Radioactive Iodine as an Indicator in Thyroid Physiology

Hertz, Saul; Roberts, Angela; Means, J. H.; Evans, Robley D.

doi:10.1152/ajplegacy.1940.128.3.565

Cited by 82 publications

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“…This necessitates a prior knowledge of Qf. The value of Qf is estimated by inspection of the curve of the observed values Q versus t, and adjusted so as to give a linear function for log (Qf -Q) versus 2 The proportional rate of removal of radioiodine from the blood by the kidneys and appearing as urinary radioiodine, is given by the product of r by Qf. The value r itself is the proportional rate of disappearance of radioiodine from the blood into all tissues into which it goes.…”

Section: Resultsmentioning

confidence: 99%

“…A minute quantity of radioiodine may be used to trace, by its radioactivity, the course of a given quantity of iodine through various chemical and biologic reactions. Hertz (1,2) was the first to call attention to the unique possibilities of this method in the study of thyroid function. Hamilton and Soley ( 12) were the first to apply it to the clinical investigation of the human thyroid.…”

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The Urinary Excretion of Radioiodine in Various Thyroid States

Mh²,

Berkson³

et al. 1947

J. Clin. Invest.

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Radioiodine and natural iodine are chemically and physiologically identical, providing the former is present in quantities so small as to be without biologic effects due to radiation per se. A minute quantity of radioiodine may be used to trace, by its radioactivity, the course of a given quantity of iodine through various chemical and biologic reactions. Hertz (1, 2) was the first to call attention to the unique possibilities of this method in the study of thyroid function. Hamilton and Soley ( 12) were the first to apply it to the clinical investigation of the human thyroid. Radioiodine tracers have subsequently been utilized in many studies dealing with the thyroid of laboratory animals, in vitro experiments and clinical investigations. The method has been applied to the study of the biosynthesis of thyroid hormone (1, 3 to 9), the action of thyrotrophic hormones (4, 10), the action of goitrogens (5, 11) and of other factors influencing the function of the thyroid (6), the functional activity of various thyroid tumors and a number of other problems.It is possible that radioiodine may prove most useful in the study of thyroid function in man. To date, relatively few definitive clinical studies employing this technique have been published. The first was that of Hamilton and Soley (12), who compared the collection by the thyroid of iodine labeled with radioiodine and its excretion in the urine and feces in normal subjects and in patients having various thyroid disorders. Radioiodine in the thyroid was measured directly by the recording of its gamma radiation by means of a Geiger-Muller counter placed over the trachea and in some instances by analysis of surgically removed specimens of thyroid tissue. It was found that an orally administered dose of labeled iodine was absorbed very rapidly and could be detected in the thyroid within 20 minutes. Normal subjects excreted 74 to 89 per cent of the dose in the urine during a period of 5 days, 53 to 81 per cent appearing during the first 24 hours. Two myxedematous patients excreted 91 and 94 per cent, respectively, in the urine during 5 days but at a slower rate than did the normals. Patients who had hyperthyroidism excreted as much in the urine as did the normals. This finding may have been due to the fact that most of the patients had received strong solution of iodine (Lugol's solution) and in part to the very large amount of iodide (14 mgm.) which was administered as a labeled dose. Fecal excretion was variable but averaged only about 1 per cent of the dose.In another series of in vivo measurements employing the same dose of iodide, Hamilton and Soley (13) recorded characteristic collection curves for various thyroid states. The curve typical of normal thyroids was a smooth curve which leveled off to a flat plateau in 2 days. Iodine collection by thyroids of hyperthyroid patients was greater and much more rapid than in normal thyroids. It rose to a peak within 4 to 8 hours and thereafter decreased almost as rapidly to a plateau lower than that of the normal thyro...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

The Urinary Excretion of Radioiodine in Various Thyroid States

Mh²,

Berkson³

et al. 1947

J. Clin. Invest.

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“…The myxedematous subjects had excreted essentially the same quantity of isotope as normals by the end of four hours. In the patient with Addison's disease, the excretion of isotope in the urine and its concentration in the 2 The serum specimens were obtained 24 hours following the administration of radioiodine; during this interval all urine was saved for analysis; two patients neglected to collect urine. The quantity of radioiodine in inorganic (II*) form in the serum was derived by subtracting the protein-bound radioiodine (PBI*) from the total radioiodine content of serum.…”

Section: Resultsmentioning

confidence: 99%

“…(Received for publication March 19, 1948) One of the earliest uses of radioiodine was as a tool for the study of thyroid physiology (1)(2)(3)(4)(5)(6)(7). Estimations of the relative quantities of isotope stored in the thyroid have been made by means of a Geiger-Muller tube held over the gland and by determining the amount present in the urine and blood.…”

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Comparisons of the Distribution of Radioactive Iodine in Serum and Urine in Different Levels of Thyroid Function

Williams¹,

Jaffe²,

Bernstein³

1949

J. Clin. Invest.

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One of the earliest uses of radioiodine was as a tool for the study of thyroid physiology (1)(2)(3)(4)(5)(6)(7). Estimations of the relative quantities of isotope stored in the thyroid have been made by means of a Geiger-Muller tube held over the gland and by determining the amount present in the urine and blood. The rate with which the level of radioiodine changes in these compartments has also been studied (7,8).In subjects with euthyroidism, radioiodine was found (8) to be excreted rapidly, within a few hours after its administration, but a plateau tended to appear after 48 hours. In myxedematous individuals, excretion was slower initially but it was more persistent, requiring four days or more; the total amount excreted after several days was greater in myxedematous subjects than in normal or thyrotoxic ones. In untreated thyrotoxic patients the rate of excretion was less than in either of the other two groups. The curves describing excretion became asymptotic relatively quickly.The differences in the metabolism of iodine in various functional states of the thyroid have prompted an investigation of the usefulness of radioiodine as a diagnostic test. One of the best tests not dealing with radioiodine that has been available is the determination of the protein-bound iodine of the plasma (9). This test is so long and difficult that it can be performed satisfactorily only under the direction of a few highly qualified individuals and even then some overlapping in the values for different degrees of thyroid function may be found (10). Moreover, the test is unreliable if the patient has recently received iodine in organic form and if highly scrupulous technique is not followed in the collection of the plasma as well as in the determination. It seemed to us that in some institutions it might be possible to use radioiodine in tests which would be more accurate, simpler and more rapid. It appears logical to assume that the quantity of protein-bound radioiodine in the serum, after the administration of tracer doses, might indicate the relative rate of manufacture of the thyroid hormone and its release into the blood stream. Of course, the values obtained would represent only an approximate balance between these two factors and the quantity of the hormone stored in the various fluids and tissues of the body, including the thyroid; also between the amount metabolized and excreted. Nevertheless, with methods not using the radioiodine, not only do these difficulties in interpretation exist, but also it is not possible to determine the time required for the changes to occur. The latter aspect would seem to be a very important one. METHODSTwo types of study were conducted following the administration of a tracer dose of radioiodine subcutaneously. In one, frequent specimens of blood and urine were collected during a 24-hour interval, for a determination of the proportion of isotope present. In the other study, which consisted of a larger number of patients, urine was saved for 24 hours and a single specimen of blood was take...

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“…Radionuclides were first clinically applied in 1927, when Blumhardt and Weiss applied radon gas to assess hemo dynamics in patients suffering from cardiac deficiency. Hertz applied radioisotope 131 I for diagnosing thyroid disorders [6] for the first time in the late 1930s. Artificial radionuclides appeared after E. Lawrence had invented the cyclotron [7], and 99 Tcm was the first radionuclide synthesized in 1938 at the Berkeley cyclotron.…”

Section: Introductionmentioning

confidence: 99%

Nuclear physics-based technologies in medicine

Chernyaev

2012

Phys. Part. Nuclei

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Radioactive Iodine as an Indicator in Thyroid Physiology

Cited by 82 publications

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The Urinary Excretion of Radioiodine in Various Thyroid States

The Urinary Excretion of Radioiodine in Various Thyroid States

Comparisons of the Distribution of Radioactive Iodine in Serum and Urine in Different Levels of Thyroid Function

Nuclear physics-based technologies in medicine

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