876 / 1359
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Dose and monitor unit calculation
Dublin 2018
Measured
Calculated
Type
Dose (Gy)
MU (Dose/MU)
meas
Dose MU
(Dose/
MU)
calc
d(i) /d%(i)
5x5
Open
0.557
100
0.00557
1.00 184.78 0.00541
0.971 / -2.9%
60º
Wedge
0.152
100
0.00152
1.00 677.73 0.00148
0.969 / -3.1%
10x10
Open
0.614
100
0.00614
1.00 165.46 0.00604
0.984 / -1.6%
60º
Wedge
0.173
100
0.00173
1.00 579.46 0.00173
1.000 / 0.0%
20x20
Open
0.673
100
0.00673
1.00 149.80 0.00668
0.993 / -0.7%
60º
Wedge
0.197
100
0.00197
1.00 527.66 0.00189
0.964 / -3.6%
30x30
Open
0.694
100
0.00694
1.00 145.35 0.00688
0.991 / -0.9%
60º
Wedge
0.206
100
0.00206
1.00 509.46 0.00196
0.951 / -4.9%
5x20
Open
0.597
100
0.00597
1.00 168.16 0.00595
0.997 / -0.3%
60º
Wedge
0.167
100
0.00167
1.00 593.02 0.00169
1.010 / +1.0%
20x5
Open
0.589
100
0.00589
1.00 172.77 0.00579
0.983 / -1.7%
60º
Wedge
0.164
100
0.00164
1.00 622.97 0.00162
0.979 / -2.1%
Data from point measurements using an ionization chamber positioned at 20 cm depth along
the central beam axis in a large water phantom, source-skin distance 90 cm, irradiated with a
beam of 18 MV x-rays.