IGRT 2016 Madrid

organs, specifically the reduction in the bla dicates the dosimetric effect of nonrigid var and normal organs and the necessity of adaptive planning modifications.

Online/Offline adaptation should not be acceptable clinically. Interfraction target (prostate and SV) deformation/rotation and intrafraction target motion were the major causes of the target dose reduction (26, 27) . Figure 2 shows the treatment dose deficits

3 strategies: 1. Daily online repositioning 2. Daily online replaning

A

%EUD of CTV

110.0%

100.0%

Daily Correction Online Planning Hybrid Adaptation

90.0%

80.0%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

B

%EUD of Rectal Wall

110.0%

Daily Correction Online Planning Hybrid Adaptation

100.0%

3. Hybrid

90.0%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

adaptation : Cumulative dose distribution on 5 post CBCT

C

%EUD of Bladder

50.0% 70.0% 90.0% 110.0%

Daily Correction Online Planning Hybrid Adaptation

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Fig. 1. The normalized equivalent uniform dose (EUD) of the clinical target volume (CTV), the rectal wall, of the individual patients for the 3 treatment techniques.

Qin A, Yan D IJROBP 2015

03/01/13