Table 1.
NEMA NU 2–2018 results across all performed tests for the 30-cm aFOV DMI Gen2 6-ring system together with the 5-ring configuration results acquired prior to the ring upgrade
| Parameter | ||
|---|---|---|
| System | DMI Gen2 5R | DMI Gen2 6R |
| Axial/transaxial FOV (cm) | 25/70 | 30/70 |
| Scintillator size (mm × mm × mm) | 3.95 × 5.3 × 25 | 3.95 × 5.3 × 25 |
| Spatial resolution (VPHD) | ||
| 1 cm radial/tangential/axial FWHM (mm) | 3.84/3.89/4.33 | 3.72/3.87/4.26 |
| 10 cm radial/tangential/axial FWHM (mm) | 4.88/3.88/3.93 | 4.80/3.79/4.55 |
| 20 cm radial/tangential/axial FWHM (mm) | 7.15/4.45/4.12 | 7.63/4.21/4.50 |
| Spatial resolution (QClear) | ||
| 1 cm radial/tangential/axial FWHM (mm) | 1.86/2.38/3.16 | 1.62/2.30/3.09 |
| 10 cm radial/tangential/axial FWHM (mm) | 1.86/1.93/2.99 | 1.94/2.01/3.36 |
| 20 cm radial/tangential/axial FWHM (mm) | 1.69/2.60/3.16 | 1.87/2.09/3.32 |
| Spatial resolution (FFBP) | ||
| 1 cm radial/tangential/axial FWHM (mm) | 4.50/4.27/4.96 | 4.25/4.21/5.02 |
| 10 cm radial/tangential/axial FWHM (mm) | 5.57/4.60/5.80 | 5.58/4.56/6.40 |
| 20 cm radial/tangential/axial FWHM (mm) | 7.45/4.99/6.14 | 7.50/4.98/6.74 |
| Sensitivity | ||
| At center (cps/kBq) | 22.01 | 32.64 |
| 10 cm (cps/kBq) | 22.59 | 32.88 |
| Count rate statistics | ||
| Peak NECR (kcps) | 312.9 | 434.3 |
| Peak NECR activity (kBq/mL) | 22.5 | 23.6 |
| Scatter fraction at peak NECR (%) | 41 | 40.21 |
| Maximum error at peak NECR (%) | 4.61 | 3.95 |
| Maximum mean error at peak NECR (%) | 2.31 | 2.77 |
| Image quality (VPFX) | ||
| 10 mm (CR (std)/BV (std); %) | 48.0 (5.4)/8.5 (0.5) | 54.5 (5.5)/6.8 (0.5) |
| 13 mm (CR (std)/BV (std); %) | 57.8 (7.7)/6.8 (0.3) | 63.2 (3.2)/5.0 (0.6) |
| 17 mm (CR (std)/BV (std); %) | 70.4 (2.6)/5.2 (0.4) | 68.0 (1.5)/4.0 (0.6) |
| 22 mm (CR (std)/BV (std); %) | 78.2 (1.3)/3.8 (0.5) | 76.9 (4.0)/3.2 (0.3) |
| 28 mm (CR (std)/BV (std); %) | 83.3 (1.7)/2.8 (0.3) | 82.4 (1.25)/2.5 (0.3) |
| 37 mm (CR (std)/BV (std); %) | 86.9 (1.3)/2.3 (0.1) | 85.8 (1.6)/1.9 (0.2) |
| Average lung error (std) (%) | 4 (0.2) | 3.16 (0.1) |
| Image quality (QClear) | ||
| 10 mm (CR (std)/BV (std); %) | 64.5 (3.5)/6.5 (0.4) | 66.4 (3.0)/4.6 (0.4) |
| 13 mm (CR (std)/BV (std); %) | 70.7 (4.6)/5.2 (0.3) | 72.5 (2.4)/3.5 (0.5) |
| 17 mm (CR (std)/BV (std); %) | 78.3 (1.7)/3.7 (0.4) | 77.7 (0.5)/2.5 (0.5) |
| 22 mm (CR (std)/BV (std); %) | 84.2 (0.8)/2.8 (0.4) | 84.8 (1.4)/1.9 (0.2) |
| 28 mm (CR (std)/BV (std); %) | 88.6 (0.8)/2.2 (0.2) | 87.4 (0.7)/1.5 (0.2) |
| 37 mm (CR (std)/BV (std); %) | 90.2 (0.7)/1.8 (0.1) | 89.6 (0.9)/1.3 (0.1) |
| Average lung error (std) (%) | 3.2 (0.1) | 2.6 (0.1) |
| Timing and energy resolution | ||
| Energy resolution (%) | 9.68 | 9.63 |
| Timing resolution at 0 kBq/mL (ps) | 391.6 | 389.6 |
| Timing resolution at 5.3 kBq/mL (ps) | 408.5 | 407.6 |
| Scatter fraction | ||
| Fraction (%) | 41 | 40.21 |
| Co-registration accuracy | ||
| Error at (0,1) (5 cm/100 cm) (mm) | 2.93/3.25 | 1.35/2.21 |
| Error at (0,20) (5 cm/100 cm) (mm) | 2.65/3.16 | 1.82/2.30 |
| Error at (20,0) (5 cm/100 cm) (mm) | 2.76/3.21 | 1.82/2.59 |