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Baibarac M, Arzumanyan G, Daescu M, Udrescu A, Mamatkulov K. Anisotropic Photoluminescence of Poly(3-hexyl thiophene) and Their Composites with Single-Walled Carbon Nanotubes Highly Separated in Metallic and Semiconducting Tubes. Molecules 2021; 26:E294. [PMID: 33435534 PMCID: PMC7827376 DOI: 10.3390/molecules26020294] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/31/2020] [Accepted: 01/05/2021] [Indexed: 11/17/2022] Open
Abstract
In this work, the effect of the single-walled carbon nanotubes (SWNTs) as the mixtures of metallic and semiconducting tubes (M + S-SWNTs) as well as highly separated semiconducting (S-SWNTs) and metallic (M-SWNTs) tubes on the photoluminescence (PL) of poly(3-hexyl thiophene) (P3HT) was reported. Two methods were used to prepare such composites, that is, the chemical interaction of the two constituents and the electrochemical polymerization of the 3-hexyl thiophene onto the rough Au supports modified with carbon nanotubes (CNTs). The measurements of the anisotropic PL of these composites have highlighted a significant diminution of the angle of the binding of the P3HT films electrochemical synthetized onto Au electrodes covered with M + S-SWNTs. This change was attributed to metallic tubes, as was demonstrated using the anisotropic PL measurements carried out on the P3HT/M-SWNTs and P3HT/S-SWNTs composites. Small variations in the angle of the binding were reported in the case of the composites prepared by chemical interaction of the two constituents. The proposed mechanism to explain this behavior took into account the functionalization process of CNTs with P3HT. The experimental arguments of the functionalization process of CNTs with P3HT were shown by the UV-VIS-NIR and FTIR spectroscopy as well as surface-enhanced Raman scattering (SERS). A PL quenching process of P3HT induced both in the presence of S-SWNTs and M-SWNTs was reported, too. This process origins in the various de-excitation pathways which can be developed considering the energy levels diagram of the two constituents of each studied composite.
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Affiliation(s)
- Mihaela Baibarac
- Optical Processes in Nanostructure Materials Laboratory, National Institute of Materials Physics, Atomistilor Str. 405 A, 77125 Magurele, Romania; (M.D.); (A.U.)
| | - Grigory Arzumanyan
- Neutron Physics, Joint Institute for Nuclear Research Laboratory, 6 Joliot-Curie Street, 141980 Dubna, Russia; (G.A.); (K.M.)
| | - Monica Daescu
- Optical Processes in Nanostructure Materials Laboratory, National Institute of Materials Physics, Atomistilor Str. 405 A, 77125 Magurele, Romania; (M.D.); (A.U.)
| | - Adelina Udrescu
- Optical Processes in Nanostructure Materials Laboratory, National Institute of Materials Physics, Atomistilor Str. 405 A, 77125 Magurele, Romania; (M.D.); (A.U.)
| | - Kahramon Mamatkulov
- Neutron Physics, Joint Institute for Nuclear Research Laboratory, 6 Joliot-Curie Street, 141980 Dubna, Russia; (G.A.); (K.M.)
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2
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Czub J, Braziewicz J, Brodecki M, Gieszczyk W, Kłosowski M, Wasilewski A, Wołowiec P, Wójcik A, Wysocka-Rabin A. CALIBRATION OF LOW ENERGY X-RAY EXPERIMENTAL SETUP WITH STRONGLY FILTERED BEAM USING DATA FROM A SEMICONDUCTOR AND A THERMOLUMINESCENT DETECTORS. Radiat Prot Dosimetry 2019; 185:266-273. [PMID: 30624748 DOI: 10.1093/rpd/ncy291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 11/25/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
Abstract
The calibration of low energy X-ray experimental setup with strongly filtered beam dedicated to radiobiological research was performed using the absorbed dose calculated from the data collected by two types detectors. For this purpose a semiconductor (Amptek, USA) and a thermoluminescent (Institute of Nuclear Physics, Krakow, Poland) detectors were applied. The absorbed dose in water values estimated by both detectors are in good agreement.
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Affiliation(s)
- Joanna Czub
- Jan Kochanowski University, Institute of Physics, ul. Świętokrzyska 15, Kielce, Poland
| | - Janusz Braziewicz
- Jan Kochanowski University, Institute of Physics, ul. Świętokrzyska 15, Kielce, Poland
- Holy Cross Cancer Center, ul. Arwińskiego 3, Kielce, Poland
| | - Marcin Brodecki
- Department of Radiological Protection, Nofer Institute of Occupational Medicine, ul. św. Teresy 8, Łódź, Poland
| | - Wojciech Gieszczyk
- Department of Radiation Physics and Dosimetry, The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Science, ul. Radzikowskiego 152, Kraków
| | - Mariusz Kłosowski
- Department of Radiation Physics and Dosimetry, The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Science, ul. Radzikowskiego 152, Kraków
| | - Adam Wasilewski
- National Centre for Nuclear Research, ul. Andrzeja Sołtana 7, Otwock, Świerk, Poland
| | - Paweł Wołowiec
- Holy Cross Cancer Center, ul. Arwińskiego 3, Kielce, Poland
| | - Andrzej Wójcik
- Department of Molecular Bioscience, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Universitetsvagen 10, Stockholm, Sweden
- Jan Kochanowski University, Institute of Biology, ul. Świętokrzyska 15, Kielce, Poland
| | - Anna Wysocka-Rabin
- National Centre for Nuclear Research, ul. Andrzeja Sołtana 7, Otwock, Świerk, Poland
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3
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Babcock HP, Huang F, Speer CM. Correcting Artifacts in Single Molecule Localization Microscopy Analysis Arising from Pixel Quantum Efficiency Differences in sCMOS Cameras. Sci Rep 2019; 9:18058. [PMID: 31792238 PMCID: PMC6889274 DOI: 10.1038/s41598-019-53698-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 05/05/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023] Open
Abstract
Optimal analysis of single molecule localization microscopy (SMLM) data acquired with a scientific Complementary Metal-Oxide-Semiconductor (sCMOS) camera relies on statistical compensation for its pixel-dependent gain, offset and readout noise. In this work we show that it is also necessary to compensate for differences in the relative quantum efficiency (RQE) of each pixel. We found differences in RQE on the order of 4% in our tested sCMOS sensors. These differences were large enough to have a noticeable effect on analysis algorithm results, as seen both in simulations and biological imaging data. We discuss how the RQE differences manifest themselves in the analysis results and present the modifications to the Poisson maximum likelihood estimation (MLE) sCMOS analysis algorithm that are needed to correct for the RQE differences.
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Affiliation(s)
- Hazen P Babcock
- Center for Advanced Imaging, Harvard University, Cambridge, MA, 02138, USA.
| | - Fang Huang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Colenso M Speer
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
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4
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Treccani M, Bedogni R, Pola A, Costa M, Monti V, Sans Planell O, Romano M, Durisi E, Visca DL, Bortot D, Gomez-Ros JM, Ferrero M, Anglesio S, Giannini G, Alikaniotis K. DEVELOPING RADIATION RESISTANT THERMAL NEUTRON DETECTORS FOR THE E_LIBANS PROJECT: PRELIMINARY RESULTS. Radiat Prot Dosimetry 2018; 180:304-308. [PMID: 29361156 DOI: 10.1093/rpd/ncx298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 06/07/2023]
Abstract
Radiation-resistant, gamma-insensitive, active thermal neutron detectors were developed to monitor the thermal neutron cavity of the E_LIBANS project. Silicon and silicon carbide semiconductors, plus vented air ion chambers, were chosen for this purpose. This communication describes the performance of these detectors, owing on the results of dedicated measurement campaigns.
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Affiliation(s)
- M Treccani
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, Frascati, Roma, Italy
- Universitat Autònoma de Barcelona, Plaça Cívica s/n, Bellaterra, Barcelona, Spain
| | - R Bedogni
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, Frascati, Roma, Italy
| | - A Pola
- Politecnico di Milano, Dipartimento di Energia, via Lambruschini 34, Milano, Italy
- INFN Sezione di Milano, via Celoria 16, Milano, Italy
| | - M Costa
- Università di Torino, via Pietro Giuria 1, Torino, Italy
- INFN Sezione di Torino, via Pietro Giuria 1, Torino, Italy
| | - V Monti
- Università di Torino, via Pietro Giuria 1, Torino, Italy
- INFN Sezione di Torino, via Pietro Giuria 1, Torino, Italy
| | - O Sans Planell
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, Frascati, Roma, Italy
| | - M Romano
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, Frascati, Roma, Italy
| | - E Durisi
- Università di Torino, via Pietro Giuria 1, Torino, Italy
- INFN Sezione di Torino, via Pietro Giuria 1, Torino, Italy
| | - D L Visca
- Università di Torino, via Pietro Giuria 1, Torino, Italy
- INFN Sezione di Torino, via Pietro Giuria 1, Torino, Italy
| | - D Bortot
- Politecnico di Milano, Dipartimento di Energia, via Lambruschini 34, Milano, Italy
- INFN Sezione di Milano, via Celoria 16, Milano, Italy
| | - J M Gomez-Ros
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, Frascati, Roma, Italy
- CIEMAT, Av. Complutense 40, Madrid, Spain
| | - M Ferrero
- INFN Sezione di Torino, via Pietro Giuria 1, Torino, Italy
| | - S Anglesio
- CIEMAT, Av. Complutense 40, Madrid, Spain
- A.O.U. San Luigi Gonzaga Orbassano, via Regione Gonzole 10, Orbassano (Torino), Italy
| | - G Giannini
- Università di Trieste, via Valerio 2, Trieste, Italy
- INFN Sezione di Trieste, via Valerio 2, Trieste, Italy
| | - K Alikaniotis
- Università di Trieste, via Valerio 2, Trieste, Italy
- INFN Sezione di Trieste, via Valerio 2, Trieste, Italy
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5
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Chen X, Zeng Z, Li R, Xue B, Xi P, Sun Y. Superior performance with sCMOS over EMCCD in super-resolution optical fluctuation imaging. J Biomed Opt 2016; 21:66007. [PMID: 27281064 DOI: 10.1117/1.jbo.21.6.066007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 05/10/2016] [Indexed: 06/06/2023]
Abstract
Super-resolution optical fluctuation imaging (SOFI) is a fast and low-cost live-cell optical nanoscopy for extracting subdiffraction information from the statistics of fluorescence intensity fluctuation. As SOFI is based on the fluctuation statistics, rather than the detection of single molecules, it poses unique requirements for imaging detectors, which still lack a systematic evaluation. Here, we analyze the influences of pixel sizes, frame rates, noise levels, and different gains in SOFI with simulations and experimental tests. Our analysis shows that the smaller pixel size and faster readout speed of scientific-grade complementary metal oxide semiconductor (sCMOS) enables SOFI to achieve high spatiotemporal resolution with a large field-of-view, which is especially beneficial for live-cell super-resolution imaging. Overall, as the performance of SOFI is relatively insensitive to the signal-to-noise ratio (SNR), the gain in pixel size and readout speed exceeds the loss in SNR, indicating sCMOS is superior to electron multiplying charge coupled device in context to SOFI in many cases. Super-resolution imaging of cellular microtubule structures with high-order SOFI is experimentally demonstrated at large field-of-view, taking advantage of the large pixel number and fast frame rate of sCMOS cameras.
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Affiliation(s)
- Xuanze Chen
- Peking University, College of Engineering, Department of Biomedical Engineering, No. 5 Yiheyuan Road Haidian District, Beijing 100871, ChinabPeking University, State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of
| | - Zhiping Zeng
- Peking University, College of Engineering, Department of Biomedical Engineering, No. 5 Yiheyuan Road Haidian District, Beijing 100871, China
| | - Rongqin Li
- Peking University, State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, No. 5 Yiheyuan Road Haidian District, Beijing 100871, China
| | - Boxin Xue
- Peking University, State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, No. 5 Yiheyuan Road Haidian District, Beijing 100871, China
| | - Peng Xi
- Peking University, College of Engineering, Department of Biomedical Engineering, No. 5 Yiheyuan Road Haidian District, Beijing 100871, China
| | - Yujie Sun
- Peking University, State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, No. 5 Yiheyuan Road Haidian District, Beijing 100871, China
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Wang C, Hill K, Yoshizumi T. Characterization of MOSFET Dosimeter Angular Response Using a Spherical Phantom for Fluoroscopic Dosimetry. Health Phys 2016; 110:45-49. [PMID: 26606064 DOI: 10.1097/hp.0000000000000370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) dosimeters, placed in anthropomorphic phantoms, are a standard method for organ dosimetry in medical x-ray imaging applications. However, many x-ray applications, particularly fluoroscopy procedures, use variable projection angles. During dosimetry, the MOSFET detector active area may not always be perpendicular to the x-ray beam. The goal of this study was to characterize the dosimeter's angular response in the fluoroscopic irradiation involved in pediatric cardiac catheterization procedures, during which a considerable amount of fluoroscopic x-ray irradiation is often applied from various projection angles. A biological x-ray irradiator was used to simulate the beam quality of a biplane fluoroscopy imaging system. A custom-designed acrylic spherical scatter phantom was fabricated to measure dosimeter response (in mV) in two rotational axes, axial (ψ) and normal-to-axial (θ), in 30° increments, as well as four common oblique angles used in cardiac catheterization: a) 90° Left Anterior Oblique (LAO); b) 70° LAO/ 20° Cranial; c) 20° LAO/ 15° Cranial; and d) 30° Right Anterior Oblique (RAO). All results were normalized to the angle where the dosimeter epoxy is perpendicular to the beam or the Posterior-Anterior projection angle in the clinical setup. The relative response in the axial rotation was isotropic (within ± 10% deviation); that in the normal-to-axial rotation was isotropic in all angles except the ψ = 270° angle, where the relative response was 83 ± 9%. No significant deviation in detector response was observed in the four common oblique angles, with their relative responses being: a) 102 ± 3%; b) 90 ± 3%; c) 92 ± 3%; and d) 95 ± 3%, respectively. These angular correction factors will be used in future dosimetry studies for fluoroscopy. The spherical phantom may be useful for other applications, as it allows the measurement of dosimeter response in virtually all angles in the 3-dimensional spherical coordinates.
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Affiliation(s)
- Chu Wang
- *Medical Physics Graduate Program, Duke University Medical Center, Durham, NC 27705; †Duke Radiation Dosimetry Laboratory, Duke University Medical Center, Durham, NC 27710; ‡Department of Medicine, Division of Pediatric Cardiology, Duke University Medical Center, Durham, NC 27710; §Department of Radiology, Duke University Medical Center, Durham, NC 27710; **Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710
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7
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Kropat G, Baechler S, Bailat C, Barazza F, Bochud F, Damet J, Meyer N, Palacios Gruson M, Butterweck G. Calibration of the Politrack® system based on CR39 solid-state nuclear track detectors for passive indoor radon concentration measurements. Radiat Prot Dosimetry 2015; 167:302-305. [PMID: 25948829 DOI: 10.1093/rpd/ncv267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Swiss national requirements for measuring radon gas exposures demand a lower detection limit of 50 kBq h m(-3), representing the Swiss concentration average of 70 Bq m(-3) over a 1-month period. A solid-state nuclear track detector (SSNTD) system (Politrack, Mi.am s.r.l., Italy) has been acquired to fulfil these requirements. This work was aimed at the calibration of the Politrack system with traceability to international standards and the development of a procedure to check the stability of the system. A total of 275 SSNTDs was exposed to 11 different radon exposures in the radon chamber of the Secondary Calibration Laboratory at the Paul Scherrer Institute, Switzerland. The exposures ranged from 50 to 15000 kBq h m(-3). For each exposure of 20 detectors, 5 SSNTDs were used to monitor possible background exposures during transport and storage. The response curve and the calibration factor of the whole system were determined using a Monte Carlo fitting procedure. A device to produce CR39 samples with a reference number of tracks using a (241)Am source was developed for checking the long-term stability of the Politrack system. The characteristic limits for the detection of a possible system drift were determined following ISO Standard 11929.
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Affiliation(s)
- G Kropat
- Institute of Radiation Physics, Lausanne, Switzerland
| | - S Baechler
- Swiss Federal Office of Public Health, Berne, Switzerland
| | - C Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
| | - F Barazza
- Swiss Federal Office of Public Health, Berne, Switzerland
| | - F Bochud
- Institute of Radiation Physics, Lausanne, Switzerland
| | - J Damet
- Institute of Radiation Physics, Lausanne, Switzerland
| | - N Meyer
- Institute of Radiation Physics, Lausanne, Switzerland
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Watterson A. Regulation of Occupational Health and Safety in the Semiconductor Industry: Enforcement Problems and Solutions. International Journal of Occupational and Environmental Health 2013; 12:72-80. [PMID: 16523986 DOI: 10.1179/oeh.2006.12.1.72] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Reports of high incidences of occupational illnesses in the semiconductor industry should have triggered global investigations and rigorous inspection of the industry. Yet semiconductor plants remain essentially unregulated. Health and safety standards are inadequate and enforcement is lax. Roles for stakeholders in laying down good practice, monitoring, and regulating are proposed, and obstacles are described. Effective regulation has advantages for the industry as well as workers. Conditions for best practice include education at all levels, protection and support for labor inspectors, government commitment to enforcing laws, recognition of the right of workers to organize, and recognition of their rights.
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Affiliation(s)
- Andrew Watterson
- Occupational and Environmental Health Research Group, University of Stirling, Scotland.
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9
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Kuchma VR, Sukhareva LM, Teksheva LM, Stepanova MI, Sazaniuk ZI. [Hygienic aspects of the use of LED light sources for general illumination in schools]. Gig Sanit 2013:27-31. [PMID: 24340905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
For the time present becoming more common semiconductor sources of artificial lighting has become a more and more frequent practice. With the aim to study the impact of LEDs on the health of schoolchildren studies in experimental conditions (specially equipped classrooms) were performed. The comparative analysis of the state of vision, mental health and emotional state of pupils in primary, middle and high schools under fluorescent and LED lighting, meeting to the regulatory requirements, has revealed that the physiological cost of schooling in the use of LED units in classrooms is lower than in a traditional, fluorescent lighting.
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10
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Helander A, Walther RI, Jones AW. [Determination of alcohol in exhaled breath may give wrong values. Warning for unspecific testing with some instruments]. Lakartidningen 2010; 107:110-112. [PMID: 20225686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Anders Helander
- Institutionen för klinisk neurovetenskap, Karolinska institutet, Stockholm.
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11
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Abe A, Takahashi N, Lee J, Oka T, Shizukuishi K, Kikuchi T, Inoue T, Jimbo M, Ryuo H, Bickel C. Performance evaluation of a hand-held, semiconductor (CdZnTe)-based gamma camera. Eur J Nucl Med Mol Imaging 2003; 30:805-11. [PMID: 12677308 DOI: 10.1007/s00259-002-1067-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2002] [Accepted: 10/28/2002] [Indexed: 02/06/2023]
Abstract
We have designed and developed a small field of view gamma camera, the eZ SCOPE, based on use of a CdZnTe semiconductor. This device utilises proprietary signal processing technology and an interface to a computer-based imaging system. The purpose of this study was to evaluate the performance of the eZ scope in comparison with currently employed gamma camera technology. The detector is a single wafer of 5-mm-thick CdZnTe that is divided into a 16x16 array (256 pixels). The sensitive area of the detector is a square of dimension 3.2 cm. Two parallel-hole collimators are provided with the system and have a matching (256 hole) pattern to the CdZnTe detector array: a low-energy, high-resolution parallel-hole (LEHR) collimator fabricated of lead and a low-energy, high-sensitivity parallel-hole (LEHS) collimator fabricated of tungsten. Performance measurements and the data analysis were done according to the procedures of the NEMA standard. We also studied the long-term stability of the system with continuous use and variations in ambient temperature. Results were as follows. INTRINSIC ENERGY RESOLUTION: 8.6% FWHM at 141 keV.LINEARITY: There was excellent linearity between the observed photopeaks and the known gamma ray energies for the given isotopes. INTRINSIC SYSTEM UNIFORMITY: For the central field of view, the integral uniformity and the differential uniformity were, respectively, 1.6% and 1.3% with the LEHR collimator and 1.9% and 1.2% with the LEHS collimator. SYSTEM SPATIAL RESOLUTION: The FWHM measurements made at the surface of the collimator were 2.2 mm (LEHR) and 2.9 mm (LEHS).CONTRAST TEST: The average S/N ratios (i.e. counts in the irradiated pixel divided by counts in the surrounding pixels) for the inner ring pixels (8)/outer ring pixels (16) using the LEHS collimator and LEHR collimator were 3.2%/0.2% and 3.7%/0.3%, respectively. COUNT RATE CHARACTERISTICS: We could not determine the maximum count rate and the 20% loss count rate from these data because the plateau was not reached while using the solutions measured. SYSTEM SENSITIVITY: The average acquisitions were 11,052 cpm/MBq (LEHR) and 28,590 cpm/MBq (LEHS). TEMPERATURE DEPENDENCE: The system displayed minimum corresponding shift in cps with temperature changes in the measured temperature range. We designed and developed a semiconductor-based gamma camera using CdZnTe. The basic performance of this camera compares favourably with the existing gamma camera technology that is deployed in the medical field today. The most significant differences include the spatial resolution, sensitivity, high count rate characteristics and energy resolution. We believe that this device will be of value for a number of clinical applications including sentinel node detection and radiopharmaceutical-guided surgery.
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Affiliation(s)
- Aya Abe
- Department of Radiology, School of Medicine, Yokohama City University, Kanagawa, Japan.
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13
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Chow AY, Pardue MT, Perlman JI, Ball SL, Chow VY, Hetling JR, Peyman GA, Liang C, Stubbs EB, Peachey NS. Subretinal implantation of semiconductor-based photodiodes: durability of novel implant designs. J Rehabil Res Dev 2002; 39:313-21. [PMID: 12173752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Selective degeneration of the retinal photoreceptor layers underlies blindness in retinitis pigmentosa (RP) and other inherited retinal disorders. Because there are no therapies for these patients, we are evaluating the possibility that electrical stimulation delivered to the subretinal space by a microphotodiode array (MPA) could replace, in some aspect, the function of diseased photoreceptors. Early MPA prototypes utilized gold as the electrode material, which gradually dissolved during the postoperative period following subretinal implantation. Here we present the results obtained when different MPA materials were used. Semiconductor-based silicon MPAs (2 mm in diameter; 50 microm in thickness), incorporating iridium/iridium oxide (IrOx) or platinum (Pt) electrodes, were implanted into the subretinal space of the right eye of normal cats with the use of vitreoretinal surgical techniques. Indirect ophthalmoscopy, fundus photography, ganzfeld electroretinography, and histology were used for the evaluation of the implanted retinas postoperatively. Infrared (IR) stimulation was used to isolate electrical responses generated by the MPA. The unimplanted left eyes were used for control purposes. After the implantation surgery, subretinal MPAs retained a stable position in the subretinal space. Up to 12 months after surgery, there was little change in the magnitude of the electrical response of IrOx- and Pt-based MPAs to a standard IR light stimulus. Overlying the implant, there was a near-complete loss of the outer retinal layer, which is likely to reflect obstruction of choroidal nourishment to these layers by the solid disk implant. In addition, the inner retinal layers showed variable disorganization. Away from the implant, the retina displayed a normal appearance. In comparison to electroretinograms (ERGs) obtained from unimplanted eyes, responses recorded from implanted eyes had a normal waveform but were slightly smaller in amplitude. These results indicate that IrOx and Pt improve implant electrode durability and that implants incorporating these materials into the electrode layer do not induce panretinal abnormalities.
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Affiliation(s)
- Alan Y Chow
- Optobionics Corporation, Wheaton, IL 60187, USA.
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14
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Abstract
This paper describes the initial physics testing necessary before diodes can be used for in vivo dosimetry as well as the development of a protocol for clinical use in head and neck treatment and the preliminary results acquired. 50 patients were entered into the pilot study. A total of 300 treatment set-ups were measured (184 entrance doses and 116 exit doses). Wedged and unwedged components of each field were measured separately, making the total number of entrance doses 284 and total number of exit doses 207. There was no significant systematic deviation in the measured entrance dose compared with the expected (mean +0.4%, SD 2.7%). Discrepancies between the observed and expected entrance doses of greater than 5% were recorded in 6% (16/284) of measurements. The mean of the measured exit doses was 2.4% lower than expected (SD 4.8%). Discrepancies between the observed and expected exist doses of greater than 5% were recorded in 32% (67/207) of measurements. Possible causes for these discrepancies are discussed. Overall analysis of the data for individual patients suggest that in one patient out of the 50 there may have been a delivered target volume dose discrepancy of greater than 5% (+6.5%). The significance of the results and the implications for routine use are discussed.
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Affiliation(s)
- C J Millwater
- Department of Clinical Oncology, University of Edinburgh, Western General Hospital, UK
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Lue SJ, Wu T, Hsu H, Huang C. Application of ion chromatography to the semiconductor industry. I. Measurement of acidic airborne contaminants in cleanrooms. J Chromatogr A 1998; 804:273-8. [PMID: 9615406 DOI: 10.1016/s0021-9673(98)00028-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The purpose of this study is to establish an analytical method for the simultaneous measurement of various acidic airborne contaminants in class 1 cleanrooms of a semiconductor fabrication facility (Fab). Acidic contaminants in air samples were adsorbed on silica gel tubes, extracted with carbonate-hydrogencarbonate solutions, and analyzed by ion chromatography. The recovery of HF was 100% and that of HCl was 91 approximately 100%. The method shows high resolution and sensitivity, and is capable for air analysis in the class 1 cleanroom. Different locations inside the cleanroom show deviations in the contaminant levels, indicating that the air quality is not the same throughout the cleanroom. The wet chemical station shows higher levels of contaminant concentrations than the other two areas. Each location also shows day-to-day variation.
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Affiliation(s)
- S J Lue
- Department of Chemical Engineering, Chang Gung University, Kwei-shan, Taoyuan County, Taiwan
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Bauer S, Werner N, Wolff I, Damme B, Oemus K, Hoffmann P. Toxicological investigations in the semiconductor industry: II. Studies on the subacute inhalation toxicity and genotoxicity of gaseous waste products from the aluminum plasma etching process. Toxicol Ind Health 1992; 8:431-44. [PMID: 7570623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Male and female Wistar rats were exposed to waste gas arising from a plasma etching process in the semiconductor industries for six hr per day, five days per week, for four weeks in order to characterize subacute organ toxicity and genotoxicity. The waste gas was a complex mixture of different chlorinated hydrocarbons, inorganic by-products, and unused process gases, diluted by room air. Neither death nor behavioral changes occurred after subacute exposure. No significant exposure-related effects on body weight gain, hematology, or cardiovascular parameters were observed. Only slight effects on organ weights and clinical chemistry were seen in the exposed animals. The exposed rats of both sexes showed statistically significant increases in chromosomal aberrations and sister chromatid exchanges in bone marrow cells.
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Affiliation(s)
- S Bauer
- Institute of Industrial Toxicology, Martin Luther University Halle, Germany
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Thompson JM, Emmett C, Smith SC, Cramb R, Hutton P. Comparison of potassium ISFETs with the Radiometer KNA1 and the Corning 902 ion selective electrode analysers for whole blood potassium ion estimation. Ann Clin Biochem 1989; 26 ( Pt 3):274-80. [PMID: 2764473 DOI: 10.1177/000456328902600313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Evaluation of the performance of potassium ion sensitive field effect transistors (K+ ISFETs), developed by Thorn EMI in a form suitable for mass production and for incorporation in 'near the patient' analysers, showed only very small constant and proportional biases against the Radiometer KNA1 and the Corning 902 for whole blood potassium ion estimation. Between batch imprecision tests with whole blood showed the K+ ISFET was comparable in performance to the Corning 902 but inferior to the Radiometer KNA1. The evaluation demonstrated that ISFET manufacturing technology has now reached a stage of development at which ISFETs should be considered seriously for use in clinical chemical analysers.
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Affiliation(s)
- J M Thompson
- Department of Chemistry, University of Birmingham, UK
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Gusev EA, Zhuravlev SN, Korolev AI, Kuleshov VK, Lanshakov. [Roentgenologic converters for medical radioscopy]. Med Tekh 1989:3-7. [PMID: 2739544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Peculiarities of use of luminescent and semiconductor converters of X-radiation in radioscopy are examined. Characteristic features of X-ray devices (electro-optical transducers, X-ray vidicons, gas discharge and luminescent converters), based on the use of luminescent and semiconductor converters are comparatively analyzed. Estimation of X-ray image quality is given. Use of gas discharge and luminescent converters is found to be the most prospective for medical radioscopy. The aforementioned converters are distinguished by high dose sensitivity, simplicity of the construction and greater size of working field.
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Harper S. Unknown variables: assessing risks in the semiconductor industry. Occup Health Saf 1986; 55:28-38. [PMID: 3785807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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