Non-invasive Measurement of PD-L1 Levels With Positron Emission Tomography (PET) in Head and Neck Malignancies and Intracranial Metastases

Inclusion Criteria for Head and Neck Cancer: * Patients with resectable squamous cell carcinoma of the oropharynx (HPV positive and HPV negative). * Resectability will be confirmed by a surgical co-investigator. * If available, HPV-association determined by institutional p16 testing (CINtec antibody demonstrating strong and diffuse nuclear and cytoplasmic staining is at least 70% of cells). * Absolute neutrophil count (ANC) \> 1500/microliter, absolute lymphocyte count (ALC) \>1000/microliter, hemoglobin \> 9 g/dl, platelets \> 100,000/microliter. * aspartate aminotransferase (AST) and alanine transaminase (ALT) \< 5 x upper limit of normal. Bilirubin \< 1.5 x upper limit of normal. * Albumin \> 0 g/dl. * Creatinine \< 5 x upper limit of normal. * Women of child-bearing potential must have a negative serum pregnancy test within 7 days prior to treatment Inclusion Criteria for Brain Metastases: * Patients with brain metastases * Tumor size equal or greater than 1 cm * Resectability or need for laser interstitial thermal therapy (LITT) will be confirmed by a surgical co-investigator. * Absolute neutrophil count (ANC) \> 1500/microliter, absolute lymphocyte count (ALC) \>1000/microliter, hemoglobin \> 9 g/dl, platelets \> 100,000/microliter * AST and ALT \< 5 x upper limit of normal. Bilirubin \< 1.5 x upper limit of normal. * Albumin \> 0 g/dl. * Creatinine \< 5 x upper limit of normal. * Women of child-bearing potential must have a negative serum pregnancy test within 7 days prior to treatment Exclusion Criteria for Head and Neck Cancer: * Medical contraindication to surgery. * Full dose anticoagulation. * Concomitant invasive malignancy, or malignancy within 2 years except for hormonally responsive breast or prostate cancer, resected non-melanoma skin cancer, resected uterine cervical carcinoma. * Inability to give informed consent. * Prior systemic therapy, radiation or gross resection for the tumor under study. * Women may not be pregnant or breast-feeding. * Receipt of other systemic therapy including investigational agents, radiation or gross resection for treatment of the tumor under study. Exclusion Criteria for Brain Metastases: * Medical contraindication to brain surgery. * Full dose anticoagulation. * Inability to give informed consent. * Women may not be pregnant or breast-feeding.