Newsgroups: sci.energy,sci.physics
From: John De Armond
Subject: Re: Questions About Radiation
Message-ID: <ww5j!8q@dixie.com>
Date: Tue, 21 Apr 92 08:40:51 GMT

mjb@acsu.buffalo.edu (Matthew J. Bernhardt) writes:

>	All of these numbers were arrived at experimentally, except for man.
>Apparently, that range is an estimate, as precise experimental data are not
>available for some strange reason. :-)

Actually the LD50 dose for man is experimentally determined.
The subjects were the japanese under the atomic bomb
detonations, various victims of acute radiation exposure in
weapons research, medical accidents and isotope accidents. While
experiments were obviously not set up in advance, radiation
transport modeling is sufficiently refined that reconstruction
of the events can be done to a great deal of accuracy.  LD50 for
man is generally now considered to be in the 500 REM range.


>	Oh, on another note, I have another table on acute radiation syndromes,
>but unfortunately, it is in units of Roentgens as well.  But let's assume
>a Rem and a Roentgen are approximately equivalent.  In this case, an acute
>dose of 1000 Rem would only kill in 4-7 days, due to gastrointestinal death.
>Doses in the 10000-100000 Rem range would kill within 2 days, due to central
>nervous system death.  Doses exceeding 100000 Rem would bring instant molecular
>death.
>	Just though you'd like to know.

This is terribly incorrect information.  Almost immediate incapacitation due to
electrolyte imbalance followed in a short period of time by death
starts in the 2000-5000 REM range.  Above 5,000 REM, dysfunction is
immediate because of disruption of the nervous system due to the ionization
energy deposited.  time to death is measured in minutes.  Dysfunction is
generally  characterized total loss of control of bodily function - messy.


Here is some data from a table in "The Effects of Nuclear Weapons", USGPO
[set tabstop=4 if this is distorted]

Definitions:
	Initial phase (IP)	- Initial effects such as nausea.
	Latent phase  (LP)	- time where outward symptoms are in remission
	Final phase   (FP)	- Recurrance of symptoms.  Consumated when victim
						  either recovers or dies.


          0-100 REM   100-200     200-600    600-1000    1000-5000  >5000
------------------------------------------------------------------------------
IP onset    -          3-6 hrs  1/2-6 hrs   1/4-1/2       5-30 mins.  immed **
 duration   -          <=1 day  1-2 days    <2 days       <1 day      immed **
 effect     -          1        2           2             3           4

LP onset    -          <=1 day  1-2 days    <2 days       << 1 day    immed **
 duration   -          <=2 wks  1-4 wks     5-10 days     0-7 days    immed **

FP onset    -          10-14 da 1-4 wks     1-4 wks        0-10 days  immed **
 duration   -          4 weeks  1-8 wks     1-4 wks        2-10 days  immed **

Therapy     -          1        2           3              4          5

Prognosis   -          1        2           2              3          3

Death       -          -        2-12 wks    1-6 wks        2-14 day   <1 day

** Initial phase merges into final phase, death usually occuring from a few
   hours to about 2 days.  There may be a very short latent phase in
   some cases.


effects:
	  1.   Moderate Leukopenia
	  2.   Severe Leukopenia, purpura, hemmorage, infection, Epilation
		   above 300 REM.
	  3.   Diarrhea, fever, electrolyte disturbance
	  4.   Convulsion, tremor, ataxia, lethargy

Therapy:
      1.   Reassurance, hemotologic surveillance
	  2.   Blood transfusion, antibiotics,
	  3.   consider bone marrow transplant.
	  4.   maintenance of  electrolyte levels, victim comfort.
	  5.   Seditation.

Prognosis
      1.   Excellent
	  2.   Guarded
	  3.   Hopeless

------------------

It should be noted that in doses >> 1000 REM, a) experience is of
necessity limited and b) effects are variable because source vs
body orientation greatly affects where the dose is absorbed.

At dose rates above about 500 REM/second, physical sensation is felt,
probably due to direct stimulation of neurons by deposited energy.
It feels like numerous pinpricks as my fingertips can attest.

An interesting fact is the effects of the Hiroshima blast have been
so carefully modeled that an anomoly in radiation effects in certain
areas of the city were accounted for with great accuracy by taking
into account the shielding provided by the lifting eye on the end of
the weapon casing.

John

From: John De Armond
Newsgroups: sci.energy,sci.physics
Subject: Re: Questions About Radiation
Message-ID: <++8jzxm@dixie.com>
Date: 23 Apr 92 19:13:58 GMT

rlbell@babbage.waterloo.edu (Richard Bell) writes:

>If I remember correctly, it was a latin american scrap merchant who dismantled
>a cancer treatment machine loaded with cobalt 60.  The dose was about 1500 rems
>and he exhibited a full recovery.  For this, he earned the nickname "Superman".

>Apparently cancer machines and other useful radioactive tools are a problem
>when they are diposed improperly.

There have been several of these both in the US and foreign.  I went out
with an HP team while at TMI to a nearby steel mill where a slab was  hot
enough with Co-60 to interfer with a gamma thickness gauge.  That was one
bloody mess.

Regarding "superman".  The doses we've been talking about are ACUTE
doses.  The same dose delivered over time  will not have the same
effect.  While the definition of "acute" is fuzzy, I'd consider acute
radiation to be delivered within 24 hours.  BTW, superman was burned
fairly badly and many of his family died.  The Co-60 was still hot
enough that his kids were fascinated by the "glowing sand" (Cerencov (sp)
glow) and rubbed it over their bodies.

John