Purpose#R##N#Patient immobilization and X-ray-based imaging provide neither a convenient nor a very accurate way to ensure low repositioning errors or to compensate for motion in cranial radiotherapy. We therefore propose an optical tracking device that exploits subcutaneous structures as landmarks in addition to merely spatial registration. To develop such head tracking algorithms, precise and robust computation of these structures is necessary. Here, we show that the tissue thickness can be predicted with high accuracy and moreover exploit local neighborhood information within the laser spot grid on the forehead to further increase this estimation accuracy.
['Tobias Wissel', 'Patrick Stüber', 'Benjamin Wagner', 'Ralf Bruder', 'Achim Schweikard', 'Floris Ernst']
Enriching 3D optical surface scans with prior knowledge: tissue thickness computation by exploiting local neighborhoods