Re: NRC Information Notice 2002-28/fluoroscopy

["Michael G. Stabin" <michael.g.stabin@vanderbilt.edu>]

Gary Isenhower wrote -



> Overexposures resulting in real harm to patients are rare in fluoroscopy

> and more rare in nuclear medicine.  So, I would not characterize this as

> a reprehensible situation, or one that should elicit outrage or

> disbelief.



Yes, Gary, I did not AT ALL mean to associate these adjectives with the

issue of fluoroscopy overexposures, only with the conscious acts of some to

thrust radiation safety duties on persons who cannot adequately perform the

duties (or aren't even aware that it has happened), due to time constraints

or lack of training. Thanks for the chance to clarify that.



> It is true that some overexposures occur due to lack of experience in the

physician

> performing the procedure.



I thought a big part was due to the fact that there is poor "live time"

knowledge of the cumulative dose. I know there are devices that supposedly

use an ultrasound signal to calculate source-to-skin distance "on the fly",

but I have heard that these devices may get interferences when the signal

bounces off objects other than the patient. Systems without this approach

tend to use pre-calculated dose values, which may not be very accurate for

each situation. So I was under the impression that if we could work harder

to just know what cumulative dose we were giving, we could avoid many of the

overexposures, while still delivering good patient care. Or at least if we

were approaching the thresholds for erythema we would know it better and not

be surprised later when effects occurred. My understanding on this is poorly

formed, however, so I would very much like to hear from people with better

experience.



Mike





Michael G. Stabin, PhD, CHP

Assistant Professor of Radiology and Radiological Sciences

Department of Radiology and Radiological Sciences

Vanderbilt University

1161 21st Avenue South

Nashville, TN 37232-2675

Phone (615) 343-0068

Fax   (615) 322-3764

e-mail     michael.g.stabin@vanderbilt.edu

internet   www.doseinfo-radar.com







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