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Biomedical subjects

S Balter

Publications and source records attributed to S Balter.

14 recordsLinked to original sources

Review of radiation safety in the cardiac catheterization laboratory.

With the increasing use of coronary arteriography and interventional procedures, radiation exposure to patients and personnel working in cardiac catheterization laboratories has increased. Proper technique to minimize both patient and operator exposure is necessary. A practical approach to radiation safety in the cardiac catheterization laboratory is presented. This discussion should be useful to facilities with well-established radiation safety programs as well as facilities that require restructuring to cope with the radiation environment in a modern cardiac catheterization laboratory.

Cardiac Catheterization

Cardiac catheterization laboratory survey: 1990. Society for Cardiac Angiography and Interventions, Laboratory Performance Standards Committee.

A survey of 117 member cardiac catheterization laboratories was undertaken by the Society for Cardiac Angiography and Interventions. The survey included numbers and types of procedures, both diagnostic and interventional, in adult as well as pediatric age groups. Radiation safety, various laboratory policies, frequency of short stay, and outpatient procedures were tabulated. Report generation, training programs, administrative organization, and laboratory equipment were all included. The results were compared with a 1978 survey. Areas of concern in terms of safety of the patient and possible underutilization of laboratories were identified.

Angioplasty, Balloon, Coronary

Optimizing radiologic costs in the DRG environment.

Previously developed consensus algorithms expressing a suggested radiologic workup for the diagnostic related groups (DRGs) specified by the prospective reimbursement policy have proven to be useful tools for investigating radiologic decision making and the resulting economic implications. The mathematical equations for determining diagnostic and therapeutic costs for two alternative algorithms for suspected acute cholecystitis are formulated. Illustrative examples and graphic displays are given regarding how such algorithms and equations are useful in finding answers to questions about the appropriate diagnostic workup, time, and cost. Exploration of the effect of different parameter values on the choice of the appropriate algorithm is illustrated.

Algorithms

Digital imaging of the chest.

The development of effective methods for producing digital chest radiographs is essential if the totally digital radiology department of the future is to evolve. Digital radiography of the chest is now possible with a variety of techniques. The most promising approach currently in clinical use involves the use of large-area detectors composed of photostimulable phosphors read with a laser to produce high-quality digital chest images. Image processing to modify contrast and latitude of the image display as well as enhancement of selected spatial frequencies and energy subtraction is possible with digital chest radiography. The wide exposure latitude of digital image receptors may allow useful images to be obtained with significantly smaller exposure doses than those required in conventional techniques and may also be used to compensate for inadvertent overexposure, eliminating the need for repeat examinations because of errors in exposure technique. Limitations of many current systems result from inadequate resolution provided by CRT display monitors. The production of hard copy images by laser printer on small format film overcomes this problem, allowing application of digital techniques for chest radiology to be incorporated into clinical practice with images comparable in spatial resolution to those of film-screen systems.

Fluoroscopy

Radiation exposure to the operator performing cardiac angiography with U-arm systems.

We measured the radiation exposure received by a group of operators performing 700 coronary angiograms. All studies were performed using the brachial artery approach and the Philips Cardio Diagnost. Nineteen sites were monitored on each operator, using lithium fluoride thermoluminescent dosimeters. Four hundred examinations were performed with a table-mounted protective shield in place. Three hundred were performed without the shield. The average exposures (in mR per study) with and without the shield were 1.9/6 for the eyes and 1.4/8.3 for the thyroid. The resulting operator exposure with the shield in place is low enough so that an operator performing 25 procedures per week on a continuous basis will not exceed the recommendations of the National Commission on Radiological Protection and Units. We therefore strongly recommend the use of properly designed and appropriately positioned shield with all U-arm systems.

Angiography

The use of photochromic eyeglasses by radiologists.

Photochromic lenses which undergo a change in density with varying intensities of sunlight have been incorporated into routine eyeglasses. Laboratory tests have shown that glasses of this type do not decrease the visual acuity of the radiologist.

Eyeglasses

Megavoltage portal films using computed radiographic imaging with photostimulable phosphors.

Conventional portal films taken with high-energy x rays are severely impaired by poor image quality, and many attempts have been made to overcome this problem. A new technology, computed radiographic imaging, has been investigated as a means of producing images taken with 6-and 10-MV x rays. The computed radiographic imaging (CRI) system is based on the principle of laser-stimulated luminescence induced in an image receptor plate exposed to ionizing radiation, and direct conversion of the light into digital form. Image processing using contrast enhancement and unsharp masking yields images at least as good as the best portal films obtainable with conventional commercial radiotherapy cassettes. Additionally, CRI offers advantages of reduced image size and digital storage. The system is capable of producing normal film densities over an extremely wide range of exposure.

Humans

On the work of the radiologist--separation of image capture from image display.

A primary function of the radiologist is that of extracting sufficient information from images, in a finite time, so as to arrive at a patient management decision. Clinically important information must be present in the images and this information must be correctly perceived. This essay discusses the work of the diagnostician viewing prerecorded images. The potentials for enhancing this work by means of different image display techniques are examined. The application of stimulable phosphor computed radiographic techniques are discussed in detail as an example of a technology which clearly separates crucial portions of the imaging process. This separation of functions might improve general radiology in the near future. The principals of the discussion are not specific to any imaging modality or to any individual display technology.

Data Display