Following advancements in diagnostic imaging and its widespread use, there has been an increase in the detection of differentiated thyroid cancers (DTC), contributing to the rising incidence of this disease. The increasing incidence of early-stage thyroid tumors with a favorable prognosis raises questions about the necessity of traditional oncological treatment approaches for all cases of DTC. Scientific research in various types of cancer with positive oncological outcomes has shifted towards exploring treatment omission without compromising safety and preserving quality of life. These trends towards a refined treatment de-escalation reflect better risk stratification in cancer care indicating that some cancers can be treated conservatively. Considering the excellent survival rates of DTC, it is worth exploring de-escalation strategies. International guidelines have been evolving to incorporate higher thresholds for thyroid cancer therapy. However, variations in clinical practice patterns exist due to discrepancies among guidelines and a lack of literature on the role of active surveillance in low-risk thyroid cancer. In this thesis, we evaluate the current clinical challenges in the management of thyroid cancer patients, focusing on incidental thyroid nodules, second primary thyroid malignancies, and thyroid cancer in adolescents and young adults. The first part of this thesis focuses on the unintended uptake of radioactive agents 18F-FDG and PSMA in the thyroid during PET/CT scans in oncological patients, known as thyroid incidentalomas. We investigated that the definition of a PSMA thyroid incidentaloma can be reliably limited to focal uptake with a SUVmax thyroid/bloodpool ratio of ≥ 2.0. We also showed that one combined radiomics feature, the Run Length Non-Uniformity, derived from the 18F-FDG PET/CT scan demonstrates a comparable diagnostic value to the TIRADS classification to classify thyroid incidentalomas. The clinical outcomes of thyroid incidentalomas in our studies were favorable despite a minority ...