Re: X-ray Acne Treatment

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

Ivor:
     I can answer your last question with some more comfort than the
others.  Yes, children are more susceptible, presumably as their cell
replication rates are high.  They should have "greater protection".
There is strong evidence for susceptibility to be greatest during the
first trimester of pregnancy.  The only organ specific attribute is that
thyroid and breast are organs with rapid growth at these ages and
are so located that they get relatively large doses of irradiation when 
head an neck irradiation occurs.  Bone marrow impact is reflected by
increased leukemia, etc.      John Goldsmith, M.D., M.P.H.

On Thu, 18 Sep 1997, Ivor Suveyor wrote:

> >>Joel:
> >     There was an extensive use of x-ray for treatmeent of ringworm of the
> >scalp in Israel between 1948 nd 1960.  Of approximately 20,000 children so
> >treated, 10,834 were studied in a follow up. Treatment was with 75 - 100
> >kVp. EAch of five scalp fields was treated with 350-400 roentgens on
> >sucessive days.  10% of subjects had more than one treatment.
> >     Ron et al report on mortality of the follow-up group in Am.
> >J.Epidemiol. vol 127, 13-25, 1988.  Modan in the 1993 G. William Morgan
> >lecture, (Health Physics vol. 65 475-480, 1993) on "Low Dose Radiation
> >Carcinogenesis" reports a two fold increase in the risk of breast cancer
> >and a fourfold increase of thyroid cancer, following a minimal exposure of
> >16 mGy and 90mGy respectively.." (These I believe are tissue dose
> >estimates ) Carcinogenesis rates were higher in the
> >children treated at younger ages.  Ron et al. report a relative risk of 3
> >for tumors of the head and neck, of 2.3 for leukemia, and bone and soft
> >tissue sarcoma of 9, all of which were significant.  The last follow-up
> >observations were in 1987.  The expectation is that radiation induced
> >solid cancers would continue to be observed. 
> >    O.K. its not acne.        John Goldsmith gjohn@BGUMAIL.bgu.ac.il
> 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 
> PERTH WA
> 19-September-1997
> 
> Dear Radsafers,
> 
> The question raised by the thread on possible cancers induced by childhood
> irradiation  are relevant to discussions on the acceptance or rejection of
> the no threshold linear hypothesis.  It is likely that supporters of the
> hypothesis would argue that the evidence from childhood irradiation  shows
> that in some instances there is NO EVIDENCE OF A THESHOLD.    I would be
> very interested to learn from expert opinion how this literature evidence
> fits with the recent HPS position paper. 
> 
> There have been a  number of reports of an association between childhood
> radiation and thyroid and cancers since Duffy  and Fitzgerald published in 1950.
> 
> Radiation was administered to treat a large variety of diseases in the upper
> chest, head and neck since the 1920's and  earlier.   Including  So called
> thymic enlargement, hypertrophy of tonsils and adenoids, deafness due to
> lymphoid hypertrophy around the Eustachin tube.    Cervical adenitis,
> mastoiditis, sinusitis, hemangioma, keloid scars, tinea capitus, and acne  (
> editorial. Walfsh PG et al JAMA 1978; 88: 261-262).         
> 
> According to Webber BN ( Ann of Int Med 1977; 86: 449-450) there are 17
> English language papers between 1920 and 1935 relating to the radiation
> treatment of whopping cough.
> 
> Thus there seemed to have been a plethora of cases for epidemiological
> study.    Some of which have been considered in an email from  Dr John
> Goldsmith. 
> 
> Modan B, Ron E, and Werner A  Radiology  1977,123: 741-744.   Gives some
> details of technique used in skull radiation.  The mean  dose to thyroid was
> less then 9 rad (90 mGy )and the risk of cancer is given as 6.3/10e6/y.
> If tissue weighting factors are applied the whole body or effective dose
> would be very small indeed.
>  
> The questions that I am putting are these.   Do experts agree that following
> a latent period of 10-15 years the association of thyroid and other cancers
> with childhood radiation is causal?.   The actual exposure to thyroid from
> scattered radiation was small. 
> Does the evidence from these studies argue against the HPS position paper?
> Is there No threshold in case of children? 
> It is unlikely that the dose estimates to thyroid are wrong by a large
> factor.  So a further question is why is the thyroid and breast tissue of
> young female children so sensitive to radiation?   If there is to be a
> relaxation in regulations, ( so as to allow for no threshold ),  will a
> special and more stringent provision have to be made for youngsters? 
>  I would be interested, if anybody can put these studies into a  modern
> perspective.  
> Ivor Surveyor
> 
> Ivor Surveyor
> Emeritus Consultant Physician, Nuclear Medicine. 
> E-mail:    isurveyor@vianet.net.au
>