780 / 1119
BT-GYN Teaching Course
D. Berger
PDR brachytherapy :
repair between successive pulses (hours) and during
the whole fraction (hours - days) is significant
(
)
−
− =
tn
sy ny
t
PDR g
µ
µ
2
12
t
e
y
µ
−
−=
1
x
e k
µ
−
=
(
)
2
1
2
1
t
nt
n
t
ke
e k enk k nk s
µ
µ
µ
−
− +
−
−
+
−−
=
21
T
2ln
=µ
µ
… repair rate
T
1/2
…
half time for repair
t …
irradiation time
for each pulse
x …
time between pulses
without irradiation
n …
number of equal pulses
2
T
1/2
4
6
8 Time [h]
. . .
Mathematical Description / Repair Function
. . .
1 h
n h
time
0 h
pulse 1
pulse 2
pulse n
T
1/2
….. Half time for repair
x
….. Time between pulses without irradiation
t
….. Irradiation time ofr each pulse
Repetition (starting point of pulse) n …. number of equal pulses
. . .
. . .
x
t
T
1/2