Inclusion Criteria:  Patients in suspicion of gastrointestinal stromal tumors by CT or ultrasonography,and being able to provide basic information and sign the written informed consent form.  Exclusion Criteria:  The exclusion criteria included claustrophobia, pregnancy, breastfeeding, kidney or liver failure, inability to fulfill the study, and undergoing any preceding local or systemic therapies that might interfere with GRPR binding.