Pocket Phantom Tool in Improving Accuracy of Quantitative PET/CT Imaging of Patients With Solid Tumors

PRIMARY OBJECTIVES: I. Optimize the pocket phantom source design and the bias estimation algorithm: determine the tolerances and variations in the source sphere geometry and radioactive filing process; evaluate the need for higher-activity sources in the presence of increased attenuation (i.e. thicker patients); optimize CT contrast levels for source boundary detection and localization from CT images; evaluate the robustness for use with different scanner parameters (e.g. CT slice thicknesses); modify bias estimation algorithm as needed to take into account changes. II. Develop automated and robust ID pocket phantom processing and web-based software as a service (SAS) analysis tools: automate initial identification of approximate location of the pocket phantom; add automated DICOM analysis for web-based SAS analysis tools for imaging sites. III. Conduct phantom studies at multiple imaging centers to evaluate the performance with different imaging protocols, scanners, and reconstruction methods. Also test at multiple time points over 6-9 months to assess longitudinal stability. IV. Conduct a comparative study with patients (at University of Washington \[UW\]) at multiple time points over 6-12 months to evaluate the performance of the pocket phantom in oncology patient imaging compared with current clinical practice. OUTLINE: Patients undergo a PET/CT scan as part of their standard clinical care. While still positioned for the clinical scan, patients undergo additional research PET/CT scans in a smaller region over 10 minutes with the pocket phantom placed nearby and a low-dose single bed position CT scan for attenuation correction (CTAC).