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Chen X, Ge L, Wan H, Jiang Y, Huang L, Pan T, Lu G, Zhang X. Measurement of sinus wall thickness and wall enhancement index in dural arteriovenous fistulae by magnetic resonance vessel wall imaging. Magn Reson Imaging 2024:S0730-725X(24)00108-5. [PMID: 38579973 DOI: 10.1016/j.mri.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/07/2024]
Abstract
BACKGROUND Dural sinus wall thickness and wall enhancement index (WEI) of dural arteriovenous fistulae (DAVFs) have not been well characterized. This study aimed to measure the sinus wall thickness and WEI by using magnetic resonance vessel wall imaging (MR-VWI). METHODS A total 27 DAVF patients and 30 normal healthy individuals were enrolled in this study. All participants were scanned by a 3 T MR scanner with the black blood sequence. The wall thickness and the WEI of the great cerebral vein, the intracranial main dural sinuses with DAVFs, and the contralateral sinuses were measured by two independent neuroradiologists. RESULTS The DAVF-affected sinuses had significantly thicker walls (2.277 ± 0.311 mm vs. 1.446 ± 0.188 mm, P < 0.001) and significantly higher WEI (2.253 ± 0.462 vs. 1.173 ± 0.418, P < 0.001) compared to the contralateral ones. They also had significantly thicker walls (2.277 ± 0.311 mm vs. 1.643 ± 0.173 mm, P < 0.001) and significantly higher WEI (2.253 ± 0.462 vs. 1.124 ± 0.254, P < 0.001) compared to the normal controls. Neither the sinus wall thickness (r = -0.317, P = 0.107) nor the WEI (r = 0.019, P = 0.923) was significantly correlated with the Cognard types in DAVF patients. The WEI of the DAVF draining vein was significantly higher compared to the static venous wall (1.972 ± 0.629 vs. 0.532 ± 0.243, P < 0.001). CONCLUSION T1-CUBE MRI is useful in measuring sinus all thickness and WEI of DAVFs, providing a new method for diagnosing this disease.
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Affiliation(s)
- Xi Chen
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Liang Ge
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Hailin Wan
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yeqing Jiang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Lei Huang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ting Pan
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Gang Lu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaolong Zhang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
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Ulrich-Pur F, Bergauer T, Galatyuk T, Hirtl A, Kausel M, Kedych V, Kis M, Kozymka Y, Krüger W, Linev S, Michel J, Pietraszko J, Rost A, Schmidt CJ, Traeger M, Traxler M. First experimental time-of-flight-based proton radiography using low gain avalanche diodes. Phys Med Biol 2024. [PMID: 38471178 DOI: 10.1088/1361-6560/ad3326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
OBJECTIVE Ion computed tomography (iCT) is an imaging modality for the direct determination of the relative stopping power (RSP) distribution within a patient's body. Usually, this is done by estimating the path and energy loss of ions traversing the scanned volume utilising a tracking system and a separate residual energy detector. This study, on the other hand, introduces the first experimental study of a novel iCT approach based on time-of-flight (TOF) measurements, the so-called Sandwich TOF-iCT concept, which in contrast to any other iCT systems, does not require a residual energy detector for the RSP determination.
Approach: A small Sandwich TOF-iCT demonstrator was built based on low gain avalanche diodes (LGADs), which are 4D-tracking detectors that allow to simultaneously measure the particle position and time-of-arrival with a precision better than 100 μm and 100 ps, respectively. Using this demonstrator, the material and energy-dependent TOF was measured for several homogeneous PMMA slabs in order to calibrate the acquired TOF against the corresponding water equivalent thickness (WET). With this calibration, two proton radiographs (pRads) of a small aluminium stair phantom were recorded at MedAustron using 83 MeV and 100.4 MeV protons.
Main results: Due to the simplified WET calibration models used in this very first experimental study of this novel approach, the difference between the measured and theoretical WET ranged between 37.09 % and 51.12 %. Nevertheless, the first TOF-based pRad was successfully recorded showing that LGADs are suitable detector candidates for Sandwich TOF-iCT.
Significance: While the system parameters and WET estimation algorithms require further optimization, this work was an important first step to realize Sandwich TOF-iCT. Due to its compact and cost-efficient design, Sandwich TOF-iCT has the potential to make iCT more feasible and attractive for clinical application, which, eventually, could enhance the treatment planning quality.
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Affiliation(s)
- Felix Ulrich-Pur
- Detector Laboratory, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Thomas Bergauer
- Institute of High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, Wien, 1050, AUSTRIA
| | - Tetyana Galatyuk
- GSI Helmholtzzentrum fur Schwerionenforschung GmbH, D-64291 Darmstadt, Germany, Darmstadt, Hessen, 64291, GERMANY
| | - Albert Hirtl
- Atominstitut, TU Wien, Stadionallee 2, Wien, 1020, AUSTRIA
| | - Matthias Kausel
- Atominstitut, TU Wien, Stadionallee 2, Wien, Wien, 1040, AUSTRIA
| | - Vadym Kedych
- Institut für Kernphysik, TU Darmstadt, Karolinenplatz 5, Darmstadt, Hessen, 64289, GERMANY
| | - Mladen Kis
- GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Yevhen Kozymka
- Institut für Kernphysik, TU Darmstadt, Karolinenplatz 5, Darmstadt, Hessen, 64289, GERMANY
| | - Wilhelm Krüger
- Institut für Kernphysik, TU Darmstadt, Karolinenplatz 5, Darmstadt, Hessen, 64289, GERMANY
| | - Sergey Linev
- GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Jan Michel
- Institut für Kernphysik, Goethe University Frankfurt, Max-von-Laue-Str. 1, Frankfurt am Main, Hessen, 60325, GERMANY
| | - Jerzy Pietraszko
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Adrian Rost
- FAIR GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Christian Joachim Schmidt
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Michael Traeger
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, Darmstadt, Hessen, 64291, GERMANY
| | - Michael Traxler
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Darmstadt, Hessen, 64291, GERMANY
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Huang L, Luo Z, Zeng L, Lin J. Detection and localization of corrosion using the combination information of multiple Lamb wave modes. Ultrasonics 2024; 138:107246. [PMID: 38309037 DOI: 10.1016/j.ultras.2024.107246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/11/2023] [Accepted: 01/13/2024] [Indexed: 02/05/2024]
Abstract
Themulti-modeanddispersionnature of Lamb waves means that a variety of modes with individual mode structures and distinct dispersion behaviors would propagate in the structures simultaneously. The existence of a corrosion would result in thickness reduction, which means the frequency-thickness product under a specific excitation would also decrease. Due to dispersion diversity, the interaction of each individual Lamb mode at the corrosion may be distinct, i.e., the velocity varies in different extent and even in opposite trends. In this paper, the combination of multiple modes, rather than a single sensitive mode, is used for structure diagnosis. Specifically, two Lamb modes both sensitive to corrosion but with opposite variation trends are taken and the corrosion index is defined on the ratio of their time-of-flight, so as to enhance the sensitivity to corrosion and eliminate the influence of difference path lengths in the sensor network. On this basis, a probabilistic reconstruction algorithm is introduced for corrosion detection and localization. Since the two modes are extracted from the same wideband Lamb wave response, the proposed method is baseline-free. The influence of mode conversion on the effectiveness of the proposed method is discussed. Ultimately, the performance of the proposed method is demonstrated by an experimental example. The results show that the defect could be correctly identified and accurately localized.
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Affiliation(s)
- Liping Huang
- School of Mechanical Engineering, Xi'an University of Science and Technology, Xi'an, Shaanxi Province 710054, China.
| | - Zhi Luo
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Liang Zeng
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China.
| | - Jing Lin
- School of Reliability and Systems Engineering, Beihang University, Beijing 100191, China.
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Lee JS, Lee MS. Advancements in Positron Emission Tomography Detectors: From Silicon Photomultiplier Technology to Artificial Intelligence Applications. PET Clin 2024; 19:1-24. [PMID: 37802675 DOI: 10.1016/j.cpet.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
This review article focuses on PET detector technology, which is the most crucial factor in determining PET image quality. The article highlights the desired properties of PET detectors, including high detection efficiency, spatial resolution, energy resolution, and timing resolution. Recent advancements in PET detectors to improve these properties are also discussed, including the use of silicon photomultiplier technology, advancements in depth-of-interaction and time-of-flight PET detectors, and the use of artificial intelligence for detector development. The article provides an overview of PET detector technology and its recent advancements, which can significantly enhance PET image quality.
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Affiliation(s)
- Jae Sung Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 03080, South Korea; Brightonix Imaging Inc., Seoul 04782, South Korea
| | - Min Sun Lee
- Environmental Radioactivity Assessment Team, Nuclear Emergency & Environmental Protection Division, Korea Atomic Energy Research Institute, Daejeon 34057, South Korea.
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Nadig V, Hornisch M, Oehm J, Herweg K, Schulz V, Gundacker S. 16-channel SiPM high-frequency readout with time-over-threshold discrimination for ultrafast time-of-flight applications. EJNMMI Phys 2023; 10:76. [PMID: 38044383 PMCID: PMC10694125 DOI: 10.1186/s40658-023-00594-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/20/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Over the past five years, ultrafast high-frequency (HF) readout concepts have advanced the timing performance of silicon photomultipliers (SiPMs). The shown impact in time-of-flight (TOF) techniques can further push the limits in light detection and ranging (LiDAR), time-of-flight positron-emission tomography (TOF-PET), time-of-flight computed tomography (TOF-CT) or high-energy physics (HEP). However, upscaling these electronics to a system-applicable, multi-channel readout, has remained a challenging task, posed by the use of discrete components and a high power consumption. To this day, there are no means to exploit the high TOF resolution of these electronics on system scale or to measure the actual timing performance limits of a full detector block. METHODS In this work, we present a 16-channel HF readout board, including leading-edge discrimination and a linearized time-over-threshold (TOT) method, which is fully compatible with a high-precision time-to-digital converters (TDCs), such as the picoTDC developed at CERN. The discrete implementation allows ideal adaptation of this readout to a broad range of detection tasks. As a first step, the functionality of the circuit has been tested using the TOFPET2 ASIC as back-end electronics to emulate the TDC, also in view of its properties as a highly scalable data acquisition solution. RESULTS The produced board is able to mitigate influences of baseline shifts in the TOFPET2 front end, which has been shown in experiments with a pulsed laser, increasing the achievable intrinsic coincidence timing resolution (CTR) of the TOFPET2 readout electronics from 70 ps (FWHM) to 62 ps (FWHM). Single-channel coincidence experiments including a [Formula: see text]-source, 2[Formula: see text]2[Formula: see text]3 mm[Formula: see text] LYSO:Ce,Ca crystals and Broadcom NUV-MT SiPMs resulted in a CTR of 118 ps (FWHM). For a 4[Formula: see text]4 matrix of 3.88[Formula: see text]3.88[Formula: see text]19 mm[Formula: see text] LYSO:Ce,Ca crystals one-to-one coupled to a 4[Formula: see text]4 array of Broadcom NUV-MT SiPMs, an average CTR of 223 ps (FWHM) was obtained. CONCLUSION The implemented 16-channel HF electronics are fully functionall and have a negligible influence on the timing performance of the back-end electronics used, here the TOFPET2 ASIC. The ongoing integration of the picoTDC with the 16-channel HF board is expected to further set the path toward sub-100 ps TOF-PET and sub-30ps TOF resolution for single-photon detection.
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Affiliation(s)
- Vanessa Nadig
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Matthias Hornisch
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Jakob Oehm
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Katrin Herweg
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Volkmar Schulz
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
- Hyperion Hybrid Imaging Systems GmbH, Pauwelsstraße 19, 52074, Aachen, Germany
- III. Physikalisches Institut B, RWTH Aachen University, Otto-Blumenthal-Straße, 52074, Aachen, Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Stefan Gundacker
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany.
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Ritter DJ. Updating "Angle-dependent spectral reflectance material dataset based on 945 nm time-of-flight camera measurements" with extended data to cover reflectance measurements mainly for vehicle varnish and moss rubber. Data Brief 2023; 51:109747. [PMID: 38053589 PMCID: PMC10694037 DOI: 10.1016/j.dib.2023.109747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/12/2023] [Accepted: 10/26/2023] [Indexed: 12/07/2023] Open
Abstract
An updated dataset based on angle-dependent spectral reflectance measurements taken for an angle range of 0° to 80° with 10° incremental steps and pictures for most measurements of the whole dataset are presented in this article. It covers two new material types regarding the material classification scheme presented in the original paper [1]: vehicle varnish and moss rubber. Vehicle varnish samples are prepared on flat steel plates to enable proper angle-dependent acquisition of the data with the same angle adjustable measurement device already presented in the original paper. The moss rubber material has a behavior similar to a Lambertian reflector and thus serves for diffuse reflectance measurement purposes. The extended dataset, including the original dataset, is published open access on the open repository Zenodo with record number 8322076 in a new version 1.1.1 [2], and currently contains 314 measurements with the addition of 70 new varnish and moss rubber measurements. The new version of the dataset further includes pictures of most of the measurements to depict how the data were acquired. The pictures enable material mapping such as the link between the measured data in the near infrared spectrum at a wavelength of λ = 945 n m and the picture taken in the optical spectrum.
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Affiliation(s)
- David J. Ritter
- Virtual Vehicle Research GmbH, Inffeldgasse 21a, Graz 8010, Austria
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Gkioulidou M, Mitchell DG, Manweiler JW, Lanzerotti LJ, Gerrard AJ, Ukhorskiy AY, Keika K, Mouikis CG, Kistler LM. Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) Revisited: In-Flight Calibrations, Lessons Learned and Scientific Advances. Space Sci Rev 2023; 219:80. [PMID: 38037569 PMCID: PMC10684722 DOI: 10.1007/s11214-023-00991-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 08/02/2023] [Indexed: 12/02/2023]
Abstract
The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on both the Van Allen Probes spacecraft is a time-of-flight versus total energy instrument that provided ion composition data over the ring current energy (∼7 keV to ∼1 MeV), and electrons over the energy range ∼25 keV to ∼1 MeV throughout the duration of the mission (2012 - 2019). In this paper we present instrument calibrations, implemented after the Van Allen Probes mission was launched. In particular, we discuss updated rate dependent corrections, possible contamination by "accidentals" rates, and caveats concerning the use of certain products. We also provide a summary of the major advances in ring current science, obtained from RBSPICE observations, and their implications for the future of inner magnetosphere exploration.
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Affiliation(s)
- Matina Gkioulidou
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | | | | | - Louis J. Lanzerotti
- Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ USA
| | - Andrew J. Gerrard
- Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ USA
| | | | - Kunihiro Keika
- Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | | | - Lynn M. Kistler
- Space Science Center, University of New Hampshire, Durham, NH USA
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Aslam MZ, Zhang H, Good M, Guo Y, Larche M. A multimodal lithium niobate-based SAW gas sensor for accurate detection of carbon dioxide at elevated temperature. Ultrasonics 2023; 138:107198. [PMID: 38011814 DOI: 10.1016/j.ultras.2023.107198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/11/2023] [Accepted: 11/04/2023] [Indexed: 11/29/2023]
Abstract
Carbon dioxide (CO2) detection is crucial for safety control, monitoring of the environment, and other industrial applications. The diverse fields of applications make the detection of CO2 a challenging task. In this paper, a study on a multimodal surface acoustic wave (SAW) CO2 sensing system was conducted to scrutinize the sensitivity of the lithium niobate-based multimodal SAW sensor towards CO2 with temperature compensation. The study focused on developing and evaluating a SAW temperature-compensated gas sensor using time-of-flight measurements. The sensor exhibited good repeatability and sensitivity toward different concentrations of CO2.
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Affiliation(s)
| | - Haifeng Zhang
- Department of Mechanical Engineering, University of North Texas, USA.
| | - Morris Good
- Pacific Northwest National Laboratory (PNNL), USA
| | - Yanming Guo
- Pacific Northwest National Laboratory (PNNL), USA
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Ferrer I, Thurman EM. Chemical tracers for Wildfires-Analysis of runoff surface Water by LC/Q-TOF-MS. Chemosphere 2023; 339:139747. [PMID: 37549742 DOI: 10.1016/j.chemosphere.2023.139747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/19/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
A quantitative methodology using high resolution mass spectrometry was developed for the identification of organic compounds derived from wildfires in surface water samples. The methodology involves the use of solid-phase extraction (SPE) followed by detection using liquid chromatography-quadrupole time of flight-mass spectrometry (LC/Q-TOF-MS) for a group of fourteen chemical compounds (pyridine, benzene, naphthalene and biphenyl polycarboxylic acids). All compounds were successfully separated chromatographically using a reversed phase column and they were identified by accurate mass using the deprotonated species and their main fragment ions. The method produced excellent accuracies (>95%) and precisions (3-10%) for all the compounds studied. This methodology was successfully applied to the identification of fourteen compounds in runoff surface waters impacted by wildfires in Colorado in 2020. Concentrations of individual compounds ranging from 0.1 to 59.5 μg/L were found in wildfire impacted waters, with totals of ∼200 μg/L, thus showing these compounds as chemical tracers of wildfire events at significantly high concentrations. In addition, non-target analysis using chromatography patterns and mass spectrometry identification by MS-MS revealed other polycarboxylic acid isomers were also present in runoff surface water samples.
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Affiliation(s)
- Imma Ferrer
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, CO 80309, USA.
| | - E Michael Thurman
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, CO 80309, USA
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Peng G, Zhu W, Zuo Z, Liu C, Zhang Z, Zhao Y, Zhang X, Wu Z, Tao L. Efficacy of modified time of flight magnetic resonance venography in diagnosis of iliac vein compression syndrome. Eur J Radiol 2023; 166:111020. [PMID: 37542815 DOI: 10.1016/j.ejrad.2023.111020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/07/2023]
Abstract
OBJECTIVE We investigated the diagnostic efficacy of modified time of flight magnetic resonance venography (mTOF-MRV) for iliac vein compression syndrome diagnosis by optimizing the scanning parameters and improving image quality. METHODS A retrospective study was conducted on 69 patients who underwent routine time of flight magnetic resonance venography (TOF-MRV) and 85 patients who received mTOF-MRV. Assessment of image quality of the two methods was performed by two radiologists using a four-point method. The sensitivity, specificity, positive and negative predictive values of TOF-MRV and mTOF-MRV in the diagnosis of significant iliac vein compression (stenosis >50%) were analyzed by calculating the iliac vein stenosis rates of the two methods and using digital subtraction angiography (DSA) as the gold standard. RESULTS Inter-observer assessment of objective data measurement revealed excellent agreement {ICC [95% confidence interval (CI)]: 0.972 (0.953 to 0.983) for TOF-MRV and 0.979 (0.965 to 0.988) for m-TOF MRV, 0.976 (0.960 to 0.986) for DSA}. The mean error of stenosis rate of mTOF-MRV was markedly smaller than that of TOF-MRV (p < 0.05). Sensitivity, specificity, positive and negative predictive values of TOF-MRV in the diagnosis of significant stenosis were 100%, 95%, 67% and 100%, respectively. The sensitivity, specificity, positive and negative predictive values of mTOF-MRV were 100%. The mean image score for the mTOF-MRV was 3.63 ± 0.59, which was significantly higher compared with that of TOF-MRV (2.19 ± 0.42). CONCLUSION mTOF-MRV has better image quality and can accurately diagnose venous stenosis. Therefore, it can be used for the detection of iliac vein compression syndrome and further assessment after endovascular interventions.
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Affiliation(s)
- Gang Peng
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Zhu
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ziyu Zuo
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Chuan Liu
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhiwei Zhang
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yu Zhao
- Department of Vascular Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoyu Zhang
- Department of Radiology, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China
| | - Zhiyi Wu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Oró-Nolla B, Dulsat-Masvidal M, Bertolero A, Lopez-Antia A, Lacorte S. Target and untargeted screening of perfluoroalkyl substances in biota using liquid chromatography coupled to quadrupole time of flight mass spectrometry. J Chromatogr A 2023; 1701:464066. [PMID: 37207413 DOI: 10.1016/j.chroma.2023.464066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/21/2023]
Abstract
Perfluoroalkyl substances (PFAS) are known to bioaccumulate and trigger adverse effects in marine birds. This study develops an extraction and analytical methodology for the target/untargeted analysis of PFAS in eggs of Yellow-legged gull (Larus michahellis) and Audouin's gull (Larus audouinii) and blood of Greater flamingo (Phoenicopterus roseus), which are used as bioindicators of organic chemical pollution. Samples were extracted by ultrasonication with acetonitrile and cleaned-up with activated carbon, and analysis was performed by ultra-high-performance liquid chromatography coupled to a quadrupole-time of flight mass spectrometer (UHPLC-Q-TOF) with negative electrospray ionization. Data-independent acquisition (DIA) was performed through full-scan acquisition to obtain MS1 at 6 eV and MS2 at 30 eV. In a first step, quantitative analysis of 25 PFAS was performed using 9 mass-labelled internal standard PFAS and quality parameters of the method developed are provided. Then, an untargeted screening workflow is proposed using the high-resolution PFAS library database from NORMAN to identify new chemicals through accurate mass measurement of MS1 and MS2 signals. The method permitted to detect several PFAS at concentrations ranging from 0.45 to 55.2 ng/g wet weight in gull eggs and from 0.75 to 125 ng/mL wet weight in flamingos' blood, with PFOS, PFOA, PFNA, PFUdA, PFTrDA, PFDoA, PFHxS and PFHpA the main compounds detected. In addition, perfluoro-p-ethylcyclohexylsulfonic acid (PFECHS, CAS number 646-83-3) and 2-(perfluorohexyl)ethanol (6:2 FTOH, CAS number 647-42-7) were tentatively identified. The developed UHPLC-Q-TOF target/untargeted analytical approach increases the scope of PFAS analysis, enabling a better assessment on contaminant exposure and promoting the use of bird species as bioindicators of chemical pollution.
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Affiliation(s)
- B Oró-Nolla
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - M Dulsat-Masvidal
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - A Bertolero
- Associació Ornitològica Picampall de les Terres de l'Ebre, La Galera 53, Amposta 43870, Spain
| | - A Lopez-Antia
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - S Lacorte
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain.
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12
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Díaz-Galiano FJ, Heinzen H, Gómez-Ramos MJ, Murcia-Morales M, Fernández-Alba AR. Identification of novel unique mānuka honey markers using high-resolution mass spectrometry-based metabolomics. Talanta 2023; 260:124647. [PMID: 37172434 DOI: 10.1016/j.talanta.2023.124647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
Mānuka honey is a valuable commodity produced by bees foraging the flowers of Leptospermum scoparium, a bush native to New Zealand and Australia. Due to its high value and proven health benefits, authenticity fraud in the sale of this food is a significant risk, as recounted in the literature. Four compulsory natural products must be present at minimum concentrations to authenticate mānuka honey (3-phenyllactic acid, 2'-methoxyacetophenone, 2-methoxybenzoic acid, and 4-hydroxyphenyllactic acid). However, spiking other kinds of honey with these compounds and/or the dilution of mānuka honey with other varieties may result in fraud going undetected. In this work, liquid chromatography coupled with high-resolution mass spectrometry and a metabolomics-based strategy has allowed us to tentatively identify 19 natural products -putative mānuka honey markers-, nine of which are reported for the first time. Chemometric models applied to these markers allowed the detection of both spiking and dilution fraud attempts of mānuka honey, even at 75% mānuka honey purity. Thus, the herein-reported methodology can be employed in the prevention and detection of mānuka honey adulteration even at low levels, and the tentatively identified markers presented in this work proved valuable for mānuka honey authentication procedures.
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Affiliation(s)
- Francisco José Díaz-Galiano
- University of Almería, Department of Physics and Chemistry, Agrifood Campus of International Excellence (ceiA3), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain
| | - Horacio Heinzen
- Pharmacognosy & Nat. Products, DQO, Facultad de Química Universidad de la República, Gral. Flores 2124, Montevideo, Uruguay
| | - María José Gómez-Ramos
- University of Almería, Department of Physics and Chemistry, Agrifood Campus of International Excellence (ceiA3), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain
| | - María Murcia-Morales
- University of Almería, Department of Physics and Chemistry, Agrifood Campus of International Excellence (ceiA3), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain
| | - Amadeo R Fernández-Alba
- University of Almería, Department of Physics and Chemistry, Agrifood Campus of International Excellence (ceiA3), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain.
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Lyne CT, Liu MF, Rovey JL. A simple retarding-potential time-of-flight mass spectrometer for electrospray propulsion diagnostics. J Elect Propuls 2023; 2:13. [PMID: 37016724 PMCID: PMC10066156 DOI: 10.1007/s44205-023-00045-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/13/2023] [Indexed: 04/06/2023]
Abstract
The time-of-flight mass spectrometer (ToF-MS) is a useful tool for quantifying the performance of electrospray thrusters and characterizing their plumes. ToF-MS data can be used to calculate the mass-to-charge distribution in the plume, but the kinetic-energy-to-charge (i.e., the potential) distribution must be known first. Here we use a ToF-MS in tandem with a retarding potential (RP) analyzer. By sweeping the retarding potential through the range of potentials present in the plume, both the mass-to-charge distribution and the potential distribution can be measured independently. We demonstrate this technique in a case study using a capillary electrospray emitter and the ionic liquid propellant 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, abbreviated EMI-Im. We report a linear correlation between retarding potential and mass-to-charge ratio that agrees with published data from more complex orthogonal RP/ToF-MS instruments. Calculated values for the jet velocity and jet breakup potential match within 2% and 12%, respectively. Using conventional ToF-MS, we estimated the propellant flow rate and compared those estimates to direct flow rate measurements. For flow rates between 233 pL/s and 565 pL/s, the error in ToF-based flow rate estimates ranged from -16% to -13% when the plume potential was assumed to be a function of mass-to-charge. Assuming a constant plume potential yielded mixed results. However, using the average stopping potential measured by a retarding potential analyzer resulted in higher errors, ranging from -26% to -30%. Data and MATLAB code are included as supplemental materials so that readers can easily apply the techniques described here. Supplementary Information The online version contains supplementary material available at 10.1007/s44205-023-00045-y.
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Affiliation(s)
- Christopher T. Lyne
- Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801 USA
| | - Miron F. Liu
- Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801 USA
| | - Joshua L. Rovey
- Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801 USA
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Tomita Y, Ichikawa Y, Sakuma H. Shine-through artifact due to high-radioactivity bladder and bowel gas in 18F-FDG PET/CT: impact of time-of-flight algorithm and radioactivity concentration of urine in the bladder on the occurrence of the artifacts. Ann Nucl Med 2022; 36:736-745. [PMID: 35635608 DOI: 10.1007/s12149-022-01756-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/16/2022] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Shine-though artifact can appear as regions with falsely increased uptake in the immediate vicinity of large hot sources in 18F-FDG PET/CT. This artifact may adversely affect the assessment of tumor involvement in the regions adjacent to the bladder. The purpose of this study was to evaluate the prevalence of shine-through artifacts in clinical 18F-FDG PET/CT examinations and the factors that can influence their occurrence and extent. METHODS PET/CT images were acquired with Discovery PET/CT 690. One hundred six patients who underwent 18F-FDG PET/CT for clinical purposes were retrospectively reviewed. PET images were reconstructed using 3-dimensional ordered-subset expectation maximization with and without time-of-flight (TOF). The shine-through artifact was defined as an erroneous accumulation of 18F-FDG between the bladder and the air region in the intestine without attenuation correction (AC) errors. The maximum standardized uptake value (SUVmax) of the artifact was measured, and the effect of TOF on this artifact was evaluated. The SUVmax in the bladder was compared in patients with and without the artifacts. A phantom containing two spheres simulating bladder and rectal gas was imaged while changing the radioactivity of 18F-FDG solution in the bladder sphere. The relationship between the bladder sphere radioactivity and the SUVmax of the shine-through artifacts was evaluated. RESULTS The shine-through artifact was more frequently observed on PET images reconstructed without TOF (12/106, 11.3%) as compared to PET images with TOF (8/106, 7.5%, p = 0.046). The SUVmax of the shine-through artifacts was significantly decreased by TOF reconstruction compared to non-TOF reconstruction (4.7 ± 1.7 vs 7.6 ± 3.1, p = 0.0078). The mean SUVmax of urinary bladders in patients with the artifacts was significantly higher than those without the artifacts on non-TOF images (74.9 ± 61.1 vs 46.3 ± 35.2, p = 0.038). In the phantom study, the SUVmax of the shine-through artifact increased as the radioactivity in the bladder-simulating sphere increased. CONCLUSION Shine-through artifacts were observed in approximately 10% of clinical 18F-FDG PET/CT examinations. Their magnitude is significantly associated with the radioactivity in the bladder and can be reduced by employing TOF. Recognizing this artifact allows for a more accurate interpretation of 18F-FDG pelvic studies.
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Affiliation(s)
- Yoya Tomita
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Yasutaka Ichikawa
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
| | - Hajime Sakuma
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
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Kang HG, Kim KJ, Kamada K, Yoshikawa A, Yoshida E, Nishikido F, Yamaya T. Optimization of GFAG crystal surface treatment for SiPM based TOF PET detector. Biomed Phys Eng Express 2022; 8. [PMID: 35180713 DOI: 10.1088/2057-1976/ac56c6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/18/2022] [Indexed: 11/12/2022]
Abstract
Coincidence timing resolution (CTR) is an important parameter in clinical positron emission tomography (PET) scanners to increase the signal-to-noise ratio of PET images by using time-of-flight (TOF) information. Lutetium (Lu) based scintillators are often used for TOF-PET systems. However, the self-radiation of Lu-based scintillators may influence the image quality for ultra-low activity PET imaging. Recently, a gadolinium fine aluminum gallate (Ce:GFAG) scintillation crystal that features a fast decay time (~55 ns) and no self-radiation was developed. The present study aimed at optimizing the GFAG crystal surface treatment to enhance both CTR and energy resolution (ER). The TOF-PET detector consisted of a GFAG crystal (3.0 × 3.0 × 20 mm3) and a SiPM with an effective area of 3.0 × 3.0 mm2. The timing and energy signals were extracted using a high-frequency SiPM readout circuit and then were digitized using a CAMAC DAQ system. The CTR and ER were evaluated with nine different crystal surface treatments such as partial saw-cut and chemical polishing and the 1-side saw-cut was the best choice among the treatments. The respective CTR and ER of 202±2 ps and 9.5±0.1% were obtained with the 1-side saw-cut; the other 5-side mechanically polished GFAG crystals had respective values which were 18 ps (9.0%) and 1.3% better than those of the all-side mechanically polished GFAG crystal. The chemically polished GFAG crystals also offered enhanced CTR and ER of about 17 ps (8.2%) and 2.1%, respectively, over the mechanically polished GFAG crystals.
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Affiliation(s)
- Han Gyu Kang
- Department of Nuclear Medicine Science, National Institutes for Quantum Science and technology, Imaging Physics Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba Japan, Chiba, Chiba, 263-8555, JAPAN
| | - Kyong Jin Kim
- Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Sendai 980 8577, Japan, Sendai, Miyagi, 980-8577, JAPAN
| | - Kei Kamada
- New Industry Creation Hatchery Center, Tohoku University, 2-1-1, Katahira, Aoba-ku,, Sendai, JP, 980-8577, JAPAN
| | - Akira Yoshikawa
- Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Sendai 980 8577, Japan, Sendai, Miyagi, 980-8577, JAPAN
| | - Eiji Yoshida
- Advanced Nuclear Medicine Science, National Institutes for Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba, Japan, Chiba, 263-8555, JAPAN
| | - Fumihiko Nishikido
- National Institutes for Quantum and Technology, 4-9-1, Anagawa, Inage-ku, Chiba, Japan, Chiba, Chiba, 263-8555, JAPAN
| | - Taiga Yamaya
- National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, JAPAN, Chiba, 263-8555, JAPAN
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16
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Han M, Smith R, Rock DA. Capillary Electrophoresis-Mass Spectrometry (CE-MS) by Sheath-Flow Nanospray Interface and Its Use in Biopharmaceutical Applications. Methods Mol Biol 2022; 2531:15-47. [PMID: 35941476 DOI: 10.1007/978-1-0716-2493-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Both capillary electrophoresis (CE) and mass spectrometry (MS) technologies are powerful analytical tools that have been used extensively in the characterization of biologics in the biopharmaceutical industry. The direct coupling of CE with MS is an attractive approach, in that the high separation capability of CE and the ultrasensitive detection and accurate identification performance of MS can be combined to provide a powerful system for the analysis of complex analytes. In this chapter, we discuss the detailed procedure of carrying out CE-MS analysis using a nano sheath-flow interface and its applications including intact mass analysis of monoclonal antibodies and fusion proteins, and a biotransformation study of two Fc-FGF21 molecules in a single-dose pharmacokinetic mice study. Optimization processes, including the finetuning of CE conditions and MS parameters, are illustrated in this chapter, with focuses on method robustness and assay reproducibility.
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Affiliation(s)
- Mei Han
- Pharmacokinetics and Drug Metabolism, Amgen Research, Amgen Inc., South San Francisco, CA, USA.
| | - Richard Smith
- Pharmacokinetics and Drug Metabolism, Amgen Research, Amgen Inc., South San Francisco, CA, USA
| | - Dan A Rock
- Pharmacokinetics and Drug Metabolism, Amgen Research, Amgen Inc., South San Francisco, CA, USA
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Abstract
Over the past couple of years, imaging mass spectrometry (IMS) has arisen as a powerful tool to answer research questions in the biomedical field. Imaging mass spectrometry allows for label-free chemical imaging by providing full molecular information. The IMS technique best positioned for cell and tissue analysis is time-of-flight secondary ion mass spectrometry (ToF-SIMS) because it has the best spatial resolution of all the molecular IMS techniques and can detect many biochemical species and especially lipids with high sensitivity. Because one must rely on the mass and isotopic pattern of an ion in combination with positive correlations with lower mass fragments to help identify its structure, one major problem during ToF-SIMS experiments is the ambiguity when assigning a molecule to a certain mass peak. The solution are instruments with tandem MS capabilities as was already the case for many MALDI-ToF instruments more than a decade ago. It has been a few years since instruments with this capability were introduced and a number of interesting publications have been produced highlighting the advantages in biological SIMS work. Here, we present a protocol describing how tandem MS can be used to elucidate the structure of unknown or ambiguous mass peaks in biological tissue samples observed during ToF-SIMS imaging based on our experiences.
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Affiliation(s)
- Sebastiaan Van Nuffel
- Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands
- Maastricht MultiModal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, The Netherlands
| | - Alain Brunelle
- Sorbonne Université, CNRS, Laboratoire d'Archéologie Moléculaire et Structurale, LAMS, Paris, France.
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Cha KH, Lee J, Lee J, Kim JH. Development of a quantitative screening method for pesticide multiresidues in orange, chili pepper, and brown rice using gas chromatography-quadrupole time of flight mass spectrometry with dopant-assisted atmospheric pressure chemical ionization. Food Chem 2021;:131626. [PMID: 34838406 DOI: 10.1016/j.foodchem.2021.131626] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 11/10/2021] [Accepted: 11/14/2021] [Indexed: 11/22/2022]
Abstract
A rapid screening method for the quantitative analysis of pesticide multiresidues using a high-resolution accurate mass (HRAM) quadrupole time-of-flight (Q-TOF) with a dopant-assisted gas chromatography-atmospheric pressure chemical ionization (GC-APCI) technique were developed. For convenient and constant supply of APCI dopant, a large-volume dopant bottle with a bypass valve was newly designed, and the developed method was tested with 415 pesticide mixtures for representative produce (orange, chili pepper, and brown rice). Methanol-enriched nitrogen gas was used to produce protonated molecular [M + H]+ ions, and fragment ions were produced by broad-band collision-induced dissociation mode. Twenty representative pesticides were selected and validated for analytical performance. The methanol dopant-assisted GC-APCI-Q-TOF technique is very promising for target and non-target screening and sensitive quantification for hundreds of pesticides in a single run.
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Sanaat A, Shooli H, Ferdowsi S, Shiri I, Arabi H, Zaidi H. DeepTOFSino: A deep learning model for synthesizing full-dose time-of-flight bin sinograms from their corresponding low-dose sinograms. Neuroimage 2021; 245:118697. [PMID: 34742941 DOI: 10.1016/j.neuroimage.2021.118697] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/21/2021] [Accepted: 10/29/2021] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Reducing the injected activity and/or the scanning time is a desirable goal to minimize radiation exposure and maximize patients' comfort. To achieve this goal, we developed a deep neural network (DNN) model for synthesizing full-dose (FD) time-of-flight (TOF) bin sinograms from their corresponding fast/low-dose (LD) TOF bin sinograms. METHODS Clinical brain PET/CT raw data of 140 normal and abnormal patients were employed to create LD and FD TOF bin sinograms. The LD TOF sinograms were created through 5% undersampling of FD list-mode PET data. The TOF sinograms were split into seven time bins (0, ±1, ±2, ±3). Residual network (ResNet) algorithms were trained separately to generate FD bins from LD bins. An extra ResNet model was trained to synthesize FD images from LD images to compare the performance of DNN in sinogram space (SS) vs implementation in image space (IS). Comprehensive quantitative and statistical analysis was performed to assess the performance of the proposed model using established quantitative metrics, including the peak signal-to-noise ratio (PSNR), structural similarity index metric (SSIM) region-wise standardized uptake value (SUV) bias and statistical analysis for 83 brain regions. RESULTS SSIM and PSNR values of 0.97 ± 0.01, 0.98 ± 0.01 and 33.70 ± 0.32, 39.36 ± 0.21 were obtained for IS and SS, respectively, compared to 0.86 ± 0.02and 31.12 ± 0.22 for reference LD images. The absolute average SUV bias was 0.96 ± 0.95% and 1.40 ± 0.72% for SS and IS implementations, respectively. The joint histogram analysis revealed the lowest mean square error (MSE) and highest correlation (R2 = 0.99, MSE = 0.019) was achieved by SS compared to IS (R2 = 0.97, MSE= 0.028). The Bland & Altman analysis showed that the lowest SUV bias (-0.4%) and minimum variance (95% CI: -2.6%, +1.9%) were achieved by SS images. The voxel-wise t-test analysis revealed the presence of voxels with statistically significantly lower values in LD, IS, and SS images compared to FD images respectively. CONCLUSION The results demonstrated that images reconstructed from the predicted TOF FD sinograms using the SS approach led to higher image quality and lower bias compared to images predicted from LD images.
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Affiliation(s)
- Amirhossein Sanaat
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
| | - Hossein Shooli
- Persian Gulf Nuclear Medicine Research Center, Department of Molecular Imaging and Radionuclide Therapy (MIRT), Bushehr Medical University Hospital, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Sohrab Ferdowsi
- University of Applied Sciences and Arts of Western, Geneva, Switzerland
| | - Isaac Shiri
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
| | - Hossein Arabi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland; Geneva University Neurocenter, University of Geneva, Geneva, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen, Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark.
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Tateishi U, Daisaki H, Tsuchiya J, Kojima Y, Takino K, Shimada N, Yokoyama K. Image quality and quantification accuracy dependence on patient body mass in 89Zr PET/CT imaging. EJNMMI Phys 2021; 8:72. [PMID: 34718913 PMCID: PMC8557230 DOI: 10.1186/s40658-021-00420-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/14/2021] [Indexed: 11/15/2022] Open
Abstract
Background This study was conducted to clarify how patient body mass affects the image quality and quantification accuracy of images obtained using 89Zr PET/CT. 89Zr PET/CT images from time-of-flight (TOF) PET/CT and semiconductor (SC) PET/CT were obtained using three types (M, L, LL; corresponding to increasing patient body weight) of custom-made body phantoms designed similarly to the National Electrical Manufacturers Association (NEMA) IEC body phantom. The phantom data were analyzed visually and quantitatively to derive image quality metrics, namely detectability of the 10-mm-diameter hot sphere, percent contrast for the 10-mm-diameter hot sphere (QH,10 mm), percent background variability (N10mm), contrast-to-noise ratio (QH,10 mm/N10mm), and coefficient of variation of the background area (CVBG). Results Visual assessment revealed that all the 10-mm-diameter hot spheres of the three types of phantoms were identifiable on both SC and TOF PET/CT images. The N10mm and CVBG values were within the proposed reference levels, and decreased with acquisition duration for both PET/CT types. At 10-min acquisition, the QH,10 mm/N10mm of SC PET/CT was greater than the proposed reference level in all phantoms. However, the QH,10 mm/N10mm of TOF PET/CT was greater than the proposed reference level in M-type phantom alone. All the SUVBG values were within 1.00 ± 0.05 for both PET/CT types. Conclusions This study showed that the image quality and quantification accuracy depend on the patient’s body mass, suggesting that acquisition time on 89Zr PET/CT should be changed according to the patient’s body mass.
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Affiliation(s)
- Ukihide Tateishi
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Hiromitsu Daisaki
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Radiological Technology, Gunma Prefectural College of Health Sciences, Gunma, Japan
| | - Junichi Tsuchiya
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuji Kojima
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keisuke Takino
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Naoki Shimada
- Department of Diagnostic Radiology, Cancer Institute Hospital, Tokyo, Japan
| | - Kota Yokoyama
- Department of Diagnostic Radiology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
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Shopa RY, Klimaszewski K, Kopka P, Kowalski P, Krzemień W, Raczyński L, Wiślicki W, Chug N, Curceanu C, Czerwiński E, Dadgar M, Dulski K, Gajos A, Hiesmayr BC, Kacprzak K, Kapłon Ł, Kisielewska D, Korcyl G, Krawczyk N, Kubicz E, Niedźwiecki S, Raj J, Sharma S, Shivani, Stȩpień EŁ, Tayefi F, Moskal P. Optimisation of the event-based TOF filtered back-projection for online imaging in total-body J-PET. Med Image Anal 2021; 73:102199. [PMID: 34365143 DOI: 10.1016/j.media.2021.102199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
We perform a parametric study of the newly developed time-of-flight (TOF) image reconstruction algorithm, proposed for the real-time imaging in total-body Jagiellonian PET (J-PET) scanners. The asymmetric 3D filtering kernel is applied at each most likely position of electron-positron annihilation, estimated from the emissions of back-to-back γ-photons. The optimisation of its parameters is studied using Monte Carlo simulations of a 1-mm spherical source, NEMA IEC and XCAT phantoms inside the ideal J-PET scanner. The combination of high-pass filters which included the TOF filtered back-projection (FBP), resulted in spatial resolution, 1.5 times higher in the axial direction than for the conventional 3D FBP. For realistic 10-minute scans of NEMA IEC and XCAT, which require a trade-off between the noise and spatial resolution, the need for Gaussian TOF kernel components, coupled with median post-filtering, is demonstrated. The best sets of 3D filter parameters were obtained by the Nelder-Mead minimisation of the mean squared error between the resulting and reference images. The approach allows training the reconstruction algorithm for custom scans, using the IEC phantom, when the temporal resolution is below 50 ps. The image quality parameters, estimated for the best outcomes, were systematically better than for the non-TOF FBP.
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Affiliation(s)
- R Y Shopa
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland.
| | - K Klimaszewski
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - P Kopka
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - P Kowalski
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - W Krzemień
- High Energy Physics Division, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - L Raczyński
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - W Wiślicki
- Department of Complex Systems, National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland
| | - N Chug
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - C Curceanu
- INFN, Laboratori Nazionali di Frascati, Frascati 00044, Italy
| | - E Czerwiński
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - M Dadgar
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - K Dulski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - A Gajos
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - B C Hiesmayr
- Faculty of Physics, University of Vienna, Vienna 1090, Austria
| | - K Kacprzak
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - Ł Kapłon
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - D Kisielewska
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - G Korcyl
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - N Krawczyk
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - E Kubicz
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - Sz Niedźwiecki
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - J Raj
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - S Sharma
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - Shivani
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - E Ł Stȩpień
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - F Tayefi
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
| | - P Moskal
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, 30-348 Cracow, Poland; Total-Body Jagiellonian-PET Laboratory, Jagiellonian University, Poland
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Olisa SC, Asiegbu CN, Olisa JE, Ekengwu BO, Shittu AA, Eze MC. Smart two-tank water quality and level detection system via IoT. Heliyon 2021; 7:e07651. [PMID: 34401568 PMCID: PMC8350529 DOI: 10.1016/j.heliyon.2021.e07651] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/20/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022] Open
Abstract
The two-tank water system is common practice for the storage and distribution of water in many homes. Water is transported via a pipeline network from the storage tank (lower tank) to the distribution tank (overhead tank) using an electric pumping machine. Due to limited control in the existing pumping system, water wastage becomes inevitable. Determining the quality of water in the overhead tank before supply in the home is still unaddressed. In this work, an integrated Android mobile App and a control system were developed to assess the water quality, perform level check in the overhead tank, and activate intelligent pumping control. An ultrasonic pulse-echo technique was used for water level checks, while the water turbidity and pH signals were used for water quality checks. Three-level control conditions (LC_1, LC_2, LC_3) and two water quality check conditions (QC_1 and QC_2) were devised and used in the intelligent control algorithm of the system. Control valve1 regulates the flushable poor water quality while valve2 regulates the house's supply of good water quality. The absolute relative error between the expected time and the system time of filling the tank level was observed to be less than 10% when the water volume is less than 81%. Hence, distortion in the sensory signals increases and worsen as the water level approaches the ultrasonic sensor position. The poor internet signal network was observed to affect the real-time monitoring and automation of the system control through delay in system responses to commands. However, the average recorded response time of the system is 3 s, and it could be less in the situation of good internet network services.
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Affiliation(s)
- Samuel C Olisa
- School of Transport, Aerospace and Manufacturing, Cranfield University, Bedford, MK43 0AL, UK.,Electronic Engineering Department, University of Nigeria, Nsukka, Nigeria
| | | | - Juliet E Olisa
- Electronic Engineering Department, University of Nigeria, Nsukka, Nigeria
| | | | - Abdulhakim A Shittu
- School of Water, Energy and Environment, Cranfield University, Bedford, MK43 0AL, UK.,Federal University Wukari, Taraba State, Nigeria
| | - Martin C Eze
- Electronic Engineering Department, University of Nigeria, Nsukka, Nigeria.,School of Engineering, Cardiff University, Cardiff, CF24 3AA, United Kingdom
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23
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Shanmugam P, Iglesias L, Michaud JF, Alquier D, Colin L, Dufour I, Certon D. Broad bandwidth air-coupled micromachined ultrasonic transducers for gas sensing. Ultrasonics 2021; 114:106410. [PMID: 33761341 DOI: 10.1016/j.ultras.2021.106410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/06/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
The present work aims to develop ultra-wide bandwidth air-coupled capacitive micromachined ultrasonic transducers (CMUTs) for binary gas mixture analysis. The detection principle is based on time-of-flight (ToF) measurements, in order to monitor gas ultrasound velocity variations. To perform such measurements, CMUTs were especially designed to work out of resonance mode, like a microphone. The chosen membrane size is 32 × 32 µm2 and gap height is 250 nm. The resonance frequency and collapse voltage were found at 8 MHz and 58 V respectively. As mentioned, the CMUTs were exploited in quasi-static operating mode, in a very low frequency band, from 1 MHz to 1.5 MHz frequencies. The transducer impulse response was characterised, and a -6 dB relative fractional frequency bandwidth (FBW) higher than 100% was measured, enabling to use CMUT for the targeted application. Additionally, a measuring cell has been designed to hold the fabricated CMUT emitter and receiver prototypes facing each other. The volume inside the cell was kept lower than 3 mL and the surface of emitter/receiver was 1.6 × 8 mm2. To validate the general principle of the proposed technique, two binary gas mixtures of CO2/N2 and H2/N2, with varying concentrations, have been tested. The results are very promising with a measured limit of detection (LOD) of 0.3% for CO2 in N2 and 0.15% for H2 in N2.
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Affiliation(s)
- P Shanmugam
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - L Iglesias
- IMS Laboratory UMR-CNRS 5218, University of Bordeaux, 351 cours de la libération, 33405 TALENCE Cedex, France.
| | - J F Michaud
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - D Alquier
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - L Colin
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - I Dufour
- IMS Laboratory UMR-CNRS 5218, University of Bordeaux, 351 cours de la libération, 33405 TALENCE Cedex, France.
| | - D Certon
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
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24
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Case JA. The Importance of Time-of-Flight Reconstruction and Point Spread Modeling in the Measurement of Myocardial Blood Flow Parameters. Curr Cardiol Rep 2021; 23:77. [PMID: 34081208 DOI: 10.1007/s11886-021-01507-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/14/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE OF REVIEW Absolute quantitation of myocardial blood flow has been recognized as one of the most important advances in nuclear cardiology. The addition of absolute myocardial blood flow quantitation has had a significant impact on the determination of normalcy, artifact/defect differentiation, and the true extent of coronary artery disease in patients with known or suspected coronary disease. Time-of-flight reconstruction and point spread function modeling of the potential to greatly improve resolution and signal to background. This combined with absolute blood flow measurements could improve the reliability of regional blood flow estimates and overall image quality. RECENT FINDINGS Recent publications have demonstrated that time-of-flight reconstruction can have an impact on the amount of spillover between the blood pool ROI and the myocardial regions. This may necessitate changes to kinetic models; however, these changes if implemented correctly may result in improved accuracy and reproducibility of blood flow estimates. This may also have the benefit of assessing blood flow in the microvasculature using newer F-18 labeled blood flow tracers. Time of flight and point spread function modeling represent significant improvements in the accuracy and quality of reconstructed myocardial perfusion PET images. This may also have significant implications for the reliability of blood flow estimates. To achieve these benefits, attention must be given to blood flow models to ensure that they have been correctly optimized for the scanner-specific time-of-flight reconstruction properties.
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Affiliation(s)
- James A Case
- Cardiovascular Imaging Technologies, 4320 Wornall Rd., Suite 114, Kansas City, MO, 64111, USA.
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25
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L'Her E, Nazir S, Pateau V, Visvikis D. Accuracy of noncontact surface imaging for tidal volume and respiratory rate measurements in the ICU. J Clin Monit Comput 2021; 36:775-783. [PMID: 33886075 PMCID: PMC8060689 DOI: 10.1007/s10877-021-00708-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/13/2021] [Indexed: 01/24/2023]
Abstract
Tidal volume monitoring may help minimize lung injury during respiratory assistance. Surface imaging using time-of-flight camera is a new, non-invasive, non-contact, radiation-free, and easy-to-use technique that enables tidal volume and respiratory rate measurements. The objectives of the study were to determine the accuracy of Time-of-Flight volume (VTTOF) and respiratory rate (RRTOF) measurements at the bedside, and to validate its application for spontaneously breathing patients under high flow nasal canula. Data analysis was performed within the ReaSTOC data-warehousing project (ClinicalTrials.gov identifier NCT02893462). All data were recorded using standard monitoring devices, and the computerized medical file. Time-of-flight technique used a Kinect V2 (Microsoft, Redmond, WA, USA) to acquire the distance information, based on measuring the phase delay between the emitted light-wave and received backscattered signals. 44 patients (32 under mechanical ventilation; 12 under high-flow nasal canula) were recorded. High correlation (r = 0.84; p < 0.001), with low bias (-1.7 mL) and acceptable deviation (75 mL) was observed between VTTOF and VTREF under ventilation. Similar performance was observed for respiratory rate (r = 0.91; p < 0.001; bias < 1b/min; deviation ≤ 5b/min). Measurements were possible for all patients under high-flow nasal canula, detecting overdistension in 4 patients (tidal volume > 8 mL/kg) and low ventilation in 6 patients (tidal volume < 6 mL/kg). Tidal volume monitoring using time-of-flight camera (VTTOF) is correlated to reference values. Time-of-flight camera enables continuous and non-contact respiratory monitoring under high-flow nasal canula, and enables to detect tidal volume and respiratory rate changes, while modifying flow. It enables respiratory monitoring for spontaneously patients, especially while using high-flow nasal oxygenation.
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Affiliation(s)
- Erwan L'Her
- Médecine Intensive Et Réanimation, CHRU de La Cavale Blanche, Bvd. Tanguy-Prigent, 29609, BREST Cedex, France. .,LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France.
| | - Souha Nazir
- LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France
| | - Victoire Pateau
- Médecine Intensive Et Réanimation, CHRU de La Cavale Blanche, Bvd. Tanguy-Prigent, 29609, BREST Cedex, France
| | - Dimitris Visvikis
- LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France
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26
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Matheoud R, Al-Maymani N, Oldani A, Sacchetti GM, Brambilla M, Carriero A. The role of activity, scan duration and patient's body mass index in the optimization of FDG imaging protocols on a TOF-PET/CT scanner. EJNMMI Phys 2021; 8:35. [PMID: 33825058 PMCID: PMC8024225 DOI: 10.1186/s40658-021-00380-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/18/2021] [Indexed: 11/22/2022] Open
Abstract
Background Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low count acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on the 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF-PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. Methods The NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR) and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/ml of FDG solution and the spheres with TBR of 21.2, 8.8 and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/ml, and images were reconstructed for ESD of 30–151 s per bed position with and without point spread function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. Results As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the BMI of the patient and TBR of the lesion. Conclusions AC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.
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Affiliation(s)
- Roberta Matheoud
- Medical Physics Department, Azienda Ospedaliero-Universitaria Maggiore della Carità, C.so Mazzini 18, 28100, Novara, Italy.
| | - Naema Al-Maymani
- Department of Physics, University of Trieste, Via Valerio 2, 34127, Trieste, Italy.,Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151, Trieste, Italy
| | - Alessia Oldani
- Università del Piemonte Orientale, School of Medicine, V. Solaroli 17, 28100, Novara, Italy
| | - Gian Mauro Sacchetti
- Nuclear Medicine Department, Azienda Ospedaliero-Universitaria Maggiore della Carità, C.so Mazzini 18, 28100, Novara, Italy
| | - Marco Brambilla
- Medical Physics Department, Azienda Ospedaliero-Universitaria Maggiore della Carità, C.so Mazzini 18, 28100, Novara, Italy
| | - Alessandro Carriero
- Radiology Department, Azienda Ospedaliero-Universitaria Maggiore della Carità, C.so Mazzini 18, 28100, Novara, Italy
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Nadig V, Schug D, Weissler B, Schulz V. Evaluation of the PETsys TOFPET2 ASIC in multi-channel coincidence experiments. EJNMMI Phys 2021; 8:30. [PMID: 33761038 PMCID: PMC7991069 DOI: 10.1186/s40658-021-00370-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 02/23/2021] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Aiming to measure the difference in arrival times of two coincident γ-photons with an accuracy in the order of 200ps, time-of-flight positron emission tomography systems commonly employ silicon photomultipliers (SiPMs) and high-resolution digitization electronics, application specific integrated circuits (ASICs). This work evaluates the performance of the TOFPET2 ASIC, released by PETsys Electronics S.A. in 2017, dependent on its configuration parameters in multi-channel coincidence measurements. METHODS SiPM arrays fabricated by different vendors (KETEK, SensL, Hamamatsu, Broadcom) were tested in combination with the ASIC. Scintillator arrays featuring different reflector designs and different configurations of the TOFPET2 ASIC software parameters were evaluated. The benchtop setup used is provided with the TOFPET2 ASIC evaluation kit by PETsys Electronics S.A. RESULTS Compared to existing studies featuring the TOFPET2 ASIC, multi-channel performance results dependent on a larger set of ASIC configuration parameters were obtained that have not been reported to this extend so far. The ASIC shows promising CRTs down to 219.9 ps in combination with two Hamamatsu S14161-3050-HS-08 SiPM arrays (128 channels read out, energy resolution 13.08%) and 216.1 ps in combination with two Broadcom AFBR-S4N44P643S SiPM arrays (32 channels read out, energy resolution 9.46%). The length of the trigger delay of the dark count suppression scheme has an impact on the ASIC performance and can be configured to further improve the coincidence resolution time. The integrator gain configuration has been investigated and allows an absolute improvement of the energy resolution by up to 1% at the cost of the linearity of the energy spectrum. CONCLUSION Measuring up to the time-of-flight performance of state-of-the-art positron emission tomography (ToF-PET) systems while providing a uniform and stable readout for multiple channels at the same time, the TOFPET2 ASIC is treated as promising candidate for the integration in future ToF-PET systems.
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Affiliation(s)
- Vanessa Nadig
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 17, Aachen, 52074 Germany
| | - David Schug
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 17, Aachen, 52074 Germany
- Hyperion Hybrid Imaging Systems GmbH, Pauwelsstrasse 19, Aachen, 52074 Germany
| | - Bjoern Weissler
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 17, Aachen, 52074 Germany
- Hyperion Hybrid Imaging Systems GmbH, Pauwelsstrasse 19, Aachen, 52074 Germany
| | - Volkmar Schulz
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 17, Aachen, 52074 Germany
- Hyperion Hybrid Imaging Systems GmbH, Pauwelsstrasse 19, Aachen, 52074 Germany
- III. Physikalisches Institut B, RWTH Aachen University, Otto-Blumenthal-Straße, Aachen, 52074 Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Forckenbeckstrasse 55, Aachen, 52074 Germany
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28
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Chapon A, Pereira D, Toews M, Belanger P. Deconvolution of ultrasonic signals using a convolutional neural network. Ultrasonics 2021; 111:106312. [PMID: 33307455 DOI: 10.1016/j.ultras.2020.106312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 09/16/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
Successfully employing ultrasonic testing to distinguish a flaw in close proximity to another flaw or geometrical feature depends on the wavelength and the bandwidth of the ultrasonic transducer. This explains why the frequency is commonly increased in ultrasonic testing in order to improve the axial resolution. However, as the frequency increases, the penetration depth of the propagating ultrasonic waves is reduced due to an attendant increase in attenuation. The nondestructive testing research community is consequently very interested in finding methods that combine high penetration depth with high axial resolution. This work aims to improve the compromise between the penetration depth and the axial resolution by using a convolutional neural network to separate overlapping echoes in time traces in order to estimate the time-of-flight and amplitude. The originality of the proposed framework consists in its training of the neural network using data generated in simulations. The framework was validated experimentally to detect flat bottom holes in an aluminum block with a minimum depth corresponding to λ/4.
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Affiliation(s)
- Arthur Chapon
- Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada
| | - Daniel Pereira
- Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada
| | - Matthew Toews
- Department of Systems Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada
| | - Pierre Belanger
- Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada.
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29
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Salvadori J, Odille F, Karcher G, Marie PY, Imbert L. Fully digital PET is unaffected by any deterioration in TOF resolution and TOF image quality in the wide range of routine PET count rates. EJNMMI Phys 2021; 8:1. [PMID: 33409746 PMCID: PMC7788141 DOI: 10.1186/s40658-020-00344-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Digital PET involving silicon photomultipliers (SiPM) provides an enhanced time-of-flight (TOF) resolution as compared with photomultiplier (PMT)-based PET, but also a better prevention of the count-related rises in dead time and pile-up effects mainly due to smaller trigger domains (i.e., the detection surfaces associated with each trigger circuit). This study aimed to determine whether this latter property could help prevent against deteriorations in TOF resolution and TOF image quality in the wide range of PET count rates documented in clinical routine. METHODS Variations, according to count rates, in timing resolution and in TOF-related enhancement of the quality of phantom images were compared between the first fully digital PET (Vereos) and a PMT-based PET (Ingenuity). Single-count rate values were additionally extracted from the list-mode data of routine analog- and digital-PET exams at each 500-ms interval, in order to determine the ranges of routine PET count rates. RESULTS Routine PET count rates were lower for the Vereos than for the Ingenuity. For Ingenuity, the upper limits were estimated at approximately 21.7 and 33.2 Mcps after injection of respectively 3 and 5 MBq.kg-1 of current 18F-labeled tracers. At 5.8 Mcps, corresponding to the lower limit of the routine count rates documented with the Ingenuity, timing resolutions provided by the scatter phantom were 326 and 621 ps for Vereos and Ingenuity, respectively. At higher count rates, timing resolution was remarkably stable for Vereos but exhibited a progressive deterioration for Ingenuity, respectively reaching 732 and 847 ps at the upper limits of 21.7 and 33.2 Mcps. The averaged TOF-related gain in signal/noise ratio was stable at approximately 2 for Vereos but decreased from 1.36 at 5.8 Mcps to 1.14 and 1.00 at respectively 21.7 and 33.2 Mcps for Ingenuity. CONCLUSION Contrary to the Ingenuity PMT-based PET, the Vereos fully digital PET is unaffected by any deterioration in TOF resolution and consequently, in the quality of TOF images, in the wide range of routine PET count rates. This advantage is even more striking with higher count-rates for which the preferential use of digital PET should be further recommended (i.e., dynamic PET recording, higher injected activities).
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Affiliation(s)
- Julien Salvadori
- Department of Nuclear Medicine and Nancyclotep Molecular Imaging Platform, CHRU-Nancy, Université de Lorraine, F54000, Nancy, France. .,Université de Lorraine, INSERM, UMR 1254, F54000, Nancy, France.
| | - Freddy Odille
- Department of Nuclear Medicine and Nancyclotep Molecular Imaging Platform, CHRU-Nancy, Université de Lorraine, F54000, Nancy, France.,Université de Lorraine, INSERM, UMR 1254, F54000, Nancy, France
| | - Gilles Karcher
- Department of Nuclear Medicine and Nancyclotep Molecular Imaging Platform, CHRU-Nancy, Université de Lorraine, F54000, Nancy, France.,Université de Lorraine, INSERM, UMR 1254, F54000, Nancy, France
| | - Pierre-Yves Marie
- Department of Nuclear Medicine and Nancyclotep Molecular Imaging Platform, CHRU-Nancy, Université de Lorraine, F54000, Nancy, France.,Université de Lorraine, INSERM, UMR 1116, F54000, Nancy, France
| | - Laetitia Imbert
- Department of Nuclear Medicine and Nancyclotep Molecular Imaging Platform, CHRU-Nancy, Université de Lorraine, F54000, Nancy, France.,Université de Lorraine, INSERM, UMR 1254, F54000, Nancy, France
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30
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Abstract
This article describes aspects of PET scanner design for long axial field-of-view systems and how these choices have an impact on scanner performance.
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Affiliation(s)
- Margaret E Daube-Witherspoon
- Department of Radiology, University of Pennsylvania, 3620 Hamilton Walk, Room 156H, Philadelphia, PA 19104, USA.
| | - Simon R Cherry
- Department of Biomedical Engineering, University of California, 451 Health Sciences Drive, Davis, CA 95616, USA
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31
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Bai H, Zhang G, Xiong Z, Li Y, Zhao D, Su M, Mo Z, Wang X, Gao F, Zhang H, Zhang Z, Wen J. A method to calibrate the n-γ discrimination property of scintillators in low energy region. Appl Radiat Isot 2020; 167:109447. [PMID: 33049654 DOI: 10.1016/j.apradiso.2020.109447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/08/2020] [Accepted: 09/23/2020] [Indexed: 10/23/2022]
Abstract
Scintillators with n-γ discrimination property are widely used in the measurement of neutrons. In sub MeV region, the n-γ discrimination property will be greatly deteriorated so that the neutron and γ-ray events can't be accurately discriminated. As a result, the determination of the proportions of neutron and γ-ray events beyond the discrimination threshold is important if scintillators are applied to measure the low energy neutrons. In the present work, a method based on the time-of-flight technique is proposed to calibrate the proportions of neutron and γ-ray events beyond the discrimination threshold. After the calibration, the numbers of the measured neutron and γ-ray events can be separately determined even if the neutron and γ-ray events can't be perfectly discriminated.
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Affiliation(s)
- Huaiyong Bai
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China; State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, 100871, China
| | - Guohui Zhang
- State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, 100871, China
| | - Zhonghua Xiong
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Yongming Li
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Deshan Zhao
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China.
| | - Ming Su
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Zhaohong Mo
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Xiaodong Wang
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Fan Gao
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Hongjun Zhang
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Zhenyu Zhang
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
| | - Ji Wen
- Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621907, China
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32
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Choi US, Kawaguchi H, Kida I. Cerebral artery segmentation based on magnetization-prepared two rapid acquisition gradient echo multi-contrast images in 7 Tesla magnetic resonance imaging. Neuroimage 2020; 222:117259. [PMID: 32798680 DOI: 10.1016/j.neuroimage.2020.117259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/12/2020] [Accepted: 08/03/2020] [Indexed: 11/20/2022] Open
Abstract
Cerebral artery segmentation plays an important role in the direct visualization of the human brain to obtain vascular system information. On ultra-high field magnetic resonance imaging, cerebral arteries appearing hyperintense on T1 weighted (T1w) images could be segmented from brain tissues such as gray and white matter. In this study, we propose an automated method to segment the cerebral arteries using multi-contrast images including T1w images of a magnetization-prepared two rapid acquisition gradient echo (MP2RAGE) sequence at 7 T. The proposed method, termed MP2rase-CA (MP2rage based RApid SEgmentation Cerebral Artery), employed a seed-based region-growing strategy and Frangi filtering as well as our brain tissue segmentation (MP2rase Brain Tissue). Time-of-flight (TOF) magnetic resonance angiography (MRA) images were obtained as a reference to evaluate the MP2rase-CA. We successfully performed vessel segmentations, from T1w MP2RAGE images, which mostly overlapped with the segmentations of large cerebral arteries from the TOF-MRA. We also investigated the effect of the large cerebral arteries on spatial transformation of anatomical images to standard coordinate space using vessel segmentation by MP2rase-CA. As a result, the T1w image without the cerebral arteries by MP2rase-CA showed better agreement with the standard atlas compared with the T1w image containing the arteries. In addition, voxel-based morphology showed significant differences between T1w images with and without cerebral arteries in brain areas nearby large arteries. Thus, because MP2rase-CA using MP2RAGE images can obtain brain tissue anatomical information as well as relatively large cerebral artery information without need for additional structure acquisition, it is useful and time saving for functional and structural studies.
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33
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Zeng GL, Lv L, Huang Q. Poisson-noise weighted filter for time-of-flight positron emission tomography. Vis Comput Ind Biomed Art 2020; 3:10. [PMID: 32350714 PMCID: PMC7190774 DOI: 10.1186/s42492-020-00048-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/14/2020] [Indexed: 12/22/2022] Open
Abstract
Image reconstruction for list-mode time-of-flight (TOF) positron emission tomography (PET) can be achieved by analytic algorithms. The backprojection filtering (BPF) algorithm is an efficient algorithm for this task. The conventional noise control method for analytic image reconstruction is the use of a stationary lowpass filter, which does not model the Poisson noise properly. This study proposes a nonstationary filter for Poisson noise control. The filter is implemented in the spatial domain in a form similar to convolution.
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Affiliation(s)
- Gengsheng L Zeng
- Department of Engineering, Utah Valley University, 800 West University Parkway, Orem, UT, 84058, USA.
- Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, UT, 84108, USA.
| | - Li Lv
- School of Biomedical Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
| | - Qiu Huang
- School of Biomedical Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
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34
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Salvadori J, Odille F, Verger A, Olivier P, Karcher G, Marie PY, Imbert L. Head-to-head comparison between digital and analog PET of human and phantom images when optimized for maximizing the signal-to-noise ratio from small lesions. EJNMMI Phys 2020; 7:11. [PMID: 32086646 PMCID: PMC7035408 DOI: 10.1186/s40658-020-0281-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
Background Routine PET exams are increasingly performed with reduced injected activities, leading to the use of different image reconstruction parameters than the NEMA parameters, in order to prevent from any deleterious decrease in signal-to-noise ratio (SNR) and thus, in lesion detectability. This study aimed to provide a global head-to-head comparison between digital (Vereos, Philips®) and analog (Ingenuity TF, Philips®) PET cameras of the trade-off between SNR and contrast through a wide-ranging number of reconstruction iterations, and with a further reconstruction optimization based on the SNR of small lesions. Methods Image quality parameters were compared between the two cameras on human and phantom images for a number of OSEM reconstruction iterations ranging from 1 to 10, the number of subsets being fixed at 10, and with the further identification of reconstruction parameters maximizing the SNR of spheres and adenopathies nearing 10 mm in diameter. These reconstructions were additionally obtained with and without time-of-flight (TOF) information (TOF and noTOF images, respectively) for further comparisons. Results On both human and phantom TOF images, the compromise between SNR and contrast was consistently more advantageous for digital than analog PET, with the difference being particularly pronounced for the lowest numbers of iterations and the smallest spheres. SNR was maximized with 1 and 2 OSEM iterations for the TOF images from digital and analog PET, respectively, whereas 4 OSEM iterations were required for the corresponding noTOF images from both cameras. On the TOF images obtained with this SNR optimization, digital PET exhibited a 37% to 44% higher SNR as compared with analog PET, depending on sphere size. These relative differences were however much lower for the noTOF images optimized for SNR (− 4 to + 18%), as well as for images reconstructed according to NEMA standards (− 4 to + 12%). Conclusion SNR may be dramatically higher for digital PET than for analog PET, especially when optimized for small lesions. This superiority is mostly attributable to enhanced TOF resolution and is significantly underestimated in NEMA-based analyses.
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Affiliation(s)
- Julien Salvadori
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France. .,IADI, INSERM, UMR 1254, Université de Lorraine, 54000, Nancy, France.
| | - Freddy Odille
- IADI, INSERM, UMR 1254, Université de Lorraine, 54000, Nancy, France
| | - Antoine Verger
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France.,IADI, INSERM, UMR 1254, Université de Lorraine, 54000, Nancy, France
| | - Pierre Olivier
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France
| | - Gilles Karcher
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France
| | - Pierre-Yves Marie
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France.,DCAC, INSERM, UMR 1116, Université de Lorraine, 54000, Nancy, France
| | - Laetitia Imbert
- Departement of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, 54000, Nancy, France.,IADI, INSERM, UMR 1254, Université de Lorraine, 54000, Nancy, France
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35
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Li M, Cappellin L, Xu J, Biasioli F, Varotto C. High-throughput screening for in planta characterization of VOC biosynthetic genes by PTR-ToF-MS. J Plant Res 2020; 133:123-131. [PMID: 31701286 PMCID: PMC6946754 DOI: 10.1007/s10265-019-01149-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/28/2019] [Indexed: 06/10/2023]
Abstract
Functional characterization of plant volatile organic compound (VOC) biosynthetic genes and elucidation of the biological function of their products often involve the screening of large numbers of plants from either independent transformation events or mapping populations. The low time resolution of standard gas chromatographic methods, however, represents a major bottleneck for in planta genetic characterization of VOC biosynthetic genes. Here we present a fast and highly-sensitive method for the high-throughput characterization of VOC emission levels/patterns by coupling a Proton Transfer Reaction Time-of-Flight Mass Spectrometer to an autosampler for automation of sample measurement. With this system more than 700 samples per day can be screened, detecting for each sample hundreds of spectrometric peaks in the m/z 15-300 range. As a case study, we report the characterization of VOC emissions from 116 independent Arabidopsis thaliana lines transformed with a putative isoprene synthase gene, confirming its function also when fused to a C-terminal 3×FLAG tag. We demonstrate that the method is more reliable than conventional characterization of transgene expression for the identification of the most highly isoprene-emitting lines. The throughput of this VOC screening method exceeds that of existing alternatives, potentially allowing its application to reverse and forward genetic screenings of genes contributing to VOC emission, constituting a powerful tool for the functional characterization of VOC biosynthetic genes and elucidation of the biological functions of their products directly in planta.
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Affiliation(s)
- Mingai Li
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, 38010, San Michele all' Adige, TN, Italy
| | - Luca Cappellin
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, 38010, San Michele all' Adige, TN, Italy
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35121, Padua, Italy
| | - Jia Xu
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, 38010, San Michele all' Adige, TN, Italy
- Dipartimento di Biologia, Università di Padova, Viale G. Colombo 3, 35121, Padua, Italy
| | - Franco Biasioli
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, 38010, San Michele all' Adige, TN, Italy
| | - Claudio Varotto
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, 38010, San Michele all' Adige, TN, Italy.
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36
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Zeng GL, Li Y, Huang Q. Analytic time-of-flight positron emission tomography reconstruction: two-dimensional case. Vis Comput Ind Biomed Art 2019; 2:22. [PMID: 32240412 PMCID: PMC7099571 DOI: 10.1186/s42492-019-0035-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/25/2019] [Indexed: 11/27/2022] Open
Abstract
In a positron emission tomography (PET) scanner, the time-of-flight (TOF) information gives us rough event position along the line-of-response (LOR). Using the TOF information for PET image reconstruction is able to reduce image noise. The state-of-the-art TOF PET image reconstruction uses iterative algorithms. Analytical image reconstruction algorithm exits for TOF PET which emulates the iterative Landweber algorithm. This paper introduces such an algorithm, focusing on two-dimensional (2D) reconstruction. The proposed algorithm is in the form of backprojection filtering, in which the backprojection is performed first, and then a 2D filter is applied to the backprojected image. For the list-mode data, the backprojection is carried out in the event-by-event fashion, and a profile function may be used along the projection LOR. The 2D filter depends on the TOF timing resolution as well as the backprojection profile function. In order to emulate the iterative algorithm effects, a Fourier-domain window function is suggested. This window function has a parameter, k, which corresponds to the iteration number in an iterative algorithm.
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Affiliation(s)
- Gengsheng L Zeng
- Department of Engineering, Utah Valley University, Orem, UT, 84058, USA. .,Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, 84108, USA.
| | - Ya Li
- Department of Mathematics, Utah Valley University, Orem, UT, 84058, USA
| | - Qiu Huang
- School of Biomedical Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
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37
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Jenčič B, Vavpetič P, Kelemen M, Vencelj M, Vogel-Mikuš K, Kavčič A, Pelicon P. MeV-SIMS TOF Imaging of Organic Tissue with Continuous Primary Beam. J Am Soc Mass Spectrom 2019; 30:1801-1812. [PMID: 31250317 DOI: 10.1007/s13361-019-02258-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
MeV-SIMS is an emerging mass spectrometry imaging method, which utilizes fast, heavy ions to desorb secondary molecules. High yields and low fragmentation rates of large molecules, associated with the electronic sputtering process, make it particularly useful in biomedical research, where insight into distribution of organic molecules is needed. Since the implementation of MeV-SIMS in to the micro-beam line at the tandem accelerator of Jožef Stefan Institute, MeV-SIMS provided some valuable observations on the distribution of biomolecules in plant tissue, as discussed by Jenčič et al. (Nucl. Inst. Methods Phys. Res. B. 371, 205-210, 2016; Nucl. Inst. Methods Phys. Res. B. 404, 140-145, 2017). However, limited focusing ability of the chlorine ion beam only allowed imaging at the tissue level. In order to surpass shortcomings of the existing method, we introduced a new approach, where we employ a continuous, low-current primary beam. In this mode, we bombard thin samples with a steady chlorine ion flux of approx. 5000 ions/s. After desorbing molecules, chlorine ions penetrate through the thinly cut sample and trigger the time-of-flight "start" signal on a continuous electron multiplier detector, positioned behind the sample. Such bombardment is more effective than previously used pulsing-beam mode, which demanded several orders of magnitude higher primary ion beam currents. Sub-micrometer focusing of low-current primary ion beam allows imaging of biological tissue on a subcellular scale. Simultaneously, new time-of-flight acquisition approach also improves mass resolution by a factor of 5. Within the article, we compare the performance of both methods and demonstrate the application of continuous mode on biological tissue. We also describe the thin sample preparation protocol, necessary for measurements with low primary ion currents.
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Affiliation(s)
- Boštjan Jenčič
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Primož Vavpetič
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Mitja Kelemen
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Matjaž Vencelj
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Katarina Vogel-Mikuš
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna pot 11, SI-1000, Ljubljana, Slovenia
| | - Anja Kavčič
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna pot 11, SI-1000, Ljubljana, Slovenia
| | - Primož Pelicon
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
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38
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Meixner CR, Liebig P, Speier P, Forman C, Hensel B, Schmidt M, Saake M, Uder M, Doerfler A, Heidemann RM, Schmitter S, Nagel AM. High resolution time-of-flight MR-angiography at 7 T exploiting VERSE saturation, compressed sensing and segmentation. Magn Reson Imaging 2019; 63:193-204. [PMID: 31434005 DOI: 10.1016/j.mri.2019.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 08/04/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND 3D Time-of-Flight (TOF) MR-angiography (MRA) substantially benefits from ultra-high magnetic field strengths (≥7 T) due to increased Signal-to-Noise ratio and improved contrast. However, high-resolution TOF-MRA usually requires long acquisition times. In addition, specific absorption rate constraints limit the choice of optimal pulse sequence parameters, especially if venous saturation is employed. PURPOSE To implement and evaluate an arterial TOF-MRA for accelerated high-resolution angiography at ultra-high magnetic field strength. FIELD STRENGTHS/SEQUENCE 7 T modified gradient-echo TOF sequence including venous saturation using Variable-Rate Selective Excitation (VERSE), Compressed Sensing (CS) and sparse application of saturation pulses, called segmentation, were included for acceleration. ASSESSMENT To analyze the acceleration techniques all volunteers were examined with the same protocols. CS with different sampling patterns and regularization factors as well as segmentation were applied for acceleration. For comparison, conventional acceleration techniques were applied (GRAPPA PAT 3 and Partial Fourier (6/8 in slice/phase encoding)). Images were co-registered and 40 mm thick transversal maximum intensity projections were created to calculate the relative number of vessels. To analyze the visibility of small vessels, the lenticulostriate arteries (LSA) were examined. This was done via multiscale vessel enhancement filtering in a VOI and quantification via Fiji ImageJ as well as qualitatively evaluation by two radiologists. Additionally, the venous/arterial vessel-to-background ratios (vVBR/aVBR) were calculated for chosen protocols. RESULTS For the acceleration of a high resolution TOF-MRA (0.31 mm isotropic), under-sampling of 9.6 showed aliasing artifacts, whereas 7.2 showed no aliasing. The regularization factor R had a strong impact on the image quality according to smoothing (R = 0.01 to R = 0.005) and noise (R = 0.0005 to R = 0.00005). With the alternating sampling patterns it was shown that the k-space center should not be under-sampled too much. Additionally segmentation could be verified to be feasible for stronger acceleration with sufficient venous suppression. CONCLUSION The combination of several independent techniques (VERSE, CS with acceleration factor 7.2, R = 0.001, Poisson disc radius of 80%, 3 segments) enables the application of high-resolution (0.31 mm isotropic) TOF-MRA with venous saturation at 7 T in clinical time settings (TA ≈ 5 min) and within the SAR limits.
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Affiliation(s)
- Christian R Meixner
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Patrick Liebig
- Siemens Healthcare GmbH, Erlangen, Germany; Max Schaldach-Stiftungsprofessur für Biomedizinische Technik (MSBT), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | | | - Bernhard Hensel
- Max Schaldach-Stiftungsprofessur für Biomedizinische Technik (MSBT), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Manuel Schmidt
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Marc Saake
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Arnd Doerfler
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt, Berlin, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Armin M Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Medical Physics, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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39
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Klingner N, Heller R, Hlawacek G, Facsko S, von Borany J. Time-of-flight secondary ion mass spectrometry in the helium ion microscope. Ultramicroscopy 2018; 198:10-17. [PMID: 30612043 DOI: 10.1016/j.ultramic.2018.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/20/2018] [Accepted: 12/23/2018] [Indexed: 10/27/2022]
Abstract
A helium ion microscope, known for high resolution imaging and modification with helium or neon ions, has been equipped with a time-of-flight spectrometer for compositional analysis. Here we report on its design, implementation and show first results of this powerful add-on. Our design considerations were based on the results of detailed ion collision cascade simulations that focus on the physically achievable resolution for various detection limits. Different secondary ion extraction geometries and spectrometer types are considered and compared with respect to the demands and limitations of the microscope. As a result the development and evaluation of a secondary ion extraction optics and time-of-flight spectrometer that allows the parallel measurement of all secondary ion masses is reported. First experimental results demonstrate an excellent mass resolution as well as high-resolution secondary ion imaging capabilities with sub-8 nm lateral resolution. The combination of high resolution secondary electron images and mass-separated sputtered ion distributions have a high potential to answer open questions in microbiology, cell biology, earth sciences and materials research.
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Affiliation(s)
- N Klingner
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, Dresden 01328, Germany.
| | - R Heller
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, Dresden 01328, Germany
| | - G Hlawacek
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, Dresden 01328, Germany
| | - S Facsko
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, Dresden 01328, Germany
| | - J von Borany
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, Dresden 01328, Germany
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40
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Muehlematter UJ, Nagel HW, Becker A, Mueller J, Vokinger KN, de Galiza Barbosa F, Ter Voert EEGT, Veit-Haibach P, Burger IA. Impact of time-of-flight PET on quantification accuracy and lesion detection in simultaneous 18F-choline PET/MRI for prostate cancer. EJNMMI Res 2018; 8:41. [PMID: 29855728 PMCID: PMC5981153 DOI: 10.1186/s13550-018-0390-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/18/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Accurate attenuation correction (AC) is an inherent problem of positron emission tomography magnetic resonance imaging (PET/MRI) systems. Simulation studies showed that time-of-flight (TOF) detectors can reduce PET quantification errors in MRI-based AC. However, its impact on lesion detection in a clinical setting with 18F-choline has not yet been evaluated. Therefore, we compared TOF and non-TOF 18F-choline PET for absolute and relative difference in standard uptake values (SUV) and investigated the detection rate of metastases in prostate cancer patients. RESULTS Non-TOF SUV was significantly lower compared to TOF in all osseous structures, except the skull, in primary lesions of the prostate, and in pelvic nodal and osseous metastasis. Concerning lymph node metastases, both experienced readers detected 16/19 (84%) on TOF PET, whereas on non-TOF PET readers 1 and 2 detected 11 (58%), and 14 (73%), respectively. With TOF PET readers 1 and 2 detected 14/15 (93%) and 11/15 (73%) bone metastases, respectively, whereas detection rate with non-TOF PET was 73% (11/15) for reader 1 and 53% (8/15) for reader 2. The interreader agreement was good for osseous metastasis detection on TOF (kappa 0.636, 95% confidence interval [CI] 0.453-0.810) and moderate on non-TOF (kappa = 0.600, CI 0.438-0.780). CONCLUSION TOF reconstruction for 18F-choline PET/MRI shows higher SUV measurements compared to non-TOF reconstructions in physiological osseous structures as well as pelvic malignancies. Our results suggest that addition of TOF information has a positive impact on lesion detection rate for lymph node and bone metastasis in prostate cancer patients.
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Affiliation(s)
- Urs J Muehlematter
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Hannes W Nagel
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Anton Becker
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
| | - Julian Mueller
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | | | | | - Edwin E G T Ter Voert
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Patrick Veit-Haibach
- Department Joint Medical Imaging, Toronto General Hospital, Toronto, ON, Canada
- University of Toronto, Toronto, ON, Canada
| | - Irene A Burger
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
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41
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Brophy P, Broeckling CD, Murphy J, Prenni JE. Ion-neutral Clustering of Bile Acids in Electrospray Ionization Across UPLC Flow Regimes. J Am Soc Mass Spectrom 2018; 29:651-662. [PMID: 29427066 DOI: 10.1007/s13361-017-1878-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 06/08/2023]
Abstract
Bile acid authentic standards were used as model compounds to quantitatively evaluate complex in-source phenomenon on a UPLC-ESI-TOF-MS operated in the negative mode. Three different diameter columns and a ceramic-based microfluidic separation device were utilized, allowing for detailed descriptions of bile acid behavior across a wide range of flow regimes and instantaneous concentrations. A custom processing algorithm based on correlation analysis was developed to group together all ion signals arising from a single compound; these grouped signals produce verified compound spectra for each bile acid at each on-column mass loading. Significant adduction was observed for all bile acids investigated under all flow regimes and across a wide range of bile acid concentrations. The distribution of bile acid containing clusters was found to depend on the specific bile acid species, solvent flow rate, and bile acid concentration. Relative abundancies of each cluster changed non-linearly with concentration. It was found that summing all MS level (low collisional energy) ions and ion-neutral adducts arising from a single compound improves linearity across the concentration range (0.125-5 ng on column) and increases the sensitivity of MS level quantification. The behavior of each cluster roughly follows simple equilibrium processes consistent with our understanding of electrospray ionization mechanisms and ion transport processes occurring in atmospheric pressure interfaces. Graphical Abstract ᅟ.
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Affiliation(s)
- Patrick Brophy
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523, USA
| | - Corey D Broeckling
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523, USA.
| | | | - Jessica E Prenni
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523, USA
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Abstract
Recent advancements in mass spectrometry (MS) and data analysis software have enabled new strategies for biological discovery using proteomics. Proteomics has evolved from routine discovery and identification of proteins to integrated multi-omics projects relating specific proteins to their genes and metabolites. Using additional information, such as that contained in biological pathways, has enabled the use of targeted protein quantitation for monitoring fold changes in expression as well as biomarker discovery. Here we discuss a full proteomic workflow from discovery proteomics on a quadrupole Time-of-Flight (Q-TOF) MS to targeted proteomics using a triple quadrupole (QQQ) MS. A discovery proteomics workflow encompassing acquisition of data-dependent proteomics data on a Q-TOF and protein database searching will be described which uses the protein abundances from identified proteins for subsequent statistical analysis and pathway visualization. From the active pathways, a protein target list is created for use in a peptide-based QQQ assay. These peptides are used as surrogates for target protein quantitation. Peptide-based QQQ assays provide sensitivity and selectivity allowing rapid and robust analysis of large batches of samples. These quantitative results are then statistically compared and visualized on the original biological pathways with a more complete coverage of proteins in the studied pathways.
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43
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Easter J. Confirmation of Pharmaceutical Identifiers via DART-TOF-MS. Methods Mol Biol 2018; 1810:69-74. [PMID: 29974418 DOI: 10.1007/978-1-4939-8579-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A direct analysis in real time ion source coupled with a time-of-flight mass spectrometer (DART-TOF-MS) is a suitable confirmatory technique for the analysis of pharmaceutical preparations, with accompanying reference sources for preparation markings. The DART-TOF-MS instrument allows for simple sample preparation and decreased analysis time, both crucial in a forensic laboratory setting. Differentiation can be made between active drug ingredients with the same molecular weight, such as hydrocodone and codeine, as well as pharmaceutical preparation mixtures, such as oxycodone and acetaminophen, using exact masses of the protonated molecules and fragment peaks compared to a standard.
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Affiliation(s)
- Jacob Easter
- Virginia Department of Forensic Science, Central Laboratory, Richmond, VA, USA.
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44
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Abstract
Screening is an integral component of an analytical scheme to identify the presence of controlled substances in submissions to the crime laboratory. Many techniques are utilized, including color tests, thin-layer chromatography, and ultraviolet spectroscopy. While these are useful techniques to guide the examiner, all will, at best, categorize the material into a broad group of compounds. Direct Analysis in Real Time (DART), coupled with a time-of-flight (TOF) mass spectrometer, is an emerging technique that yields highly definitive screening data leading to the identity of controlled substances present in a case sample. Sample preparation is quick and simple and run times are typically only a few minutes. Collected data will allow the examiner to determine appropriate standards for confirmation, making the overall analysis much more efficient. Presented here is a guide to using this technique for the screening of case submissions for controlled substances.
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Affiliation(s)
- Robert R Steiner
- Virginia Department of Forensic Science, Central Laboratory, Richmond, VA, USA.
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45
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Renard D, Le Bars E, Arquizan C, Gaillard N, de Champfleur NM, Mourand I. Time-of-flight MR angiography in cerebral venous sinus thrombosis. Acta Neurol Belg 2017; 117:837-840. [PMID: 28936607 DOI: 10.1007/s13760-017-0835-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/15/2017] [Indexed: 11/24/2022]
Abstract
Recently, time-of-flight (TOF) and gadolinium-enhanced MR angiography (MRA) imaging have been used to demonstrate subacute intramural hematoma in cervical artery dissection and to detect intraplaque haemorrhage. Our aim was to perform an exploratory study to analyse if venous thrombus-related signal changes (potentially showing iso- or hyperintensity) in cerebral venous sinus thrombosis (CVST) could be observed on 3D-TOF MRA imaging. We analysed retrospectively MRIs of CVST patients in whom both contrast-enhanced MR venography (CEMRV) and 3D-TOF sequences were performed in the acute/subacute phase (i.e. < 31 days after symptom onset). The occluded sinus segments were defined on CEMRV. First, analyses of signal changes in occluded venous sinuses segments (defined by and unblinded to CEMRV) on native 3D-TOF images and morphological MRI sequences were performed. Second, a blinded (to CEMRV and other morphological MRI sequences) analysis was performed on 3D-TOF imaging assessing signal changes on 3D-TOF considering all sinus segments. Twenty-five CVST patients were included. 3D-TOF imaging showed signal changes (most often hyperintensity and less often isointensity) in 84% of the occluded sinus segments. Signal changes were observed in 91% of the occluded sinus segments on T1-weighted imaging, in 69% on T2-weighted imaging, in 68% on FLAIR, in 32% on DWI, and in 55% on T2*-weighted imaging. On blinded analysis, sensitivity of 3D-TOF sequences decreased to 80%, whereas specificity was only 65%. Abnormal signal in the venous sinuses on 3D-TOF may possibly help to suspect CVST, especially when CEMRV sequences lack.
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Affiliation(s)
- Dimitri Renard
- Department of Neurology, Nîmes University Hospital, 4 Rue du Pr Debré, 30029, Nîmes Cedex 4, France.
| | - Emmanuelle Le Bars
- Department of Neurororadiology, Institut d, Imagerie Fonctionnelle Humaine, Montpellier University Hospital, 80 Avenue Augustin Fliche, 34000, Montpellier, France
| | - Caroline Arquizan
- Department of Neurology, Montpellier University Hospital, 80 Avenue Augustin Fliche, 34000, Montpellier, France
| | - Nicolas Gaillard
- Department of Neurology, Montpellier University Hospital, 80 Avenue Augustin Fliche, 34000, Montpellier, France
| | | | - Isabelle Mourand
- Department of Neurology, Montpellier University Hospital, 80 Avenue Augustin Fliche, 34000, Montpellier, France
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46
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García-Toraño E. Concept design of a time-of-flight spectrometer for the measurement of the energy of alpha particles. Appl Radiat Isot 2018; 134:219-24. [PMID: 28757352 DOI: 10.1016/j.apradiso.2017.07.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 11/21/2022]
Abstract
The knowledge of the energies of the alpha particles emitted in the radioactive decay of a nuclide is a key factor in the construction of its decay scheme. Virtually all existing data are based on a few absolute measurements made by magnetic spectrometry (MS), to which most other MS measurements are traced. An alternative solution would be the use of time-of-flight detectors. This paper discusses the main aspects to be considered in the design of such detectors, and the performances that could be reasonably expected. Based on the concepts discussed here, it is estimated that an energy resolution about 2.5keV may be attainable with a good quality source.
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47
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van der Vos CS, Koopman D, Rijnsdorp S, Arends AJ, Boellaard R, van Dalen JA, Lubberink M, Willemsen ATM, Visser EP. Quantification, improvement, and harmonization of small lesion detection with state-of-the-art PET. Eur J Nucl Med Mol Imaging 2017; 44:4-16. [PMID: 28687866 PMCID: PMC5541089 DOI: 10.1007/s00259-017-3727-z] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 05/09/2017] [Indexed: 01/09/2023]
Abstract
In recent years, there have been multiple advances in positron emission tomography/computed tomography (PET/CT) that improve cancer imaging. The present generation of PET/CT scanners introduces new hardware, software, and acquisition methods. This review describes these new developments, which include time-of-flight (TOF), point-spread-function (PSF), maximum-a-posteriori (MAP) based reconstruction, smaller voxels, respiratory gating, metal artefact reduction, and administration of quadratic weight-dependent 18F-fluorodeoxyglucose (FDG) activity. Also, hardware developments such as continuous bed motion (CBM), (digital) solid-state photodetectors and combined PET and magnetic resonance (MR) systems are explained. These novel techniques have a significant impact on cancer imaging, as they result in better image quality, improved small lesion detectability, and more accurate quantification of radiopharmaceutical uptake. This influences cancer diagnosis and staging, as well as therapy response monitoring and radiotherapy planning. Finally, the possible impact of these developments on the European Association of Nuclear Medicine (EANM) guidelines and EANM Research Ltd. (EARL) accreditation for FDG-PET/CT tumor imaging is discussed.
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Affiliation(s)
- Charlotte S van der Vos
- Department of Radiology and Nuclear Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Daniëlle Koopman
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
- Department of Nuclear Medicine, Isala Hospital, Zwolle, The Netherlands
| | - Sjoerd Rijnsdorp
- Department of Medical Physics, Catharina Hospital, Eindhoven, The Netherlands
| | - Albert J Arends
- Department of Medical Physics, Catharina Hospital, Eindhoven, The Netherlands
| | - Ronald Boellaard
- Department of Nuclear Medicine & Molecular Imaging, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Jorn A van Dalen
- Department of Nuclear Medicine, Isala Hospital, Zwolle, The Netherlands
- Department of Medical Physics, Isala, Zwolle, The Netherlands
| | - Mark Lubberink
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | - Antoon T M Willemsen
- Department of Nuclear Medicine & Molecular Imaging, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Eric P Visser
- Department of Radiology and Nuclear Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands.
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48
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Scherzinger J, Al Jebali R, Annand JRM, Bala A, Fissum KG, Hall-Wilton R, Hamilton D, Mauritzson N, Messi F, Perrey H, Rofors E. Tagging fast neutrons from a 252Cf fission-fragment source. Appl Radiat Isot 2017; 128:270-274. [PMID: 28755547 DOI: 10.1016/j.apradiso.2017.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 05/16/2017] [Accepted: 05/28/2017] [Indexed: 11/15/2022]
Abstract
Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a 252Cf source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous 4He scintillator detector. Together with α particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1-6MeV.
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Affiliation(s)
- J Scherzinger
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden; Detector Group, European Spallation Source ESS AB, SE-221 00 Lund, Sweden
| | - R Al Jebali
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - J R M Annand
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - A Bala
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - K G Fissum
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden; Detector Group, European Spallation Source ESS AB, SE-221 00 Lund, Sweden.
| | - R Hall-Wilton
- Detector Group, European Spallation Source ESS AB, SE-221 00 Lund, Sweden; Mid-Sweden University, SE-851 70 Sundsvall, Sweden
| | - D Hamilton
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - N Mauritzson
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden
| | - F Messi
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden; Detector Group, European Spallation Source ESS AB, SE-221 00 Lund, Sweden
| | - H Perrey
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden; Detector Group, European Spallation Source ESS AB, SE-221 00 Lund, Sweden
| | - E Rofors
- Division of Nuclear Physics, Lund University, SE-221 00 Lund, Sweden
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49
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Crecelius AC, Michalzik B, Potthast K, Meyer S, Schubert US. Tracing the fate and transport of secondary plant metabolites in a laboratory mesocosm experiment by employing mass spectrometric imaging. Anal Bioanal Chem 2017; 409:3807-3820. [PMID: 28357483 PMCID: PMC5427159 DOI: 10.1007/s00216-017-0325-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/28/2017] [Accepted: 03/16/2017] [Indexed: 01/06/2023]
Abstract
Mass spectrometric imaging (MSI) has received considerable attention in recent years, since it allows the molecular mapping of various compound classes, such as proteins, peptides, glycans, secondary metabolites, lipids, and drugs in animal, human, or plant tissue sections. In the present study, the application of laser-based MSI analysis of secondary plant metabolites to monitor their transport from the grass leaves of Dactylis glomerata, over the crop of the grasshopper Chorthippus dorsatus to its excrements, and finally in the soil solution is described. This plant-herbivore-soil pathway was investigated under controlled conditions by using laboratory mesocosms. From six targeted secondary plant metabolites (dehydroquinic acid, quinic acid, apigenin, luteolin, tricin, and rosmarinic acid), only quinic acid, and dehydroquinic acid, an in-source-decay (ISD) product of quinic acid, could be traced in nearly all compartments. The tentative identification of secondary plant metabolites was performed by MS/MS analysis of methanol extracts prepared from the investigated compartments, in both the positive and negative ion mode, and subsequently compared with the results generated from the reference standards. Except for tricin, all secondary metabolites could be tentatively identified by this approach. Additional liquid-chromatography mass spectrometry (LC-MS) experiments were carried out to verify the MSI results and revealed the presence of quinic acid only in grass and chewed grass, whereas apigenin-hexoside-pentoside and luteolin-hexoisde-pentoside could be traced in the grasshopper body and excrement extracts. In summary, the MSI technique shows a trade-off between sensitivity and spatial resolution. Graphical abstract Monitoring quinic acid in a mesocosm experiment by mass spectrometric imaging (MSI).
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Affiliation(s)
- Anna C Crecelius
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany.
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
| | - Beate Michalzik
- Institute of Geography, Friedrich Schiller University Jena, Löbdergraben 32, 07743, Jena, Germany
| | - Karin Potthast
- Institute of Geography, Friedrich Schiller University Jena, Löbdergraben 32, 07743, Jena, Germany
| | - Stefanie Meyer
- Institute of Geography, Friedrich Schiller University Jena, Löbdergraben 32, 07743, Jena, Germany
| | - Ulrich S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
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50
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Shang K, Cui B, Ma J, Shuai D, Liang Z, Jansen F, Zhou Y, Lu J, Zhao G. Clinical evaluation of whole-body oncologic PET with time-of-flight and point-spread function for the hybrid PET/MR system. Eur J Radiol 2017; 93:70-75. [PMID: 28668434 DOI: 10.1016/j.ejrad.2017.05.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/18/2017] [Accepted: 05/22/2017] [Indexed: 11/30/2022]
Abstract
PURPOSE Hybrid positron emission tomography/magnetic resonance (PET/MR) imaging is a new multimodality imaging technology that can provide structural and functional information simultaneously. The aim of this study was to investigate the effects of the time-of-flight (TOF) and point-spread function (PSF) on small lesions observed in PET/MR images from clinical patient image sets. MATERIALS AND METHODS This study evaluated 54 small lesions in 14 patients who had undergone 18F-fluorodeoxyglucose (FDG) PET/MR. Lesions up to 30mm in diameter were included. The PET data were reconstructed with a baseline ordered-subsets expectation-maximization (OSEM) algorithm, OSEM+PSF, OSEM+TOF and OSEM+TOF+PSF. PET image quality and small lesions were visually evaluated and scored by a 3-point scale. A quantitative analysis was then performed using the mean and maximum standardized uptake value (SUV) of the small lesions (SUVmean and SUVmax). The lesions were divided into two groups according to the long-axis diameter and the location respectively and evaluated with each reconstruction algorithm. We also evaluated the background signal by analyzing the SUVliver. RESULTS OSEM+TOF+PSF provided the highest value and OSEM+TOF or PSF showed a higher value than OSEM for the visual assessment and quantitative analysis. The combination of TOF and PSF increased the SUVmean by 26.6% and the SUVmax by 30.0%. The SUVliverwas not influenced by PSF or TOF. For the OSEM+TOF+PSF model, the change in SUVmean and SUVmax for lesions <10mm in diameter was 31.9% and 35.8%, and 24.5% and 27.6% for lesions 10-30mm in diameter, respectively. The abdominal lesions obtained the higher SUV than those of chest on the images with TOF and/or PSF. CONCLUSION Application of TOF and PSF significantly increased the SUV of small lesions in hybrid PET/MR images, potentially improving small lesion detectability.
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Affiliation(s)
- Kun Shang
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Bixiao Cui
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Jie Ma
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Dongmei Shuai
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Zhigang Liang
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China
| | | | - Yun Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Jie Lu
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China.
| | - Guoguang Zhao
- Department of Nuclear Medicine, Xuanwu Hospital of Capital Medical University, Beijing, China; Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China
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