[ RadSafe ] RE: Q ?? Uranium (and Canada) A Discussion Guide -- Questions &Answers (1)

[Philippe J. Duport]

If no detrimental effect is observed, wsubR (formerly Q) or wsubT
(tissue weighting factor) must be zero or close to it, whatever the type
of radiation; otherwise, the ICRP system of dose effective calculation
(absorbed dose x wsubT x wsubR) is meaningless (it is for everyone to
draw his-her own conclusions).  I am not sure there is a dose level at
which radon decay products produce beneficial effects in the bronchial
tree.  From animal experiments with alpha emitters, it seems that it is
the combination dose and dose rate that matters - a low dose given at a
high dose rate may be harmful, the same low dose at a low dose rate
might be neutral or beneficial (there are some examples, but difficult
to prove or to generalize).  Bernie Cohen's data show a
difficult-to-refute possibility of a benefice.  Whatever the type of
radiation, it looks as if the dose - dose rate combination is the
relevant parameter.

 

Philippe Duport

 

________________________________

From: howard long [mailto:hflong at pacbell.net] 
Sent: February 20, 2007 13:44
To: Philippe J. Duport; Roger Helbig; radsafelist
Cc: rad-sci-l at WPI.EDU; lewhelgeson at helge.com
Subject: Q ?? Uranium (and Canada) A Discussion Guide -- Questions
&Answers (1)

 

"Quality factor (Q): A factor which indicates the power of a ray or beam
to produce a physiologic change. Q = 1 in low LET radiation. In high LET
radiation, Q= 2-200 [ ! ! ! ]

depending on the particle, its energy, and the biologic parameter
studied. Depending upon the absorbtion of a ray, Gy x Q =Sv." Radiation
Hormesis, TD Luckey [! by Long]


 

So, is the Startrek "Q" at work here? 

What dose of alpha from radon in the bronchial tubes is good and at what
level does it become bad? 

 Is there original mouse or epidemiologic study to suggest that dose? 

Where does the customary 20x factor come from for alpha effect?

 

Howard Long


"Philippe J. Duport" <pduport at uottawa.ca> wrote:

	
	Alpha radiation is the type of radiation for which there is the
largest
	number of peer-reviewed references that show unambiguous
apparent or
	real thresholds for the induction of cancer by alpha emitters.
The list
	of references is copious, both for animal experiments and human
	populations.
	
	When there is an apparent threshold, either the radiation
weighting
	factor, or the tissue weighting factor, or both are close or
equal to
	zero, in which case alpha radiation is certainly not 20 times
more
	dangerous than beta or gamma radiation. Perhaps, Gordon Edwards
refers
	to in vitro experiments, in which the "bullet" effect of alpha
radiation
	can be shown. However, in vitro experiments are not
representative of
	what happens in the whole organism, in which natural defense
mechanisms
	play their full role. Just one quotation, from someone who knows
what
	he is taking about: 
	
	"Radiation weighting factors are considered to be independent on
dose,
	dose rate/fractionation, effect level, end point considered in a
cell
	(inactivation, mutation, ...), organ/tissue, gender and age. All
these
	assumption are likely to be wrong (example: Radon, where the
"equivalent
	dose concept" can be tested and proved inaccurate)" Prof. Dr.
Dr.
	Herwig G. Paretzke (RBE for different radiation particles and
dose
	levels. (International Radiation Protection Association, 11th
	International Congress, Madrid, 2004)
	
	Professor Paretzke is director of the Gsf- Institute of
Radiation
	Protection, Neuherberg, honorary professor at the Physics
Department,
	Technical University of Munich, and University Lecturer at the
	Leopold-Franzens-University of Innsbruck, Austria. He is speaker
of the
	multi- national EU-project "Biophysical models for the induction
of
	cancer by radiation", member of the International Commission on
	Radiation Units and Measurements (ICRU), International
Commission on
	Radiological Protection (ICRP), OECD- Committee on Radiation
Protection
	and Public Health (CRPPH), etc. 
	
	Philippe Duport
	
	-----Original Message-----
	From: radsafe-bounces at radlab.nl
[mailto:radsafe-bounces at radlab.nl] On
	Behalf Of Roger Helbig
	Sent: February 19, 2007 23:33
	To: radsafelist
	Subject: [ RadSafe ] Uranium (and Canada) A Discussion Guide --
	Questions &Answers (1)
	
	This seems to be generally accurate, but I wonder if it all is
and I
	would appreciate your assistance in evaluating it.
	http://www.ccnr.org/nfb_uranium_0.html
	
	For example it states 
	
	"Inside the body, however, alpha emitters are the most
dangerous. They
	are about 20 times more damaging than beta emitters or gamma
emitters.
	Thus, although alpha radiation cannot penetrate through a sheet
of paper
	or a dead layer of skin, alpha emitters are extremely hazardous
when
	taken into the body by inhalation or ingestion, or through a cut
or open
	sore."
	
	I would really wonder whether it is more dangerous to take in an
Alpha
	emitter rather than one that emits Gamma radiation.
	
	This same website also hosts Rosalie Bertell's paper connecting
the Gulf
	War Syndrome to depleted uranium and that appears to be highly
suspect
	so I wonder about the rest of the site.
	
	Thank you.
	
	Roger Helbig