Background/Objectives: Medullary thyroid carcinoma (MTC) is a highly aggressive tumor, as it is characterized by a high probability of local recurrence and distant metastases, even after surgical treatment. Early detection of disease recurrence is critical for improving long-term treatment outcomes and overall patient survival. By comparing different radiopharmaceuticals, this analysis aimed to strengthen existing guidelines and help bridge the gap between the recommendations of the ESMO and the ATA, highlighting the importance of PET/CT scanning in the postoperative follow-up of patients with MTC. Methods: This research was carried out using three searchable databases, PubMed, ScienceDirect, and ResearchGate, resulting in 575 bibliographic studies up to the date of 20 June 2024. A meta-analysis of diagnostic accuracy was performed using the software Meta—DiSc, Version: 2.0 (Universidad Complutense, Barcelona, Spain), which led to aggregate assessments and the design of the SROC. Results: A quality assessment of the eligible studies was conducted, and the key findings were summarized. Conclusions: Regardless of methodology, PET/CT scanning exhibits high sensitivity and specificity values in the diagnosis of local recurrence and metastases in surgical patients with medullary thyroid carcinoma. Furthermore, based on a comparative analysis of18F-FDG and GA68-DOTATE, it appears that these misunderstood radiopharmaceuticals are particularly sensitive and reliable for highlighting MTC, and it was found that there were no statistical differences in terms of sensitivity and specificity. Therefore, these two modalities appear to be complementary in monitoring MTC patients.