Inclusion Criteria:  1. Aged >18 years old; ECOG 0 or 1; 2. Patients with Gastrointestinal tumors; 3. Has at least one measurable target lesion according to Response Evaluation Criteria in Solid Tumors (RECIST V1.1); 4. life expectancy >=12 weeks.  Exclusion Criteria:  1. Significant hepatic or renal dysfunction; 2. Is pregnant or ready to pregnant; 3. Cannot keep their states for half an hour; 4. Refusal to join the clinical study; 5. Suffering from claustrophobia or other mental diseases; 6. Any other situation that researchers think it is not suitable to participate in the experiment.