762-763 / 2239
A/a
3.E-03
4.E-03
From photon beam database
From TPR(20/10)
6 MV
Pencil beam kernel parameterization - 2
Double exponential, incl. depth parameterization, solely based on
TPR
20,10
(extracted from photon beam database)
T Nyholm, et al (2006)
Radiother Oncol 78
, 347-51.
B/b
9.E-04
1.E-03
0.E+00
1.E-03
2.E-03
0
10 20 30 40 50 60
Depth /cm
/cm
2
g
-1
a
0
5
10
15
20
0
20
40
60
Depth /cm
/cm
-1
b
0
0.04
0.08
0.12
0.16
0
10
20
30
40
50
60
Depth /cm
/cm
-1
From photon beam database
From TPR(20/10)
0.E+00
3.E-04
6.E-04
0
10
20
30
40
50
60
Depth /cm
/cm
2
g
-1
Corresponds to
primary dose (
R
=
∞
)
Corresponds to
scatter dose (
R
=
∞
)
R
scatter
(98%)=ln(0.02)/b
~ 33 cm
R
primary
(98%)=ln(0.02)/a
~ 1.3 cm
If one assumes that lateral
equilibrium is established
when one gets 98% of the
total dose on axis from a
field with infinite field size