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Biomedical subjects

S Rudin

Publications and source records attributed to S Rudin.

At least 37 records · Page 2Linked to original sources
PubMed1995

Implementation of region-of-interest fluoroscopy by using the road mapping mode of a real-time digital radiographic unit.

In region-of-interest (ROI) fluoroscopy, a filter is used to greatly attenuate the x-ray beam outside the ROI and digital image processing is used to equalize the displayed brightness. The method is applicable to real-time imaging procedures such as vascular interventions for which a high-quality image is essential only over an ROI (eg, near the catheter tip), whereas the noise-degraded periphery may be acceptable for visualizing landmarks. Use of ROI fluoroscopy can greatly reduce radiation exposure to the patient and to staff while image quality in the ROI is maintained or improved. Exposure reduction factors greater than 5 were demonstrated for coil placement in a canine aneurysm model by using standard digital angiographic equipment operating in the road mapping mode. Potential applications for which future work will determine the clinical acceptability of ROI fluoroscopy include many of the highest-dose interventional procedures, in addition to general gastrointestinal fluoroscopy.

Animals↗
PubMed1992

Minimizing radiation dose to patient and staff during fluoroscopic, nasoenteral tube insertions.

It is possible to reduce greatly fluoroscopic radiation dose if some image degradation is acceptable. Since the fluoroscopic image during nasoenteral tube placements is used for guidance and not for diagnosis, a lower contrast image with increased quantum mottle can be easily tolerated. The three methods to reduce the radiation dose rate that were investigated consisted of removing the antiscatter grid, increasing the diameter of the optical aperture controlling the percentage of light reaching the television camera from the image intensifier output phosphor, and setting the fluoroscopic mA to the minimum value so that the kVp could be maximized. Fluoroscopic frozen video frames of a clinical tube insertion comparing the images with and without the dose-saving techniques are presented. Measurements of the radiation dose rates using a Plexiglas phantom show that the dose for patient and staff during fluoroscopic-guided nasoenteral tube placements can be reduced by over a factor of 10 without significantly adversely affecting the actual placement procedure.

Adult↗
PubMed1991

Blurred-mask density compression for improved reproduction of radiographs.

A film-based, blurred-mask subtraction technique can be used to reduce the apparent density range of medical radiographs so that a wider range of actual densities can be captured with video digitizers or reproduced on photographic paper for publication. The density compression and the edge enhancement resulting from this process is examined. A good balance between compression and enhancement for small structures was obtained with a 6-mm gap between the subtraction film and the original when producing the mask. As an example, a photographic print of a compressed chest film showed significant condensation of image information within the restricted reflection density scale of the print paper; detail was well demonstrated in the mediastinal, retrocardiac, and subdiaphragmatic regions that was not shown in the noncompressed print.

Humans↗
PubMed1991

Dose reduction during fluoroscopic placement of feeding tubes.

By both increasing the optical iris of the video camera and removing the grid in fluoroscopic procedures involved in placement of a Dubbhoff feeding tube, the radiation dose to patients and staff was reduced by five to seven times. An average expected dose to a patient of about 300 mGy per procedure was reduced by two to three times when the grid was removed and by an additional three times when an iris of increased diameter was used. Because Dobbhoff procedures do not involve obtaining a diagnosis, the image degradation was acceptable and did not affect the total exposure times or ability to conduct the procedure. With the grid out, the difference between the mean exposure times of 5.1 minutes in 96 patient studies done with a normal iris opening and 4.0 minutes in 52 studies done with an enlarged iris was not statistically significant. The importance of reducing patient dose is reinforced by the finding that one-third of the patients underwent repeated procedures, accounting for almost 60% of the total.

Environmental Exposure↗