Cervix BT - 2016

 PDR brachytherapy :  repair between successive pulses (hours) and during the whole fraction (hours - days) is significant Mathematical Description / Repair Function T 1/2 ….. Half time for repair x ….. Time between pulses without irradiation t ….. Irradiation time ofr each pulse

. . .

pulse 1

pulse 2

pulse n

t

x

2 −−

1

t µ

n

nt e k enk k nk s µ − +

−

+

  

   tn sy ny µ 2

− − =

(

)

=

12

PDR g

(

) 2

t µ

t µ

1

−

ke

−

. . .

y T 1/2

21 T 2ln =µ

t e µ

− −= 1

x e k µ

− =

µ … repair rate T 1/2 irradiation time for each pulse x … time between pulses without irradiation n … number of equal pulses 2 T 1/2 4 6 1 h n h Repetition (starting point of pulse) n …. number of equal pulses . . . … half time for repair t …

0 h

time

. . .

8 Time [h]

BT-GYN Teaching Course

D. Berger