Case Studies
Nicholas Stergiou in Nonlinear Analysis for Human Movement Variability, 2018
Healthy and Parkinson’s mice were filmed in the lateral view using cineradiography at 250 frames per second. Cineradiography is a technique that allows recording the successive positions of every bone segment of animals in motion. Markers (small radio-opaque balls) were placed at the right and left forelimb and hindlimb foot. All mice walked on the treadmill at two different treadmill speeds: 6.9 and 15.1 cm s−1 (Figure 9.18). In total, three healthy mice and five Parkinson’s mice walking at the speed of 6.9 cm s−1, and four healthy mice and three Parkinson’s mice walking at the speed of 15.1 cm s−1 were analyzed. The y-coordinate (vertical displacement) for each marker was analyzed. All time series contained a minimum of 946 data points. Data were analyzed unfiltered so as to get a more accurate representation of the fluctuations within the time series. Furthermore, since the same instrumentation was used for all mice, it is assumed that the level of measurement noise was consistent for all mice. For the mice data set, a 2 × 3 (group by treadmill speed) analysis of variance (ANOVA) was performed on ApEn and largest LyE values for all the marker displacement data (Kaplan and Glass 1995; Wolf et al. 1985).
X-Ray-Computed Tomography: Advanced Systems and Applications in Biomedcal Research and Diagnosis
Richard A. Robb in Three-Dimensional Biomedical Imaging, 2017
The trend in development of X-ray-computed tomography systems over the past decade has been toward faster and faster scanners, with concomitant improvement in image quality. However, current conventional CT systems still do not scan rapidly enough to eliminate motion blurring in images of moving organs like the heart and circulation, and still produce only 1 or 2 two-dimensional slices in each scan. The preliminary results from the DSR scanner suggest the advent of two new, powerful dimensions in X-ray CT — high temporal resolution and synchronous volume scanning. That is, true stop-action, full three-dimensional imaging at a high repetition rate is possible with CT scanners. The continuing evolution of these capabilities can be expected to approach the speed and spatial resolution of cineradiography, with the simultaneous advantages of true three-dimensional tomography and higher contrast resolution than provided by conventional film or fluoroscopic techniques.
Instrumentation for Assessing mTBI Events
Mark A. Mentzer in Mild Traumatic Brain Injury, 2020
Numerous test requirements motivate the development of flash X-ray cineradiography systems with multi-anode configuration for repetitive imaging in closely spaced time frames (Mentzer et al., 2010). Applications include the following: Shaped charge detonations to further understand properties of jet formation and particulationExplosively formed projectile detonations to quantify launch and flight performance characteristicsDetonations of small caliber grenades and explosive projectiles to verify fuse function times and fragmentation patternsPerformance and behavior of various projectiles and explosive threats against passive, reactive, and active target systemsHuman effects studies including body armor, helmets, and footwearBehind armor debris studies of large caliber ammunition against various armor materialsSmall caliber projectile firings to study launch, free flight, and target impact results
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
Standard mono- and biplane X-ray cine angiography and fluoroscopy (XRF) used during interventional cardiology procedures, primarily enable contrast-based visualization and are less suitable for the characterization of soft tissues. The increasing complexity of interventional procedures requires visualization of the topographic surrounding of interventional targets. This increases the radiation exposure and use of contrast medium during these interventions, which is potentially harmful to the patients and staff.5 This paradigm drives the development of new techniques aiming to improve visualization while reducing radiation and contrast exposure. Currently, XRF is often supported side-by-side by pre- or peri-procedurally acquired imaging modalities as 2D/3D ultrasound, MRI, CT or a combination of these. Fusion of multiple imaging modalities, for instance fluoroscopy with CT, is referred to as hybrid imaging (HI).6
Radiation impacts on toxicity of cobalt–chromium (CoCr) implant debris
Published in Nanotoxicology, 2023
Kevin L. Trout, Sanghamitra Majumdar, Anil K. Patri, Tariq Fahmi
Patients with metal implants often undergo routine surveillance to ensure successful surgical placement and to monitor for complications. Noninvasive imaging approaches include magnetic resonance imaging (MRI), ultrasound, and radiological imaging (Mushtaq et al. 2019). Metal implants pose unique imaging challenges, as certain metals may torque or heat due to interaction with MRI magnetic fields (Winter et al. 2021; Shellock 2002) or cause artifacts that need to be mitigated with techniques, such as metal artifact reduction sequence (MARS) (Jungmann et al. 2017). Radiological imaging procedures may include conventional X-rays, computed tomography (CT), fluoroscopy, or nuclear medicine options, such as bone scintigraphy (Mushtaq et al. 2019). Higher radiation energies tend to be used with metal implants to reduce artifact due to beam hardening, which can result in increased radiation dose (Kataoka et al. 2010). In addition, studies have shown that metal implants can amplify radiation exposure to surrounding tissue (Song et al. 2019; Reft et al. 2003; Rosengren et al. 1993). While continued implant surveillance may improve patient outcomes, recurrent exposure to ionizing radiation increases the risk of adverse deterministic or stochastic health effects, such as widespread cellular damage or cancer. These are a result of genetic damage caused by direct absorption of radiation energy, indirect damage caused by free radicals, or other bystander effects (Council 2006; Desouky, Ding, and Zhou 2015).
Radiographers’ knowledge, attitude and adherence to standard COVID-19 precautions and the policy implications: a national cross-sectional study in Nigeria
Published in Annals of Medicine, 2023
Charles Ikechukwu Ezema, Okechukwu Felix Erondu, Ogochukwu Kelechi Onyeso, Chiedozie James Alumona, Andrew Wueseter Ijever, Charity Ndidiamaka Amarachukwu, Amaeze Augustine Amaeze
Of the 255 participants, 96 (37.6%) worked in facilities that attended to patients with COVID-19, and 44 (17.3%) had imaged confirmed cases. Out of the 44 radiographers, 27 (61.4%) attended to COVID-19 patients brought into the radiology unit, 6 (13.6%) each imaged the patients in emergency and intensive care units, while the rest worked with stable patients in the isolation wards (n = 5, 11.4%). Two participants (4.5%) imaged COVID-19 patients who were under 15 years of age, 11 (25.0%) imaged people between 16 and 30 years, 22 (50.0%) imaged people between 31 to 45 years, 25 (56.8%) imaged people between 46 and 60 years, and others 19 (43.2%) imaged patients above 60 years of age. The comorbidities presented by the patients include diabetes, hypertensive heart disease, chronic kidney and liver diseases and prostate cancer, as was reported by 6 (13.6%) frontline radiographers. The indications for imaging received by this cohort were scans for the chest (n = 43, 97.7%), brain (n = 14, 31.8%), spine (n = 10, 22.7%) limbs (n = 9, 20.5%), vascular (n = 8, 18.2%), neurological (n = 7, 15.9) and abdominal scans (n = 1, 2.3%). Imaging modalities utilized were conventional X-ray (n = 34, 77.3%), CT (n = 17, 38.6%), ultrasound (n = 10, 22.7%), MRI (n = 2, 4.5%), fluoroscopy (n = 2, 4.5%) and ECG (n = 1, 2.3).
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