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te
EFFECTS OF FALLOUT RADIATION ON TILE SKIN
Table Lis made up of data from animal
studies from several investigators and stows
the energy dependence of betas from various
isotopes in producing recognizable skin reactions.
Note that the surface doses for thresh-
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T
T
T
T
|
EPICERMIS
oor
50% ATTENUATION IN SKIN (MICRONS)
Estimation of beta doses to the skin from
fallout is an exceedingly complicated problem
and I will leave the main discussion of the subject to other speakers. The degree of skin
reaction and damage is more dependent on the
depth dose than on the surface dose of beta
radiation and the depth dose is dependent on
the energies of the beta particles of the component isotopes. Thus soft radiation confined
largely to the dead horny layer and upper
epidermis would be relatively ineffective in
producing a reaction in the skins more energetic
radtation, penetrating through the epidernis,
could result in) transepidermal necrosis; and
deeper penetration into the dermis could result
in more severe ulcerating Jesions. Each radioisotope has its own characteristic spectrum of
energies with a maximum energy, but since
relatively few particles are of this energy, the
average cnergy, which is roughly one-third of
the maximum energy and the 50 percent attenuation in tissue are more meaningful in estimating skin effects,
Figure 1 shows roughly the 50 percent attenuation in skin of several tsotopes. With the
same surface dose the more energetic beta
emmiting isotopes will naturally result in
greater damage to the skin.
137
200 -300 ;-400 f500 f-
> DERMIS
600 LTO...
600
g06r-
10007——LL
at
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to
a2
a3
L
L
i
l
0.4
O35
a6
0.7
BETA ENERGY (ove)
Fiounrt 1.—60 percent attenuation tn ekin (microns).
old reaction (erythema, epidermal atrophy) are
fairly dependent on the energy of the beta
particles of the various isotopes. Thus it takes
20,000-30,000 rep from S® (average energy 0.1
Mev.) to produco a reaction while it only takes
1500-2000 rep of Sr®-Y" or Y*' (average
energy 0.5-0.6 Mev.) to produce the same
reaction. It is of intercst that Moritz and
Henriques found that the dose at 0.09 mm.
depth of the pigskin (estimated to be the
epidermal thickness) was constant within
several hundred rep to produce transepidermal
injury [15]. Wilhelmy has also noted that it
takes roughly the same dose of electrons and
soft X-rays at the level of the subpapillary
laver to produce erythema [19]. On this basis
Taste 1.--SURFACHK DOSE REQUIRED TO PRODUCI RECOGNIZABLE EPIDERMAL INJURY
Investigntor
Henshaw, ct al... 0-2-2 2 eee.
Snider and Raper... .....------.---- 2-2 -eRaper and Barnes... . 2222.22. eee
Lushbaugh.-..-..-.....-----2---------------Moritz and Henriques
.__.2 2222-2. eee _..-|
Animal
Rata. 2.2 ue leek
Mice.....- 2-222 -2Rubbita._ 22222222.
Sheep_.-.-...-----Pigs .-.----- 22. _
Do... 2 a ee eee eee eee eee eee wales ee do... .--- ee
Do__o... 0. eee eee eee dee do.----2- 2 lee
Do. 1-222 -----eeeeeee Lee ee eee ete ee do_. lee
Do___..- we cee eee eee ee ee fee ee do__ 2 ee
OT ~...-dO..--- 2 Lee
Tsutope
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ps
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Average ene
emy (Mev.)
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0.5
.6
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47
Surface dose (req)
1, 500-4,
2,
5,
2, 500-5,
900
500
000
000
4,
2,
1,
1,
1,
000
000
000
600
GOO
20, 000-30, 000
000-5,
000-3,
500-2,
500-2,
500-2,
: