Re: ED for a bitewing?

[julian.gibbs@mcmail.vanderbilt.edu]

     I addressed this issue in:
     
     Radiation Doses to Sensitive Organs from Intraoral Dental Radiology. 
     S. J. Gibbs, A. Pujol, Jr., T.-S. Chen, J. C. Carlton, M. A. Dosmann, 
     A. W. Malcolm, and A. E. James, Jr. Dentomaxillofacial Radiol. 
     16:67-77, 1987.
     This paper provided doses to essentially all organs in head, neck and 
     trunk, computed by a Monte Carlo model, from various intraoral dental 
     projections, in mrad per R at skin entry.  Data were provided for 70, 
     80, and 90 kVp and three common projection geometries.  You should be 
     able to compute ED from these data.  I also computed EDE for these 
     studies in:
     Patient Risk from Intraoral Dental Radiology. S. J. Gibbs, A. Pujol, 
     Jr., T.-S. Chen, and A. E. James, Jr. Dentomaxillofacial Radiol. 
     17:15-24, 1988.
     These data were summarized in:
     Influence of Organs in the ICRP's Remainder on Effective Dose 
     Equivalent Computed for Diagnostic Radiation Exposures.  S. J. Gibbs.  
     Health Phys. 56:515-520, April 1989.
     I hope this is helpful.  Let me know if you need more.
     Julian Gibbs
     


______________________________ Reply Separator _________________________________
Subject: ED for a bitewing?
Author:  radsafe@romulus.ehs.uiuc.edu at +inet
Date:    3/17/97 2:32 PM


Group:
I need some help with this problem.
     
A dentist friend has asked what Equivalent Dose (ED) should be assigned 
to a patient for each bitewing taken? He uses a cone, so the area is 
known
     
For each bitewing the mas and the kV are known. He uses a filter so the 
effective energy is known
     
Also known are the age and sex of the patient.
     
Also known and recorded is the blackening on the film, which is directly 
proportional to ED(Sv).
     
Then, using the weighting factors, W(t) and W(r), for this procedure, it 
should be possible to estimate the ED delivered by each bitewing.
     
However, I don't know what values to use for W(t) and W(r).
     
Can someone tell me where a table of them may be found, or give me a 
reference to a document, i.e., ICRP/NCRP?
     
Medical procedures are the most important source of ED for the 
population so, in keeping with ALARA, these W(t) and W(r) values must 
exist.
     
-- 
Wade
     
mailto:hwade@talltown.com
     
H.Wade Patterson
1116 Linda Lane
Lakeview OR 97630
ph 541 947-4974
     
     

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     S. Julian Gibbs, DDS, PhD                           Voice 615-322-3190
     Professor of Radiology                                FAX 615-322-3764
     Vanderbilt University Medical Center
     Nashville TN 37232-2675      mailto:julian.gibbs@mcmail.vanderbilt.edu
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