Radiobiology 2016

1/03/2016

Urinary bladder (mouse) • Original tolerance restored between 25-50 days

10 15 20 25 30 initial RT: 5x5.3 Gy / 5 d

First treatment: 5 × 5.3 Gy over 1 week Endpoint: 50% reduction in bladder storage capacity at 1–3 weeks post retreatment

Retreatment ED 50 (Gy)

retreatment alone

0 5

0

20

40

60

80 100 120

Time after first treatment (days)

15

Basic Clinical Radiobiology, 4th Ed, page 262; Satthoff & Dörr unpublished

Retreatment principles: early effects • Can achieve complete restoration of the initial tolerance • Epidermis: 2-3 months (rodents) • Oral mucosa: 12 days (but long term effects possible) • Restoration of the stem cell compartment may take longer than “morphological” recovery

16

8