This pilot study tests the pocket phantom tool in improving the accuracy of quantitative positron emission tomography/computed tomography (PET/CT) imaging of patients with solid tumors. The pocket phantom tool may help test the accuracy of the PET/CT scanner and indicate whether adjustments need to be made to get consistent information.
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).
Study Type
OBSERVATIONAL
Enrollment
2
Undergo PET/CT scan as clinically indicated (Note: CT is for attenuation correction and not for diagnostic purposes).
Undergo limited field of view PET scan with the Pocket Phantom placed nearby to assist in scanner calibration. No additional PET tracer will be used.
Undergo PET/CT scan as clinically indicated.
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, United States
Difference in measured versus known quantitative values of the pocket phantom
Compare measured activity of the pocket phantom (as measured by a PET/CT scanner) to the known values of the pocket phantom (as calculated based on half-life activity of known source) to determine accuracy and precision of scanner calibration. This will be used to validate quantitative clinical measurements, like SUV (standardized uptake values), of known solid tumors.
Time frame: At day 1 (All data will be collected during the clinically scheduled appointment. Analysis will follow typical image reconstruction times.)
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