MOLOKHIA, ROBINSON, HUFFMAN AND NORMAN 
913 
Table I. — Nuclear Radiation Characteristics of Radioisotope Sources 
Nuclear Source 
Identification 
Neutron source strength (Neutron/sec.) 
Neutron dose rate at 8 cm. (MREM/hr.). 
Photon dose rate at 8 cm. (MREM/hr.)... 
Total dose rate at 8 cm. (MREM/hr.).. 
Pu-238 
16 watt 
RES-24 
Stainless steel 
attenuator 
Pu-238 
24 watt 
RES-50 
Tantalum 
attenuator 
1.02 X 10= 
11.0 
9.0 
20.0 
1.20 X 10= 
13.2* 
19.0 
32.2 
1.50 X 1015 
20.3 
14.0 
34.3 
2.40 X 10= 
32* 
60 
82 
* Assumes fission and AM-24/Be neutrons to be dose equivalent. 
Lymphocytes were cultured for 72 hours and 
prepared by a slightly modified version of a 
method described by Moorhead et al.''' Most scor- 
ing of aberrations was done visually with the 
high-power, oil-immersion objective of the mi- 
croscope. The slide was scanned under low 
magnification (~ 100 X), and when suitable 
figures were found they were scored at higher 
magnifications. As a rule, 50 mitotic figures 
were scored in each preparation. Crude karyo- 
type analyses were done visually. When it 
seemed appropriate, a more complete analysis 
was made from an enlarged photomicrograph of 
the chromosome spread. Any count of chromatid 
breaks below 2% was considered normal on the 
basis of control slides. Occasionally fluorescent 
microscopy karyotyping was used in the pri- 
mate group studies. 
RESULTS 
Blood values of all the animals remained 
within normal limits. Representative data from 
some of the RES dogs are given in Figure 2. 
Results of the chromosomal studies are sum- 
marized in Figure 3. Despite meticulous care in 
carrying out Moorhead's technique, some prep- 
arations were not usable. Three months after 
--3308 o o 04172 oooooo 5453 •»»~ 5932 
DIFFERENTIAL P 
COUNT % L 
WBC 
Figure 2. — Hematologic data from dogs implanted with radioactive sources. 
