This is an open-label positron emission tomography/computed tomography (PET/CT) study to investigate the diagnostic performance and evaluation efficacy of 68Ga-NOTA-RM26 in Gastrointestinal stromal tumor（GIST）patients. A single dose of 55.5 to 148 MBq(1.5-4 mCi) of 68Ga-NOTA-RM26 will be injected intravenously. Patients underwent whole-body PET/CT scans at 30-90 minutes after intravenous injection.

Rm26 is a bioactive polypeptide containing 9 amino acid residues, which can specifically bind to gastrin releasing peptide receptor (GRPR, BB2 receptor). Previous studies have confirmed that there are a large number of GRPR receptors in human common types of tumors, such as lung cancer, breast cancer, prostate cancer, head and neck squamous cell carcinoma, glioma and gastrointestinal tumors. Therefore, the use of various radionuclide labeled gastrin releasing peptide receptor analogues RM26 for tumor targeted imaging and treatment greatly improves the early detection rate of tumor, and has important clinical significance and value in tumor staging, prognosis evaluation and curative effect evaluation.This prospective pilot study investigated the use of 68Ga-NOTA-RM26, an antagonist targeting gastrin-releasing peptide receptor (GRPR), for evaluating breast cancer using positron-emission tomography/computed tomography (PET/CT).

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.