UNASSIGNED: Molecular imaging of thyroid and parathyroid diseases has changed in recent years due to the introduction of new radiopharmaceuticals and new imaging techniques. Accordingly, we provided an clinicians-oriented overview of such techniques and their indications.
UNASSIGNED: A review of the literature was performed in the PubMed, Web of Science, and Scopus without time or language restrictions through the use of one or more fitting search criteria and terms as well as through screening of references in relevant selected papers. Literature up to and including December 2023 was included. Screening of titles/abstracts and removal of duplicates was performed and the full texts of the remaining potentially relevant articles were retrieved and reviewed.
UNASSIGNED: Thyroid and parathyroid scintigraphy remains integral in patients with thyrotoxicosis, thyroid nodules, differentiated thyroid cancer and, respectively, hyperparathyroidism. In the last years positron-emission tomography with different tracers emerged as a more accurate alternative in evaluating indeterminate thyroid nodules [18F-fluorodeoxyglucose (FDG)], differentiated thyroid cancer [124I-iodide, 18F-tetrafluoroborate, 18F-FDG] and hyperparathyroidism [18F-fluorocholine]. Other PET tracers are useful in evaluating relapsing/advanced forms of medullary thyroid cancer (18F-FDOPA) and selecting patients with advanced follicular and medullary thyroid cancers for theranostic treatments (68Ga/177Ga-somatostatin analogues).

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.
OBJECTIVE: 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.
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).
CONCLUSIONS: 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.

Radioiodine therapy for benign and malignant thyroid diseases was introduced about 70 years ago, however, there is still a lack of consensus regarding indications, doses and procedure. This review covers treatment results in immunogenic hyperthyroidism including the problem of orbitopathy. Radioiodine therapy for toxic and non-toxic multinodular goiter is also discussed with striking possibility of enhanching the radioiodine uptake. In this respect the recombinant human thyrotropin should be mentioned. Thyroid cancer treatment protocol has changed, too, due to ineffectivity in low-risk patients. More attention is needed to the carcinogenecity of radioiodine. The numerous problems mentioned above require large and well-designed prospective trials to resolve the fundamental questions. The author emphasizes that radioiodine dose should be administered in doses as low as reasonably achievable.