NEMA NU 2-2012 performance studies for the SiPM-based ToF-PET component of the GE SIGNA PET/MR system

• Published in: Medical physics (Lancaster) Vol. 43; no. 5; pp. 2334 - 2343
• Main Authors: Grant, Alexander M., Deller, Timothy W., Khalighi, Mohammad Mehdi, Maramraju, Sri Harsha, Delso, Gaspar, Levin, Craig S.
• Format: Journal Article
• Language: English
• Published: United States American Association of Physicists in Medicine 01.05.2016
• Subjects: Biological material, e.g. blood, urine; Haemocytometers; biomedical MRI; Equipment Design; Fluorodeoxyglucose F18; Germanium; Humans; Image reconstruction; Image scanners; Image sensors; Involving electronic [emr] or nuclear [nmr] magnetic resonance, e.g. magnetic resonance imaging; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Measuring half‐life of a radioactive substance; Measuring neutron radiation; Medical image quality; Medical image reconstruction; Multimodal Imaging - instrumentation; Multimodal Imaging - methods; NEMA; PET/MR; Phantoms, Imaging; positron emission tomography; Positron emission tomography (PET); Positron-Emission Tomography - instrumentation; Positron-Emission Tomography - methods; Radiopharmaceuticals; RF interference; Scattering, Radiation; Scintigraphy; silicon photomultiplier; Spatial resolution; Temperature; Time Factors; time of flight spectrometers; Whole Body Imaging - instrumentation; Whole Body Imaging - methods; RF interference; silicon photomultiplier; PET/MR; NEMA
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.4945416

Purpose: The GE SIGNA PET/MR is a new whole body integrated time-of-flight (ToF)-PET/MR scanner from GE Healthcare. The system is capable of simultaneous PET and MR image acquisition with sub-400 ps coincidence time resolution. Simultaneous PET/MR holds great potential as a method of interrogating molecular, functional, and anatomical parameters in clinical disease in one study. Despite the complementary imaging capabilities of PET and MRI, their respective hardware tends to be incompatible due to mutual interference. In this work, the GE SIGNA PET/MR is evaluated in terms of PET performance and the potential effects of interference from MRI operation. Methods: The NEMA NU 2-2012 protocol was followed to measure PET performance parameters including spatial resolution, noise equivalent count rate, sensitivity, accuracy, and image quality. Each of these tests was performed both with the MR subsystem idle and with continuous MR pulsing for the duration of the PET data acquisition. Most measurements were repeated at three separate test sites where the system is installed. Results: The scanner has achieved an average of 4.4, 4.1, and 5.3 mm full width at half maximum radial, tangential, and axial spatial resolutions, respectively, at 1 cm from the transaxial FOV center. The peak noise equivalent count rate (NECR) of 218 kcps and a scatter fraction of 43.6% are reached at an activity concentration of 17.8 kBq/ml. Sensitivity at the center position is 23.3 cps/kBq. The maximum relative slice count rate error below peak NECR was 3.3%, and the residual error from attenuation and scatter corrections was 3.6%. Continuous MR pulsing had either no effect or a minor effect on each measurement. Conclusions: Performance measurements of the ToF-PET whole body GE SIGNA PET/MR system indicate that it is a promising new simultaneous imaging platform.