Dose Course 2018_Flipping book
10
The widening of the pencil is limited
❑ The pencil-beam width (
❑ This is due to the reduction or loss of the number of electrons in the beam at large depths due to range straggling
MCS ) as a function of depth agrees well with experiment at small and moderate depths.
❑ Then it continues to increase, whereas in reality it goes through a maximum and finally decreases.
❑ This is managed by the g(x) function or has to be managed in other ways in some systems
From Handbook of Radiotherapy Physics Ed Mayles, Nahum and Rosenwald
Dublin 2018
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