evidence is not particularly helpful in deciding specific causation
in any individual."
Both of these statements are incorrect.
First,
it is well known that epidemiologic studies have documented that
radiation not only causes
cancer but also that radiation causes
cancer of specific histologic type.
In fact, there can be little doubt that, under a wide variety
of circumstances,
in humans.
ionizing radiation is carcinogenic and leukomogenic
This conclusion is supported by numerous evidemiologic
Studies conducted among human populations
Giversity of exposure to radiation.
which have experienced a
Epidemiologic studies of
uranium miners exposed to alpha and gamma radiation have demonstrated
a large excess of bronchogenic cancer.
In addition, these studies
have demonstrated a preponderance of a specific
histologic type of
cancer, viz small cell undifferentiated carcinoma, when compared to
the general population.
Epidemiologic studies of the survivors of
the atomic bomb explosians at Hiroshima and Nagasaki provide reliable
data on the carcinogenic effects of whole body exposure to camma rays
and neutrons.
Among those individuals, an excess of lung, thyroid
and breast cancer, as well as leukemia, has been demonstrated.
This
excess of leukemia was shown to be predominantly of the myelogenous
and granulocytic type.
Conclusive evidence that therapeutic radia-
tion can be carcinogenic and leukomogenic comes from studies of
patients irradiated for ankylosing spondylitis, thymic
enlargement
and gynecological disorders.
In like manner, epidemiologic studies
have shown that radiologists
exposed to radiation have an excess of
leukemia when compared to other physicians not so exposed.