Needle-stability maps for brain-tumor biopsies

Minimally invasive surgical procedures like biopsies require the insertion of a needle to reach a specific tissue from where samples are taken. This process is affected by a number of errors that can lead to a different needle pathway than originally planned. In the case of brain-tumor biopsies, these errors can be caused by the brain shifting when the skull is drilled, measurement errors due to the physical framework that supports the biopsy needle or some other human errors. To provide support for preoperative planning, we introduce the concept of a biopsy-needle stability-map. This map provides information on how stable a biopsy-needle pathway is. We also introduce an algorithm for finding the reachable points on the tumor border from one specific entry point. A technique for automatically selecting the needle pathway that offers the biggest minimal distance to any blood vessel is also presented. A 3D representation of the regions of interest (tumor, blood vessels) together with the needle pathway and the reachable points of the tumor has also been implemented. The resulting stability map visually represents, using color-coding, how close to any blood vessel the pathways surrounding the main one are.