PhytoBeta imager: a positron imager for plant biology.
Several positron emitting radioisotopes such as (11)C and (13)N can be used in plant biology research. The (11)CO(2) tracer is used to facilitate plant biology research toward optimization of plant productivity, biofuel development and carbon sequestration in biomass. Positron emission tomography (PET) imaging has been used to study carbon transport in live plants using (11)CO(2). Because plants typically have very thin leaves, little medium is present for the emitted positrons to undergo an annihilation event. The emitted positrons from (11)C (maximum energy 960 keV) could require up to approximately 4 mm of water equivalent material for positron annihilation. Thus many of the positrons do not annihilate inside the leaf, resulting in limited sensitivity for PET imaging. To address this problem we have developed a compact beta-positive, beta-minus particle imager (PhytoBeta imager) for (11)CO(2) leaf imaging. The detector is based on a Hamamatsu H8500 position sensitive photomultiplier tube optically coupled via optical grease to a 0.5 mm thick Eljen EJ-212 plastic scintillator. The detector is equipped with a flexible arm to allow its placement and orientation over or under the leaf to be studied while maintaining the leaf's original orientation. To test the utility of the system the detector was used to measure carbon translocation in a leaf of the spicebush (Lindera benzoin) under two transient light conditions.
Thomas Jefferson National Accelerator Facility, Newport News, VA, USA. drew@jlab.org
Andrew G
AG
Weisenberger
Brian
B
Kross
Seungjoon
S
Lee
John
J
McKisson
J E
JE
McKisson
Wenze
W
Xi
Carl
C
Zorn
Chantal D
CD
Reid
Calvin R
CR
Howell
Alexander S
AS
Crowell
Laurie
L
Cumberbatch
Brent
B
Fallin
Alexander
A
Stolin
Mark F
MF
Smith
D002245:Carbon Dioxide; D002250:Carbon Radioisotopes; D027443:Lindera / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000295:instrumentation*
D002250:Carbon Radioisotopes; D002245:Carbon Dioxide