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).

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%.

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.

A detective quantum efficiency for spectroscopic X‐ray imaging detectors

2021 ◽  
Author(s):  
Jesse Tanguay ◽  
Devon Richtsmeier ◽  
Christopher Dydula ◽  
James A. Day ◽  
Kris Iniewski ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Detective Quantum Efficiency ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Detectors

Optimization of GEM-based detector readout electrode structure for SXR imaging of tokamak plasma

2021 ◽  
Vol 16 (11) ◽  
pp. C11014
Author(s):  
K. Malinowski ◽  
M. Chernyshova ◽  
S. Jabłoński ◽  
I. Casiragi
Keyword(s):  
Energy Range ◽  
Tokamak Plasma ◽  
Detective Quantum Efficiency ◽  
Actual Number ◽  
Electrode Structure ◽  
X Ray ◽  
X Ray Imaging ◽  
Input Spectrum ◽  
Electron Avalanches ◽  
Time Coincidence

Abstract The paper presents an optimization of a readout structure of the GEM-based detector designed for X-ray imaging for DTT tokamak in the energy range of 2–15 keV. The readout electrode of approximately 100 cm2 surface is composed of hexagonal pixels connected in a way that allows reducing the actual number of signal pixels (electronics channels). At the same time, based on time coincidence analysis, it makes possible to unambiguously identify the position of the recorded X-ray photon. For the input spectrum, the Detective Quantum Efficiency (DQE) of the detector was calculated using the Geant4 program and the spatial distributions of electron avalanches at the readout electrode were simulated using the Garfield++ program. These were conducted for a given energy range of radiation and a statistical distribution consistent with the shape of the spectrum considering the DQE of the detector. As a result, the size of a single hexagonal pixel was proposed to capture the position of the recorded radiation quanta in an optimal and effective way.

scholarly journals Megavoltage X-Ray Imaging Based on Cerenkov Effect: A New Application of Optical Fibres to Radiation Therapy

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
A. Teymurazyan ◽  
G. Pang
Keyword(s):  
Optical Fibres ◽  
X Rays ◽  
Modulation Transfer ◽  
Imaging Device ◽  
Active Matrix ◽  
X Ray ◽  
X Ray Imaging ◽  
Order Of Magnitude ◽  
Detection Quantum Efficiency ◽  
Cerenkov Effect

A Monte Carlo simulation was used to study imaging and dosimetric characteristics of a novel design of megavoltage (MV) X-ray detectors for radiotherapy applications. The new design uses Cerenkov effect to convert X-ray energy absorbed in optical fibres into light for MV X-ray imaging. The proposed detector consists of a matrix of optical fibres aligned with the incident X rays and coupled to an active matrix flat-panel imager (AMFPI) for image readout. Properties, such as modulation transfer function, detection quantum efficiency (DQE), and energy response of the detector, were investigated. It has been shown that the proposed detector can have a zero-frequency DQE more than an order of magnitude higher than that of current electronic portal imaging device (EPID) systems and yet a spatial resolution comparable to that of video-based EPIDs. The proposed detector is also less sensitive to scattered X rays from patients than current EPIDs.

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