The short pulse laser ablation have been extensively studied for confirmation and discussion of damage formation including estimations of damage thresholds and probabilities of surface machining. Irradiation examines by the femtosecond soft xray laser reveals formations of smooth craters on silica glass surfaces, and the appropriate selection of the laser wavelength can make the nanometer size modification on silicon surface in the vicinity of the damage threshold. On the other hand, we also revealed that damage thresholds and modification structures obtained by the picosecond soft x-ray laser irradiation provide the same results as the femtosecond soft x-ray laser. This means that not only femtosecond but also picosecond soft x-ray laser irradiation experiments can be contribute to deep understandings of the ablation phenomena.

Background: Dye-enhanced laser ablation (DLA) using a low-power diode laser for indocyanine green (ICG)-stained tissue has proven its effectiveness in dye-enhanced laser photocoagulation of retinal vessels or endoscopic surgical mucosectomy. We have applied DLA in hepatectomy and described its histological distinction in comparison with the cavitron ultrasonic surgical aspirator (CUSA). Methods: A diode laser (UDL-60 Laser unit, Olympus, Tokyo, Japan) with 810 ± 20 nm wavelength was employed for this study. The ICG dye (Diagnogreen^®, Daiichi Pharmaceutical, Tokyo, Japan) with a peak absorption wavelength at 800–810 nm was injected topically into the resection plane of the liver. The liver tissue was divided by touching the tip of the diode laser. Three different concentrations of ICG solution such as 2.0, 1.0 and 0.5 mg/ml were tested in the preliminary animal experiment. The use of a low-power diode laser at 10 W with an ICG concentration of 0.5 mg/ml was the appropriate combination for liver resection. In the clinical series, 27 hepatectomies were performed by DLA, and 10 with CUSA. Results: DLA demonstrated smooth cutting and good hemostasis in liver resection. Among the hepatectomy cases given DLA, no postoperative hemorrhage or bile leakage was noted. The postoperative hospital stay was significantly shorter in the DLA than the CUSA group. The cut surface of the liver was sealed microscopically with a layer of protein coagulum. Conclusions: A layer of protein sealant on the cut surface of the liver contributes to the short postoperative hospital stay when using DLA.

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