Setup and characterisation according to NEMA NU 4 of the phenoPET scanner, a PET system dedicated for plant sciences

Abstract

The phenoPET system is a plant dedicated Positron Emission Tomography (PET) scanner consisting of fully digital photo multipliers with lutetium-yttrium oxyorthosilicate crystals and located inside a custom climate chamber. Here, we present the setup of phenoPET, its data processing and image reconstruction together with the performance according to the NEMA standard for small animal PET systems. The spatial resolution for a 22Na point source at a radial distance of 5mm to the center of the Field-of-View (FOV) is 1.45mm, 0.82mm and 1.88mm with Filtered Back Projection in radial, tangential and axial direction, respectively. A hot rod phantom with 18F gives a spatial resolution of up to 1.6mm. The peak noise-equivalent count rates are 550kcps@35.08MBq, 308kcps@33MBq and 45kcps@40.60MBq for the mouse, rat and monkey size scatter phantoms, respectively. The scatter fractions for these phantoms are 12.63%, 22.64% and 55.90%. We observe a peak sensitivity of up to 3.6% and a total sensitivity of up to SA,tot=2.17%. For the NEMA image quality phantom we observe a uniformity of %STD=4.22% with Ordinary Poisson Maximum Likelihood Expectation-Maximization with 52 iterations. Here, recovery coefficients of 0.12, 0.64, 0.89, 0.93 and 0.91 for 1mm, 2mm, 3mm, 4mm and 5mm rods are obtained and spill-over ratios of 0.08 and 0.14 for the water-filled and air-filled inserts, respectively. The phenoPET and its laboratory are now in routine operation for the administration of [11C]CO2 and non-invasive measurement of transport and allocation of 11C-labelled photoassimilates in plants.

Construction and initial performance evaluation of a newly developed plant PET system

“…Although there has been research on a new PET system for plant research designed and evaluated through simulation [19], an entirely new, ring-shaped PET system optimized for plants, that enables three-dimensional imaging and is cost-effective as well as user-friendly in imaging of plants, has not been realized yet. Very recently, a PET system specifically designed for plants has been reported [20], but the concept differs from our cost-effective PET system.…”