Plasma-mediated ablation of brain tissue in liquid media and applicationin stereotactic laser neurosurgery,

摘要

Abstract: The application of focused picosecond laser pulses in stereotactic neurosurgery requires the knowledge of ablation efficiency and quality in consideration of clinical practice. In neurosurgical operations the laser beam must be guided through a thin endoscopic probe, which can be inserted into the human brain and is equipped with a rinsing/aspiration system. Thus, the laser ablation must be performed within a surrounding of rinsing liquid. We performed in vitro ablation experiments with a two-stage picosecond Nd:YLF laser system at 1053 nm to investigate the effects of liquid media on the ablation efficiency and quality. Ablations of fresh bovine tissue within a surrounding of distilled water and physiological saline, respectively, showed a nearly linear dependency of ablation depth on applied energy. The tissue residuals. The diameters of single ablation fragments were measured to be less than 50 $mu@m. Following these results and taking into account the absorption of physiological saline, we designed the focusing optics as well as the aspiration channels inside the stereotactic laser probe. We also present the working principle and main system parameters of the stereotactic laser probe and describe the assigned operating strategy. !7