Recent results from a "dual-ring" high-resolution PET demonstrator

436 Objectives Dual-ring PET systems, where the inner ring comprises a detector having high spatial resolution, can exhibit sub-millimeter resolution over small fields-of-view (FOV). The goal of this work was to develop a demonstration device with an in inner detector with high resolution surrounded by a outer detector with modest resolution. Methods A partial-ring device was constructed. The inner detector consists of two 22mm x 44mm x 1mm silicon detectors with 512 1.4mm x 1.4mm detector pads in a 16x32 array. The silicon detectors are located on opposite sides of the 4cm dia. FOV and are separated by 14cm. The outer detector ring is constructed using BGO block detectors scavenged from a CTI 931 PET instrument. Each detector has an 8 x 4 array of 6mm x 12mm x 30mm BGO crystals. Twelve detectors are located symmetrically on each side of the FOV at a 500mm radius from the center. Custom data readout and data acquisition electronics were developed and allow simultaneous acquisition of the three main event classes: Si-Si, Si-BGO, and BGO-BGO. Results As expected, reconstructions from the Si-Si events demonstrate the highest resolution: ~0.7mm FWHM uniformly across the FOV. However, even with the relatively poor resolution BGO detectors (>6mm), spatial resolution for Si-BGO events is Conclusions While the sensitivity and countrate capabilities of the demonstration instrument are low, spatial resolution is high and the device will be used to further evaluate dual-ring PET configurations as well as PET magnifying probes. Research Support NIH R01 EB430, European Commission FP7 project MADEIR