Fast-channel LSO detectors and fiber-optic encoding for excellent dual photon transmission measurements in PET

Improved attenuation correction remains critical to PET. Currently with dua l photon rotating rod sources, benefits of windowing are limited by countin g losses of detectors nearest the rods, the near detectors. With single pho ton sources, improved statistics are offset by a greater need for collimati on and more complex emission background correction. Now, a dual photon poin t source array with fast-channel, near detectors improves on these earlier techniques - here, adding transmission measurement to dual-head rotating PE T. Arrays of collimated point sources (Ge-68/Ga - 3 to 21 per head) are ali gned axially and orbit the FOV. With each source is a dedicated near detect or (LSO crystal). Crystals couple to photomultipliers (PMTs). As the crysta ls are not "block" encoded, pulse-processing time is reduced (to 120 ns). R educed processing time lowers dead time and permits hotter sources. For imp roved axial sampling, larger arrays (21 sources/head) may be configured. To reduce cost, crystals couple fiber-optically into unique PMT pairs - decre asing the total number of near-detector PMTs by 71%.