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Radiotherapy
1: Day to day, random changes
Cervix
Bladder
Radiotherapy
Cervix cancer, classical approach
Uterus motion: large and depending on bladder filling
Cervix motion: smaller and depending on rectal filling
Margin proposals:
Taylor: 15, 15 and 7 mm
Chan et al:
(90% of the fractions within the PTV)
40 mm at fundus (top of uterus)
15 mm at cervix
90% for intrafraction (30 minutes)
only:
10 and 5 mm
Radiotherapy
Example of target outside PTV
“mover”
CT and CBCT week 1-5
Grey: Bladder
Black: CTV combined
White: - PTVuterus (CT)
- PTVcervix (CT)
Courtesy Peter de Ruyter and Monique Bloemers
Radiotherapy
Example of target inside PTV
“non-mover”
CT and CBCT week 1-5
Grey: Bladder
Black: CTV combined
White: - PTVuterus (CT)
- PTVcervix (CT)
Courtesy Peter de Ruyter and Monique Bloemers
Radiotherapy
Cervix plan of the day made easy
•Bondar et al IJROBP 2011
1 PTV
2 PTV’s
3 PTV’s
Radiotherapy
Cervix: back to the basics:
The Target
Still the most determining aspect of IGRT!