F-18 FDOPA PET/CT Versus I-123 MIBG Scintigraphy With SPECT/CT for the Diagnosis of Pheochromocytoma and Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are chromaffin cells-derived tomours that originate from the adrenal medulla (80\~85%) and the extra-adrenal sympathetic paraganglia in thorax, abdomen and pelvis (15\~20%) or parasympathetic paraganglia in the head and neck region (\~1%), respectively. Functional imaging, such as 123I-Meta-Iodobenzylguanidine (MIBG) scintigraphy with single photon emission computed tomography with a CT (SPECT/CT), offers high specificity for PPGL but necessitates 24-hour delayed imaging, pre-processing thyroid protection with a potassium iodide solution, and medication reconciliation to prevent the inhibition of 123I-MIBG uptake. Conversely, 18F-L-dihydroxyphenylalanine (FDOPA), a radiopharmaceutical for positron emission tomography (PET) imaging, is specifically absorbed and accumulated by chromaffin cells, offering better image quality and convenience compared to 123I-MIBG scintigraphy. 18F-FDOPA PET/CT has been approved for the localization, staging, and detection of PPGL recurrences in European and other countries. Therefore, the aim of this study was to compare prospectively the diagnostic performances of 18F-FDOPA PET/CT and 123I-MIBG scintigraphy with SPECT/CT in patients with PPGL.