Patent ID: 8721660

Claim:
In a framebased stereotactic therapy system, a fiducial marker system for frameless imaging of a patient comprising a first unit and a second unit, wherein said first unit is patient affixable and configured to be secured directly to a bony anatomical structure of said patient during frameless imaging and framebased stereotactic therapy, and wherein said first unit comprises a partly spherical inner surface having a first center point, which partly spherical inner surface is adapted to receive a touch probe measurement head for measuring said spatial position of said first center point for said framebased stereotactic therapy, and partly spherical outer surface; and wherein said second unit comprises a circular tube filled with an agent detectable by an image modality and has a second center point, wherein said second unit is releasably attachable to said partly spherical outer surface of said first unit such that said first center point and said second center point are substantially identical; and wherein said outer surface of said first unit is configured to releasably receive said second unit for said frameless imaging.