To use the molecular probe PET radionuclide (Ga-68 or F-18) WL12 peptide to detect the expression of PD-L1 in the primary and metastatic lesions in patients with solid tumor; to detect the expression heterogeneity of PD-L1 in the lesion and inter-lesions; to observe the change of PD-L1 expression in the course of treatment. To provide an approach for screening patients with high expression of PD-L1, efficacy monitoring, drug resistance and early warning of recurrence and metastasis to achieve the Individualized antitumor treatment of targeted drugs.

In many clinical trials, Anti-PD-1/PD-L1 mAbs have achieved great success than expected in a variety of refractory and recurrent tumor patients. The latest research shows that it is not all cancer patients would respond to Anti-PD-1/PD-L1 mAbs. At present, immunohistochemistry (IHC) is still a common method to screen patients that will benefit from this therapy by detecting the expression level of PD-1 and PD-L1. However, the results of IHC were not very exact because of limitations of IHC such as the heterogeneity of expression, the influence of host cell PD-L1 expression and the changes in the course of the disease. Moreover, the tumor tissue used in IHC must obtained through the invasive method. It is difficult to dynamically monitor the expression level of PD-1 / PD-L1 during the treatment. Immuno-PET molecular imaging By radiolabeling Anti-PD-1/PD-L1 mAbs with radionuclides can be used to noninvasive assessment of biodistribution of monoclonal antibodies and provide a new strategy for patient screening.

In this study, 18F-WL12 or 68Ga-WL12 PET / CT imaging will be performed in patients with solid tumors to access the potential of 18F-WL12 or 68Ga-WL12PET / CT to screen patients who can benefit from JS001 treatment.

Inclusion Criteria:

• 1. Aged >18 years old; ECoG 0 or 1;
• 2. Patients with solid 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.