ar
repeated doses were required, the uptake was usually progressively 1 ss and the
retention of the isotope more sustained.
As has been pointed out i
previous re-
raorts, some of the data collected in the past represents some of the
ost complete
observations cn individual patients available.
£ the National
Thyrotoxicosis Follow-Up Study.
collected
These became a2 part
In addition to enormous amounts of chemical data
over several months on each of these vatients, there has been continu-
ous long-term follow-up of physiological function of the radiated g land.
A knowledge
of the precise rad dose received by the gland is the only way that the outcome of
radioiodine therapy can be evaluated.
Unfortunately, the dose that was administered
to the patient is no measure of the amount of radiation received wi hout detailed study
In a few cases, histologic samples of the gland have become available because
surgery was indicated owing to the appearance of a mass or persistance of hyperthyroidism.
The procurement of tissue has provided an opportunity to study by auto-
radiography the effects of the radiation in various areas of the g and.
Thus, we
have continued to follow our radioiodine therapy cases diligently | vith repeated
examinations to look for the development of masses and to reapprais > thyroid function.
Some of the significant biochemical, radiological, and clinic hl correlations
that have been found are:
If the serial quantitative chromatograms on the blood fdllowing a therapeutic dose of 131; show radioiodinated mono- and diiodotyros ine after a few
days, a precipitous decline in radioactivity over the thyroid usually occurs
and this is followed by extensive destruction of the gland.
Chromatograph-
ically insoluble iodinated polypeptides also appear in the b lood.
indicates
gross destruction of the gland with the releas
Material into the circulation.
This
of colloid