Physics Bucharest 2017

Blurring → ‘unsharpened’ dose distribution

• Averaging or smearing of the dose distribution near beam edges → increased beam penumbra → loss in dose homogeneity and conformity • The amount of blurring depends on the amplitude and the characteristics of the motion and on the “sharpness” (inhomogeneity) of the static dose distribution • Worst for IMR/PT → margin reduction

25%

McCarter&Beckam, PMB (45) 2001