Vol. VII, N° 3-4
RADIOIODINE UPTAKE MEASUREMENT
consisted of the upper half of a body that
was completely filled with a body-back-
ground radiation. A simulated thyroid gland,
filled with either a higher or lower amount
of mock-iodine, was placed in the neck region. A small thigh section was included
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perthyroid simulated activities. For each type
a 10 microcurie and a 50 microcurie total
dose was made. The figures shown in Table 1
are the nominal uptakes of the manikins.
They are not the true figures. The true calibrations of the uptakes of these manikins
Fic. 5. X rays of a manikin to show the shape and position of the babbit metal thyroid.
with the manikin and also a set of nine 100
per cent dose standards. These 100 per cent
dose standards ranged from thesize of a gelatin capsule to that of a 100 cc paper cup
and very closely simulated most of the types
of “100 per cent dose standards” that were
used in clinical practice.
Figure 5 shows an X ray of one of the
completed manikins illustrating the positioning of the babbit metal thyroid in the manikin. In the survey manikins, a 25 ml volume thyroid was simulated with two lateral
lobes and a median lobe. The simulated thy-
roid was placed in a position forward in the
neck closely simulating the anatomical position of the true thyroid gland.
Six manikins were originally made for the
survey. Nineteen manikins have now been
made, plus one additional one for training
purposes and two for more complex problems
of scanning. The six survey manikins were
divided into euthyroid, hypothyroid, and hy-
have been destroyed since it was not the purpose of the survey to determine that some
methods were correct and sowe were incorrect. This is a much more complex problem
and will be taken up in the third phase of
the calibration program. For the survey, all
that was wanted was to determine whether
there was or was not a variation in the way
in which physicians measured thyroid uptake.
Table 2 shows the results of the survey
to date. More than 200 laboratories have
participated in the test. The answers given
from the laboratories ranged from an 8 per
cent uptake to a 154 per cent uptake. Well
over 90 per cent of the laboratories were
more than 10 percentage points off the true
answer. Any of the manikins could have been
diagnosed in the laboratories in the United
States and England as either hyperthyroid,
hypothyroid or euthyroid. Since some of the
best research laboratories in the United States and England wereincluded in this survey,