Performance and Workflow of a new sequential PET/MR System, the Mediso nanoScan^®

Aim:

In this study we describe the performance and workflow of the commercially available small animal sequential PET/MR system, the Mediso nanoScan^®.

Material and Methods:

The system consists of a PET scanner (Mediso Ltd. Budapest, Hungary) based on LYSO crystals (1.12 x 1.12 x 13mm) with an axially FOV of 94.7mm and a 1 tesla permanent magnet (Aspect Imaging, Toronto, Canada). The fringe fields of this magnet enable the use of Position Sensitive PMTs (PSPMTs) for the PET gantry.
The PET performance was assessed by using NEMA NU 4-2008 standard to derive the sensitivity and spatial resolution. The MR based attenuation correction for this device is tested by using different homogenous volumes (syringes); the activity is reconstructed and compared to the uncorrected data to determine the impact of this method. The image quality of the system is presented in through different MR scans of rat and mice as well as in coregistered PET/MR images.

Conclusion:

The PET performance has no visible influence by the MRI system. The first results deliver an absolute sensitivity of 8.4% and an axial resolution of 1.1mm FWHM (radial 1.5, tangential 1.3). Anatomic good quality brain images are obtained in 20 minutes and a basic 3D scout in 4.5 minutes. The reproduced activity of the attenuation corrected data verifies the efficiency of the implemented method, while the residual deviation in homogenous phantoms is +1.3% (5ml, 10ml and 20ml syringes).
The nanoScan^® PET/MR scanner allows fast, high resolution anatomical MR- and precise PET-imaging with a special regard to brain studies.