Radiobiology 2016

1/03/2016

Lung • Retreatment tolerance of the mouse lung

Initial dose <50% tolerance: full recovery , 2 months Higher initial doses: partial recovery , 3 months Only applies for pneumonitis phase: retreatment tolerance fibrosis might be poorer

pneumonitis

14

treatment alone

12

post 6 Gy

10

post 8 Gy

Retreatment-LD50 (Gy) 6 8

post 10 Gy

Terry Int J Radiat Oncol Biol Phys 1988

0

1

2

3

4

5

6

Time after first treatment (months)

19

Kidney • Retreatment tolerance mouse kidney

10 12 14

No recovery between 1 day and 6 months after initial treatment Progression of (subclinical) damage Retreatment tolerance decreases with time Extreme caution when re-irradiating kidneys!

6.5 mo post 6 Gy

Stewart Int J Radiat Oncol Biol Phys 1989

Reduced kidney function 0 2 4 6 8

2 wks post 6 Gy

treatment alone

Reirradiation dose (Gy) 0 2 4 6 8 10 12 14 16

20

10