TY - JOUR T1 - Performance of a Brain PET Camera Based on Anger-Logic Gadolinium Oxyorthosilicate Detectors JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1340 LP - 1349 VL - 44 IS - 8 AU - Joel S. Karp AU - Suleman Surti AU - Margaret E. Daube-Witherspoon AU - Richard Freifelder AU - Christopher A. Cardi AU - Lars-Eric Adam AU - Kilian Bilger AU - Gerd Muehllehner Y1 - 2003/08/01 UR - http://jnm.snmjournals.org/content/44/8/1340.abstract N2 - A high-sensitivity, high-resolution brain PET scanner (“G-PET”) has been developed. This scanner is similar in geometry to a previous brain scanner developed at the University of Pennsylvania, the HEAD Penn-PET, but the detector technology and electronics have been improved to achieve enhanced performance. Methods: This scanner has a detector ring diameter of 42.0 cm with a patient aperture of 30.0 cm and an axial field of view of 25.6 cm. It comprises a continuous light-guide that couples 18,560 (320 × 58 array) 4 × 4 × 10 mm3 gadolinium oxyorthosilicate (GSO) crystals to 288 (36 × 8 array) 39-mm photomultiplier tubes in a hexagonal arrangement. The scanner operates only in 3-dimensional (3D) mode because there are no interplane septa. Performance measurements on the G-PET scanner were made following National Electrical Manufacturers Association NU 2–2001 procedures for most measurements, although NU 2–1994 procedures were used when these were considered more appropriate for a brain scanner (e.g., scatter fraction and counting-rate performance measurements). Results: The transverse and axial resolutions near the center are 4.0 and 5.0 mm, respectively. At a radial offset of 10 cm, these numbers deteriorate by approximately 0.5 mm. The absolute sensitivity of this scanner measured with a 70-cm long line source is 4.79 counts per second (cps)/kBq. The scatter fraction measured with a line source in a 20-cm-diameter × 19-cm-long cylinder is 39% (for a lower energy threshold of 410 keV). For the same cylinder, the peak noise equivalent counting rate is 60 kcps at an activity concentration of 7.4 kBq/mL (0.20 μCi/mL), whereas the peak true coincidence rate is 132 kcps at an activity concentration of 14 kBq/mL (0.38 μCi/mL). Images from the Hoffman brain phantom as well as 18F-FDG patient scans illustrate the high quality of images acquired on the G-PET scanner. Conclusion: The G-PET scanner attains the goal of high performance for brain imaging through the use of an Anger-logic GSO detector design with continuous optical coupling. This detector design leads to good energy resolution, which is needed in 3D imaging to minimize scatter and random coincidences. ER -