Positron emission tomography (PET) of radiotracer uptake and distribution in living plants: methodological aspects

The use of radioisotopes as tracers in biology was pioneered in 1923 by Hevesy in the study of the uptake and distribution of lead in the bean plant. This seminal work has spawned applications of nuclear analytical methods in the life sciences. In medicine, nuclear imaging has become a standard part of patient care. Positron emission tomography (PET) is a nuclear medicine imaging modality that allows assessment of biochemical processes in vivo, to diagnose and stage diseases and monitor their treatment. Going full circle to Hevesy's original biological study, PET imaging can be applied to the assessment of radiotracer uptake and distribution in living plants non-invasively. In order to apply PET imaging to the study of plants, several methodological aspects were examined in this study with the goal of establishing protocols that would be useful to investigators with access to commercial small animal PET scanners. The methodological aspects examined in this study included (a) the selection of suitable plant models, (b) standardization of scanning strategies such as PET tracer injection into plants and (c) imaging protocols to optimize detection of annihilation gammas.