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. 2019 May 13;92(1098):20180670. doi: 10.1259/bjr.20180670

Table 6.

MRI guidance radiotherapy systems

Elekta Unity MR Linac
72,76
ViewRay MRIdian Cobalt 60
73,77
ViewRay MRIdian Linac Australian MRI-Linac
74
Canadian Aurora Magnet X MR Linac 75
Magnet 1.5 T closed 0.35 T split bore 0.35 T split bore 1.0 T split bore 0.5 T biplanar rotating geometry
Radiotherapy source 7 MV 3 Cobalt-60 heads 6 MV 6 MV 6 MV
MLC effective leaf width at isocentre 0.72 cm 1.05 cm 0.83 cm
MLC maximum leaf speed 6 cm/sec 2.0 ± 0.1 cm/sec >2 cm/ sec
Magnetic field orientation to delivery Perpendicular Perpendicular Perpendicular Perpendicular and parallel Perpendicular and parallel
Bore Size 70 cm 70 cm 70 cm 50 cm 60 cm
Magnetic field homogeneity ≤2.0 ppm over 50 × 50×45 cm3 <25 ppm over 45 cm DSV <25 ppm over 45 cm DSV
Maximum imaging field of view 50 cm DSV 50 cm DSV 50 cm DSV
Maximum treatment field size 57.4 × 22 cm2 27.3 × 27.3 cm2 27.4 × 24.1 cm2
4D capabilities Yes Yes Yes No No
Functional imaging Yes Yes Yes No No
Treating patients Yes Yes Yes No No
CE Marked/ FDA approved Yes Yes Yes No No

DSV, diameter of spherical volume; MLC, multileaf collimator; Ppm, parts per million.