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Head scatter: equivalent square of a rectangular field
example of data
x
y
Sc
Meas.
c
e
Sc
Calc.
% diff
30
40
1.043
35.3
1.038
0.4%
5
40
0.999
10.6
1.003
0.3%
10
40
1.020
18.,3
1.026
0.6%
20
40
1.036
28.7
1.036
0.0%
5
30
0.998
10.1
1.000
0.2%
10
30
1.017
16.7
1.022
0.5%
10
20
1.012
14.3
1.016
0.4%
ELEKTA, Precise 6 MV
1.04
1.06
0.96
0.98
1.00
1.02
0
5
10
15
20
25
30
35
40
Sc(c
e
)
eq. square field size [cm]
rectangular fields
GE Saturne 43, 25 MV