Table 1.
Current PET/MR systems
| PET/MR system | Biograph mMR (Siemens) | Ingenuity TF (Philips) | Discovery PET/CT 690 + MR 750 (GE) |
|---|---|---|---|
| PET-system | |||
| Crystal material | LSO | LYSO | LYSO |
| Crystal elements dimension | 4x4x20 mm3 | 4x4x22 mm3 | 4.7x6.3x25 mm3 |
| Photomultipliers | No, 4032 APDs | 420 | 1024 |
| Ring diameter | 65.6 cm | 90.3 cm | 88.6 cm |
| Transaxial FoV | 59.4 cm | 67.6 cm | 70 cm |
| Axial FoV | 25.8 cm | 18.0 cm | 15.7 cm |
| Energy window | 430-610 keV | 460-665 keV | 425-650 keV |
| Coincidence window | 5.9 ns | 6 ns | 4.9 ns |
| Time-of-flight | No | Yes | Yes |
| MR-system | |||
| Field strength | 3 Tesla | 3 Tesla | 3 Tesla |
| Bore diameter | 60 cm | 60 cm | 60 cm |
| Max FoV | 50x50x45 cm3 | 50x50x45 cm3 | 48x48x48 cm3 |
| Field homogeneity (40cm3) | 0.25 ppm | 0.5 ppm | 0.25 ppm |
| PET/MR | |||
| Acquisition | Simultaneous | Sequential (same room) | Sequential (2 separate rooms) |
| PET-attenuation corr. | MR-based | MR-based | CT-based |