The work of Laskin, et al,
thou:a not specifically
involving deep respiratory tissue, does demonstrate a source
4
;
intensity-respense curve for lung tissue 9
A Ru-1O06
cylindrical source was implanted in the bronchi of rats,
and
cancers were observed to arise from the bronchial epithelium.
The response curve indicates a substantial response (7 percent)
even at 0.003 uCi burden,
and a slow,
approximately logarithmic
increase of tumor incidence over three orders of magnitude
4
i
Fy
Corresponding
first-year
doses to
+4ee oe
Saad
in the source intensity.
adjacent bronchial epithelium varied from 103 rad to 106 raa>’,
Animals were
followed until death and it was
observed that
the tumor incicence generally increased with the dose accumulated
at death.
The Lowest accumulated dose associ
cancer was
14°79
rad.
For
an
accumulated dose of the order of
106 rad the incidence was approximately two-thirds.
=
we eee
fortified glass seads
of Sr-90,
rats.
(0.3 u diameter) with several microcuries
and single beads were
Tumers
were
Cember
observed
in
implanted in the lungs of
7 of 23
animals.
In
a
second
deer Cle
experiment Cerber exnosed rat lungs to Ce-144 particles.
49/
Laskin,
S., M.
Kuschner, N.
Harley and M. Daniels,
Nelson,
For
B. Altshuler, J.H.
"Carcinoma of the lung in rats exposed
to the beta-radiation of intra-bronchial rutheniuml%6 pellets.
1.
Dose response relationshivos," J.
2a omee
1963, pp. 219-231.
50/
Altshuler, B.,
"Dosimetry
pellet," Radiation Res.
9,
Natl.
Cancer Inst.
31,
from a Rul96_-coated olatinum
1958, pp. 626-632.
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