Target Volume Determination 2015

Optic nerve tolerance & risk

Emami 1991 – (blindness within 5 years) Probably too conservative 5% risk 50 Gy 50% risk 65 Gy

Mayo 2010 – for 1.8 – 2.0 Gy/# 50 Gy = “near zero” incidence 3 – 7% risk 55 – 60 Gy (? 5% for 57.5 Gy)

(Tolerance might be lower with co-morbidity)

Emami B et al IJROBP 1991; 21: 109-122 Mayo C et al IJROBP 2010; 76(3 Suppl): S28–S35 (QUANTEC)