Re:

[rfong@snd10.med.navy.mil (RAY FONG)]

Response to posting re dental exposure:
In 1980 the Quality Assurance Task Force (H-7), now known as the Committee
on Quality Assurance in Diagnostic Radiology, through the Conference of
Radiation Control Program Directors, Inc. (CRCPD), published patient
exposure guides for routine diagnostic x-ray projections.  This publication
was an attempt at providing recommended exposure guides as a tool for
reducing unecessary radiation exposure to patient, while maintaining or
improving image quality.  The guide (1988) provides several tables listing
average Entrance Skin Exposures (ESE) for several modalities.  Included are
the ESEs for dental radiography (Dental cephalometric ESE, Dental Intraoral
bitewing ESE); For example, an average patient ESE range for a standard
bitewing at 70 kVp using "E" speed film is 120 - 170 mR.

Ray Fong
RSO


>     Let's not forget who to thank on this one.  It isn't just HPs, but the 
>     people who work at Kodak, Polaroid, etc.  Most of the 
>     order-of-magnitude reduction in dental x-ray dose is from improvements 
>     in film sensitivity.  If I recall correctly, a full panoramic used to 
>     entail an exposure of about 4 mSv, vs ~.01 mSv inferred for the single 
>     intra-oral Dr. Gibbs notes below.  Someone more schooled in medical HP 
>     please correct me, if necessary, on this historical trivia.
>     
>     V/R
>     george_cicotte@health.ohio.gov
>     
>     With respect to Dr. Gibbs' post:
>     
>     ===================reply separator===================
>      . . . ."A dental x-ray is equal to a day in the sun" has turned out 
>     to be a remarkably accurate projection--even if for all the wrong 
>     reasons. . . . The effective dose from a single intraoral film, done 
>     with state-of-the-art technology in 1997, is approximately equal to 
>     one day's natural background--using the NCRP estimate of 3 mSv/y. . .
>     
>
>
Andy Waters
Radiology Dept.
Naval Medical Center, San Diego

Comm:(619) 532-8715