Dose selection for radioiodine therapy of borderline hyperthyroid patients according to thyroid uptake of 99mTc-pertechnetate: applicability to unifocal thyroid autonomy?
OBJECTIVE
The aim of this study was to evaluate the feasibility of applying a previously described dose strategy based on (99m)Tc-pertechnetate thyroid uptake under thyrotropin suppression (TcTU(s)) to radioiodine therapy for unifocal thyroid autonomy.


METHODS
A total of 425 consecutive patients (302 females, 123 males; age 63.1+/-10.3 years) with unifocal thyroid autonomy were treated at three different centres with (131)I, using Marinelli's formula for calculation of three different absorbed dose schedules: 100-300 Gy to the total thyroid volume according to the pre-treatment TcTU(s) (n=146), 300 Gy to the nodule volume (n=137) and 400 Gy to the nodule volume (n=142).


RESULTS
Successful elimination of functional thyroid autonomy with either euthyroidism or hypothyroidism occurred at a mean of 12 months after radioiodine therapy in 94.5% of patients receiving 100-300 Gy to the thyroid volume, in 89.8% of patients receiving 300 Gy to the nodule volume and in 94.4% receiving 400 Gy to the nodule volume. Reduction in thyroid volume was highest for the 100-300 Gy per thyroid and 400 Gy per nodule strategies (36+/-19% and 38+/-20%, respectively) and significantly lower for the 300 Gy per nodule strategy (28+/-16%; p<0.01).


CONCLUSIONS
A dose strategy based on the TcTU(s) can be used independently of the scintigraphic pattern of functional autonomous tissue in the thyroid.
Department of Nuclear Medicine, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53127, Bonn, Germany. michael.reinhardt@ukb.uni-bonn.de
Michael J
MJ
Reinhardt
Kim
K
Biermann
Michael
M
Wissmeyer
Freimut D
FD
Juengling
Holger
H
Brockmann
Dirk
D
von Mallek
Samer
S
Ezziddin
Alexius Y
AY
Joe
Thomas M
TM
Krause
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013670:Sodium Pertechnetate Tc 99m / Q000493:pharmacokinetics; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m