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Biomedical subjects

F Kotula

Publications and source records attributed to F Kotula.

15 recordsLinked to original sources
PubMed1993

Improved mammography with a reduced radiation dose.

A 2-cm-high focused air-interspaced grid with a 7:1 ratio and eight lamellae per inch was devised. The grid is arc-shaped and pivots on its focal point, the anode-cathode axis. Milliamperage was 35% less for breast phantom radiographs obtained with the new grid versus those obtained with a conventional 5:1 mammographic grid. In a comparison study of five mammograms, each evaluated for five parameters, the images obtained with the new grid were judged to be of equal or better quality than those obtained with a conventional grid in 17 of 20 comparisons.

Female↗
PubMed1985

Detachable steel spring coils for vessel occlusion.

Spring coils for vessel occlusion were modified to include a screw-on attachment for delivery wire, which permitted safe and accurate placement of the coils. We successfully implanted coils in a dog and a lamb. They were easily retrieved from within the delivery catheters and the vessels, which is not possible with conventional coils. Coil design is described.

Blood Vessels↗
PubMed1985

Very stiff guide wire with a floppy tip.

Many interventional procedures, particularly dilation of tracts, require stiff guide wires with a floppy tip. Such a guide wire was specially constructed and is commercially available.

Bile Ducts↗
PubMed1984

A new vena caval filter for percutaneous placement and retrieval: experimental study.

A new vena caval filter that can be inserted percutaneously through an angiographic catheter is described. The filter is secured by controlled penetration of the caval wall and is designed for percutaneous retrieval. The filter was easily and safely placed and removed in 11 mongrel dogs, and in an in vitro study, the filter was shown to be highly effective and less dependent than the Greenfield filter on positioning. The authors believe that the filter will be suitable for prophylactic placement in patients at high risk for pulmonary thromboembolic disease.

Animals↗
PubMed1982

Sources of artifacts in rotational scanography.

The images produced in rotational scanography, currently under investigation at several institutions, may contain several kinds of artifacts. The sources of such artifacts are: 1. vertical and horizontal misalignment of the focal spot with the axis of rotation; 2 misalignment of the primary and secondary slits; 3 a density gradient due to slit cut-off; 4 vibration of the x-ray tube during rotation; 5. A density gradient due to variation in motor speed; 6. radiographic striations due to ripple of the tube output. Striations are present even if a 12-pulse generator is used, but they disappear if a constant potential generator is employed.

Humans↗
PubMed1982

Ivalon shavings: technical considerations of a new embolic agent.

Ivalon (polyvinyl alcohol sponge) shavings can be used as a permanent embolic material. When injected as a suspension with assorted particles of proper size, congenital arteriovenous malformations can be cured, eliminating the need for surgical excision.

Adolescent↗
PubMed1981

Radiographic scanning in barium examinations of the gastrointestinal tract.

The possibility of using radiographic scanning for gastrointestinal studies was evaluated experimentally. Two tubular barium-filled phantoms containing simulated ulcers and polyps were placed in a 25-cm water container, and radiographs made with the conventional technique and scanographic technique were compared. Images obtained with the radiographic scanner were superior in contrast and sharpness. Two-millimeter polyps could be easily detected in the larger phantom. Due to improved latitude the larger phantom could be adequately penetrated without overexposing the smaller phantom. This was not possible with the standard technique. Best results were obtained with a heavily filtered 140-kVp beam. Radiographic scanning has great promise in barium examinations of the gastrointestinal tract.

Barium Sulfate↗
PubMed1980

Changerless peripheral angiography: a new concept.

The authors describe a new technique using the principle of rotational scanography, in which the x-ray tube is rotated through the center of the focal spot and scans the field of interest. A single primary and secondary slot system in conjunction with an 8:1 grid is used for efficient scatter removal. If the speed of blood flow is increased by reactive hyperemia and a large amount of contrast medium is injected, the abdomen to the toes can be scanned with one injection. The advantages of this technique are that a 127-cm field can be covered with a 6 degree or 12 degree target tube and without an especially high ceiling, and the film changer is eliminated. The angiograms are markedly improved because virtually all scatter is eliminated, and exposure is reduced since only one radiograph is necessary.

Angiography↗