We propose a method for the creation of an anatomically and mechanically realistic brain phantom from polyvinyl alcohol cryogel (PVA-C) for validation of image processing methods for segmentation, re- construction, registration, and denoising. PVA-C is material widely used in medical imaging phantoms for its mechanical similarities to soft tis- sues. The phantom was cast in a mold designed using the left hemiphere of the Colin27 brain dataset [1] and contains deep sulci, a complete in- sular region, and an anatomically accurate left ventricle. Marker spheres and inflatable catheters were also implanted to enable good registration and simulate tissue deformation, respectively. The phantom was designed for triple modality imaging, giving good contrast images in computed tomography, ultrasound, and magnetic resonance imaging. Multimodal data acquired from this phantom are made freely available to the image processing community (http://pvabrain.inria.fr) and will aid in the validation and further development of medical image processing tech- niques.