From 'Microsoft Research Podcast - Machine Learning and the InnerEye for Cancer Treatment with Dr. Antonio Criminisi' (with other descriptions further on in the passage)

"And what the technology does is, analyzes those images, at a pixel-by-pixel level, to figure out exactly where the tumor is. But also, to do what’s called the delineation or contouring, of organs around the tumor. They are called organs-at-risk. And the reason why this is important is because, for instance, in radiation therapy, you need to instruct the machine that delivers the radiation, the therapy, to exactly where the target is, i.e., the tumor, but also the organs that need to be spared from nasty radiation. This is normally a process that is done manually, with somewhat archaic tools. And we can help, precisely in that area, to make the delineation, the contouring, and therefore, the radiotherapy planning, a lot quicker and also more cost-effective."

https://www.microsoft.com/en-us/research/podcast/machine-lea...

"détourage -
2. ARTS GRAPHIQUES. PHOT. Opération par laquelle on élimine ce qui constitue le fond de l'image pour mettre le sujet en valeur."
https://www.cnrtl.fr/definition/academie9/détourage