Radiojodtherapie der funktionellen Autonomie unter Verwendung des funktionellen autonomen Volumens

[131I and 99mTc-Uptake in focal thyroid autonomies. Development in Germany since the 1980s]

Germany has developed into a country with a nationwide largely sufficient iodine supply due to improved alimentary iodine supply. The reduction of iodine uptake in focal autonomies induced by reduced iodine avidity was evaluated by Gotthardt et al. 2006, showing a significant decline of pertechnetate uptake up to the year 2004.

AIM

This study was intended to carry this investigation forward to the present day to analyze the course of a conjectural stabilization of iodine uptake values.

PATIENTS, MATERIAL, METHODS

283 patients who underwent radioiodine therapy for focal thyroid were analyzed retrospectively. Pertechnetate uptake was measured scintigraphically, thyroid volume sonographically and iodine uptake by iodine uptake test. The uptake percentage in the autonomous volume was correlated with autonomous volume and the resulting values tracked over a time period of seven years.

RESULTS

Mean thyroid volume ranged from 24 to 29 ml, autonomous volume from 7.2 to 9.4 ml. Pertechnetate uptake ranged from 0.2 to 0.25%/ml autonomous volume. Iodine uptake values ranged from 3.2 to 4.2%/ml autonomous volume. None of the changes observed were statistically significant (all p>0.05).

CONCLUSION

Prophylactic measures towards improvement of the general public´s iodine supply in Germany had led to a decline of pertechnetate and iodine uptake in the thyroid up until the turn of the millennium. The here presented data show a stabilization of ^99mTc-Uptake. Our study could also show that actual iodine uptake has stabilized at a steady level over the preceding seven years.

Functional autonomies of thyroid and efficacy of radioiodine therapy

In this paper, the authors present their experience with the radioiodine therapy of thyroid functional autonomies. The aims of this study were to establish the efficacy and determine the adverse effects of radioiodine therapy of patients with thyroid functional autonomies. Over a period of 31 years (from 1974 to 2005) 868 patients (766 women, 102 men with the age from 33 to 86 years; average age, 58.5) with unifocal functional autonomy, multifocal functional autonomy, and disseminated functional autonomy, received at least one treatment of radioiodine in our Department of Nuclear Medicine. For diagnostics and the evaluation of the radioiodine therapeutic effect of functional autonomies, a thyroid scintigraphy is the basic and necessary procedure. We have also performed a thyroid ultrasonography, an assessment of a serum level of a total and free thyroxine, total tri-iodothyronine, thyroid-stimulating hormone (TSH), the radioiodine accumulation test, the estimation of the radioiodine effective half-life, and in some patients, thyrotrophin-releasing hormone (TRH)-TSH test. The follow-up examinations were done in all patients after 4-6 months, another examination after 1 year in 585 patients, and after 2 years in 284 patients. One therapeutic dose received 798 patients (91.9%) and it was sufficient for an elimination of functional autonomies. Some patients were retreated if there was the evidence of small or no treatment effect and no elimination of functional autonomies. Sixty-six (66) patients (7.6%) received two radioiodine treatments and 4 patients (0.5%) three treatments. Before radioiodine therapy, an average serum level of total thyroxine was 165.8 nmol/L, of free thyroxine 21.2 pmol/L, and of total triiodothyronine 3.3 nmol/L, and in all patients, TSH was suppressed. Before therapy, patient complaints were cardiovascular in 87%, neurological in 72%, hypermetabolic in 70%, and local in 31% of patients. After therapy, the average serum levels of total thyroxine were 110.9 nmol/L, free thyroxine 12.7 pmol/L, and total triiodothyronine 2.1 nmol/L with an improvement of symptoms in 91.5% of patients, no improvement in 8.2% and a worsening in 0.3% of patients. The suppression of TSH disappeared in 668 of treated patients (77%). An average volume reduction of thyroid of 40% was achieved in any type of functional autonomy after radioiodine treatment. Side-effects were minimal, and in some patients, presented as a transient neck pressure or pain and neck swelling. Postradiation hypothyroidism was diagnosed in 38 patients (4.4%). The results of this study show that the radioiodine therapy of the thyroid functional autonomies is safe, with a low incidence of adverse effects. It is effective, and for patients, is a nondemanding procedure.