Computer-guided laser probe for ablation of brain tumours with ultrashort laser pulses

A computer-guided laser probe has been developed for the application of ult rashort-pulsed lasers in neurosurgery. It is parr of a novel operation conc ept for the treatment of deep-seated brain rumours. The system combines the positioning accuracy of stereotactic or neuronavigated instruments with th e precise and therefore gentle characteristics of surgical lasers. The probe has an outer diameter of 5.5 mm and is directly inserted into the target volume. By a synchronized movement of three coaxial tubes, which gu ide the embedded optics, the laser radiation is focused at any time onto th e current tissue surface. Since every single laser pulse has only a small e ffective volume of about 8 x 10(5) mu m(3), the application of a large numb er of succeeding pulses can be adapted to required geometries. Tissue fragm ents are removed from the growing operation cavity by continuous irrigation and suction through the laser probe. Blood vessels are detected by a confo cal laser-scanning microscope, which is integrated into the probe, and can be closed by an additional coagulating laser. In this paper, the design and technical properties of the laser probe as we ll as its use in ablation and coagulation experiments are presented. A desc ription of the overall operation system is given.