PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “X-Ray Intensifying Screens”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1978

[Experimental study of intensifying screens used in diagnostic radiography (author's transl)].

A physical experimental study of intensifying screens for diagnostic radiography was set up. Experimental conditions were identical with those of medical practice. Spectra speeds of several films and spectral emission of intensifying screens were built up. Speeds of screen-film combinations, as well as definitions, were measured. Results are available to range the different screens-film systems after their speed factor, at 40, 70 and 120 kV, with mention of definition of these systems. It so objectively appears that rare-earth intensifying screens make possible a decrease of X-ray exposure for patient under a factor 2 to 2,5 and a less early wearing of apparatus, namely of X-ray tubes.

Evaluation Studies as Topic↗
PubMed1979

The Nicholas Research Award for Radiographers 1977: anatomical and radiological registration in whole body computed tomography.

Accurate registration of a section 13 mm in depth in different patients or reregistration in the same patient during whole body computed tomography is a significant problem. The method described here attempts to overcome some of these difficulties. The feasibility of using the EMI Scanner X-ray tube and a pair of Kodak Lanex intensifying screens in a vacuum pack cassette has been examined. A registration system which as an accuracy to within 1 pixel has been described. This technique has its major application in the registration and recognition of the axial skeleton, on fixed bony structures. The registration of soft tissue structures, subject to greater physiological variation poses problems which are the subject of further investigation.

Bone and Bones↗
PubMed1979

[Examinations of rare-earth film-screen-systems for image detectors in mammography (author's transl)].

Intensifying screens based on Gd2 O2 S : Tb were analysed for x-ray exposure reduction and resolution using in mammorgraphy. The contrast of these screens coupled with a single emulsion film was tested and the density dominante was determined. A resolution grid on this density exposured shows the detail resolution and judge the quality profile of these new film-screen-combinations. To all factors was compared a non-screen industrial film for long time processing. The application of Gadolinium intensifying screens in mammography allowed an exposure reduction of 75% at the same image quality like a nonscreen industrial film.

Female↗
PubMed1979

[Modern urography].

An IVP optimum quality should be tailored to the particular needs of a given case and consequently most be supervised by the radiologist when it is being performed. The most meticulous technique is needed, the adequate amount of contrast medium should be used, compression of the ureters should be performed and under optimum conditions tomography during the nephrographic phase should be performed whenever the circumstances should require it. With only very few exceptions no significant differences between different contrast media exist. The use of medium speed high contrast x-ray films as well as the use of rare earth intensifiers screens avoid the need for extremely powerful generators that are very costly. Film processing is a critical step in obtaining a good study and should be automatic.

Contrast Media↗
PubMed1978

[New aspects concerning exposure factors during direct geometrical X-ray magnification (author's transl)].

The paper is concerned with the use of rare-earth intensifying screens in order to overcome some of the exposure problems during magnification techniques using very small focal spots. Theoretical experiments and tests with biological objects indicate that the use of high intensifying screens under these circumstances is acceptable and useful. A comparison has been carried out between the results of conventional techniques without magnification and magnification techniques using very small focal spots and rare-earth intensifying screens.

Film Dosimetry↗
PubMed1979

Application of magnification radiography to the biliary system.

Magnification radiography was applied for the diagnosis of the biliary tract diseases including cancer. Our X-ray unit was consisting of HITACHI DR-155-23 U-6M-55P and 0.1 mm focal-spot tube, FFD 80 cm giving a magnification of x2 with the conditions of 60 kVp, 20 mA, 0.8 sec. Intensifying screens such as Kyokko LH II (for a standard sized subject) or DuPont Q II (for an obese subject) were used in combination with Fuji RX films. We confirmed a high diagnostic value in revealing early lesions of this sytem. The skin dose test indicated that this technique was routinely applicable with safety for clinical use.

Biliary Tract↗
PubMed1979

Contact double-contrast cholangiography.

Recently operative cholangiography has become an essential step in biliary surgery. However, an usual technique in which x-ray film is set beneath the patient has its limitation in visualization of fine changes. The author devised a new technique to resolve this problem. A triangular mammography film designed for good positioning is vaccum-packed, coupled with an intensifying screen of the same size, and then is sterilized in advance. Barium solution mixed with Gascon drop (a defoaming agent) is used as contrast material. The duodenum and head of the pancreas are mobilized. Usual cholangiography is performed at first, introducing angiographic media through a catheter placed into the catheter placed into the common duct via the cystic duct. After this study a triangle film pack is set beneath the second part of the duodenum. Two to three milliliters of barium, 1 to 2 ml of Gascon, and 15 ml of air are pushed in; thus a contact double-contrast cholangiogram is obtained. This technique promises clear demonstration of the distal bile duct without risk, and even fine mucosal plicae may be discernible in the film.

Adult↗
PubMedDate not supplied

Noise characteristics of a microchannel plate x-ray image intensifier.

The noise performance of an experimental microchannel plate x-ray image intensifier has been evaluated. The intensifier, constructed for use with photons of energies between 20 and 150 keV, uses an MCP as the photon-to-electron converter. The influence of noise was determined by analysis of the optical-density fluctuations of a photograph of the viewing screen of the intensifier when the conversion layer was exposed to between 1 and 60 mR. Additionally, the contrast-detail performance of the experimental device was determined. The influence of both stochastic noise, due to quantum mottle and pulse-height variations, and structural noise, due to fluctuations in inherent gain from point to point, have been considered by using a model that adds these components.

Models, Theoretical↗
PubMedDate not supplied

Heuristic model for understanding x-ray film characteristics.

A simple, heuristic model of a photographic emulsion is described for the purpose of illustrating the fundamental physical processes and emulsion properties which determine the characteristics of an x-ray film (viz., the shape of the H - D curve, film gamma, and film speed). By means of this model, it is shown that the contrast multiplication afforded by an x-ray film (i.e., a film gamma greater than unity) is a direct result of the exponential attenuation of the viewing light by the developed film, and that film gamma is proportional to grain size, grain density, and emulsion thickness. The difference in the H - D curve that is observed when the same film is exposed to light from an intensifying screen or directly to x rays is also predicted by the model.

Models, Theoretical↗
PubMed1979

[Comparison of screens and screen-film-systems (author's transl)].

Important details are to be payed attention in comparison of different scrreens resp. screen-film-systems: 1. Physical characteristics of different groups of luminescent materials: f.i. calcium tung-state, rare-earths compounds, double halogenides. - 2. Different types of screens: highest details up to highest speed intensifying screens, have to be defined more specifically and differentiated against to each other too. - 3. Besides intensification, resolution has to be included into consideration since one of these dates alone does not allow any statement on the total function of a screen or a screen-film-system. - 4. The technical methodological conditions of apparatuses, object and its positioning have to be defined, f.i. X-ray quality, distances, grid, and in automatically controlled exposition, if necessary, position of ionization chamber as well as absorption of cassetts and screen. - 5. Considering these points gradation curves have to include the whole necessary or interesting diagnostic range. - 6. Due to functional correlation between intensification and resolution, the resolution has to be taken in consideration due to application; its interdependence of density and object (f.i. scattered radiation) is often not taken enough in consideration.

Humans↗
PubMed1978

[X-ray dose reduction in examination of infant's hip with image-intensifier-fluoroscopy-system (author's transl)].

An image intensifier--70mm camera--fluoroscopy system combined with a conventional X-ray tube is used for routine examination of the infant's hip. The high quality of 85% of these 70mm exposures makes immediate diagnostic interpretation possible. An even higher percentage can be achieved by most exact positioning of the patients. Apart from the radiation protection of the gonades, the X-ray skin dose of the primary beam is reduced by 90-95% compared with full size radiography using film screen combinations. This exposure technique can certainly be used not only for the examination of the infant's hip.

Fluoroscopy↗
PubMedDate not supplied

A digital-radiographic technique for in vitro tissue thickness measurement using iodine displacement.

A novel digital radiographic method has been developed for measuring the thickness of a tissue sample by iodine displacement. This simple, accurate method is useful both in medical research and in the comparison of pathological and clinical findings. Radiographic measurements of tissue samples in air suffer from the limitation that the quantity measured depends on the product of both thickness and radiographic attenuation coefficient. This technique allows one to obtain thickness measurements from a digital radiograph of a tissue sample suspended in a bath of radio-opaque contrast agent. The attenuation of the iodinated contrast agent is much higher than that of tissue or calcium. Thus the resulting image is determined largely by the contour of the surrounding bath, and is only slightly influenced by the composition of the tissue. This technique improves both the accuracy and precision of radiographic thickness determination. In this paper the iodine displacement technique is described and the accuracy and precision of thickness measurements in appropriate phantoms are quantified. This technique has been used with both image intensifier and screen-film based imaging systems to obtain thickness maps of calcified human aorta, with precision better than 4% and spatial resolution of 2.5 mm-1.

Aged↗
PubMed1977

Eye dose measurements using conventional and rare-earth screens during tomography of the para-nasal sinuses.

Eye dose measurements have been performed when using medium speed conventional and rare-earth screen-film combinations during tomography of the para-nasal sinuses. The measurements show that using conventional intensifying screens with the A.P. view a total eye dose of about 20 rad may be given during an examination. This eye dose can be reduced by 98% using the P.A. position. If rare-earth screen/film combinations are employed the eye dose measured in the A.P. view was reduced by 75% of that obtained with conventional screens without detectable loss of image quality. A total eye dose reduction of about 99.5% was measured in the P.A. view with the rare-earth systems.

Ear, Middle↗
PubMed1978

[Trends in dental radiology--a review of the literature].

Dental radiology is experiencing a marked improvement in equipment and its comfort of use. The production of intensifying screens with calcium tungstate stratification causes considerable diminution of radiation damage although at the price of changes in the structure of the picture. Xeroradiography is stagnating after promising beginnings. The protection of the patient against radiation has improved and recent work shows that in the dental field, more care must be given to preserve the lens of the eye from radiation hazard. Pantomography as a diagnostic means is progressing although it has not been able to substitute for the conventional radiography. TMJ radiography does not make exception in the same sense, so the knowledge of the correct use of special cranial radiographs remains.

Humans↗
PubMed1992

[The influence of the spectrum and the type of exposure on the contrast of double-sided coated x-ray film].

The present article describes the circumstances concerning the use of testing aids such as sensitometers with one-sided exposure. It is shown which phenomena must be considered if radiographic films coated on both sides are exposed with a) standard pocket sensitometers (one-sided exposure), b) lab sensitometers (double-sided exposure to ANSI Ph 2.9 [1964]), c) x-radiation in the cassette, intensifying screen and film system (to DIN 6867 T 1). The effect of the emission spectrum on the resulting contrast factor is described. The importance of different emulsion technologies (e.g. orthochromatic anticross-over films) for the contrast factor with one-sided exposure is described. The cross-over factor (c.o.), the apparent variation in sensitivity of the front and back emulsion with one-sided exposure, is the cause of the reduction in the contrast factor (G average) as against double-sided exposure: delta G(%) = c.o.2 x 10(3)/8.4

Lighting↗