Radioiodine therapy of benign thyroid-disorders Assessment of the effective half-lives and determination of influence factors within a Southwestern German cohort

摘要

Aim: In radioiodine therapy (RIT) of benign thyroid-disorders empirical half-lives (HLemp) may be used to calculate therapeutic dose. In this study the effective half-life (HLeff) as well as potential influence factors were retrospectively determined in order to better estimate HLemp. Methods: Data from patients undergoing RIT from 01/09 to 04/14 were analysed (empirically estimated HLeff stratified by metabolic state and diagnosis). Inclusion criteria were: Benign thyroid-disorders, singular capsule administration and >= 6 dosimetry time-points (i.e. > 72 h inpatient stay). The effects of metabolic state, previous thy-reostatic medication and sex on HLeff were assessed by non-parametric ANOVA. The effects of target-volume and patient-age were assessed by regression analysis and non parametric correlation (Spearman). Results: Data of 1,498 patients were analyzed: Graves' Disease (GD), n=286; multinodular goiter/disseminated autonomy (AMG/DA), n=751; autonomous thyroid nodules (ATN), n=421; euthyroid goiter (EG), n=40. Mean HLeff (days +/- SD) was 5.4 +/- 1.5 in GD, 6.6 +/- 1.2 in AMG/DA, 5.5 +/- 1.6 in ATN and 6.9 +/- 0.7 in EG. HLeff differed by metabolic state in GD, AMG/DA, and ATN, whereas neither thyreostatic medication nor sex were relevant. Moreover, target-volume (all diagnoses) and age (ATN and GD only) were associated with HLeff, although the effect was small (R-2 < 3.8%). Conclusion: When using standard HLeff for RIT, diagnosis and metabolic state should be considered for dose-calculations in RIT. Despite partial significance, the effects of target-volume and patient-age are small and a correction of HLeff, for these factors doesn't appear to be necessary in a routine setting.