Abstract: The embodiments disclose a device, method and system for assisting in the determination of one or more ablation regions for covering a target region to be ablated. The device comprises a processor configured to receive vascular structure information of vessels inside the target region and derive a parametric map for the target region based on the received vascular structure information, each value in the parametric map indicating a metric of a corresponding voxel of the target region to be inside the one or more ablation regions. The parametric map serves to assist in the determination of the one or more ablation regions.