Technical Note: Performance evaluation of a small‐animal PET/CT system based on NEMA NU 4–2008 standards

Abstract

Purpose The MetisTM PET/CT is a self‐developed, silicon photomultiplier (SiPM) detector‐based, rodent PET/CT system. The objective of this study was to evaluate the performance of the system using the National Electrical Manufacturers Association (NEMA) NU 4–2008 standard protocol. Methods Energy resolution, spatial resolution, sensitivity, scatter fraction (SF), noise‐equivalent count rate (NECR), and image quality (IQ) characteristics were measured. A micro Derenzo phantom experiment was performed to evaluate the spatial resolution using three‐dimensional ordered‐subsets expectation maximization (3D‐OSEM) and maximum likelihood expectation maximization (MLEM) reconstructed images. In addition, the CT imaging agent Ioverol 350 was mixed with fluorine‐18 (18F)‐fluorodeoxyglucose (FDG) and then injected into the micro Derenzo phantom to evaluate the PET/CT imaging. In vivo PET/CT imaging studies were also conducted in a healthy mouse and rat using 18F‐FDG. Results The mean energy resolution of the system was 15.3%. The tangential resolution was 0.82 mm full‐width half‐maximum (FWHM) at the center of the field of the view (FOV), and the radial and axial resolution were generally lower than 2.0 mm FWHM. The spatial resolution was significantly improved when using 3D‐OSEM, especially the axial FWHM could be improved by up to about 57%. The system absolute sensitivity was 7.7% and 6.8% for an energy window of 200–750 and 350–750 keV respectively. The scatter fraction was 8.2% and 12.1% for the mouse‐ and rat‐like phantom respectively. The peak NECR was 1343.72 kcps at 69 MBq and 640.32 kcps at 53 MBq for the mouse‐ and rat‐like phantom respectively. The 1‐mm fillable rod in the IQ phantom can be clearly observed. We can identify the 0.6‐mm aperture of the micro Derenzo phantom image clearly using 3D‐OSEM (10 subsets, 5 iterations). We also performed the fusion of the PET and CT images of the mouse and the brain imaging of the rat. Conclusions The results show that the system has the characteristics of high‐resolution, high‐sensitivity, and excellent IQ and is suitable for rodent imaging‐based research.

Performance Evaluation of a PET of 7T Bruker Micro-PET/MR Based on NEMA NU 4-2008 Standards

“…In the FLEX triumph X-PET [33], only attenuation is performed, the scatter correction is not taken into account, and two different type of reconstruction algorithm are used, 2D-FBP and 2D-OSEM. Inveon [30], Argus PET [34], Metis TM PET/CT [37], LFER 150 PET/CT [38], and Bruker PET/MRI both apply corrections in their data, but their reconstruction techniques are different-e.g., FORE + 2D FBP (Inveon), 3D-OSEM (Argus PET and Metis PET/CT), 2D-MLEM (LFER 150 PET/CT), and 3D-MLEM (Bruker PET/MRI)). The image quality test's reconstruction algorithms and correction factors strongly affect the results.…”

“…Table 5 compares the image quality of Bruker's small animal PET scanner with other preclinical scanners. [32], Inveon [30], FLEX Triumph X-PET (2D-FBP) [33], FLEX Triumph X-PET (2D-OSEM) [33], Argus PET [34], VrPET/CT [35], LabPET-8 TM [36], Metis TM PET/CT [37], XTRIM-PET [7], and LFER 150 PET/CT [38].…”

Technical opportunities and challenges in developing total-body PET scanners for mice and rats

“…NanoPET Commercially available scanner provided by Mediso [45] A-PET An animal PET scanner developed by Dr. Suleman Surti [40] Inveon Siemens Inveon PET [43] Metis Metis PET is commercially provided by Shandong Madic Technology Co.,Ltd [47] IRIS IRIS PET is commercially provided by Medilumine Inc [46] ClairvivoPET ClairvivoPET is a commercial provided by Shimadzu Corp., Japan [41] HiPET A small animal PET scanner developed by Dr. Zheng Gu [30] LabPET-12 Scanner developed at University de Sherbrooke, Canada [42] ClearPET ClearPET was manufactured by Raytest Isotopenmessgeraete GmbH, Germany [44] Albira Si PET Bruker Albira Si fully integrated PET/SPECT/CT [29] SIAT aPET A small animal PET developed at Shenzhen Institute of Advanced Technology, China [31] β-CUBE Scanner developed by MOLECUBES, Belgium [28] quadHIDAC32 Scanner developed by Oxford Positron Systems [38] SimPET-X A PET insert for simultaneous mouse total-body PET/MR imaging [13] Yamaya's PET A total-body small animal PET is underdeveloped at Dr. Taiga Yamaya's Lab, Japan [21] Mouse J-PET A total-body mouse J-PET simulated by Jagiellonian University [48] Rat J-PET A total-body rat J-PET simulated by Jagiellonian University [48] HS-BGO PET A total-body small animal PET with ~ 330-mm axial FOV is underdeveloped at University of California at Davis H 2 RS160 A high-resolution (0.5 mm) and high sensitivity PET with 254-mm axial FOV simulated at University of California at Davis [12] UHS-PET An over 50% sensitivity PET proposed and simulated by University of California at Davis [50]…”

Physical and imaging performance of SIAT aPET under different energy windows and timing windows

“…In the previous publications that described the performance evaluation results of different small animal PET scanners, the sensitivity, SF, and NECR of several EWs were usually provided, but the spatial resolution and image quality were only provided for one EW. Almost all performance parameters are only provided for one TW 8–32 . It is well known that the sensitivity of a PET scanner increases as the EW and TW become wider.…”