Table 2 Radiotherapy Planning targets, Organs at Risk and Dose Guidance

GTV_45Gy^b

Contoured using fused contrast enhanced MRI images.

45Gy

98% covered by 100% dose

Hotspot > 110% within GTV

95% covered by 95% dose

Lesion visible on at least 2 scan slices.

Coverage to be comprised to meet OAR constraints

PTV_45Gy^b

GTV + 0-2 mm isotropic margins

45Gy

98% covered by 95% dose

90% covered by 90% dose

Coverage to be comprised to meet OAR constraints

GTV_40Gy^b

Tumour volume within/ ≤5 mm from OAR

40Gy

95% covered by 95% dose

Hotspot > 110% within GTV

90% covered by 95% dose

Lesion visible on at least 2 scan slices.

Coverage to be comprised to meet OAR constraints

PTV_40Gy^b

PTV_40Gy = GTV_40Gy; i.e. no expansion

40Gy

95% covered by 95% dose

90% covered by 90% dose

Coverage to be comprised to meet OAR constraints

GTVall_5mm^b

All GTVs + 5 mm isotropic margins

–

–

For plan optimisation

Left & Right Hippocampus

Contoured using fused MRI as per RTOG contouring atlas (http://www.rtog.org//corelab/contouringatlases/hippocampalsparing.aspx), excluding any GTV

D100% (Dose to 100% volume) ≤ 9Gy

Dmax ≤16Gy

Dmax ≤33Gy^a

D100% ≤ 10Gy

Dmax ≤17Gy

Dmax ≤44Gy^ab

Dmax to 0.03 cc

Hippocampal Avoidance Zone (HAZ)

Hippocampus + 5 mm isotropic margins

–

–

For plan optimization

Left & Right Optic chiasm

–

Dmax ≤33Gy

Dmax ≤37.5Gy^b

Dmax ≤40Gy^ab

Dmax to 0.03 cc

Left & Right Optic nerve

–

Dmax ≤33Gy

Dmax ≤35Gy^b

Dmax to 0.03 cc

Left & Right Orbits

–

Dmax ≤33Gy

Dmax ≤35Gy^b

Dmax to 0.03 cc

Left & Right Lens

–

Dmax ≤6Gy

Dmax ≤10Gy^b

Dmax to 0.03 cc

Brain Stem

–

Dmax ≤33Gy

Dmax ≤37.5Gy^b

Dmax ≤40Gy^ab

Dmax to 0.03 cc

Left & Right

Cochlear

–

Dmax ≤33Gy

Dmax ≤35Gy^a

Dmax to 0.03 cc

Brain

Brain parenchyma down to cranial margin of dens

30Gy

–

–

PTV_Brain

(Brain + 3 mm isotropic margins) – (GTVall_5mm^b + HAZ)

95% of volume covered by 30Gy

D2% ≤ 37.5Gy

D98% (Dose to 98% of volume) ≥ 25Gy

90% of volume covered by 30Gy

D98% ≥ 22.5Gy^b

D2% ≤ 40Gy^b

–