A phantom design for assessment of detectability in PET imaging. Issue 9 (10th August 2016)

• Record Type: Journal Article
• Authors: Wollenweber, Scott D.; Alessio, Adam M.; Kinahan, Paul E.
• Is Part Of: Medical physics. Volume 43:Issue 9(2016)
• Page Start: 5051
• Page End: 5062
• Publication Date: 2016-08-10
• Subjects: cancer -- feature extraction -- image reconstruction -- medical image processing -- phantoms -- plastics -- positron emission tomography -- tumours; Positron emission tomography (PET) -- Cancer -- Reconstruction; Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Scintigraphy -- Measuring half‐life of a radioactive substance; image quality -- positron emission tomography (PET) -- detection; Positron emission tomography -- Medical image reconstruction -- Computed tomography -- Image reconstruction -- Image detection systems -- Medical image contrast -- Medical image noise -- Three dimensional sensing -- Image scanners; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4960365
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: The primary clinical role of positron emission tomography (PET) imaging is the detection of anomalous regions of 18 F‐FDG uptake, which are often indicative of malignant lesions. The goal of this work was to create a task‐configurable fillable phantom for realistic measurements of detectability in PET imaging. Design goals included simplicity, adjustable feature size, realistic size and contrast levels, and inclusion of a lumpy (i.e., heterogeneous) background. Methods: The detection targets were hollow 3D‐printed dodecahedral nylon features. The exostructure sphere‐like features created voids in a background of small, solid non‐porous plastic (acrylic) spheres inside a fillable tank. The features filled at full concentration while the background concentration was reduced due to filling only between the solid spheres. Results: Multiple iterations of feature size and phantom construction were used to determine a configuration at the limit of detectability for a PET/CT system. A full‐scale design used a 20 cm uniform cylinder (head‐size) filled with a fixed pattern of features at a contrast of approximately 3:1. Known signal‐present and signal‐absent PET sub‐images were extracted from multiple scans of the same phantom and with detectability in a challenging (i.e., useful) range. These images enabled calculation and comparison of the quantitative observer detectability metrics between scanner designs and image reconstruction methods. The phantom design has several advantages including filling simplicity, wall‐less contrast features, the control of the detectability range via feature size, and a clinically realistic lumpy background. Conclusions: This phantom provides a practical method for testing and comparison of lesion detectability as a function of imaging system, acquisition parameters, and image reconstruction methods and parameters.