Entwicklung des thyreoidalen Jod – und Technetium – Uptakes bei Patienten mit unifokaler Autonomie seit den 1980er Jahren in Deutschland bei zunehmender Verbesserung der Jodversorgung.Müssen die geltenden Normal – und Grenzwerte den veränderten Bedingungen angepasst werden?

Aim: The clinical relevance of thyroidal autonomy, i.e. the risk of a patient to become hyperthyroid after exposure to iodine, can be estimated by measurement of the thyroidal 99m Tc uptake under suppression of TSH (TcTUs). The upper tolerable limit has been set to 2% some 25 years ago. Considering the increase in nutritional iodine uptake over the last 15 years, we wanted to find out if the TcTUs per ml of autonomous volume may have changed. Patients, methods: We performed an analysis including 1063 patients from 1987-2004 with unifocal autonomy (UFA). In these patients, the volume of the autonomous tissue can be determined precisely thus allowing for exact determination of TcTUs per ml of autonomous volume. Results: In the analysis of UFA, 500 from the 1063 patients fulfilled the inclusion criteria. In these patients, the TcTUs per ml of autonomous volume has fallen from an average of 0.48% to an average of 0.28%. These results are statistically significant as determined by ANOVA testing (p = 0.032). Conclusion: As the TcTUs in relation to autonomous volume has dropped by approximately 40% over the last 25 years, the upper limit for a normal TcTUs should be reduced to 1-1.4%, dependent on regional factors.