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Proceedings Paper

The Role Of Hospital Physicists In Performance Specifications
Author(s): Peter M. Joseph
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Paper Abstract

The concept of the radiological consumer writing specifications for x-ray equipment prior to purchase is both very new and well established. It is new in that many medical centers, who are now employing full time professional physicists and engineers to evaluate their existing equipment, are quite logically beginning to generate pre purchase specifications. However, at least one federal agency, the Veterans Administration, has for years required that all x-ray equipment purchased for their hospitals meet a long list of fairly demanding qyccifications. These requirements, published as Federal Specifications GG-X-635' , are an example of the kind of thing which a customer can demand and the industry can provide. If anything, the VA specifications err in the direction of being too specific and detailed, and most hospitals would be foolishi to adopt them in a wholesale manner. For example, they require that the MA meter shall have double or triple scales, that the unit fit in a room of between 9 and 10-1/2 feet, that an electrical steroscopic shift be available, etc. Obviously, also, any set of specifications must be upgraded to allow for new technologies as they come along. However, the VA has demonstrated that the x-ray industry can meet these standards of quality. By contrast, it has been our experience that, in the absence of any hospital based program of quality evaluation, even brand new x-ray installations can be seriously deficient in some way or other. For example, we have not only suffered from installation errors in such areas as TV systems, KV calibration, or tube protection circuits, but also from faults of design wherein the equipment could not possibly meet performance standards as good as those in GG-X-635. For example, we have a generator used in tomographic examinations at low KVP, where the KVP changes by 10 when switching MA stations. Other examples include timers with incorrect resistors values used in the design, KVP values which change by as much as 10 KVP during a given exposure (see figure 1) and between successive angiographic exposures, and phototimers that simply do not work. I emphasize that these faults were apparently not due to faulty installation or failure of components, but represent designed limitations in the original equipment.

Paper Details

Date Published: 25 March 1976
PDF: 4 pages
Proc. SPIE 0070, Application of Optical Instrumentation in Medicine IV, (25 March 1976); doi: 10.1117/12.954604
Show Author Affiliations
Peter M. Joseph, Columbia-Presbyterian Medical Center (United States)

Published in SPIE Proceedings Vol. 0070:
Application of Optical Instrumentation in Medicine IV
Joel E. Gray; William R. Hendee, Editor(s)

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