Re: dental x-ray web information

["Gibbs, S Julian" <s.julian.gibbs@vanderbilt.edu>]

Effective doses (or effective dose equivalents) from dental 
x-ray procedures have been derived from (1) organ doses 
measured in RANDO phantoms from exposure by dental x-ray 
beams, chiefly at University of Texas at San Antonio; and 
(2) Monte Carlo calculations of organ doses, chiefly in my 
laboratory.  The best review is by Stuart White, 
Dentomaxillofacial Radiol 21:118-126, 1992.  There has 
been little of consequence added since 1992.  Stu has 
concluded that effective doses for full-mouth intraoral 
exams (14-22 films) range from  30 to 150 uSv and for 
panoramic exams from 4 to 15 uSv.  Most authors have 
compared these doses to effective doses from all 
environmental exposure, including particulates in the 
lungs, to avoid the apple/orange problem.  Full-mouth 
intraoral exams done with state-of-the-art technology 
(E-speed film, rectangular collimation, etc.) then deliver 
doses equivalent to about 1 day of environmental exposure.  
For techniques in common clinical use (D-speed film, 7-cm 
round beams) in the US, the dose is equivalent to about 1 
week of environmental exposure.  We now know how to reduce 
dental dose significantly below that in common clinical 
practice.  This is like anything else: it takes years to 
transfer technology from lab to clinic.

***********************************************************
S. Julian Gibbs, DDS, PhD               Voice: 615-322-3190
Professor of Radiology                    FAX: 615-322-3764 
Dept. of Radiology & Radiological Sciences
Vanderbilt University Medical Center
Nashville TN 37232-2670 Email:s.julian.gibbs@Vanderbilt.Edu