RE: Radiation hypersensitivity

[Tom Morgan <tmorgan@ISOTOPEPRODUCTS.COM>]

There is a genetic disorder that causes patients to be hypersensitive to

ionizing radiation - Atxia telangectasia.  Cells from these patients are

about three times more sensitive than cells from normal individuals.

Clinical treatment with therapeutic doses of radiation causes such serious

problems (e.g, necrosis, etc.) that they are never irrdiated.



These patients are usually diagnosed early in life becuase they exhibit

serious symptons such as loss of motor control and very prominent blood

vessels in the skin.  By the time they are teenagers they are confined to a

wheelchair and most die as young adults.



Ataxia telangectasia strikes about 1 in 100,000 children.  This disease is

caused by homozygous recessive mutations in the two AT alleles.  It has been

hypothesized that heterozygous mutations (one allele mutant and the other

normal) might render the patient sensitive to ionizing radiation.  Although

the disease is rare, it has been hypothesized that up to 10 percent of

woment diagnosed with breast cancer carry the heterozyous mutation.  It is

important to note that this connection is still theoretical - there is no

solid evidence as yet.



However, these patients exhibit no outward symptoms.  The gene was cloned

some five years ago and several groups are developing tests for these

mutations.  



Patients who enter a radiation oncology clinic for therapeutic treatment

show a broad range of responses.  Approximately 5% rapidly develop such

serious side effects that treatment must be suspended or halted altogether.

However, these symptons develop after doses of about 20 Gy.   To date, there

is no test that is specifically designed to detect these individuals.  



Confessions of a reformed radiation biologist.



Thomas L. Morgan, Ph.D.

Director of Health Physics

Radiation Safety Officer

661-309-1033



-----Original Message-----

From: Jerry Cohen [mailto:jjcohen@PRODIGY.NET]

Sent: Wednesday, October 10, 2001 2:23 PM

To: radsafe@list.vanderbilt.edu; rad-sci-l@ans.ep.wisc.edu

Subject: Radiation hypersensitivity





From: Prof.Dr.Klaus.Becker <Prof.Dr.Klaus.Becker@t-online.de>

 >We should perhaps think a little about this question of "radiation

>allergy"

> and how to deal with it, before it is (technically and legally) feasible

to

> do large-scale genetic screening, e.g. of radiation workers. Obviously,

>the

> percentage must be small, but does any of you have good data or arguments?



     I think  the possibility that some individuals may be hypersensitive to

radiation deserves serious consideration. A good analogy to this situation

can be found in the field of Industrial Hygiene as pertains to Beryllium

exposure. From past observations it is apparent that the most workers who

have experienced  high levels of exposure exhibit no harmful effects, while

a certain few show very serious effects and death from even the slightest

exposure.

    Given a situation of this nature, how should we determine what a "safe"

exposure level should be?

>From a societal standpoint, is it in the best interests of public health to

protect the most sensitive person, or what? Considering that some people may

be sensitive (allergic) to just about anything, to what extent should we go

to: (a) find such people and isolate them from possible exposure, or (b)

restrict or eliminate the offending agent from use? One problem I envision

assuming that some day  we could identify radio-hypersensitive individuals,

should we restrict their travel to high background radiation areas?

[jjcohen@prodigy.net]





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