Inclusion Criteria:  1. The subjects voluntarily signed the informed consent form and were able to complete the test according to the protocol requirements; 2. Over 18 years old, male or female; 3. Diagnosed as lymphoma and intended to receive CD19 car-t treatment; 4. ECOG score is 0-1; The estimated survival time shall not be less than 3 months;  Exclusion Criteria:  1. Participate in other clinical trials other than CAR-T treatment at the same time or within 28 days. If participating in a non intervention clinical trial, it can be included in this study; 2. Patients with a history of allergy; 3. Patients who cannot tolerant PET / CT imaging； 4. Patients who are using anticoagulant drugs or need to use anticoagulant drugs during the study;