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Design and Assessment Principles of Semiconductor Flat-Panel Detector-Based X-Ray Micro-CT Systems for Small-Animal Imaging
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
Alejandro Sisniega, J. J. Vaquero, M. Desco
In the development of x-ray micro-CT systems, most approaches make use of detectors based on x-ray image intensifiers and charge-coupled devices (CCDs) to which a scintillator screen is connected either directly or using light guides (e.g., fiber optic plates) [7–9]. Recent developments in semiconductor detectors have made it possible to use new, compact devices—flat-panel detectors—for x-ray detection. These flat-panel devices can be categorized into two different groups according to the process carried out to convert the x-ray photons (primary quanta) to electric charges that are gathered and converted into a digital signal. The first approach makes use of photoconductors that directly convert the incident x-ray radiation into electric charges as secondary quanta. Devices that conform to this approach are called direct conversion flat-panel detectors. The second approach is based on scintillation screens that stop incident x-ray photons, thus producing optical photons as secondary quanta. These optical photons are then stopped by a photodiode array that provides the electric charges required by the device readout electronics. The detectors that implement this scheme are known as indirect conversion flat-panel detectors.
X-ray Cone Beam Computed Tomography
Published in Paolo Russo, Handbook of X-ray Imaging, 2017
With the development of large area digital X-ray detectors with a sensitive area up to 30 cm × 40 cm, it is feasible to build a cone beam CT system to image human objects. These detectors are typically called “flat-panel detectors,” and were originally developed for X-ray digital radiography and fluoroscopy. Many clinical applications of flat-panel detector based CBCT systems have been quickly utilized, including the on-board imager for radiation therapy guidance and dedicated breast CT. With the transition from image-intensifier based fluoroscopy to flat-panel based fluoroscopy (see Section II, Chapter 27), a standard C-arm system (with the X-ray tube and detector mounted on a “C” shaped gantry) can naturally produce CBCT data if the angular information of the gantry during acquisition is available. These systems provide extreme flexibility to guide clinical procedures, especially when a standard clinical CT system is not available within the procedure room.
Applications of Hybrid Pixel Detectors for High Resolution Table-Top X-Ray Imaging
Published in Salim Reza, Krzysztof Iniewski, Semiconductor Radiation Detectors, 2017
In the case of systems designed for scanning large objects, where the use of highly penetrating radiation is necessary, or if scan time is a crucial parameter, a flat-panel detector is typically used. As flat-panel detectors are based on CMOS technology, they provide very fast data readout. Further, they provide a large FOV, pixel size usually in tens or hundreds of microns, and high detection efficiency for hard radiation. It is widely used in industry or even in medical radiographic systems. Shared limitations of all conventional scintillation-based x-ray imaging cameras are the occurrence of the dark current decreasing the signal-to-noise ratio of the data and the diffusion of the light within the sensor causing image blur. Both mentioned drawbacks are avoided in the case of a PCD.
Progress in large field-of-view interventional planar scintigraphy and SPECT imaging
Published in Expert Review of Medical Devices, 2022
Martijn M.A. Dietze, Hugo W.A.M de Jong
There are two disadvantages to the hybrid detector configuration. First, the detection sensitivity for higher energy photons (e.g. those used in therapeutic applications) will be low since the flat panel detector is optimized for x-rays with a mean energy < 100 keV. This challenge may be mitigated to some extent by increasing the thickness of the scintillator material. And second, a normal flat panel detector system will generally not be able to perform photon energy measurements. The lack of energy selection and subsequent inclusion of all scattered photons in the data places additional requirements on the SPECT reconstruction. It may be taken into account in the reconstruction (e.g. by detailed model-based scatter correction) so that quantitative images are still achieved.
Deep Learning Based Steel Pipe Weld Defect Detection
Published in Applied Artificial Intelligence, 2021
Dingming Yang, Yanrong Cui, Zeyu Yu, Hongqiang Yuan
The real-time X-ray imaging system used in this paper is shown in Figure 2. The system mainly consists of a welded pipe moving part, HS-XY-225 X-ray machine, PS1313DX high-speed digital panel detector, image capture card, and display part. In the welded pipe moving part, the spiral submerged arc welded pipe is moved using a transmission vehicle with four longitudinal rollers fixed on the vehicle for rotating the spiral submerged arc welded pipe. The X-ray machine is fixed to the wall on one side and deep into the pipe on the other side, emitting X-rays that penetrate the weld seam. A flat panel detector absorbs the X-ray photons that pass through the weld, creating electronic data that retains information on the attenuation of the photons. An image capture card is used to convert the electronic data into a digital image sequence, which is then transferred to a computer for processing and display. Limited to hardware performance, only eight X-ray images per second can be captured and processed.