scholarly journals On the Response of a Micro Non-Destructive Testing X-ray Detector

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 888
Author(s):  
Dionysios Linardatos ◽  
Vaia Koukou ◽  
Niki Martini ◽  
Anastasios Konstantinidis ◽  
Athanasios Bakas ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Coefficient Of Determination ◽  
Noise Power ◽  
Modulation Transfer ◽  
Destructive Testing ◽  
Transfer Property ◽  
X Ray ◽  
Cmos Sensor ◽  
Imaging Performance ◽  
Pixel Pitch

Certain imaging performance metrics are examined for a state-of-the-art 20 μm pixel pitch CMOS sensor (RadEye HR), coupled to a Gd2O2S:Tb scintillator screen. The signal transfer property (STP), the modulation transfer function (MTF), the normalized noise power spectrum (NNPS) and the detective quantum efficiency (DQE) were estimated according to the IEC 62220-1-1:2015 standard. The detector exhibits excellent linearity (coefficient of determination of the STP linear regression fit, R2 was 0.9978), while its DQE peaks at 33% and reaches 10% at a spatial frequency of 3 cycles/mm, for the measured with a Piranha RTI dosimeter (coefficient of variation CV = 0.03%) exposure value of 28.1 μGy DAK (detector Air Kerma). The resolution capabilities of the X-ray detector under investigation were compared to other commercial CMOS sensors, and were found in every case higher, except from the previous RadEye HR model (CMOS—Gd2O2S:Tb screen pair with 22.5 μm pixel pitch) version which had slightly better MTF. The present digital imager is designed for industrial inspection applications, nonetheless its applicability to medical imaging, as well as dual-energy is considered and certain approaches are discussed in this respect.

PERFORMANCE OF A CDTE-BASED DIGITAL GAMMA IMAGING SYSTEM WITH A 75SE RADIOISOTOPE FOR NONDESTRUCTIVE TESTINGS

2008 ◽  
Vol 22 (11) ◽  
pp. 1045-1050
Author(s):  
H. S. CHO ◽  
S. I. CHOI ◽  
K. Y. KIM ◽  
J. E. OH ◽  
S. Y. LEE ◽  
...  
Keyword(s):  
Imaging System ◽  
Spot Size ◽  
Noise Power ◽  
Modulation Transfer ◽  
Operation Condition ◽  
X Ray ◽  
Gamma Imaging ◽  
X Ray Imaging ◽  
Imaging Performance ◽  
First Time

As a continuation of our digital radiographic sensor R&D, we have developed a digital gamma imaging system based upon the cadmium-telluride ( CdTe ) photoconductor for the applications of industrial gamma imaging. The imaging system consists of a commercially-available CMOS pixel array of a 100 × 100 μ m 2 pixel size and a 5.4 % 151.0 mm 2 active area, coupled with a 750-μm-thick CdTe photoconductor, and a collimated selenium (75 Se ) radioisotope of an about 62.8 Ci activity and a physical size of 3.0 mm in diameter. In this study, we, for the first time, succeeded in obtaining useful gamma images of several test phantoms with the 75 Se radioisotope from the imaging system and evaluated its imaging performance in terms of the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE). For comparison, we also tested its X-ray imaging performance with a microfocus X-ray tube of an about 5 μm focal spot size at an operation condition of 90 kVp and 100 μA.

Simulated sensor characterization for virtual clinical trials in mammography and digital breast tomosynthesis

2022 ◽  
Vol 17 (01) ◽  
pp. C01041
Author(s):  
A. Sarno ◽  
R.M. Tucciariello
Keyword(s):  
Clinical Trials ◽  
Power Spectrum ◽  
Detector Response ◽  
Noise Power ◽  
Noise Power Spectrum ◽  
Flat Panel ◽  
X Ray ◽  
The Impact ◽  
Simulated Images ◽  
Pixel Pitch

Abstract Virtual clinical trials in X-ray breast imaging permit to compare different technical solutions and imaging modalities at reduced costs, involved personnel, reduced times and reduced radiation risks to patients. In this context, the detector characteristics (spatial resolution, noise level and efficiency) play a key role for an appropriate generation of simulated images. The project AGATA proposes to compute images as dose deposit maps in a detector layer of defined materials. Simulated images are then post-processed on the basis of suitable comparison between intrinsic characteristics of real and simulated detectors. With this scope, as first step for the post-processing manipulations, we evaluated the presampled modulation transfer function (MTF), the detector-response function and the noise power spectrum (NPS) of the simulated detectors. Two detectors were simulated: (1) 0.20 mm-thick a-Se direct flat panel with 70 µm pixel pitch and (2) CsI(Tl) indirect flat panel with 100 µm pixel pitch and scintillator layer 0.25 mm thick. In addition, the impact of simulating the de-excitation processes (Auger emission and fluorescence) was explored. Simulated detector characteristics were evaluated for W/Rh spectra between 25 kV and 31 kV. The in-silico platform used a Monte Carlo software based on Geant4 toolkit (vers. 6). First, the simulation and tracking of electrons generated from photoelectric or Compton interactions was shown to have neglectable influence on the pixel values for the explored spectra, with the produced electrons presenting short ranges with respect to the pixel dimension. In the case of the CsI detector, which has fluorescence energies higher than those of the simulated X-ray photons, the deexcitation processes have not noticeable influence on the calculated pixel values. On the other hand, the MTF of the a-Se detector resulted slightly lower when the fluorescence is simulated in the detector materials, due to the dose spread derived from the fluorescence photons, which can travel far from the initial ionization interaction. Regarding the a-Se detector, the noise power spectrum resulted lower with simulated deexcitation.

Investigation of Scintillation Screens for X-Ray Imaging

2006 ◽  
Vol 321-323 ◽  
pp. 1056-1059 ◽  
Author(s):  
Jung Min Kim ◽  
Ho Kyung Kim ◽  
Min Ho Cheong ◽  
Min Kook Cho ◽  
Cheol Soon Shon ◽  
...  
Keyword(s):  
Transfer Function ◽  
Modulation Transfer Function ◽  
Columnar Structure ◽  
Diagnostic Radiology ◽  
Modulation Transfer ◽  
X Ray ◽  
X Ray Imaging ◽  
Conventional Film ◽  
Wide Range ◽  
Imaging Performance

Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) phosphor screen is the most popular X-ray converter in diagnostic radiology. We have investigated the fundamental imaging performance of Gd2O2S:Tb screens in terms of X-ray sensitivity and MTF (modulation-transfer function). The measurements were performed for a wide range of coverages (34 – 135 mg/cm2) by using a conventional film radiographic method. In addition, CsI:Tl having columnar structure was also investigated.

scholarly journals Image Quality Assessment of a CMOS/Gd2O2S:Pr,Ce,F X-Ray Sensor

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Christos Michail
Keyword(s):  
Image Quality ◽  
Optical Sensor ◽  
Image Quality Assessment ◽  
Beam Quality ◽  
Detector Response ◽  
Noise Power ◽  
Modulation Transfer ◽  
Custom Made ◽  
Cmos Sensor ◽  
Edge Method

The aim of the present study was to examine the image quality performance of a CMOS digital imaging optical sensor coupled to custom made gadolinium oxysulfide powder scintillators, doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The screens, with coating thicknesses 35.7 and 71.2 mg/cm2, were prepared in our laboratory from Gd2O2S:Pr,Ce,F powder (Phosphor Technology, Ltd.) by sedimentation on silica substrates and were placed in direct contact with the optical sensor. Image quality was determined through single index (information capacity, IC) and spatial frequency dependent parameters, by assessing the Modulation Transfer Function (MTF) and the Normalized Noise Power Spectrum (NNPS). The MTF was measured using the slanted-edge method. The CMOS sensor/Gd2O2S:Pr,Ce,F screens combinations were irradiated under the RQA-5 (IEC 62220-1) beam quality. The detector response function was linear for the exposure range under investigation. Under the general radiography conditions, both Gd2O2S:Pr,Ce,F screen/CMOS combinations exhibited moderate imaging properties, in terms of IC, with previously published scintillators, such as CsI:Tl, Gd2O2S:Tb, and Gd2O2S:Eu.

scholarly journals RAD_IQ: A free software for characterization of digital X-ray imaging devices based on the novel IEC 62220-1-1:2015 International Standard

2021 ◽  
Vol 2090 (1) ◽  
pp. 012107
Author(s):  
A Konstantinidis ◽  
N Martini ◽  
V Koukou ◽  
G Fountos ◽  
N Kalyvas ◽  
...  
Keyword(s):  
Diagnostic Radiology ◽  
Noise Power ◽  
The Novel ◽  
Transfer Property ◽  
Noise Component ◽  
X Ray ◽  
International Standard ◽  
Software Products ◽  
X Ray Imaging

Abstract Characterization of digital X-ray imaging devices is very important because it can be used to measure and compare the performance of detectors used in Diagnostic Radiology. This characterization is usually made through the calculation of Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). These parameters, especially the DQE, are very important because they quantify the effect of spatial resolution, contrast and noise on Radiographic image quality (IQ). The IEC 62220-1-1:2015 International Standard provides comprehensive guidelines how to capture and analyze X-ray images to characterize digital X-ray detectors. A novel, fast and free MATLAB-based software was developed, named RAD_IQ, to calculate the Signal Transfer Property (STP), perform Noise Component Analysis (NCA), and calculate the parameters MTF, NPS & DQE of X-ray detectors based on the novel IEC 62220-1-1:2015 International Standard for General Radiography and IEC 62220-1-1:2007 for Digital Mammography. Our results were validated against well-established software products used for quantitative image analysis of digital X-ray detectors. The calculated parameters were within 5% difference compared to available software products. The conclusion of our study was that RAD_IQ can be easily used from Medical Physicists, Biomedical Engineers and researchers without any programming experience to characterize the performance of digital X-ray detectors used in Diagnostic Radiology.

Resolution and Noise Properties of CMOS and CR Digital Radiography Systems

2012 ◽  
Author(s):  
Khairul Anuar Mohd Salleh ◽  
Wan Muhamad Saridan Wan Hassan ◽  
Ab. Razak Hamzah
Keyword(s):  
Metal Oxide ◽  
Digital Radiography ◽  
Computed Radiography ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Noise Power ◽  
Non Destructive Testing ◽  
Modulation Transfer ◽  
Destructive Testing ◽  
Non Destructive

Seiring dengan perkembangan teknologi perkomputeran dan pemprosesan imej, radiografi industri berbentuk konvensional telah bertukar arah kepada radiografi industri berasaskan digital. Dalam kajian ini, dua jenis alat radiografi industri digital untuk ujian tanpa memusnah (NDT), iaitu complimentary metal oxide semiconductor (CMOS) dengan jarak piksel 50 μm dan computed radiography (CR) dengan jarak piksel 25 μm telah diuji dan diukur untuk menentukan kesesuaiannya dalam NDT. Pengukuran fungsi hantaran modulasi (MTF) dan spektrum kuasa hingar (NPS) telah dilakukan ke atas kedua–dua peralatan ini bagi menilai kualiti imej yang dihasilkan. Daripada pengukuran dan pengiraan yang dilakukan, purata MTF untuk CR dan CMOS pada modulasi 20% ialah 4.48 kitar/mm dan 2.83 kitar/mm. Untuk NPS pula keputusan menunjukkan CMOS memberikan hingar yang lebih tinggi daripada CR tetapi CR mempunyai keupayaan MTF yang lebih pada ukuran 20% modulasi. Daripada pengukuran dan pengiraan yang dijalankan, dapatlah dikatakan bahawa untuk menjalankan satu ujian NDT, pengguna perlu tahu keupayaan sebenar sesebuah alat dan bagaimana ia dibina supaya ujian NDT memberi gambaran tepat ke atas sesuatu sampel atau barangan yang diuji. Kata kunci: Ujian tanpa memusnah (NDT); radiografi industri berasaskan digital (IDR); fungsi hantaran modulasi (MTF); spektrum kuasa hingar Due to development of computer technology and image processing, conventional industrial radiography has changed to digital radiography system. In this study, two types of industrial digital radiography (IDR) modules for non destructive testing (NDT), namely complimentary metal oxide semiconductor (CMOS) with 50 μm pixel pitch and computed radiography (CR) with 25 μm pixel pitch have been evaluated for NDT applications. The modulation transfer function (MTF) and noise power spectrum (NPS) measurement and calculation were adapted in order to evaluate the image quality of IDR images. From the measurement and calculation, the averaged MTF for CR and CMOS at 20% modulation are 4.48 cycles/mm and 2.83 cycles/mm, respectively. NPS measurement and calculation show that CMOS produced higher noise than CR. The CR system has lower and more stable NPS but has lower modulating capability at 20% compared to the CMOS system. The study shows that in order to perform NDT by using the evaluated modules, the user must know the true capability of system and how it is designed for specific application and discontinuity ditection. Key words: Non destructive testing (NDT); industrial digital radiography (IDR); modulation transfer function (MTF); noise power spectrum (NPS); complimentary metal oxide semiconductor (CMOS) and computed radiography (CR)

Characterization of CMOS Pixel Detectors for Digital X-Ray Imaging

2006 ◽  
Vol 321-323 ◽  
pp. 1052-1055 ◽  
Author(s):  
Min Kook Cho ◽  
Ho Kyung Kim ◽  
Thorsten Graeve ◽  
Jung Min Kim
Keyword(s):  
Spatial Frequency ◽  
Imaging System ◽  
Complementary Metal Oxide Semiconductor ◽  
Cost Effective ◽  
Oxide Semiconductor ◽  
Noise Power ◽  
Modulation Transfer ◽  
X Ray ◽  
Pixel Detectors ◽  
X Ray Imaging

In order to develop a cost-effective digital X-ray imaging system, we considered a CMOS (complementary metal-oxide-semiconductor) photodiode array in conjunction with a scintillation screen. Imaging performance was evaluated in terms of MTF (modulation-transfer function), NPS (noise-power spectrum) and DQE (detective quantum efficiency). The presampled MTF was measured using a slanted-slit method. The NPS was determined by 2-dimensional Fourier analysis. Both the measured MTF and NPS, and a self-developed computational model for the X-ray spectral analysis were used to determine the spatial frequency-dependent DQE. From the measured MTF, the spatial resolution was found to be about 10.5 line pairs per millimeter (lp/mm). For a 45-kVp tungsten spectrum, the measured DQE around zero spatial frequency was about 40%.

scholarly journals Evaluation of digital X-ray detectors for medical imaging applications

2011 ◽  
Author(s):  
Αναστάσιος Κωνσταντινίδης
Keyword(s):  
Thin Film Transistor ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Noise Power ◽  
International Electrotechnical Commission ◽  
Modulation Transfer ◽  
Large Area ◽  
X Ray ◽  
Active Pixel

Οι ψηφιακοί ανιχνευτές ακτίνων Χ είναι πλέον διαδεδομένοι σε αρκετές εξετάσεις με ακτίνες Χ. Άρχισαν να χρησιμοποιούνται στην κλινική ιατρική την τελευταία δεκαετία αλλά εξακολουθούν να υπάρχουν συνεχείς εξελίξεις στην τεχνολογία. Η τεχνολογία συμπληρωματικών ημιαγωγών μεταλλικού οξειδίου (complementary metal oxide semiconductor - CMOS) με αισθητήρα ενεργού εικονοστοιχείου (active pixel sensor - APS) είναι μια νέα ψηφιακή τεχνολογία που προσφέρει πλεονεκτήματα σε σύγκριση με μερικές από τις πιο καθιερωμένες τεχνολογίες (π.χ. α) συσκευές συζευγμένου φορτίου (charge-coupled devices - CCD), β) ανιχνευτές με τρανζίστορ λεπτών υμενίων (thin film transistor - TFT) και γ) CMOS με αισθητήρα παθητικού εικονοστοιχείου (passive pixel sensor - PPS)). Η συγκεκριμένη διδακτορική διατριβή εξετάζει την απόδοση των ψηφιακών ανιχνευτών νέας τεχνολογίας και επιχειρεί να προσδιορίσει το ρόλο τους σε μελλοντικές εφαρμογές ιατρικής απεικόνισης.Πιο συγκεκριμένα, παρουσιάζονται αξιολογήσεις (με χρήση ορατών φωτονίων και ακτίνων Χ) απόδοσης δύο νέων ανιχνευτών CMOS APS, ονομαστικά Large Area Sensor (LAS) και Dexela CMOS x-ray detector. Η αξιολόγηση έγινε χρησιμοποιώντας τις παρακάτω τεχνικές: α) καμπύλη μεταφοράς φωτονίων (photon transfer curve - PTC), β) συνάρτηση μεταφοράς διαμόρφωσης (modulation transfer function - MTF), γ) κανονικοποιημένο φάσμα ισχύος θορύβου (normalized noise power spectrum - NNPS) και δ) ανιχνευτική κβαντική αποδοτικότητα (detective quantum efficiency - DQE). Έγιναν κάποιες τροποποιήσεις ώστε να επεκταθούν οι υπάρχουσες τεχνικές με σκοπό την εξάλειψη τεχνικών περιορισμών. Η απόδοση των δύο νέων ψηφιακών ανιχνευτών συγκρίθηκε με τρία εμπορικά συστήματα ψηφιακών ανιχνευτών (α) Remote HR RadEye (CMOS APS), β) Hamamatsu C9732DK (CMOS PPS) και γ) Anrad SMAM (a-Se TFT)) σε τρία φάσματα ακτίνων Χ (28 kV για μαστογραφία και 52 kV και 74 kV για γενική ακτινοδιαγνωστική) με βάση τα πρότυπα της Διεθνούς Ηλεκτροτεχνικής Επιτροπής (International Electrotechnical Commission - ΙEC). Αμφότεροι οι νέοι ψηφιακοί ανιχνευτές παρουσιάζουν υψηλή απόδοση. Επίσης αξιολογήθηκε το φαινόμενο της ενδογενούς μη-γραμμικής μεταφοράς σήματος και θορύβου των ανιχνευτών CMOS APS.Τέλος, οι πειραματικά μετρημένες παράμετροι απόδοσης των ψηφιακών ανιχνευτών χρησιμοποιήθηκαν για να προσομοιώσουν εικόνες σε συνθήκες μαστογραφίας με σκοπό να διαπιστωθούν πιθανές εφαρμογές ιατρικής απεικόνισης για τους δύο νέους ψηφιακοί ανιχνευτές. Δύο ψηφιακά ομοιώματα (το ένα αντιπροσωπεύει ένα τρισδιάστατο μοντέλο μαστού και το άλλο το εργαλείο δοκιμής CDMAM) χρησιμοποιήθηκαν για να προσομοιώσουν διάφορες μαστογραφικές συνθήκες. Τα αποτελέσματα δείχνουν ότι αμφότεροι οι νέοι ανιχνευτές CMOS APS προσφέρουν υψηλή ποιότητα εικόνας σε σύγκριση με τα εμπορικά συστήματα ανιχνευτών.

scholarly journals X-ray inspection systems for electronic parts

2018 ◽  
Vol 28 (4) ◽  
pp. 52-58
Author(s):  
A. O. Ustinov
Keyword(s):  
Reading Speed ◽  
Inspection System ◽  
Non Destructive Testing ◽  
Electronic Components ◽  
Flat Panel ◽  
Destructive Testing ◽  
X Ray ◽  
Flat Panel Detector ◽  
Cmos Sensor ◽  
Non Destructive

An X-ray inspection is one of the basic methods of non-destructive testing along with optical inspection. Lack of Russian manufacturers in this sector of measuring equipment was a barrier for implementation of the State program «Development of the electronics and radio electronics industry, 2013–2025». High sensitivity X-ray flat panel detector and inspection system concept for non-destructive testing of electronic components were developed. The detector is based on CMOS sensor with pixel pitch 50 um. Key features of the flat panel detector are: limiting spatial resolution 10 LP/mm, reading speed 30 fps, anode voltage range from 20 to 300 kV. Availability of technologies for the production of microfocus sources and flat panel detectors allows creating X-ray inspection system for electronic components for the needs of the microelectronics industry.

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