Table 1.

Prometheus PTV and rectal wall dose constraint guidelines. Total Dose (TD) was either 19 or 20 Gy

PROMETHEUS trial dose constraints
Structure	Per‐protocol	Minor variation	Major variation
CTV D98	>100% TD	95–100% TD	<95% TD
PTV D50	<105% TD	105–110% TD	>110% TD
PTV D90	>100% TD	95–100% TD	<95% TD
PTV D95	>95% TD	90–95% TD	<90% TD
PTV D99	>16 Gy	15–16 Gy	<15 Gy
PTV Dmax to 0.1 cc	<110% TD	110–120% TD	>120% TD
PTV Dmax	Not in OAR		In OAR
Rectal Wall Dmax to 0.1 cc	<17 Gy	17–17.5 Gy	>17.5 Gy
Rectal Wall V16 Gy	<0.5 cc	0.5–1 cc	>1 cc
Rectal Wall V14 Gy	<3 cc	3–5 cc	>5 cc
Rectal wall V12 Gy	<30% TD	30–40% TD	>40% TD
Rectal wall V10 Gy	<40% TD	40–50% TD	>50% TD
Rectal wall V8 Gy	<60% TD	60–70% TD	>70% TD

CTV, clinical target volume; PTV, planning target volume; TD, total dose; Gy, dose in grey; V, structure volume.