  A myriad of algorithms for the automatic analysis of brain MR images is
available to support clinicians in their decision-making. For brain tumor
patients, the image acquisition time series typically starts with a scan that
is already pathological. This poses problems, as many algorithms are designed
to analyze healthy brains and provide no guarantees for images featuring
lesions. Examples include but are not limited to algorithms for brain anatomy
parcellation, tissue segmentation, and brain extraction. To solve this dilemma,
we introduce the BraTS 2023 inpainting challenge. Here, the participants' task
is to explore inpainting techniques to synthesize healthy brain scans from
lesioned ones. The following manuscript contains the task formulation, dataset,
and submission procedure. Later it will be updated to summarize the findings of
the challenge. The challenge is organized as part of the BraTS 2023 challenge
hosted at the MICCAI 2023 conference in Vancouver, Canada.
