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

Abstract

Objective. The pheno PET 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 pheno PET, its data processing and image reconstruction together with its performance. Approach. The performance characterization follows the national electrical manufacturers association (NEMA) standard for small animal PET systems with a number of adoptions due to the vertical oriented bore of a PET for plant sciences. In addition temperature stability and spatial resolution with a hot rod phantom are addressed. Main results. The spatial resolution for a 22 Na point source at a radial distance of 5 mm to the center of the field-of-view (FOV) is 1.45 mm, 0.82 mm and 1.88 mm with filtered back projection in radial, tangential and axial direction, respectively. A hot rod phantom with 18 F gives a spatial resolution of up to 1.6 mm. The peak noise-equivalent count rates are 550 kcps @ 35.08 MBq, 308 kcps @ 33 MBq and 45 kcps @ 40.60 MBq 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 S A , 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 1 mm, 2 mm, 3 mm, 4 mm and 5 mm rods are obtained and spill-over ratios of 0.08 and 0.14 for the water-filled and air-filled inserts, respectively. Significance. The pheno PET and its laboratory are now in routine operation for the administration of [ 11 C]CO 2 and non-invasive measurement of transport and allocation of 11 C-labelled photoassimilates in plants.

Plant phenotyping relevance

植物専用PETスキャナーの構築、データ処理・画像再構成、性能評価を中心に扱い、植物体内の光合成産物の輸送・配分を非侵襲測定するフェノタイピング基盤である。

Code and data availability

The article's data availability statement states all supporting data are contained within the article itself; no public phenotype dataset, image/sensor data, author analysis code, or trained model repository is deposited or linked. The Hinz 2021 thesis DOI and other URLs are cited prior works, not paper-specific repro-

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