title: Performance evaluation of the positron scanner ECAT EXACT.
abstract: The Cologne Special is a prototype of the ECAT EXACT (model 921), a new generation of Siemens-CTI PET scanners. It consists of three rings of 48 BGO block detectors each, covering an axial field of view of 16.2 cm with a patient port of 56.2 cm diameter. This results in a total of 24 rings with 384 crystals each, giving 47 contiguous image planes in two-dimensional (2D) mode. Total system sensitivity is 216 kcps/microCi/ml for a 20 cm cylinder phantom in 2D. This increases to 1.5 Mcps/microCi/ml in 3D. Data are acquired in the stationary mode only (no wobble motion), resulting in a transaxial spatial resolution of better than 6 mm full width at half-maximum (FWHM) at the center, which degrades to 7.5 mm tangentially and 9.6 mm radially at a radius of 20 cm. Average axial resolution changes from 5.0 mm FWHM at the center to 8.1 mm at R = 20 cm. Count rate performance was investigated at different low energy discriminator settings and found to be linear up to 2.5 microCi/ml with a 20 cm phantom. The magnitude and distribution of scatter were evaluated for both septa-extended and septa-retracted conditions for a range of energy thresholds. Brain, heart, and whole-body studies with the new tomograph demonstrate the versatility of its applications without compromising on physical performance.
authors.affiliation: Max-Planck-Institut für neurologische Forschung, Köln, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Wienhard
authors.forename: L
authors.initials: L
authors.lastname: Eriksson
authors.forename: S
authors.initials: S
authors.lastname: Grootoonk
authors.forename: M
authors.initials: M
authors.lastname: Casey
authors.forename: U
authors.initials: U
authors.lastname: Pietrzyk
authors.forename: W D
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006801:Humans; D014055:Tomography, Emission-Computed / Q000295:instrumentation*