ECAT ART - A CONTINUOUSLY ROTATING PET CAMERA - PERFORMANCE-CHARACTERISTICS, INITIAL CLINICAL-STUDIES, AND INSTALLATION CONSIDERATIONS IN ANUCLEAR-MEDICINE DEPARTMENT

Advances in fully three-dimensional (3D) image reconstruction techniqu es have permitted the development of a commercial, rotating, partial r ing, fully 3D positron emission tomographic (PET) scanner, the ECAT AR T. The system has less than one-half the number of bismuth germanate d etectors compared with a full ring scanner with the equivalent field o f view, resulting in reduced capital cost. The performance characteris tics, implications for installation in a nuclear medicine department, and clinical utility of the scanner are presented in this report. The sensitivity (20 cm diameterx20 cm long cylindrical phantom, no scatter correction) is 11400 cps . kBq(-1). ml(-1). This compares with 5800 a nd 40500 cps . kBq(-1). ml(-1) in 2D and 3D respectively for the equiv alent full ring scanner (ECAT EXACT). With an energy window of 350-650 keV the maximum noise equivalent count (NEC) rate was 27 kcps at a ra dioactivity concentration of similar to 15 kBq . ml(-1) in the cylinde r. Spatial resolution is similar to 6 mm full width at half maximum on axis degrading to just under 8 mm at a distance of 20 cm off axis. In stallation and use within the nuclear medicine department does not app reciably increase background levels of radiation on gamma cameras in a djacent rooms and the dose rate to an operator in the same room is 2 m u Sv . h(-1) for a typical fluorine-18 fluorodeoxyglucose (F-18-FDG) s tudy with an initial injected activity of 370 MBq. The scanner has bee n used for clinical imaging with F-18-FDG for neurological and oncolog ical applications. Its novel use for imaging iron-52 transferrin for l ocalising erythropoietic activity demonstrates its sensitivity and res olution advantages over a conventional dual-headed gamma camera. The E CAT ART provides a viable alternative to conventional full ring PET sc anners without compromising the performance required for clinical PET imaging.