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.

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%.

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.

A novel x-ray imaging system and its imaging performance

2006 ◽  
Author(s):  
Chunyu Yu ◽  
Benkang Chang ◽  
Shiyun Wang ◽  
Junju Zhang ◽  
Xiao Yao
Keyword(s):  
Imaging System ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Performance

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.

Quantitative digital x-ray imaging of the outer shell layer of mytilus edulis (Bivalvia)

1992 ◽  
Vol 50 (2) ◽  
pp. 1746-1747
Author(s):  
Donald L. Parker ◽  
Gary D. Rosenberg
Keyword(s):  
Mytilus Edulis ◽  
High Spatial Resolution ◽  
Imaging System ◽  
Image Data ◽  
Outer Shell ◽  
Shell Layer ◽  
X Ray ◽  
Growth Increments ◽  
X Ray Imaging ◽  
First Time

Compositional mapping using digital x-ray imaging has been applied to a variety of applications. The extension of these procedures permitting complete quantitation allows EPM application where detailed structures exist requiring higher resolution. We apply these techniques here for the first time to the study of the molluscan shell. The outer shell layer of the mussel, Mytilus edulis, consists of fibrous calcific prisms (1-3μm diameter) which are organized structurally as layers corresponding to growth increments (up to ca.100μm thick, deposited daily, normal to the direction of growth). Digital imaging is used here to precisely determine the composition of these layers with high spatial resolution.Digital images were obtained with a Cameca® three spectrometer EPM system interfaced to a Kevex 8000® analyzer/imaging system. Images are stored as WDS intensity pixels, with final extraction of image data for complete quantitation being performed offline. The extracted intensities were corrected for dead time, background and transformed into K-ratios for full matrix correction using the CITZAF routines.Shells were sectioned along selected growth axes and polished using alumina followed by ultrasonic cleaning. All specimens were coated with ∼50nm of aluminum (as opposed to carbon) to retard degradation of the carbonate during analysis.

A Flat-Panel X-Ray Imaging Module for Medical Imaging and Nondestructive Testing

2006 ◽  
Vol 321-323 ◽  
pp. 1004-1007
Author(s):  
Hyo Sung Cho ◽  
Sung Il Choi ◽  
Bong Soo Lee ◽  
Sin Kim
Keyword(s):  
Medical Imaging ◽  
Nondestructive Testing ◽  
System Response ◽  
Detective Quantum Efficiency ◽  
Noise Power ◽  
Pixel Size ◽  
Modulation Transfer ◽  
Flat Panel ◽  
X Ray ◽  
X Ray Imaging

In this study, we designed a flat-panel digital X-ray imaging module based upon the amorphous silicon (a-Si) technology and tested potential for medical imaging and nondestructive testing. The module employs a commercially available a-Si photosensor array of a 143 μm x 143 μm pixel size and a 42.9 cm x 42.9 cm active area, coupled with a CsI(Tl) scintillator of a 550 μm thickness, and a readout IC board which can be accessed through our home made GUI software. The experimental test was performed to evaluate the system response with exposure, modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE).

Sign in / Sign up

Export Citation Format

Share Document