Re: Deterministic Effects Threshold Doses

[John Goldsmith <gjohn@bgumail.bgu.ac.il>]

Dear Radsafers:
     For the 8-16 week old fetus, threshold effects on central nervous 
system development are well under 1 Gray, in subjects exposed
 at Hiroshima-Nagasaki (Otake M. and Schull WJ, Brity. J. RAdiolofgy, vol 
57, pps 409-414, 1984).
       John Goldsmith, M.D., M.P.H., gjohn@BGUMAIL.bgu.ac.il

On Fri, 31 Jan 1997, Eugene H Carbaugh wrote:

>      
>      The most convenient compilation I have found of threshold doses for 
>      deterministic effects is in ICRP Publication 41, "Nonstochastic 
>      Effects of Ionizing Radiation.  Table 5 (on page 25) which is taken 
>      from a 1972 publication by Rubin and Casarett. 
>      
>      That table shows the lowest dose threshold for effect in only 1-5% of 
>      patients as fetal death (2 Gy) and bone marrow hypoplasia (2 Gy). 
>      Increasing the frequency to 25-50% of the patients raises the 
>      threshold dose to 4.5 and 5.5 Sv, respectively.
>      
>      I haven't heard of 50 mSv as a deterministic effects threshold dose 
>      for any specific effect.  I have heard that cytogenetic studies have 
>      be capable of detecting doses on the order of 150-250 mSv, but the 
>      confidence at those levels has been low.  I am not sure I would 
>      consider chromosome abberations a deterministic effect - by the basic 
>      definition of the effect, I would think it falls in the stochastic 
>      category.
>      
>      Gene Carbaugh
>      Internal Dosimetry
>      Pacific Northwest National Laboratoy
>      eh_carbaugh@pnl.gov
>