2392-2393 / 3107
Example: Single posterior beam spine
Fixed SSD
at 100cm, single field
8cm*15cm
,
Prescription: Single fraction
8Gy
, prescribed
at 7cm
depth.
Basic Dose Caculation
Principles 2012
“
Willow
”
6MV PDD* Output
Depth
Equivalent Square Field Size (cm)
(cm)
4
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
9.5 10 10.5
Dmax (1.5) 93.6 94.5 95.4 95.7 95.9 96.6 97.3 97.7 98.2 98.5 98.8 99.4 100.0 100.2
2.0
92.7 93.7 94.7 94.8 94.8 95.5 96.1 96.6 97.1 97.4 97.7 98.3 99.0 99.1
2.5
90.5 91.5 92.6 92.8 93.0 93.5 94.1 94.6 95.1 95.4 95.8 96.3 96.9 97.1
3.0
88.0 89.1 90.1 90.4 90.7 91.2 91.8 92.3 92.8 93.2 93.6 94.3 95.0 95.2
3.5
85.8 86.9 88.0 88.3 88.7 89.2 89.8 90.3 90.8 91.2 91.6 92.1 92.6 93.0
4.0
83.7 84.7 85.7 86.0 86.3 87.0 87.7 88.2 88.6 89.1 89.5 90.2 90.8 91.1
4.5
81.3 82.2 83.1 83.6 84.2 84.9 85.6 86.1 86.5 87.0 87.4 88.0 88.6 89.0
5.0
79.1 80.0 80.8 81.5 82.2 82.8 83.4 84.0 84.5 84.9 85.4 86.0 86.7 87.0
5.5
76.7 77.9 79.0 79.3 79.6 80.5 81.3 81.9 82.4 82.8 83.3 84.0 84.7 84.9
6.0
74.7 75.6 76.5 77.2 77.8 78.5 79.1 79.7 80.3 80.9 81.6 82.1 82.5 82.8
6.5
72.5 73.6 74.7 75.2 75.7 76.6 77.4 77.9 78.4 78.8 79.2 79.9 80.5 80.8
7.0
70.5 71.5 72.5 73.1 73.7 74.4 75.1 75.8 76.4 76.9 77.3 77.8 78.4 78.8
7.5
68.3 69.5 70.7 71.2 71.6 72.4 73.2 73.8 74.3 74.8 75.3 76.1 76.8 77.1
8.0
66.4 67.5 68.5 69.2 69.8 70.5 71.2 71.9 72.6 72.9 73.3 74.1 74.8 75.1
8.5
64.5 65.6 66.6 67.3 67.9 68.6 69.3 70.0 70.7 71.1 71.5 72.2 72.9 73.2
9.0
62.5 63.6 64.8 65.4 66.1 66.7 67.4 68.1 68.7 69.1 69.5 70.3 71.1 71.4
9.5
60.8 61.9 63.0 63.5 64.1 64.8 65.5 66.2 66.9 67.5 68.0 68.6 69.2 69.5
10.0
58.8 59.9 61.1 61.7 62.3 63.1 63.8 64.5 65.1 65.6 66.1 66.8 67.5 67.9
10.5
57.1 58.3 59.5 60.0 60.4 61.2 62.1 62.7 63.2 63.8 64.4 65.0 65.6 65.9
11.0
55.5 56.6 57.7 58.2 58.7 59.5 60.4 61.0 61.6 62.2 62.8 63.4 64.0 64.4
11.5
53.9 55.0 56.0 56.5 57.1 57.9 58.8 59.4 60.1 60.6 61.1 61.6 62.2 62.7
12.0
52.3 53.4 54.4 55.0 55.6 56.3 57.1 57.7 58.4 58.9 59.4 60.1 60.8 61.2
=1017 MU
=10.4 cm
Calculated
Eq.Sq.