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Results for “FLUOROSCOPY”

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At least 811 records · Page 45Linked to original sources
PubMed1977

Evaluation of the physiological function of the ureter by fluoroscopy in bilharziasis.

Of 40 cases of bilharziasis of the urinary tract examined by excretory urography, 26 (65%) showed evidence of abnormal ureteral motility. Although the severe ureteral dilatation of bilharziasis is generally believed to be caused by fibrotic strictures, only 2 strictures were seen. Abnormal peristalsis was also found in ureters which were not dilated. Upper urinary tract changes in S. haematobium infestation are shown to be more often due to disturbances of ureteral peristalsis rather than ureteral stricture.

Adult↗
PubMed1975

Fluoroscopy of the upper gastrointestinal tract by the radiological technologist.

A pilot program was established to train an experienced radiological technologist to perform fluorescopy of the upper gastrointestinal tract. Patients were prescreened and films reviewed by a staff radiologist. The quality of the films obtained by the technologist equaled that of the department's resident radiologists.

Fluoroscopy↗
PubMedDate not supplied

Choice of phantom material and test protocols to determine radiation exposure rates for fluoroscopy.

The image intensifier entrance exposure rate (IIEER)) and entrance skin exposure rate (ESER) are two characteristics that can be used to determine whether a fluoroscope is adjusted to operate at an optimal dose rate level. This article presents solutions to some of the practical problems that are encountered when measuring these parameters. Because the energy response of the ion chamber used to measure exposure rates is different from that of the image intensifier, a fluoroscope with a perfect automatic exposure rate control will have an IIEER that depends on the phantom composition, phantom thickness, and x-ray tube potential. The authors developed a simple mathematic model to investigate the relationship of ion chamber response to image intensifier response and to determine the effects of phantom composition and thickness. Results from this model were compared with measurements made with two C-arm fluoroscopes. Variations of 40% or more in the IIEER and ESER can be ascribed to these phenomena.

Acrylic Resins↗
PubMedDate not supplied

The AAPM/RSNA physics tutorial for residents: X-ray image intensifiers for fluoroscopy.

The x-ray image intensifier converts the transmitted x rays into a brightened, visible light image. Within an image intensifier, the input phosphor converts the x-ray photons to light photons, which are then converted to photoelectrons within the photocathode. The electrons are accelerated and focused by a series of electrodes striking the output phosphor, which converts the accelerated electrons into light photons that may be captured by various imaging devices. Through this process, several thousand light photons are produced for each x-ray photon reaching the input phosphor. Most modern image intensifiers use cesium iodide for the input phosphor because it has a high absorption efficiency and thus decreases patient dose. Image intensifiers come in various sizes, most having more than one input image size or magnification mode. Modern image intensifiers are specified by conversion factors, which is the measure of how efficiently an image intensifier converts x rays to light. Because of design restrictions, image intensifiers are subject to inherent and induced artifacts that contribute to image degradation. Both spatial and contrast resolution gradually decrease during the lifetime of the image intensifier because the brightness gain of an image intensifier decreases with time as the phosphor ages. A well-run quality control program for the image intensifier is needed to detect the inevitable changes in settings before they appear on clinical images.

Fluoroscopy↗