NEMA NU4-2008 Performance Evaluation of Albira: A Two-Ring Small-Animal PET System Using Continuous LYSO Crystals
Malgorzata Z. Pajak1, 3, *, David Volgyes2, Sally L. Pimlott3, 6, Carlos C. Salvador4, Antonio S. Asensi5, Clare McKeown6, Jens Waldeck7, Kurt I. Anderson1
1 Beatson Institute for Cancer Research, Glasgow, UK
2 Gyovik University College, Faculty of Computer Science and Media Technology, Norway
3 University of Glasgow, College of Medical, Veterinary and Life Sciences, Glasgow, UK
4 Oncovision, Valencia, Spain
5 Institute for Molecular Imaging Instrumentation (I3M), Valencia, Spain
6 NHS Greater Glasgow & Clyde, Glasgow, UK
7 Bruker BioSpin MRI GmbH, Ettlingen, Germany
Goals: This paper presents the performance review based on a dual-ring Positron Emission Tomography (PET) scanner being a part of Bruker Albira: a multi-modal small-animal imaging platform. Each ring of Albira PET contains eight detectors arranged as octagon, and each detector is built using a single continuous lutetium-yttrium oxyorthosilicate crystal and multi-anode photo multiplier tube. In two-ring configuration, the scanner covers 94.4 mm in axial- and 80´80 mm in trans-axial direction, which is sufficient to acquire images of small animals (e.g. mice) without the need of moving the animal bed during the scan.
Methods: All measurements and majority of data processing were performed according to the NEMA NU4-2008 standard with one exception. Due to the scanner geometry, the spatial resolution test was reconstructed using iterative algorithm instead of the analytical one. The main performance characteristics were compared with those of the other PET sub-systems of tri-modal small-animal scanners.
Results: The measured spatial resolution at the centre of the axial field of view in radial, tangential and axial directions was 1.72, 1.70 and 2.45 mm, respectively. The scatter fraction for the mouse-like phantom was 9.8% and for the rat-like phantom, 21.8%. The maximum absolute sensitivity was 5.30%. Finally, the recovery co-efficients for 5, 4, 3, 2, 1 mm diameter rods in image quality phantom were: 0.90, 0.77, 0.66, 0.30 and 0.05, respectively.
Conclusion: The Bruker Albira is a versatile small-animal multi-modal device that can be used for variety of studies. Overall the PET sub-system provides a good spatial resolution coupled with better-than average sensitivity and the ability to produce good quality animal images when administering low activities.
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (https://creativecommons.org/licenses/by-nc/4.0/legalcode), which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Correspondence: *Address correspondence to this author at the Beatson Institute for Cancer Research, Switchback Road, Glasgow, G61 1BD, UK; Tel: +44 141 330 6046; Fax: +44 141 942 6521; E-mail: Malgorzata.Pajak@glasgow.ac.uk