FAP and metastatic malignant neoplasm in the lymph nodes: However, further research is required to validate PET imaging with FAP-targeting radiopharmaceuticals to more precisely determine the significance in evaluating lymph node metastases, to better define which TBR regions are more effective to improve a semiquantitative image evaluation, and to explore its potential as a longitudinal biomarker during treatment in order to develop more consistent clinical recommendations.