Question regarding the expanded masks.

Dear organizers, I came across another topic that asked about the masked and it was told it expanded to limit the amount of area considered to be air. But isnt any part of the image that is not a brain essentially air? so why a non-dilated mask that tightly fit the brain, excluding any pixels outside the brain was not used?

Dear Abdullah,

Sure, outside the brain there is mostly air (a cushion is generally used, and along with other positioning devices sometimes). The body dilation is used to make sure that a model would be able to consistently represent the body contour. By adopting a tight mask, this border would have not been fully considered in the metrics/by the model.

Let me know whether you may have any other consideration.

Warm Regards,

Matteo

So its to insure that the results are realistic and that the model can actually differentiate between what is brain and what is not without relying on the sharp non dilated mask edges?

A model could behave consistently inside the body, but not around it. Keeping the dilation is one of the way to check how a model behave.

Whether a model is realistic or not in the body contour is up to what the participants will submit. For radiotherapy purposes, body contour is important, especially for proton planning.

Thanks for the clarification