The small insulinoma can not be detected by the CT or MRI. We use 68Ga-NOTA-exendin-4 positron emission tomography/computed tomography (PET/CT) to detect the insulinoma for the patient diagnosed with endogenous hyperinsulinemic hypoglycaemia. And the diagnostic value will be performed. A single dose of 37-111 Mega-Becquerel (MBq) 68Ga-NOTA-exendin-4 will be injected intravenously. Visual and semiquantitative method will be used to assess the PET/CT images.

The glucagon-like peptide-1 receptor (GLP-1R) is an emerging target due to its high expression in benign insulinomas. 68Ga-NOTA-exendin-4 is an optimal probe targeting GLP-1R. The clinical use of 68Ga-NOTA-exendin-4 PET/CT in detecting insulinomas will be evaluated. And the comparation between PET diagnostic value and CT / MRI will be done.

Inclusion Criteria:

• 1.age ≥6 years old 2.Patients with hypoglycaemia 3.Endogenous hyperinsulinemic hypoglycaemia 4.Enhanced CT or MRI within 1 month 5.Signed written consent

Exclusion Criteria:

• 1. Breast feeding 2.Pregnancy or the wish to become pregnant within 6 months 3.Renal function: serum creatinine during 41-73umol/L 4.Any medical condition may significantly interfere with study compliance; 5.Known allergy