138
THE SHORTER-TRRM BIOLOGICAL HAZARDS OF A FALLOUT FIBLD
Parker has advocated the use of beta detecting
instruments with chamber walls corresponding
in milligrams per square centimeter to the
thickness of the relatively inert epidermal
layer {20]. Thus in expressing skin dosage it
is probably more informative to use the depth
dose at the depth of the epidermal layer of the
skin.
The above table also indicates the species
difference in skin sensitivity to beta radiation.
Rabbits and sheep required larger doses than
mice to produce the sameeffect with roughly
the same energy beta. Porcine skin, which is
reputedly more like human skin than other
animals, apparently is more sensitive than the
rabbit or sheep skin. Some of these differences, aside from species differences, may be
due to variation in thickness of the skin of
different species and differences in techniques
used.
.
Table 2 shows beta dosage data from some
human experiments and accidents found to
produce various effeets on the skin. These
data must be interpreted with great caution
due to differences in experimental techniques
and
dosimetry.
The severity
of
reactions is represented by degrees.
the
skin
A first.
degree reaction implies erythema and/or dry
desquamation; a second degree, transepidermal
necrosis with ulceration; and third degree,
furthor breakdownof the skin with the develop-
ment of chronic radiation dermatitis. It can
be seen that there is a considerable variation in
dose reported to produce the various reactions.
EFFECTS OF FALLOUT RADIATION ON THE SKIN
In the Marshallese the skin dose could not be
estimated with any degree of accuracy due to
the complicated smear of beta spectra varying
with time and the uneven distribution of the
material on the skin.
The beta component of the fallout was found
to have two major peaks of energy, one at 100
kev which accounted for 50-80 pereent of the
activity and one at 600 kev which accounted
for 20-50 percent of the activity [1].
Fifty
percent attenuation of the 100 kev component
oecurs at aboul 80 microns, about the depth of
the epidermis. Fifty percentattenuation of the
600 kev componentoccurs at about 800 microns,
fairly deep in the dermis; deep enough to
irradiate many of the hair follicles. The
relatively soft nature‘of the radiation was borne
out by the superficial nature of most of the
lesions that developed.
A vory rough biological estimate of the dose
ta the scalp of the Rongelap people might be
made by using the index of epilation.
It is
knownthat with 200 kvp X-ray a dose of about
Robbins ef al....
Knowlton ef af ..
.
“Hattmated dose in 1st mm.layer.
Rodiation
penctratian.
Estimations of the dose of skin irradiation
from ground source heta has been made by
Sondhaus[1].
Hf no shielding occurred and exposure is
139
in the skin. These changea maybe in the form
of simple tanning, pigmentation, and mild
desquamation with low doses.
This reaction
might be classed as a first degree reaction.
With higher doses vesiculation, complete epi-
dermolysis and ulevration may occur.
This
considered continuous the dose at the level of
the dorsum of the feet was calculated to be
severity of reaction might be classed ag a
second degree reaction. Spotty epilation may
any lesions, though it probably contributed
lesion. Healing is usually accomplished within
a week or two with repigmentation of the skin
ation from the groundsource could be sufficient
with some scarring and lack of repigmentation.
Chronic radiation effects.---With larger doses of
about 2,000 rep, at hip level 600 rep and at
head level 300 rep. This source of radiation
was apparently insufficient, alone, to produce
significantly to the severity of the foot, lesions
observed. With larger amounts offallout, radiin itself to produce skin lesions.
Actte effects of beta radiation an the skin. - In
general beta radiation effects on the skin are
similar 10 effects produced by more penetrating radiation such as gamma, or X-radiation.
However, the less penetrating beta radiation
produces more superficial lesions with less
damage to the dermis. Consequently thoy are
usually less painful and heal more rapidly.
The time sequence of development of beta
oceur along with lesions of the scalp. Regrowth of hair is likely with a second degree
in milder lesions.
Deeper lesions may heal
radiation chronic radiation dermatitis may develop. These lesions do not heal well and on
healing may break down and ulcerate again.
Badly scarred skin with telangiectatic vessels
may result. These severe reactions might be
classed as third degree reactions. Repeated re-
pair and breakdown mayoceur duc to instability
hair follicles must have been in the above range.
This dose must have been largely from the 600
or may not be observed beginning a few hours
after exposure, This was not seen in the
and poor vascularity of the dermis. It is in
skin of type that malignant change may later
take place.
Malignant changes in the skin has been observed in animals as a late effect: of beta
irradiation of the skin and presumably could
also occur in the human skin. Though malig-
from this component must have been 4 to 5
times higher or in the range of 1,600-3,500 rep.
The surface dose from the more abundant 100
experienced.
radiation dermatitis, as a result of repeated exposure to radiation it has been reperted to
occur in animals following a single exposure to
400 r is necessary to produce epilation, and
doses above about 700 r produce permanent.
epilation.
Since regrowth of hair took place
in the epilated Marshallese the dose to the
kev component.
Therefore the surface dose
kev component musthave been muchhigher, by
Tas. 2.-HUMAN EXPOSURE TO BETA RADIATION
Investigator
a factor of 5, 10 or more, bul. with very Httle
Eat. dose (rep)
635
1, 180
.
*143
7, 000-17, G00
1,000- 2,000
8, 000- 4,000
5, 000-10, 000
| 5, 000-10, 000
8, 000-16, 000
Reaction
Ist degree (threshold).
2nd degree (threshold).
ist degree (threshold).
2nd degree,
3rd degree.
2nd degree,
3rd degree.
3rd degree.
3rd degree.
lesions from fallout varies considerably with
the dose to the skin. A primary erythema may
Marshallese, perhaps due to the dark color of
their skin. During the first day or so itching,
burning, or tingling of the affected skin maybe
As was pointed out these symp-
toms might in part be due to the chemical
nature of the fallout. These early signs and
symptomsare usually followed by an asvmptomatic latent period before full-blown lesions
develop. The length of the latent period may
vary from a few days to several weeks which is
usually related to the dose to the skin; the
higher the dose the shorter the latent period.
In the Marshallese the mere heavily exposed
group developed skin lesions about a week
before less heavily exposed groups. Dueto the
particulate nature and uneven distribution of
the fallout on the skin the developing lesions
are likely to be spotty. A secondary wave of
erythema maybe seen along with gross changes
448029 0—58——10
nancy usually develops at the site of chronic
beta radiation with little or no chronie change
in the skin.
Treatment of acute beta lesions is mainly
symptomatic. With mild lesions, daily cleansing,
application of bland antipruitie ointments and
lotions may be all thatis necessary.
For more.
severe ulcerating lesions, cleaning with daily
dressings, splinting and use of antibiotic ointments or antibiotics parenterally in case of
secondary infections may be indicated. The
use of Aloe Vera plant applications is claimed
by some to enhance healing of radiation burns
(21). Lesions of chronic radiation dermatitis
may be quite painful and the only effective
therapyin such cases is carly skin grafting (22).