scholarly journals Whole-body x-ray dark-field radiography of a human cadaver

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Jana Andrejewski ◽  
Fabio De Marco ◽  
Konstantin Willer ◽  
Wolfgang Noichl ◽  
Alex Gustschin ◽  
...  
Keyword(s):  
Effective Dose ◽  
Human Body ◽  
Small Angle ◽  
Dark Field ◽  
Whole Body ◽  
High Signal ◽  
Human Cadaver ◽  
Contrast Imaging ◽  
Beam Hardening ◽  
X Ray

Abstract Background Grating-based x-ray dark-field and phase-contrast imaging allow extracting information about refraction and small-angle scatter, beyond conventional attenuation. A step towards clinical translation has recently been achieved, allowing further investigation on humans. Methods After the ethics committee approval, we scanned the full body of a human cadaver in anterior-posterior orientation. Six measurements were stitched together to form the whole-body image. All radiographs were taken at a three-grating large-object x-ray dark-field scanner, each lasting about 40 s. Signal intensities of different anatomical regions were assessed. The magnitude of visibility reduction caused by beam hardening instead of small-angle scatter was analysed using different phantom materials. Maximal effective dose was 0.3 mSv for the abdomen. Results Combined attenuation and dark-field radiography are technically possible throughout a whole human body. High signal levels were found in several bony structures, foreign materials, and the lung. Signal levels were 0.25 ± 0.13 (mean ± standard deviation) for the lungs, 0.08 ± 0.06 for the bones, 0.023 ± 0.019 for soft tissue, and 0.30 ± 0.02 for an antibiotic bead chain. We found that phantom materials, which do not produce small-angle scatter, can generate a strong visibility reduction signal. Conclusion We acquired a whole-body x-ray dark-field radiograph of a human body in few minutes with an effective dose in a clinical acceptable range. Our findings suggest that the observed visibility reduction in the bone and metal is dominated by beam hardening and that the true dark-field signal in the lung is therefore much higher than that of the bone.

X-ray imaging with ultra-small-angle X-ray scattering as a contrast mechanism

2004 ◽  
Vol 37 (5) ◽  
pp. 757-765 ◽  
Author(s):  
L. E. Levine ◽  
G. G. Long
Keyword(s):  
Small Angle ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Sample Volume ◽  
Contrast Imaging ◽  
X Ray ◽  
X Ray Scattering ◽  
X Ray Imaging ◽  
Contrast Mechanism ◽  
Ray Scattering

A new transmission X-ray imaging technique using ultra-small-angle X-ray scattering (USAXS) as a contrast mechanism is described. USAXS imaging can sometimes provide contrast in cases where radiography and phase-contrast imaging are unsuccessful. Images produced at different scattering vectors highlight different microstructural features within the same sample volume. When used in conjunction with USAXS scans, USAXS imaging provides substantial quantitative and qualitative three-dimensional information on the sizes, shapes and spatial arrangements of the scattering objects. The imaging technique is demonstrated on metal and biological samples.

scholarly journals Limitations in the assessment of radon dose: the role of activity measurements in the human body

2019 ◽  
Vol 24 ◽  
pp. 92
Author(s):  
J. Kalef-Ezra ◽  
S. Valakis
Keyword(s):  
Effective Dose ◽  
Human Body ◽  
Detection Efficiency ◽  
Medical Physics ◽  
High Sensitivity ◽  
Temporal Variations ◽  
Cold Season ◽  
Whole Body ◽  
Group I ◽  
Activity Measurements

Radon-222 is classified in the Group I of the human carcinogens. The in situ decay of inhaled 222Rn and its short-lived decay products (T1/2 <30 min) is the main source of radiation burden to the general population of natural origin. The corresponding effective dose is routinely calculated as the product of the 222Rn concentration in air, a predetermined dosimetric constant and a factor that depends on the space type (e.g. residential or public building, cave, mine, etc). However, in practice, there are large spatial and temporal variations in the activity ratio of each progeny to 222Rn in air, the characteristics of the progeny carrying particles and the metabolism of each progeny depending on air quality, as well as differences in the anatomic and physiological characteristics between individuals, that vary substantially even with time. Therefore, the currently employed dosimetric approach may introduce large uncertainties. In the hypothetical case of acute deposition and full retention in the human body of equal activities of all 222Rn progeny, about 93% of the effective dose is due to the decaying 214Po. The 214Po activity can be assessed by measurement of its γ-emitting precursor, 214Bi, which is in full equilibrium with 214Po in the human body. The 214Bi activity can be measured using a high-sensitivity whole-body counter with high counting uniformity, such as the one in use at the Ioannina University Medical Physics Department. Its detection efficiency and its dependence on body shape and size were assessed by Monte Carlo simulations. Measurements carried out in healthy adult volunteers residing at a short distance from the counter, indicated a mean total body 214Bi activity (TBBi) of ~100 Bq during the cold season of the year and lower during the hot one. Higher mean TBBi levels were found in male than in female adults. Therefore, TBBi measurements may allow for accurate radon-related risk assessment on individual base.

scholarly journals DIAGNOSTIC IMAGING AND IONIZING RADIATION EXPOSURE IN A LEVEL 1 TRAUMA CENTRE POPULATION MET WITH TRAUMA TEAM ACTIVATION: A ONE-YEAR PATIENT RECORD AUDIT

2020 ◽  
Vol 189 (1) ◽  
pp. 35-47
Author(s):  
Anna Bågenholm ◽  
Pål Løvhaugen ◽  
Rune Sundset ◽  
Tor Ingebrigtsen
Keyword(s):  
Diagnostic Imaging ◽  
Radiation Exposure ◽  
Effective Dose ◽  
Trauma Team ◽  
Trauma Centre ◽  
Whole Body ◽  
Reference Level ◽  
Dose Length Product ◽  
Trauma Team Activation ◽  
X Ray

Abstract This audit describes ionizing and non-ionizing diagnostic imaging at a regional trauma centre. All 144 patients (males 79.2%, median age 31 years) met with trauma team activation from 1 January 2015 to 31 December 2015 were included. We used data from electronic health records to identify all diagnostic imaging and report radiation exposure as dose area product (DAP) for conventional radiography (X-ray) and dose length product (DLP) and effective dose for CT. During hospitalization, 134 (93.1%) underwent X-ray, 122 (84.7%) CT, 92 (63.9%) focused assessment with sonography for trauma (FAST), 14 (9.7%) ultrasound (FAST excluded) and 32 (22.2%) magnetic resonance imaging. One hundred and sixteen (80.5%) underwent CT examinations during trauma admissions, and 73 of 144 (50.7%) standardized whole body CT (SWBCT). DAP values were below national reference levels. Median DLP and effective dose were 2396 mGycm and 20.42 mSv for all CT examinations, and 2461 mGycm (national diagnostic reference level 2400) and 22.29 mSv for a SWBCT.

scholarly journals A proof-of principal study using phase-contrast imaging for the detection of large airway pathologies after lung transplantation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephan Umkehrer ◽  
Carmela Morrone ◽  
Julien Dinkel ◽  
Laura Aigner ◽  
Maximilian F. Reiser ◽  
...  
Keyword(s):  
Lung Transplantation ◽  
Phase Contrast ◽  
Small Animal ◽  
Lung Parenchyma ◽  
Dark Field ◽  
Contrast Imaging ◽  
X Ray ◽  
Contrast Mechanism ◽  
Contrast Information

Abstract In this study we aim to evaluate the assessment of bronchial pathologies in a murine model of lung transplantation with grating-based X-ray interferometry in vivo. Imaging was performed using a dedicated grating-based small-animal X-ray dark-field and phase-contrast scanner. While the contrast modality of the dark-field signal already showed several promising applications for diagnosing various types of pulmonary diseases, the phase-shifting contrast mechanism of the phase contrast has not yet been evaluated in vivo. For this purpose, qualitative analysis of phase-contrast images was performed and revealed pathologies due to previous lung transplantation, such as unilateral bronchial stenosis or bronchial truncation. Dependent lung parenchyma showed a strong loss in dark-field and absorption signal intensity, possibly caused by several post transplantational pathologies such as atelectasis, pleural effusion, or pulmonary infiltrates. With this study, we are able to show that bronchial pathologies can be visualized in vivo using conventional X-ray imaging when phase-contrast information is analysed. Absorption and dark-field images can be used to quantify the severity of lack of ventilation in the affected lung.

scholarly journals Detection of individual sub-pixel features in edge-illumination x-ray phase contrast imaging by means of the dark-field channel

2019 ◽  
Vol 53 (9) ◽  
pp. 095401
Author(s):  
Norihito Matsunaga ◽  
Kazuhiro Yano ◽  
Marco Endrizzi ◽  
Alessandro Olivo
Keyword(s):  
Phase Contrast ◽  
Dark Field ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
X Ray

scholarly journals Varying Collimation for Dark-Field Extraction

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Ge Wang ◽  
Wenxiang Cong ◽  
Haiou Shen ◽  
Yu Zou
Keyword(s):  
Aspect Ratio ◽  
Small Angle ◽  
Dark Field ◽  
Small Angle Scattering ◽  
Primary Beam ◽  
Scattering Data ◽  
Projection Data ◽  
X Ray ◽  
X Ray Imaging ◽  
Angle Scattering

Although x-ray imaging is widely used in biomedical applications, biological soft tissues have small density changes, leading to low contrast resolution for attenuation-based x-ray imaging. Over the past years, x-ray small-angle scattering was studied as a new contrast mechanism to enhance subtle structural variation within the soft tissue. In this paper, we present a detection method to extract this type of x-ray scattering data, which are also referred to as dark-field signals. The key idea is to acquire an x-ray projection multiple times with varying collimation before an x-ray detector array. The projection data acquired with a collimator of a sufficiently high collimation aspect ratio contain mainly the primary beam with little scattering, while the data acquired with an appropriately reduced collimation aspect ratio include both the primary beam and small-angle scattering signals. Then, analysis of these corresponding datasets will produce desirable dark-field signals; for example, via digitally subtraction. In the numerical experiments, the feasibility of our dark-field detection technology is demonstrated in Monte Carlo simulation. The results show that the acquired dark field signals can clearly reveal the structural information of tissues in terms of Rayleigh scattering characteristics.

A beam hardening and dispersion correction for x-ray dark-field radiography

2016 ◽  
Vol 43 (6Part1) ◽  
pp. 2774-2779 ◽  
Author(s):  
Georg Pelzer ◽  
Gisela Anton ◽  
Florian Horn ◽  
Jens Rieger ◽  
André Ritter ◽  
...  
Keyword(s):  
Dark Field ◽  
Dispersion Correction ◽  
Beam Hardening ◽  
X Ray

scholarly journals Factors Affecting the Spatial Resolution in 2D Grating–Based X-Ray Phase Contrast Imaging

2021 ◽  
Vol 9 ◽  
Author(s):  
Siwei Tao ◽  
Congxiao He ◽  
Xiang Hao ◽  
Cuifang Kuang ◽  
Xu Liu
Keyword(s):  
Spatial Resolution ◽  
Phase Contrast ◽  
Imaging System ◽  
Diffraction Theory ◽  
Dark Field ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Transform Method ◽  
Factors Affecting ◽  
X Ray

X-ray phase contrast imaging is a promising technique in X-ray biological microscopy, as it improves the contrast of images for materials with low electron density compared to traditional X-ray imaging. The spatial resolution is an important parameter to evaluate the image quality. In this paper, simulation of factors which may affect the spatial resolution in a typical 2D grating–based phase contrast imaging system is conducted. This simulation is based on scalar diffraction theory and the operator theory of imaging. Absorption, differential phase contrast, and dark-field images are retrieved via the Fourier transform method. Furthermore, the limitation of the grating-to-detector distance in the spatial harmonic method is discussed in detail.

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