Advanced Physics for Brachytherapy 2018

Effect of uncertainties on observed dose response relationships

Comparison of model dose response curve (based on published curves, see previous slides), and simulated „observed“ dose response curves assuming different systematic and random uncertainties.

random dosimetric uncertainty e.g. rectum D 2cm³

systematic dosimetric uncertainty e.g. rectum D 2cm³

( ± 10, ± 20, ± 30 % / fx)

(+3,+5,+10,+15 % / fx)

100%

100%

90%

90%

80%

80%

70%

70%

60%

60%

50%

50%

40%

Response NTCP

40% Response TCP

30%

30%

20%

20%

10%

10%

0%

0%

45

65

85

105

125

145

165

45

65

85

105

125

145

165

Dose (Gy EQD2)

Dose (Gy EQD2)

n=10000 patients per dose level, total dose = 45Gy EBRT + 4 fx BT (equal PD for each fx) model based on Georg er al. 2012, IJROBP

Nesvacil et al., ESTRO33, 2014