A compact planar positron imaging system

A planar imaging system for positron-emitting radiotracers was developed and its physical performance was evaluated. The new device consists of two opposing planar detectors, each having 4 (columns) × 6 (rows) detector units, and each unit composed of 10×10 arrays of 2×2×20 mm3 pillars of Bi4Ge3O12 (BGO) scintillators and a metal-packaged position-sensitive photomultiplier tube. The system is very compact and has a simple structure that allows versatile positioning of detectors in the horizontal or vertical mode. Focal plane images are constructed from coincidence data collected by opposing planar detectors. The system provides good quality images even in a short period of time or with low tracer activity. Spatial resolutions of 1.6–2.1 mm FWHM were achieved for the entire field of view. The sensitivity was 107 cps/kBq/ml measured in a uniform flat phantom. In this study, the capability of the new system was demonstrated by the imaging of radiotracer distribution in rats and plants.