A Pilot Study of Glutamine PET Imaging of Head and Neck Squamous Cell Carcinoma

Primary Objective: The primary objective of this trial is to evaluate the ability of 11C-Gln and 18F-FSPG PET imaging to detect tumors in patients with HNSCC. Hypotheses: 11C-Gln PET and 18F-FSPG PET will yield standardized uptake values SUVs; within HNSCC primary and metastatic lesions that are significantly higher relative to SUV of background tissue. Primary Outcome Measures 11C-Gln standardized uptake value (SUV) including SUVmax, SUVpeak, and SUVmean for tumors and normal tissue 18F-FSPG standardized uptake value (SUV) including SUVmax, SUVpeak, and SUVmean for tumors and normal tissue Secondary Objectives: A secondary objective of this trial is to compare PET imaging data to standard-of-care MRI or CT. Another secondary objective is to determine the tumor-to-background ratios (TBR) for 11C-Gln and 18F-FSPG. A third secondary objective is to determine the safety of 11C-Gln. Hypotheses: 11C-Gln PET and 18F-FSPG PET will detect additional sites of disease that are not visualized by CT or MRI. In addition, tumor-to-background ratios (TBR) for either tracer will exceed 2. Finally, 11C-Gln will be safe at the doses administered in this study. Secondary Outcome Measures: Number of lesions. Lesion count will be determined on a per patient basis. Tumor size (e.g., long-axis diameter, short-axis diameter, tumor volume) derived from standard-of-care (SOC) CT or MRI. Tumor size will be defined according to RECIST v1.1 \[10\] with the longest diameter measured for tumor lesions and the short-axis diameter measured for malignant lymph nodes. Tumor-to-background ratios (TBR) for 11C-Gln and 18F-FSPG Adverse events associated with 11C-Gln Exploratory Objectives: An exploratory objective of this trial is to compare 11C-Gln PET/CT and 18F-FSPG PET/CT imaging to conventional 18F-FDG PET when feasible. Another exploratory objective is to compare uptake of 11C-Gln and 18F-FSPG between HPV-positive and HPV-negative patients. Hypothesis: The SUVmax and TBR for 11C-Gln PET or 18F-FSPG PET will be greater than 18F-FDG PET. We also hypothesize based on the published expression data that 11C-Gln and 18F-FSPG avidity will differ between HPV-positive and negative patients, with 11C-Gln having higher uptake in HPV-positive patients, while 18F-FSPG will have higher uptake in HPV-negative patients.