Thyroid Function Assay With Radioiodine. I. Physical Basis of Study of Early Phase of Iodine Metabolism and Iodine Uptake 1

Thyroid Function Assay With Radioiodine. Iii. Clinical Test Results and Diagnostic Limits for Rate Constants 1

“…Because the mathematical treatment (1) has been restricted to the early phase of iodine uptake, the resulting equations cannot be applied to the 'Assisted by grants from the National Institute of Health Division of Research Grants, and from the Arkansas Heart Association. 2 Visitng Assistant Professor, Department of Radiology, University of Arkansas, on a Fulbright Fellowship.…”

“…)-or the corresponding pair of rate factors-thyroidal (k, min.-') and renal (k2 min.') --as defined in an earlier paper (1).…”

“…Moreover, the possible excretion of organic radioiodine from the thyroid gland may lower the observed per cent uptake to such a value that a hyperthyroid case may appear in the normal range of values; this makes the per cent uptake a one-sided parameter. The (1), it is seen that the clearance rates are related to the rate factors by the following: ki = g/sVo (1) k2= r/nVo (2) In this paper equations prefixed I refer to those given in the first paper (1) in this series.…”

“…(Submitted for publication January 24, 1955; accepted March 23, 1955) In an effort to increase the accuracy of assay of thyroidal function, two earlier papers (1,2) have given a numerical and mathematical description of the short-time behavior of radioiodine observed in the neck tissue, thyroid, plasma, and urine. It remains: a) to apply these data to the conversion of several of the diagnostic parameters currently in use in this type of investigation so as to achieve a common basis for comparison; b) to describe the authors' clinical results; and c) to provide a set of diagnostic limits for routine use based upon a maximum amount of published information.…”

Thyroid Function Assay With Radioiodine. Ii. Routine Calculation of Thyroidal and Renal Rate Factors 1

“…Fixed time schedules are necessary because otherwise a large number of charts is required. For convenience the pertinent equations from the preceding paper (1) All the symbols used are as defined in the preceding paper (1), namely: E = The fraction of the original dose excreted by the kidneys up to time t minutes after injection. k min.-' = The average combined (thyroid plus kidneys) fractional rate of removal of radio-iodide from the iodide space during the time interval t = 0 to 30 minutes; that is, an average fraction k of the circulating iodide pool is removed each minute.…”