◽  
Author(s):  
P Sievers ◽  
T Weber ◽  
T Michel ◽  
J Klammer ◽  
L Büermann ◽  
...  
Keyword(s):  
Photon Counting ◽  
X Rays ◽  
Photon Counting Detectors

scholarly journals Time-over-threshold readout to enhance the high flux capabilities of single-photon-counting detectors

2011 ◽  
Vol 18 (6) ◽  
pp. 923-929 ◽  
Author(s):  
Anna Bergamaschi ◽  
Roberto Dinapoli ◽  
Dominic Greiffenberg ◽  
Beat Henrich ◽  
Ian Johnson ◽  
...  
Keyword(s):  
Dynamic Range ◽  
State Of The Art ◽  
Single Photon ◽  
Photon Counting ◽  
Rate Capability ◽  
Background Suppression ◽  
High Flux ◽  
X Rays ◽  
Single Photon Counting ◽  
Photon Counting Detectors

The MYTHEN single-photon-counting (SPC) detector has been characterized using the time-over-threshold (ToT) readout method,i.e.measuring the time that the signal produced by the detected X-rays remains above the comparator threshold. In the following it is shown that the ToT readout preserves the sensitivity, dynamic range and capability of background suppression of the SPC mode, while enhancing the count-rate capability, which is the main limitation of state-of-the-art SPC systems.

Tantalum superconducting tunnel junctions for photon counting detectors

2002 ◽  
Vol 12 (3) ◽  
pp. 145-148
Author(s):  
C. Jorel ◽  
P. Feautrier ◽  
J.-C. Villégier ◽  
A. Benoit
Keyword(s):  
Tunnel Junctions ◽  
Photon Counting ◽  
Superconducting Tunnel Junctions ◽  
Photon Counting Detectors

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.

Dark-Field X-Ray Microscopy of Immunogold-Labeled Cells

1996 ◽  
Vol 2 (2) ◽  
pp. 53-62 ◽  
Author(s):  
Henry N. Chapman ◽  
Jenny Fu ◽  
Chris Jacobsen ◽  
Shawn Williams
Keyword(s):  
Colloidal Gold ◽  
Dark Field Image ◽  
Dark Field ◽  
X Rays ◽  
X Ray ◽  
Scanning Transmission ◽  
A Cell ◽  
Specific Antigens ◽  
Genetic Sequences ◽  
Novel Method

The methods of immunolabeling make visible the presence of specific antigens, proteins, genetic sequences, or functions of a cell. In this paper we present examples of imaging immunolabels in a scanning transmission x-ray microscope using the novel method of dark-field contrast. Colloidal gold, or silver-enhanced colloidal gold, is used as a label, which strongly scatters x-rays. This leads to a high-contrast dark-field image of the label and reduced radiation dose to the specimen. The x-ray images are compared with electron micrographs of the same labeled, unsectioned, whole cell. It is verified that the dark-field x-ray signal is primarily due to the label and the bright-field x-ray signal, showing absorption due to carbon, is largely unaffected by the label. The label can be well visualized even when it is embedded in or laying behind dense material, such as the cell nucleus. The resolution of the images is measured to be 60 nm, without the need for computer processing. This figure includes the x-ray microscope resolution and the accuracy of the label positioning. The technique should be particularly useful for the study of relatively thick (up to 10 μm), wet, or frozen hydrated specimens.

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