457 / 1245
pencil kernel parameterization:
Math curiosity, goes to infinity when r->0.
e
e
,
z
z
a r
b r
z
z
A
B
p
r z
r
r
Dose on the main axis for a circular field of fluence
:
2
0 0
,
d
R
p
D z
r z r r
what happens when field size R goes to zero?
2
0 0
e
e
d
z
z
R
a r
b r
z
z
A
B
r r
r
r
1 e
1 e
2
z
z
a R
b R
z
z
z
z
A
B
a
b
Ahnesjö et al (1992)
Med Phys
19, 263-273