High Throughput PET/CT Imaging Using a Multiple Mouse Imaging System

A considerable limitation of current small animal positron emission tomography/computed tomography (PET/CT) imaging is the low throughput of image acquisitions. Subsequently, to design sufficiently-powered studies, high costs accumulate. Together with Mediso Medical Imaging Systems, a four-bed mouse hotel was developed to simultaneously image up to four mice, thereby reducing the cost and maximising radiotracer usage when compared to scans performed with a single mouse bed. Methods: For physiological evaluation of the four-bed mouse hotel, temperature and anaesthesia were tested for uniformity, followed by [ 18 F]fluorodeoxyglucose (FDG) PET/CT imaging of mini image quality (IQ) phantoms specifically designed to fit the new imaging system. Post-reconstruction, National Electrical Manufacturers Association (NEMA) NU-4 tests examined uniformity, recovery coefficients (RCs) and spill-over ratios (SORs). To evaluate the bed under standard in vivo imaging conditions, four mice were simultaneously scanned by dynamic [ 18 F]FDG PET/CT over 60 minutes using the four-bed mouse hotel, with quantified images compared to those acquired using a single mouse bed. Results: The bed maintained a constant temperature of 36.8°C ± 0.4°C (n = 4), with anaesthesia distributed evenly to each nose cone (2.9 ± 0.1 L/min, n = 4). The NEMA tests performed on reconstructed mini IQ phantom images acquired using the four-bed mouse hotel revealed values within the tolerable limits for uniformity, RC values in >2mm rods, and SORs in the non-radioactive water- and air-filled chambers. There was low variability in radiotracer uptake in all major organs of mice scanned using the four-animal bed versus those imaged using a single bed imaging platform. Conclusion: Analysis of images acquired using the four-bed mouse hotel confirmed its utility to increase the throughput of small animal PET imaging without considerable loss of image quality and quantitative precision. In comparison to a single mouse bed, the cost and time associated with each scan were substantially reduced.