906 
GENETIC AND BIOLOGICAL EFFECTS OF RADIATION 
Since it is the consensus that the most likely 
site for implantation of a power source in the 
human being would be the abdominal cavity, an 
abdominal site has been chosen for our studies. 
A pocket between the internal and external 06- 
lique muscle in the left paralumbar fossa is used 
for placement of the implantation capsule. A ra- 
diograph of a loaded implantation device in 
place in the left flank of a Labrador Retriever is 
shown (Figure 1) . 
Radiation Source 
Because of the undesirable heat associated 
with the use of a -^^Pu source a mock source 
has been devised which provides radiation 
characteristics similar to those of plutonium, 
but has no accompanying heat. The radiations 
of biological concern from -^®Pu are photons and 
Figure 1. — Radiograph of stainless steel implantation 
capsule, with contained ^Cf and '"Sr sources, in 
place in the left paralumbar fossa of a Labrador Re- 
triever dog. 
neutrons.^ The composite source consists of 
^^-Cf to provide the neutron component and 
oogj.^ 90Y Bremsstrahlung sources to spike the 
photon flux of the ^^^Cf up to that of ^^^Pu, 
In order to obtain some information as to the 
radiation levels needed to produce effects, and 
yet not to make the number of animals included 
in the project excessively large, sources that 
produce the same radiation flux as would be ex- 
pected from a 30 watt ^^^Pu source (nominal, 
or IX sources) as well as sources which produce 
five times the radiation level that would be ex- 
pected from such a source (5X sources) have 
been used. In addition, some animals have been 
implanted with either 15X or 70X sources. 
The dose rates from the various source con- 
figurations used in this study have been meas- 
ured and/or calculated using data from studies 
in water phantoms and Labrador Retriever ca- 
davers and compared with data from dosimetry 
studies of ^^^Pu sources.^ A comparison of the 
dose rates from our source configurations with 
that of a 30 watt plutonium source is shown 
(Table I). It can be seen that the dose from a 
nominal composite source is almost identical to 
that of the equivalent plutonium source. Dose 
rates to various organs and surfaces from a 
70X source are also given (Table II) . 
Experimental Protocol 
Animals have been implanted in four groups 
of twelve dogs each. Each group consists of 
four large source dogs, four small source dogs. 
Table I. — Dose Rate in Tissue (HiO) from Simulated 
Sources Implanted in Labrador Retriever Dogs Com- 
pared to Estimated Dose Rate from 30 Watt Plu- 
tonium-238 Source (Electro-Refined Metal) under 
Similar Conditions 
Source 
Contents 
Total Dose Rate (mrads/hr) at Given 
Distance from Surface of Capsule (cm) 
Factor above 
Nominal 
1 
6 
10 
0.373 Of 
BOO mCi Sr 
1991 
602 
226 
72 
0.0745 ^ Of 
100 mCi Sr 
398 
120 
46 
14.4 
0.373 Of 
5.7 
30 mCi Sr 
0.0745 ^ Of 
6 mCi Sr 
158.4 
27.6 
46.5 
8.1 
16.7 
2.9 
1 
238pu 
28.2 
8.6 
3.2 
30 Watt 
