IMRT Course 2016

Unknown late effects

• Increased peripheral dose:

• 0.12% prescribed dose

• Less with 6MV vs 15MV

• Clinical consequence unclear

• Second cancer risk

• Absolute risk 1.75% at 10 years compared

with 1% for 3D-CRT

• Due to increased low dose volume (0.5%)

and MU (0.25%)

• Higher energy worse; <1% absolute increase

risk

Salz et al 2012, Hall et al 2003, Zwahlen et al 2009