Performance characteristics of a new 3-dimensional continuous-emission and spiral-transmission high-sensitivity and high-resolution PET camera evaluated with the NEMA NU 2-2001 standard.
The SET-3000 G/X (clinical tomograph with high resolution and a large axial field of view) is a 3-dimensional (3D) (only) dedicated PET camera with germanium oxyorthosilicate (GSO) and bismuth germanate (BGO) scintillators. The main characteristic of the SET-3000 G/X PET scanner is 3D continuous-emission and spiral-transmission (CEST) scanning, yielding a reduction in whole-body scan time. We evaluated the physical performance of the SET-3000 G/X PET scanner with the National Electrical Manufacturers Association (NEMA) NU 2-2001 standard.


METHODS
A GSO 3D emission scanner is combined with a BGO transmission scanner separated axially by a lead shield. In the GSO scanner, small and thick scintillators (2.45 x 5.1 x 30 mm(3)) are arranged in small blocks (23.1 x 52 mm) to achieve high resolution and a high counting rate. The detector ring has a large solid angle with a diameter of 664 mm and an axial coverage of 260 mm (50 rings). The transmission scanner consists of BGO block detectors with a diameter of 798 mm and an axial width of 23.1 mm and is equipped with a rotating (137)Cs point source of 740 MBq and a tungsten collimator. The low- and high-energy thresholds are set to 400 and 700 keV, respectively, in the emission system. The coincidence time window is set to 6 ns. In CEST acquisition, the patient couch moves continuously through the emission and transmission scanners in a 1-way motion. Emission coincidence data are acquired in the histogram mode with on-the-fly Fourier rebinning, and transmission single data are acquired with emission contamination correction.


RESULTS
With the NEMA NU 2-2001 standard, the main performance results were as follows: the average (radial and tangential) transverse and axial spatial resolutions (full width at half maximum) at 1 cm and at 10 cm off axis were 3.49 and 5.04 mm and 4.48 and 5.40 mm, respectively; the average sensitivity for the 2 radial positions (0 and 10 cm) was 20.71 cps/kBq; the scatter fraction was 50%; the peak noise equivalent count rate was 62.3 kcps at 9.8 kBq/mL; and the peak random rate was 542.1 kcps at 37.6 kBq/mL.


CONCLUSIONS
The new integrated SET-3000 G/X PET scanner has good overall performance, including high resolution and sensitivity, and has the potential of reducing whole-body acquisition time to less than 10 min while improving small-lesion detectability with a low radiation dose.
Matsumoto
Keiichi
K
Department of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Japan. matsumoto@fbri.org
Kitamura
Keishi
K
Mizuta
Tetsuro
T
Tanaka
Kazumi
K
Yamamoto
Seiichi
S
Sakamoto
Setsu
S
Nakamoto
Yuji
Y
Amano
Masaharu
M
Murase
Kenya
K
Senda
Michio
M
D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods / Q000592:standards; D015902:Gamma Cameras; D017408:Guidelines as Topic; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000592:standards; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000592:standards; D007564:Japan; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity