Evaluation of the Karolinska new positron camera system; the Scanditronix PC2048-15B

The PC2048-15B is the brain version of the new generation of Scanditronix positron camera systems, now being installed at the Karolinska Hospital in Stockholm, Sweden. The system has eight rings with 256 BGO crystals per ring. The dimensions of the crystals are 6×12×30 mm. Data corresponding to 15 image slices are simultaneously recorded. The detector rings are based on block-detector units, each with 16 scintillation crystals mounted on two dual photomultiplier tubes. The system is described, and test results including spatial resolution, sensitivity to true and random coincidences, scatter correction, count rate linearity, spatial independence, and reproducibility are presented. Clinical results are discussed, including rCBF studies and receptor studies, to cover the two most extreme situations met in brain PET (positron emission tomography) studies, i.e. high count rate and high resolution requirements