ESTRO 2024 - Abstract Book

S4233

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

Structure

Objective

DVH Parameters V95%_100%

Reference Plan

Scheduled Plan

P value

PTV PTV PTV

PTV1 PTV1 PTV1

99.87(0.14)

96.57(1.92)

.0042 .0178 .8972 .6889 .6315 .4592 .9515 .0540 .7870 .0645 .0175 .1615 .8125 .6875 .1694

Dmax

116.18(8.91)

118.72(10.36)

V105%_5%

4.40(2.75)

4.35(2.37)

Bladder

Dmean_35Gy

32.83(2.57)

33.17(3.21)

Bowel bag

V45Gy_195cm3

46.31(60.50)

43.77(48.47)

Reference Plan

Adapted Plan

PTV PTV PTV

PTV1 PTV1 PTV1

V95%_100%

99.87(0.14)

99.91(0.07)

Dmax

116.18(8.91)

116.20(9.00)

V105%_5%

4.40(2.75)

3.81(2.42)

Bladder

Dmean_35Gy

32.83(2.57)

33.17(2.48)

Bowel bag

V45Gy_195cm3

46.31(60.50)

44.04(60.25)

Adapted Plan

Delivered Plan

PTV PTV PTV

PTV1 PTV1 PTV1

V95%_100%

99.91(0.07)

99.53(0.35)

Dmax

116.20(9.00)

116.60(8.98)

V105%_5%

3.81(2.42)

3.90(2.27)

Bladder

Dmean_35Gy

33.17(2.48)

32.64(1.13)

Bowel bag

V45Gy_195cm3

44.04(60.25)

45.48(59.19)

Conclusion:

Our initial clinical experience with CBCT-based online adaptive radiotherapy showed improvement in target coverage with adaptive radiation therapy. The average time for adaptation was consistent with published data. There was no difference in planned and delivered dose due to intrafraction motion with average time of about 18 minutes between the scans. Our next step to see if the initial and delivered dosimetry would be maintained with reduction of PTV margin to 3 mm.

Keywords: Adaptive, Ethos, Intrafraction

1200

Digital Poster

Clinical introduction of a real-time MLC-tracking system for lung and prostate motion

André Haraldsson 1,2 , Emilia Persson 1 , Tobias Pommer 1 , Hedda Enocson 1 , Adalsteinn Gunnlaugsson 3 , Jens Engleson 3 , Per Munck af Rosenschold 1 1 Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden. 2 Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden. 3 Oncology, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden