Gynae BT 2017

Anorectum

Empty the rectum at EBRT simulatio Avoid systematic error in PTV coverage Delineate Rectum + contents

Recto-sigmoid junction

Where rectum looses round shape in axial plane & loops anteriorly to connect with sigmoid colon Commonly: close to inferior level of SI joints.

EBRT

Ano-rectal sphincter

Use metallic marker at anal verge. Commonly: bottom of ischial tuberosities

From: RTOG atlas

Separate delineation of anus not specified…

Gay H, et al. Int J Radiat Oncol Biol Phys 2012;83(3):353-362.

http://www.rtog.org/CoreLab/ContouringAtlases/Anorectal.aspx Michalski 2010 IJROBP