TABLE 1.
A summary of the operating characteristics and components of the RefleXion™ X1 system
| Hardware | |
|---|---|
| Source‐isocenter distance | 85.0 cm |
| Bore diameter | 85.0 cm |
| Gantry rotation speed | 60 rpm |
| Linear accelerator | |
|---|---|
| Photon beam energy | 6 MV flattening‐filter‐free |
| Dose rate | 850 MU/min |
| Jaws | Two sets situated above and below the MLCs. Capable of 1 or 2 cm field widths in IEC‐Y |
| MLCs | 64 binary, double‐focused, width of 6.25 mm at isocenter, maximum field width of 40 cm in IEC‐X |
| Firing positions | 50 (i.e., every 7.2 degrees) |
| Beam delivery modes |
IMRT (1 pass)/SBRT (4 passes)/BgRT (4 passes) Axial delivery in 2.1 mm table increments |
| TPS | |
|---|---|
| Optimization algorithm | Accelerated proximal gradient based on FISTA algorithm |
| Dose calculation algorithm | Collapsed cone convolution (CCC) superposition |
| Dose calculation grid size | 2.1 mm |
| Tongue‐and‐groove | Included in beam model |
| kVCT | |
|---|---|
| Tube current | 45‐400 mA |
| Tube voltage | 120 kV |
| Imaging geometry | Fan beam |
| Acquisition mode | Helical with pitch = 0.22, 0.5, or 1.33 |
| FOV | 50 cm |
| Maximum scan length | 95 cm |
| Slice thickness | 1.25 mm |
| kVCT isocenter distance from treatment isocenter | 38.6 cm |
| PET BgRT | |
|---|---|
| FOV (transverse) | 50 cm |
| FOV (longitudinal) | 5.0 cm |
| PET spatial resolution | 4.0 × 4.0 × 2.1 mm3 |