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Results for “Radiographic Magnification”

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At least 55 records · Page 3Linked to original sources
PubMed1980

Effect of radiographic magnification on image contrast of blood vessels.

Blood vessel phantoms 0.5--4 mm in diameter were radiographed with a 0.1 mm x-ray tube with and without scattering medium. The contrast of the blood vessel images was determined by densitometry. Without scattering medium, magnification did not increase the image contrast for 1 mm or larger vessels. With scattering medium, contrast improved significantly due to the reduction of scattered radiation by the air gap between object and film.

Absorptiometry, Photon↗
PubMed1991

[Direct radiographic magnification in experimental research on the stomatognathic system].

A new X-ray tube with a less than 10 microns microfocus enables investigations supported by direct radiological magnification. It allows the nondestructive examination of mineralized structures up to microscopic dimensions. For experimental research on bony tissue, teeth and in the field of dental material science, new and interesting areas have been opened. Examples demonstrate possibilities of this special radiographic method.

Animals↗
PubMed1991

[Direct radiographic magnification in experimental medicine].

Some aspects of direct radiological magnification in experimental medicine are shown by teratological investigations of the fetal rat skeleton and by indirect lymphadenography in rabbits. A combination of microfocal radiography and high-resolution non-screen films or digital image processing allows the evaluation of structures with a minimum size of 5 microns. Pseudo-3D images correlate directly with scanning electron micrographs of equivalent casts. Therefore radiography with direct magnification can make difficult preparations and time-consuming staining processes unnecessary. Besides saving time, the main advantage of this method is the amount of new information it yields. For the first time, for example, the filling mechanism becomes visible even in minute vessels, such as the intranodal sinuses, which measure about 10 microns. Hitherto, we have only been able to infer this mechanism from histological specimens. A further benefit of direct radiological magnification over the conventional microscopical method is the smaller number of experimental animals needed.

Abnormalities, Drug-Induced↗
PubMed1978

Application of radiographic magnification technique with an ultra-high-speed rare-earth screen/film system to oral cholecystography.

2X magnification employing a 200-mu focal spot and an Alpha 8-XM screen/film system was applied to oral cholecystography and the results compared with those for the conventional contact technique with the Par-RP system. The basic imaging properties of the system, as well as phantom studies, indicated that the image quality obtained with magnification is comparable to or better than that for the conventional technique. In clinical studies on the detection of gallstones, the conventional technique revealed 5 true-positive and 17 true-negative cases and 1 false-positive and 2 false-negative cases, while the magnification technique provided 7 true-positive and 18 true-negative cases but no false cases. With the magnification technique the skin dose was reduced to approximately half that for the conventional contact technique.

Cholecystography↗
PubMed1991

[Direct radiographic magnification in forensic medicine].

The aims in medico-legal investigation of wounds are description of the wound morphology, the characterization of force applied and the identification of the weapon used. The detection of foreign bodies (paint fragments, glass particles, sand or gravel particles, rust particles and powder residues) in or around the wound can be of great value. The suitability of X-ray magnification for the detection of such foreign bodies was investigated in the present study. Other possible applications of this method in forensic practice are discussed.

Foreign Bodies↗
PubMed1997

[Direct radiographic magnification mammography with a new microfocus tube. Experimental studies of resolution and radiation exposure].

A recently developed X-ray unit for mammography using microfocal (spot size 0.12-0.05 mm) direct magnification radiography will soon be introduced into clinical practice. Unit arrangement and tube construction have been demonstrated. Mean surface dose was measured using PMMA-phantoms. A dose reduction of up to 50% was obtained in 1.7-fold magnification mammography (full sized views) compared with conventional techniques. The image quality was almost equivalent. However, in comparison with 1.7-fold magnification mammography, a comparable dose range for 4-fold magnifications with the microfocus system was measured with a substantial gain in spatial resolution. These findings satisfy the demands of a modern mammographic unit.

Equipment Design↗
PubMed1991

[Dosimetry and technical quality parameters of the Microfox G-10 medical direct radiographic magnification unit].

Measurements of the entry dose for four- and eightfold magnifications were carried out in phantoms and patients with the new magnification X-ray-unit Microfox G-10 (fine focus). The skin dose for the fourfold magnification is in the order of conventional radiography, at corresponding voltages. The entry dose for the fourfold magnification of a wrist is about 0.1 cGy (tube voltage 60 kVp, time 0.7 s). In addition measurements were made to determine parameters for quality control. The deviations from the German standards are discussed. Proposals are made how to implement the German Abnahmeprüfung and Konstanzprüfung.

Germany↗
PubMed1991

[Direct radiographic magnification in dental radiology].

Panography using small focal spots was an accepted radiodiagnostic method in dentistry before it was replaced by pantomography. Meanwhile, a new microfocus X-ray tube with a much smaller focal size is available. In comparison with the former focal system no new aspects are discernible. On the other hand, the new tube will be especially helpful for preparative diagnostic work before histological evaluations.

Humans↗
PubMed1991

[Direct radiographic magnification in combination with digital radiography for bone imaging].

The usefulness of direct radiological magnification is inversely related to the resolution of film-screen systems when very small focal spots are used. Thus, spatial resolution of digital luminescence radiography (DLR) may closely approximate that of high-detail screens at the expense of a more restricted field of view. Apart from the major drawback of limited spatial resolution, DLR makes it possible to take full advantage of image-processing techniques and an unmatched dynamic range.

Bone and Bones↗
PubMedDate not supplied

[Direct radiographic magnification: a contribution to the study of bone pathology].

Direct magnification radiography was evaluated on 46 patients with skeletal disorders. The equipment employed was based on a microfocus tube and it gave a magnification factor of 3 X. This technique was judged to be more useful than standard X-ray films in 35/46 cases (76%). The size of the part examined played an important role in the effectiveness of this technique, since the most useful and impressive results were obtained in thin anatomic sites, like the extremities. The highest value of direct magnification radiography was found to be in uraemic osteodistrophy, in particular for the study of the hands. This technique appeared to be very useful also in bone tumours, since it allowed a detailed evaluation of the trabecular structure and of the cortical outline.

Adolescent↗
PubMed1991

[Direct radiographic magnification in experimental otorhinolaryngology].

Isolated intact ossicles, the smallest bones in the human body, impressively demonstrate the possibilities of a high-grade radiographic direct-enlargement technique with a microfocus X-ray tube. In a complete skull, however, superposition effects reduce its advantages, as was seen with artificial skull-base defects. Visualization of movements of the ossicle joints in direct radiological magnification resulted in the discovery of a protective mechanism in the ossicular chain.

Ear Ossicles↗
PubMed1978

[Role of direct radiographic magnification in the evaluation of various morphological changes].

Radiograms with direct enlargement of the image were performed by means of X-ray apparatus "PEIC" designed by the firm "Svetlana", Leningrad. The status of the hand bones was studied in persons with posttraumatic bone regeneration, as well as angioarchitectonics of organs in experimental animals. In radiograms with direct enlargement some details characterising the process of ageing in the hand bones are observed more distinctly than in routine radiograms. The investigators succeeded in obtaining age changes in the structure of spongy substance and of cortical layer of phalanxes. The apparatus "PEIC" presents new possibilities for vital investigation of bone ostructures in experimental and clinical work, as well as to examine preparations of organs and their histological sections.

Adult↗