Qualification of PET Scanners for Use in Multicenter Cancer Clinical Trials: The American College of Radiology Imaging Network Experience

Abstract

The PET Core Laboratory of the American College of Radiology Imaging Network (ACRIN) qualifies sites to participate in multicenter research trials by quantitatively reviewing submitted PET scans of uniform cylinders to verify the accuracy of scanner standardized uptake value (SUV) calibration and qualitatively reviewing clinical PET images from each site. To date, cylinder and patient data from 169 PET scanners have been reviewed, and 146 have been qualified. Methods: Each site is required to submit data from 1 uniform cylinder and 2 patient test cases. Submitted phantom data are analyzed by drawing a circular region of interest that encompasses approximately 90% of the diameter of the interior of the phantom and then recording the mean SUV and SD of each transverse slice. In addition, average SUVs are measured in the liver of submitted patient scans. These data illustrate variations of SUVs across PET scanners and across institutions, and comparison of results with values submitted by the site indicate the level of experience of PET camera operators in calculating SUVs. Results: Of 101 scanner applications for which detailed records of the qualification process were available, 12 (12%) failed because of incorrect SUV or normalization calibrations. For sites to pass, the average cylinder SUV is required to be 1.0 6 0.1. The average SUVs for uniform cylinder images for the most common scanners evaluated-Siemens Biograph PET/CT (n 5 43), GE Discovery LS PET/CT (n 5 15), GE Discovery ST PET/CT (n 5 34), Philips Allegro PET (n 5 5), and Philips Gemini PET/CT (n 5 11)-were 0.99, 1.01, 1.00, 0.98, and 0.95, respectively, and the average liver SUVs for submitted test cases were 2.34, 2.13, 2.27, 1.73, and 1.92, respectively. Conclusion: Minimizing errors in SUV measurement is critical to achieving accurate quantification in clinical trials. The experience of the ACRIN PET Core Laboratory shows that many sites are unable to maintain accurate SUV calibrations without additional training or supervision. This raises concerns about using SUVs to quantify patient data without verification.

Quantitative PET/CT Scanner Performance Characterization Based Upon the Society of Nuclear Medicine and Molecular Imaging Clinical Trials Network Oncology Clinical Simulator Phantom

“…This criterion 610% permissible variability is consistent with criteria of most other organizations that are currently addressing limits for acceptable quantitative PET scanner calibration performance for clinical trials (2,(13)(14)(15)18). Because spheres of different sizes are placed within the phantom in different background settings, and scanner-specific performance in this complex environment was originally unknown, rigid sphere-specific acceptance criteria for SUV max for the various sphere sizes are currently not strictly set.…”

“…These differences are not evident in the more common ACRIN-style cylindric phantom test of scanner uniformity. ACRIN's own observation of differences in mean liver SUV between vendors supports the existence of this problem (13).…”

“…Organizations such as the American College of Radiology Imaging Network (ACRIN), The Radiologic Society of North America's Quantitative Imaging Biomarker Alliance, the American Association of Physicists in Medicine, the European Association of Nuclear Medicine's Research 4 Life, and the Society of Nuclear Medicine and Molecular Imaging (SNMMI), both alone and together, have made significant strides in this area. Several of these organizations administer PET/CT phantom imaging programs to aid in the standardization of quantitation in clinical trials and clinical practice (13)(14)(15)(16). These programs are separate and distinct from clinical accreditations such as those administered by the American College of Radiology and the Intersocietal Accreditation Commission as well as the Joint Commission.…”

First Clinical Experience with Integrated Whole-Body PET/MR: Comparison to PET/CT in Patients with Oncologic Diagnoses

“…This discrepancy may be due to several factors: First, it may be a consequence of systematic differences in the technologic specifications and data-processing algorithms of the 2 scanners. Previous studies have shown that SUV measurements may not be highly reproducible across different scanner types or even between sites using the same scanners (32,38). The obvious differences in SUV reported in these previous studies have been observed despite the fact that phantom or patient data acquired under identical conditions have been used to test the reproducibility of the SUV.…”

Variability in PET quantitation within a multicenter consortium

“…The spheres and the background needed to be filled with 18 F, and due to the 110 min half-life of 18 F, the data acquisition had to be appropriately timed to the filling to attain the desired activity concentration, making it difficult to perform repeat experiments with the same background and target activity concentrations as has been shown in several investigations. [14][15][16] Kinahan et al previously performed a multicenter phantom investigation of accuracy 17 and precision 18 of instrumental factors affecting PET tracer uptake measurements. In that study, the phantom was sent to centers with good physics support to assure the appropriateness of the data acquisition and analysis.…”