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Principles of Radiation Detection and Image Formation
Published in Ken Holmes, Marcus Elkington, Phil Harris, Clark's Essential Physics in Imaging for Radiographers, 2021
The second issue relates to radiation dose during fluoroscopic examinations. While flat panel detectors are comparable in terms of dose with other systems for still images they initially gave relatively high doses when used for moving fluoroscopic images. Traditional fluoroscopic systems including digital image intensifier systems using CCD technology could produce images of good quality using relatively low mA. Image quality was still acceptable with even more aggressive dose reduction techniques where the beam was pulsed during fluoroscopic mode. This allowed a significant lowering of the overall dose the patient received for an examination.
The Frequently Forgotten Pediatrics
Published in Christopher M. Hayre, William A. S. Cox, General Radiography, 2020
Assessing current practice with national guidance and also exploring the potential to optimize tube voltage and X-ray beam filtration combined with improving image quality without detrimental impact on radiation dose to pediatric patients are important. Owing to the variety of X-ray units used clinically, X-ray examinations cannot be standardized. Therefore, optimization is necessary for each particular X-ray unit and for each X-ray examination (Sun et al., 2012). This is achieved through as already discussed in aforementioned sections like considering the type of equipment and its characteristics, for example, Ysio digital X-ray system, with a direct digital flat panel detector (Siemens Medical Solutions, Erlangen, Germany). This type of image receptor is composed of a cesium iodide scintillator coupled to a thin film transistor matrix with amorphous silicon technology. Note the pixel size, which is 144 µm, with an active detector area of 34 × 43 cm. The maximum spatial resolution of the system is mainly limited by its pixel size.
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
Flat-panel detectors can be classed as direct conversion and indirect conversion devices (Figure 15.2). Below, the features of flat-panel detectors are presented according to this classification. A comparative study of direct and indirect conversion flat-panel detectors can be found in [28].
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
The next system concerns the smart integration of two existing imaging modalities: planar scintigraphy and fluoroscopy. This combined imaging modality is named ‘Interventional X-ray and Scintigraphy Imaging’ (IXSI) (see Figure 2a) [42–46]. The scanner consists of an x-ray flat panel detector that is positioned in front of a gamma camera that is mounted with a cone-beam collimator. The detector stack is placed together with an x-ray tube on a custom-made gantry. The focal length of the cone-beam collimator is approximately the same as is the distance of the x-ray tube to the flat panel detector so that x-ray and nuclear projections are intrinsically registered. By rotating the detector around the patient (using parameterized non-circular orbits), SPECT and CBCT reconstructions can furthermore be acquired. The CBCT reconstruction can be used for attenuation correction so that the SPECT reconstruction becomes quantitative.
Exploration of temporal bone anatomy using mixed reality (HoloLens): development of a mixed reality anatomy teaching resource prototype
Published in Journal of Visual Communication in Medicine, 2020
Pavithran Maniam, Philipp Schnell, Lilly Dan, Rony Portelli, Caroline Erolin, Rodney Mountain, Tracey Wilkinson
Surface scans (taken using an Artec Space Spider structured light scanner) of Adam,Rouilly plastic models of the temporal bone and a micro CT scan of an adult male skull (a specimen >100 years old from the Dundee Dental School, taken by Dr. Erolin using a Nikon XT H 225ST microCT scanner) were used to develop an anatomically accurate temporal bone model. The scans were imported into Zbrush (Version 4R8, Pixologic, Los Angeles, CA, United States) where they were used as 3D templates to allow medical artists to create an accurate model. The micro CT scanner has a 2000 × 2000 pixel flat panel detector, measuring 400 mm × 400 mm in size, which is positioned 1130 mm away from the source. This means that for very small specimens, a resolution of a few µm can be achieved. However, for larger objects, as in the case of this skull (up to 250 mm in diameter, moved closer to the detector to fit in the frame), this drops to around 125 µm. The model was created by a medical artist (rather than simply using the original scan data) to ensure a tidy mesh was retained, allowing for a low poly version to be exported later without issue. This was important for maximising the application’s performance due to the limited computing power of the HoloLens. In addition, the medical artist sculpted several anatomical features directly in Zbrush, including the facial nerve, middle and inner ear structures. Blender (Version 2.79b) was used to create a basic head and neck model into which the anatomical structures could be placed. This acted as a useful orientation aid at the beginning of the application.
3D Hybrid Imaging for Structural and Congenital Heart Interventions in the Cath Lab
Published in Structural Heart, 2018
Hans Thijs van den Broek, René van Es, Gregor J. Krings, Quirina M. B. De Ruiter, Michiel Voskuil, Mathias Meine, Peter Loh, Pieter A. Doevendans, Steven A. J. Chamuleau, Frebus J. van Slochteren
All major XRF vendors offer flat-panel detector systems that provide CBCT imaging options as well as pre-procedural image integration (Table 1), and market penetration is likely to increase in the future.9 The institutional costs for these systems range between US$1.2 million and US$5.0 million depending on the vendor, specifications, single or biplane system, and the integration of various advanced imaging modalities such as 3D echocardiography for TEE-XRF fusion.43 These prices can differ depending on the agreements made between the institution and vendor.