The aim of this study is to evaluate the diagnostic performance and tumor burden of 18F-metafluorobenzylguanidine (18F-MFBG) positron emission tomography (PET) in patients with pheochromocytoma.

Pheochromocytoma highly expresses norepinephrine transporter (NET) which is targeted by function alanalogue of norepinephrine, 123/131I-MlBG. However, low spatial resolution of 123/131I-MlBG and inaccurate attenuation correction of single photon emission tomography (SPECT/CT) will affect the image quality of MlBG SPECT and lead to poor diagnosis of small lesions. In addition, 123l-MlBG imaging is usually performed at 24h after injection, while 131I-MlBG is performed at 48h or even 72h after injection. The procedure is complicated and takes a long time, which limits clinical application. 18F-labeled MFBG is an ideal tracer to show the expression of NET. Preliminary data show that 18F-MFBG imaging is safe and has favorable biodistribution and kinetics with good targeting of lesions. Patients can undergo PET 0.5 hours after injection without special preparation. Our study will assess the safety profile, image quality and evaluate the diagnostic performance and tumor burden of 18F-MFBG. Patients with suspected or histologically confirmed pheochromocytoma will be enrolled in this study.

Inclusion Criteria:

1. Aged 30-80 years old, primary school or above, with a regular caregiver;
2. Clinically diagnosed patients with pheochromocytoma;
3. Can provide informed consent, can understand and comply with the study requirements.

Exclusion Criteria:

1. Patients with serious primary diseases such as heart, brain, liver, kidney and hematopoietic system;
2. Uncontrolled hypertension or high-risk BP (i.e., systolic BP > 180 mmHg or diastolic BP > 110 mmHg);
3. Patients with mental disorders or primary affective disorders;
4. Unable to understand and adhere to the study protocol or provide informed consent;
5. Contraindications to PET imaging (including pregnant women, lactating women, and women of childbearing age with recent childbearing plans, etc.);
6. Allergy to imaging agents;
7. Patients who were unable to cooperate with PET scanning, such as hypoglycemia, severe pain or tremor.

patients with suspected or confirmed pheochromocytoma