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1. I need to be efficient, angular discretization
•
discretization artifacts or “rays”: an artificial buildup of particle fluence along the finite
number of directions used
with high gradients of scatter fluence, at points where primary dose is small
with N
directions
& voxel size at the expense of calculation time and potential volume
averaging
3 4 5 6 7 8 9 10
Away, cm
-10
-8
-6
-4
-2
0
2
4
6
8
10
-2.5 %
-1.5 %
-0.5 %
0.5 %
1.5 %
2.5 %
3.5 %
4.5 %
3 4 5 6 7 8 9 10
Away, cm
-10
-8
-6
-4
-2
0
2
4
6
8
10
3 4 5 6 7 8 9 10
Away, cm
-10
-8
-6
-4
-2
0
2
4
6
8
10
Along, cm
Figure from: Venselaar, Baltas, Meigooni,
Hoskin (Eds), Comprehensive
Brachytehrapy: physical and clinical
aspects. CRC Press, Taylor & Francis, ©
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360
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