Radium-226 in the human body poses unique problems for whole body
counters. People who have accumulated this nuclide only because of the
minute amounts occurring naturally in food and water have counts of only
two or three disintegrating atoms per second, and this amount cannot be
distinguished from background radiation. Whole body counters are useful,
however, in diagnosing effects in persons who have been overexposed to
radium. These include persons who formerly were employed to paint watch
dials with a luminous paint containing radium. (See table below.)
[Illustration: Figure 10 _A group of radium dial painters at work in a
watch factory in 1922. Almost all these employees have been identified
and the living ones recently have participated in a study at Argonne
National Laboratory to determine the extent of radium accumulation in
their bodies. Whole body counters aided in their examinations._]
Excerpts from case records of one research center show the high counts
found in several patients and the source of the radium or thorium (a
closely related element) that their bodies had taken up:
Case Body burden in
disintegrating atoms
per second
Born 1900, drank 210 bottles of “Radithor” 63,640
in 1927[2]
Born 1897, drank approximately 78 ounces of 32,780
“Radium Water” in 1932[2]
Born 1925, worked as radium chemist since 14,800
1946
Born 1922, radium chemist for 7 years 7,000
Born 1898, two injections of “Thorotrast” 3,300
for X-ray diagnosis
Born 1898, radium dial painter in watch 72,500
factory, 1918 to 1921
Born 1902, radium dial painter for 4½ months 1,924
in 1924
Scientists at the Argonne National Laboratory, Argonne, Illinois, have
attempted to improve crystal whole body counters so that they will be
more useful in determining the amount of radium-226 in humans. Rolf
Sievert at the Swedish Atomic Energy Commission also has studied the
radium-226 detection. He devised a highly accurate whole body counter
with 10 ion chambers arranged around a curved aluminum bed on which the
subject rested. The instrument was installed below ground to reduce the
interference of background radiation.
[Illustration: Figure 11 _The spectrum of gamma radiation emitted by the
body of a man three years after he accidentally inhaled radium-226. The
solid line shows the normal radiation due to potassium-40, the dotted
line the total from potassium-40 and radium-226._]
Showing:
COUNTS/MINUTE PER 95-KEV CHANNEL
Subject G (total)
Subject G (potassium-40)