The Radiological Anatomy of the Scaphoid

1997 ◽  
Vol 22 (1) ◽  
pp. 8-15 ◽  
Author(s):  
J.P. COMPSON ◽  
J.K. WATERMAN ◽  
F.W. HEATLEY
Keyword(s):  
Complex Shape ◽  
X Rays ◽  
Radiological Anatomy ◽  
Anatomical Features ◽  
X Ray ◽  
Radiopaque Markers

The complex shape of the scaphoid and its orientation within the carpus makes the radiological interpretation of scaphoid anatomy difficult. To improve our understanding of how the anatomy appears on plain X-ray, a study was performed using dry cadaver bones. Salient anatomical features were outlined using radiopaque markers, the bones set in wax blocks and the blocks X-rayed in the same axis as six “standard” scaphoid views. The pictures obtained were then compared with clinical X-rays.

Radiological anatomy of the oral cavity

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Soft Tissues ◽  
Three Dimensional ◽  
Compact Bone ◽  
X Rays ◽  
Radiological Anatomy ◽  
X Ray ◽  
Periodontal Tissues ◽  
Sensitive Film ◽  
Mineralized Tissues ◽  
Pass Through

The radiographs most frequently taken in general dental practice are of the teeth and their immidiate supporting tissues for detection of dental caries or assessment of bone loss in periodontal disease. Intraoral radiographs are taken by placing the X-ray-sensitive film or receptor in the mouth close to the teeth being investigated. Extraoral radiographs use larger films or receptors positioned externally and produce a view of the entire dentition and its supporting structures on a single film; they are used to ascertain the state of development of the dentitions prior to orthodontic treatment, for example. Dental panoramic tomographs (DPTs) are the most frequent extraoral radiographs. A radiograph is a negative photographic record. Dense structures such as bone are designated as radio-opaque; they absorb some X-rays and appear white on radiographs. More X-rays pass through less dense radiolucent structures such as air-filled cavities which show up as black areas. The contrast between different tissues of the structures which the X-ray beam passes through is determined by their radiodensity which, in turn, is largely due to their content of metallic elements. Calcium and iron are the prevalent heavy metals in the body. Calcium is combined with phosphate to form hydroxyapatite crystals in bones and mineralized tissues in teeth. Iron is present in haemoglobin in blood, but only large concentrations of blood, such as those found within the heart chambers, show up on X-rays. In sequence from densest to most lucent, the radiodensity of the dental and periodontal tissues are: enamel, dentine, cementum, compact bone, cancellous bone, demineralized carious enamel and dentine, dental soft tissues such as pulp and periodontal ligament, and air; gold and silver–mercury amalgam metallic restorative materials are even denser than enamel. A radiograph is a two-dimensional representation of a three-dimensional situation. The orientation of anatomical structures relative to the X-ray beam is a major factor determining their appearance on the film. For example, a beam travelling through the long axis of a radiodense structure will produce a whiter image on the film than one passing through its shorter axis because more X-rays are absorbed; the structure will also have a different shape.

scholarly journals X-ray and anatomical features of arterial aneurisms of bifurcation of basilary artery

2020 ◽  
Vol 31 (1) ◽  
pp. 42-55
Author(s):  
V.V. Moroz
Keyword(s):  
Complex Shape ◽  
Clinical Course ◽  
Hemorrhagic Transformation ◽  
Hemorrhagic Disease ◽  
Anatomical Features ◽  
X Ray ◽  
Vertebral Arteries ◽  
Large Size ◽  
Dynamic Observation ◽  
Wide Neck

Objective ‒ to determine the main x-ray anatomical characteristics of arterial aneurisms (AA) of bifurcation of basilar artery (BA) and predictors of hemorrhagic transformation, taking into account the main options for the course of the disease.Materials and methods. Total on examination and treatment in the vascular departments of Romodanov Neurosurgery Institute for the period from 1998 to 2019 there were 687 (100 %) patients with AA of vertebrobasilar basin. AA of bifurcation of BA was diagnosed in 210 (30.6 %) patients. The hemorrhagic type of the course of the disease, in the presence of AA of bifurcation of BA occurred in 138 (65.7 %) cases. Asymptomatic unbroken AA of bifurcations of BA were detected in 58 (27.6 %) patients. The pseudotumor type of disease was diagnosed in 12 (5.7 %), ischemic in 2 (0.9 %) patients. Results. The main variants of the clinical course of AA of bifurcation of BA are established. Given the X-ray and anatomical features, certain prevailing for a particular variant of the course of the disease, the most stable characteristics of AA of bifurcation of BA, including the size, shape, neck and the ratio of the height of the dome to the diameter of the neck of AA.Conclusions. According to the results of the study, the main variants of the clinical course of AA of bifurcation of BA were identified: hemorrhagic (65.7 %), asymptomatic (27.6 %), pseudotumor (5.7 %) and ischemic (0.9 %). Localization of AA in the area of ​​BA bifurcation is a rather formidable predictor of a possible hemorrhagic variant of the course of the disease (138 (65.7 %)) out of 210 patients). Based on the analysis of the results of the examination of patients with AA of bifurcation of BA with hemorrhagic disease, it should be considered that convincing factors (predictors) of a possible rupture of AA of bifurcation of BA are its sizes from 4 to 15 mm (81 %) in combination with complex (incorrect) form AA (76 %). With the size of AA of bifurcation of BA <4 mm or having sizes from 16 to 25 mm, the risk of hemorrhagic course is much lower, respectively 10.1 and 7.9 %. The ratio of the height of the dome to the width of the neck of the AA of bifurcation of BA >3.0, according to the results of our study, is not a predictor of the hemorrhagic course of AA of bifurcation of BA, in the presence of a narrow neck of AA. In the presence of a small size of AA of bifurcation of BA (<4 mm), regardless of its shape, the probability of hemorrhagic transformation, without taking into account risk factors and the results of dynamic observation of the size and shape of AA, is minimal. The probable factors that can explain the absence of hemorrhagic transformation of AA of bifurcation of BA with a pseudotumor course are the mismatch between the internal and external sizes of AA according to data of CT and SCAG, which indicate a significant thickness of the AA wall of this group and the presence of thrombogenesis or stratification in its cavity. The ischemic type of the course of the disease in the presence of AA of bifurcation of BA of large size, complex shape and wide neck of AA can be argued for by the presence of concomitant pronounced deformations of vertebral arteries in extracranial sections.

scholarly journals Recognition of X-rays bones: Challenges in the Past, Present and Future

2019 ◽  
Vol 8 (10) ◽  
pp. 1958-1966
Keyword(s):  
Image Processing ◽  
Image Segmentation ◽  
Splitting Methods ◽  
X Rays ◽  
Radiological Imaging ◽  
Imaging Analysis ◽  
Anatomical Features ◽  
X Ray ◽  
The Past ◽  
Research Analysis

Image processing tool is a key role in medical uses, by extracting anatomical features the contouring of the regions from medical images. The discovery of bone sketch from X-ray images has recently introduced a new dimension in the literature as it proves to be an important step of radiological imaging analysis. X-ray images are segmented to study bone skeleton where the image is split into several parts, to examine the fracture of bones, and to plan for treatment before surgery. This report's, purpose is to survey digital image splitting methods. In image segmentation, research analysis is important for categories and it is important to provide an overview of assistive segmentation techniques with highlighting advantage and disadvantage.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

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