Physics Bucharest 2017
Beam Modifiers Approximations
A line can be drawn from a sub- source through the MLC to the isocenter plane In the MLC this line is split up into many short intervals. For each end point of an interval it is determined whether the point falls inside or outside tungsten One simply sums the geometric path lengths X 1 and X 2 in the leaf material to apply an attenuation correction
X 1
X 2
yx e ,
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