SHORT-TERM RESULTS OF (NAI)-I-131 TREATMENT OF HYPERTHYROIDISM EVALUATED USING AN EXTENDED DOSIMETRIC METHOD

Objective: To assess and evaluate the short-term results of radio-iodi ne treatment using an extended dosimetric method. Methods: Sixty-five patients with Graves disease (GD) and 32 patients with toxic multinodu lar goitre (TMG) received a pre-therapeutic dosage of (NaI)-I-123. The overall indicative radiation dose (D-ind) and the indicative dosage ( A(ind)) was calculated for the individual patient using the dosimetric results found. In the therapeutic setting dosimetric measurements wer e performed again. The quotient of the administered dose (A) and the i ndicative dosage and the quotient of the absorbed radiation dose (D-ab s) and the indicative radiation dose were used to evaluate treatment r esults after 1 year of follow-up. Results: Clinical outcome after 1 ye ar for GD was 26% hyper-, 48% eu- and 26% hypothyroidism and for TMG 3 2, 59 and 9%, respectively. Within the percentile range P-25-P-75 of A /A(ind) these results were 27, 46 and 27% for GD and 36, 64 and 0% for TMG. Within the percentile range P-25-P-75 of D-abs/D-ind these resul ts were 23, 59 and 18% for GD and 33, 67 and 0 for TMG. Correlation co efficients between pre- and therapeutic dosimetric measurements in GD and TMC were 0.76 and 0.38, respectively. Conclusions: The short-term outcome after 1 year of follow-up is 48 and 59% euthyroidism for GD an d TMG, respectively. Clinical outcome within the percentile range P-25 -P-75 of A/A(ind) did not change these results, Within the percentile range P-25-P-75 of D-abs/D-ind euthyroidism was achieved in 59% and 67 % for GD and TMG, respectively. The pre-therapeutic values inaccuratel y represent the therapeutic values for GD and even more for TMG.