RECUVERY FROM LATENT RADIATION INJURY
THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIELD
incapacity, even though it would presumably
entail the same danger of lethality, as 200 r
received promptly. Evidence on this point
might be obtainable on the dog or some other
species in which post-radiation blood changes
may persist for months. At present it would
probablybe safer to limit the effective dose for
prolonged exposures to a level somewhat less
than 200 r or such other level as is permitted
for short exposure.
For adequate control of prolonged or multiple
exposures at substantial levels itis necessary to
employ considerations of recovery rather than
of total dose and the parameters and methods
developed by Davidson appear to be the best
available at this time.
The lethal dose for partial body exposure is
higher than for whole body[11] and recoveryis
faster according to present
indications
{2].
Yonsequently safe estimates for whole body
exposure will be even more conservative for
partial body exposure.
Dependingon facilities for radiation measurement and other factors it may be advisable to
set permissible emergency limits for both total
dose and effective dose and to use the one most
feasible at the time.
.
REFERENCES
1. Buarr, H. A., Data Pertaining to Life-Shortening
by Ionizing Radiation, University of Rocherter
Report, WR~442, 1966.
2. Carsren, A. L, and Noonan, T. R., Determination
of the Recovery from Lethal Effects of Lower
Body Irradiation in Rats, University of Rochester
Report UR-445, 1956.
3. The Same—-Unpublished Observations.
4. Hacen, C, W. and Simmons, E. L., Effects of Total
Body X-irradiation on Rats. Part I. Lethal
Action of Single, Paired and Periodic Doses,
University of Chicago Metallurgical Laboratory
Report CH-3815, 1947,
aan
J, Radiol., 30, 40, 1956,
_
~ Davinson, H. ©., Ir, Biological Effeets of Wholebody Gamma Irradiation on Human Beings.
The Johns Hopkins University Press, Baltimore,
1957.
. Some Effeets of Lonizing Radiation on Human
Beings, Edited by EK. P. Cronrire, V. P. Bonn
and C. L. Dusan, TI)-5358, Superintendent
of Documents, U. 8. Government Printing Office,
Washington 25, D.C.
. Hesse, J. B., Noonan, T. R., Casarert, G. and
Vaw Siyxe, F., Reduction of Life Span of Rats
by Roentgen Irradiation, Am. J. Roent. Rad.
Ther. and Nuc. Med., 74, 130, 1955.
10. Warnen, Suieups, Longevity and Causes of Death
fram Irradiation in Physicians, J. A. Af. A., 162,
R
dose of 200 r remaining from a greater total dose
would at all times lead to the same degree of
2
tive dose should be permitted in man because
the concepts employed are based on lethality.
Ttis not clear, for example, whether an effective
. Srorer, J. B., This Symposium.
. Moun, R. H., Quantitative Observations on Recovery from Whole Body Irradiation in Mice, Bret.
464, 1956.
. Biatr, H. A., Acute Lethality of Partial Body in
Relation to Whole Body Irradiation, University
=
116
of Rochester Report UR-462, 1956.
DISCUSSION
H. A. Blair
the peripheral blood of many species has been
studied and varies considerably. It is also
known to a great extent i man from the
Marshallese studies.
L would like to ask, Dr. flair, has the half
time for recovery of the various species been
correlated with the rapidity of the recovery of
the blood picture in the various species?
Dr. Buarr. I suppose the two extremes we
knownow are either guinea pigs or burro versus
mouse. They have the shortest and longest
recovery half times, I think, of the animals we
know. Tt would be interesting to see if there
was a relation between recovery rate and clini-
cal manifestations inthese species.
Dr. Rosertson (Brookhaven).
I would just
the shortening of life span use the averagefor a
group, whereas if mortality rates are plotted on
e Gompert’s type function, the displacement of
that?
Dr, Buarn. I don’t have a good answer. 1
have talked with a number of radiologists who
wonder if he has thought about it in these
from 1,000 by a factor of more than two or so.
irradiated are storing up irreversible injury,
periods, there might have been more clinical
the doses gotten recently. The kind of data I
was talking about here are the after effects of
exposure. The radiationis stopped long before
manifestation of injury.
Radiologists have
not complained much about anything except
burns of one kind or another. There have been
instances of anemia, but they are not very
common,
Dr. Cronxire.
The rapidity of recovery of
In regard to Dr.
looked at relations between the average survival
timeestimates and the Gomperts thing.
Dr. Bertin. The Chair will not enter into
a discussion at this time.
Dr. Ssacnur.
I am afraid the burden falls
the estimation of parameters. However, I
showed two curves; one the estimate of cumu-
That is, that
count the automatic increase in death rate that
Tf the daily dose rate got very high over long
Dr. Sacuen (Argonne).
Robertson's question, I believe that you, Dr.
Berlin, could probably discuss this to good
advantage, because you havealready, I believe,
is occurring with age, and therefore the average
is not truly applicable to the individual, thatis,
think deserves more emphasis.
Dr. Blair and Dr. Sacher, too, in considering
gists and physicians, and thought it was very
interesting, but we did not do anything about
the dose sustained by the people. I have been
very curious how Dr. Blair arrived at his
thousand roentgen figure.
were fairly well agreed that it didn’t likely differ
from residual injury. Allowanee must. be made
for this in calculating shortening of life span
per roentgen as an after-effect of radiation.
that using the average does not take into ac-
like to make a point that has been mentioned by
Dr. Berlin in a recent publication, which I
the lines for an irradiated group from the normal
group is a litUle greater. I take this as meaning
Dr. Bert. I think that is an interesting
question, Dr. Blair. Would you like to answer
radiation has slopped short of death. Ata high
level, such as 5 or 10 roentgens per day, the
animal maydie half from acute injury and half
on me, T believe that the Gompert’s analysis
is the most unbiased analysis that we can
bring to lethality data, because it considers
the lethality as a process that is going on
continuouslyin anirradiated population. However, in looking at data today in terms of mean
survival times, 1 did this out of sheer necessity,
because in the daily dose studies we are usually
dealing with very small populations of animals.
T have notactually given serious consideration
to correcting for bins in the mean survival time
Capt. O'Donocuus (Bureauof Medicine and
Surgery). J have often lookedat figures like the
last slide and instance of leukemia in radiolo-
117
the effect on the individual is a little greater
than is deduced from the average.
Perhaps Dr. Blair’s theory is flexible enough
to make a bit of correction for this, and I
terms.
Dr. Buair.
I don’t think this has anvthing
ta do with theory.
Animals being currently
but on top of that they have acute injury from
death so any acute injury that may have
occurred has been healed. You have to be
careful about this, because there are not very
many data in the literature for which chronic
estimates, because I have not used them for
lative lethality function and the derivative,
two sets of curves, The first was based on
Mean survival times and the second based on
an analysis using the Gompert’s function. I
think if yourecall these you will recall that they
were of the same form and my problem essentially is to find a scaling factor for them. Dr.
Blair has mentioned the point that causes
serious concern in the application of these
theories to lethality under conditions when the
radiation is being received up to the time of
death, and thatis the accumulation of injury
due to the latest increments of dose received.
T should say that when you use the deduced
empirical function approach that I have used,
you note that the injury curve takes on the
order of 10 or 20 days to build to a maximum.