Performance evaluation of a rotatory dual-head PET system with 90^̂increments for small animal imaging

Abstract

A: A rotatory dual-head positron emission tomography (PET) system with 90°increments has been built up by our lab. In this study, a geometric calibration phantom was designed and then used to calibrate the geometric offset of the system. With the geometric calibration, the artifacts in the reconstructed images were greatly eliminated. Then, we measured the imaging performance including resolution, sensitivity and image quality. The results showed that the full width at half maximum (FWHMs) of the point source were about 1.1 mm in three directions. The peak absolute sensitivity in the center of the field of view varied from 5.66% to 3.17% when the time window was fixed to 10 ns and the energy window was changed from 200-800 keV to 350-650 keV. The recovery coefficients ranged from 0.13 with a standard deviation of 17.5% to 0.98 with a standard deviation of 15.76%. For the air-filled and water-filled chamber, the spill-over ratio was 14.48% and 15.38%, respectively. The in vivo mouse experiment was carried out and further demonstrated the potential of our system in small animal studies.

Comparison of GPU reconstruction based on different symmetries for dual‐head PET

“…In this system, the small distance between the detector heads is helpful to get higher sensitivity of the system. In our previous work, the performance of this system has been reported in 2017, and the absolute sensitivity in the center of the FOV is about 5.66% . In the reconstruction, the voxel size is 0.5 mm × 0.5 mm × 0.5 mm.…”

“…In our previous work, the performance of this system has been reported in 2017, and the absolute sensitivity in the center of the FOV is about 5.66%. 22 In the reconstruction, the voxel size is 0.5 mm 9 0.5 mm 9 0.5 mm. There are two reasons why we applied voxel with a small size.…”

“…The MC simulation was simulated with the software of Geant4 Application for Tomographic Emission (GATE) v6.2 on the workstation with the environment of Ubuntu 14.04, 64 GB RAM and double Intel Xeon Processor E5‐2660 v2 (25 MB Cache, 2.20 GHz, 10 cores 20 threading). In the simulation, each detector head contains 26 × 52 LYSO crystals with a size of 13 mm × 2.0 mm × 2.0 mm . The activity of each point source is 2500 Bq.…”

“…We have built a dual‐head prototype PET system for small animal imaging in our lab . Each panel detector consists of 26 × 52 crystals with a size of 13 mm × 2.0 mm × 2.0 mm, and the distance between the two detectors is 50 mm.…”

“…In the simulation, each detector head contains 26 9 52 LYSO crystals with a size of 13 mm 9 2.0 mm 9 2.0 mm. 22 The activity of each point source is 2500 Bq. In the simulation, we extended the number of detector heads to 104 9 104 in order to employ the symmetry properties to populate all of the elements of the SRM.…”