[ RadSafe ] Chris Busby
Bill Prestwich
prestwic at mcmaster.ca
Thu Apr 21 14:28:47 CDT 2011
My apologies-I was looking at the 90Sr half-life not the 90Y half life. The
average time between decay events is 3.9 days. This is still a relatively
long time.
Bill
-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu
[mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Bill Prestwich
Sent: Thursday, April 21, 2011 10:54 AM
To: 'The International Radiation Protection (Health Physics) Mailing List'
Subject: Re: [ RadSafe ] Chris Busby
This argument is not convincing for two reasons. Studies in which tritium
has been intentionally introduced into hydrogen positions in DNA have shown
that such substitutions are not significant. The long range damage of even
this very low energy beta particle results in non-localized damage.
Radionuclide binding to DNA is simply not relevant. Secondly, the
consequence of misrepair leads to a great deal of the subsequent deleterious
consequences. Hence the lack of repair in not necessarily a bad thing. It
may indeed provoke the desired response of either cell apoptosis or loss of
proliferative capability. The average time between 90Sr and 90Y decays is
40.5 years, so application of the concept in this case is really rather
inapt.
Bill
-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu
[mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Busby Chris
Sent: Wednesday, April 20, 2011 1:44 PM
To: The International Radiation Protection (Health Physics) Mailing List;
radsafe at agni.phys.iit.edu
Subject: Re: [ RadSafe ] Chris Busby
Hurrah!
At last a scientific dialogue.
The Second Event Theory is simple.
Some internal radionuclides that bind to DNA have sequential decays
In certain circumstances, there are also external dose fractionations with
two or more tracks across the target in 12 hours. e.g. CT scans of road
accident victims.
Why 12 hours?
This is the cell cycle from G(0) to M.
At the end of this cycle is the XTP. After this no repair is possible. The
cell sensitivity varies enormously and is very high at the end of G(0)M.
Therefore is a cell is inducted into G(0) M cycle from quiescence by a first
"hit" and then hit again after the repair, no further repair is possible and
a fixed mutation is inevitable.
There is already evidence from cell cultuires that support this.
Certain sequential decaying internal nuclides are unsafe, the worst is
Sr90/Y90.
It is all explained in Wings of Death 1995 and some later papers.
There is plenty of evidence that Sr90 is very serious mutagen not modelled
by ICRP dose coefficients.
But I started with the Chernobyl infants and that is what I would like to
focus on.
Sincerely
Chris
-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu on behalf of John R Johnson
Sent: Wed 20/04/2011 16:09
To: radsafe at agni.phys.iit.edu
Subject: [ RadSafe ] Chris Busby
Radsafers
I don't understand all this criticism of Chris Busby. I used google to find
http://en.wikipedia.org/wiki/Christopher_Busby to looked at his background
and he looks like a scientist
we should encourage discussion with. I am an "internal dosimetrist" and one
of the items given in the web site I would like to hear more about is the
"Second Event Theory" which
distinguishes between hazards of external and internal radiation.
Chris is no relation of Bruce Busby from Seattle as far as I know
John
***************
John R Johnson, PhD
CEO, IDIAS, Inc.
4535 West 9th Ave
Vancouver, B. C.
V6R 2E2, Canada
idias at interchange.ubc.ca
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