CGA and neoplasm: At the follow up, 2.5 months after completion of PRRT, all patients presented with stable disease (RECIST 1.1) and decreasing or stable CgA levels, whereas TTV increased in three patients and thus showed heterogenous response.<h4>Conclusion</h4>In metastatic PPGL, [<sup>18</sup>F]SiTATE effectively visualizes tumor burden and supports patient selection and response assessment for PRRT.