Design and initial performance of PlanTIS

Positron emitters such as 11C, 13N and 18F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is CO2 since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, frontend electronics and data acquisition architecture of the scanner are based on the ClearPETTM system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements. (Some figures in this article are in colour only in the electronic version) 3 Simone Beer published under the name of Simone Weber until 2007. 4 Maryam Khodaverdi is now at Philips Healthcare Germany, Aachen, Germany. 0031-9155/10/030635+12$30.00 © 2010 Institute of Physics and Engineering in Medicine Printed in the UK 635