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Lessons Learned in Using Laser Interstitial Thermal Therapy for Treatment of Brain Tumors: A Case Series of 238 Patients from a Single Institution
摘要： Background: Laser interstitial thermal therapy (LITT) is a novel, minimally invasive alternative to craniotomy, and as with any new technology, comes with a learning curve. Objective: We present our experience detailing the evolution of this technology in our practice in one of the largest patient cohorts to date regarding LITT in neuro-oncology. Methods: We reviewed 238 consecutive brain tumor patients treated with LITT at our institution. Data on patient, surgery and tumor characteristics, and follow-up were collected. Patients were categorized into two cohorts: Early (<2014, 100 patients) and Recent (>2015, 138 patients). Median follow up for the entire cohort was 8.4 months. Results: The indications for LITT included gliomas (70.2%), radiation necrosis (21.0%), and metastasis (8.8%). Patient demographics stayed consistent between the two cohorts, with the exception of age (Early: 54.3, Recent: 58.4, p=0.04). Operative time (6.6 versus 3.5, p<0.001) and number of trajectories (53.1% versus 77.9% with 1 trajectory, p<0.001) also decreased in the Recent cohort. There was a significant decrease in permanent motor deficits over time (15.5 versus 4.4%, p=0.005) and 30-day mortality (4.1% versus 1.5%) also decreased (not statistically significant) in Recent cohort. In terms of clinical outcomes, poor preoperative KPS (≤70) were significantly correlated with increased permanent deficits (p=0.001) and decreased overall survival (p<0.001 for all time points). Conclusions: We observed improvement in operative efficiency and permanent deficits over time and also patients with poor preoperative KPS achieved suboptimal outcomes with LITT. As many other treatment modalities, patient selection is very important in this procedure.
关键词： Stereotactic Laser Ablation,Radiation Necrosis,Tumor,Glioblastoma,Glioma,Minimally-Invasive
更新于2025-09-23 15:19:57
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Laser-Induced Wettability Gradient Surface of the Aluminum Matrix Used for Directional Transportation and Collection of Underwater Bubbles
摘要： The control of underwater bubble behavior on a solid surface has great research significance. However, the control of the spontaneous directional transport and collection of numerous underwater bubbles remains a challenge. A new technique of a metal mesh with superhydrophobic/hydrophobic properties is demonstrated here, which creates a wettability gradient coupled with a microporous array by means of pulsed fiber laser ablation and chemical modification of the aluminum sheet. The resultant wettability surface effectively achieved the spontaneous movement of bubbles along the directional wettability gradient (superaerophobicity to aerophilicity) and through the metal mesh (aerophilicity to superaerophilicity) in the direction of decreasing free energy. Theoretical analysis accounted first for the spontaneous sliding of bubbles on the wettability gradient surface as a result of the action of an unbalanced surface tension force and second for the spontaneous transition of bubbles from the aerophilic to superaerophilic side as a result of the combined action of Laplace pressure and buoyancy. A device with the capability of directional transportation and collection of underwater bubbles was designed based on the samples with a wettability gradient and a superhydrophobic/hydrophobic microporous array as the core components. The potential application is laser ablation of wettability gradient surfaces and metal mesh with superhydrophobic/hydrophobic properties for directional transportation and collection of underwater bubbles.
关键词： wettability gradient,collection,directional transportation,underwater bubbles,laser ablation
更新于2025-09-23 15:19:57
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Efficacy of cellulose paper treated with Cu and Ag oxide nanoparticles synthesized via pulsed laser ablation in distilled water in the annihilation of bacteria from contaminated water
摘要： In the present work, nanoparticles of copper and silver synthesized via pulsed laser ablation of the respective targets in distilled water are applied to cellulose filter paper to check their effectiveness in the annihilation of bacteria from contaminated water. The treatment of the filter paper with the nanoparticles is found to be an excellent way to get rid of two common bacteria, Staphylococcus aureus and Escherichia coli, from contaminated water. The spread plate method on agar, employed to test the antibacterial efficacy of the nanoparticle-treated papers, clearly shows the absence of bacterial growth upon coming into contact with the nanoparticles in the filter paper. These results were further substantiated by the growth kinetic study of the bacteria that exhibited slow growth of the bacteria that were exposed to the nanoparticles. The morphology of the bacteria that came into contact with the nanoparticles is found to be adversely affected by the nanoparticles. Both copper and silver nanoparticles show a similar extent of antibacterial activity.
关键词： antibacterial,cellulose filter paper,pulsed laser ablation,nanoparticles,contaminated water
更新于2025-09-23 15:19:57
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[Laser Institute of America ICALEO?? 2014: 33rd International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - San Diego, California, USA (October 19a??23, 2014)] International Congress on Applications of Lasers & Electro-Optics - Laser ablation cutting of thin silicon subtrates with tunable ultra-short pulsed lasers from 200FS-10PS
摘要： In this paper the influence of the pulse duration in a range of 200 fs up to 10 ps on the cutting process of thin silicon is investigated. The experiments are carried out with a Light Conversion Pharos with various pulse duration between 190 fs and 10 ps. The laser is operated at the second harmonic wavelength of 515 nm and a repetition rate of 200 kHz. Although the ablation threshold, which is determined with the method of Liu [1], amounts 0.27 J/cm2 for 0.2, 1 and 10 ps, one can find extremely different ablation behavior during the cutting experiments. It turns out that independent from pulse energy and pulse overlap the shortest pulse duration at 200 fs leads to a deeper cutting depth and furthermore to a higher cutting speed. This difference can be explained with higher pulse peak intensities and shorter interaction time between laser and material for the 200 fs pulse duration. Nevertheless the general ablation geometry is very similar for all tested pulse durations. We explain this with a simple geometric model. This model considers the projection from a Gaussian beam profile in an existing cutting kerf.
关键词： cutting process,laser ablation,ultra-short pulsed lasers,pulse duration,thin silicon substrates
更新于2025-09-23 15:19:57
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Morphological characteristics of nanoholes induced by single-shot femtosecond laser ablation of borates and aluminate silicates
摘要： Single-shot femtosecond laser ablation experiments with linearly and circularly polarized light were conducted in order to investigate the morphological characteristics of surface nanostructures in lithium borate crystals and glasses, a strontium borate crystal, lanthanide containing borate crystals, and aluminate silicate crystals: Li2B4O7 (LTB) and LiB3O5 (LBO) crystals and Li2O?2B2O3 (LTB) and Li2O?3B2O3 (LBO) glasses; SrB4O7 (SBO) crystal; Li6Gd(BO3)3 (LGB) and LaSc3(BO3)4 (LSB) crystals; and Ca2Al2SiO7 (CAS) and CaSrAl2SiO7 (CSAS) crystals. In the present study, the material and laser polarization dependance of the morphology of nanoholes was examined in these crystals and glasses. A single nanohole or two holes (a primary hole and a secondary hole) were observed in the borate and aluminate silicate crystals. The size of the nanohole is not restricted by the diffraction limit but instead is dependent on the laser fluence and the materials. It is suggested that the formation of these secondary nanoholes in the studied crystals is attributed to a spontaneous reshaping of the incoming Gaussian pulse into a Gaussian–Bessel pulse. In the LTB and LBO crystals, nanoholes (both primary and secondary holes) with subwavelength sides exhibit a quadrilateral (approximately square or rectangular) morphology, regardless of linear or circular polarization. The sides of the quadrilateral nanoholes lie approximately in the {h h 0} planes on the LTB crystal and in the ({h 0 0} and {0 0 l}) planes on the LBO crystal. We found that the nanohole morphology did not reflect the spatial distribution of the laser intensity. These phenomena were the first observations on the anisotropic morphology of nanoholes. These morphologies do not correspond to the circular symmetric pattern of the Gaussian intensity distribution of the incoming laser beam. This is contrary to the expectations based on the generally accepted laser ablation mechanism. The quadrilateral nanoholes could be an inherent morphology in the LTB and LBO crystals. The morphology of the network structure in their quadrilateral holes in the LTB and LBO crystals is considered to reflect the continuous BO3 and/or BO4 3? 5? respective tetragonal or orthorhombic unit cells, in which self-tapped excitons are formed in an initial process under multiphoton excitation. In contrast, the SBO, LGB, LSB, CAS, and CSAS crystals and the LTB and LBO glasses exhibit circular nanoholes with subwavelength diameters independent of the laser polarization, the structure, or the composition. The isotropic morphology of nanoholes in these samples reflects the circular pattern of the Gaussian intensity profile of the focused laser beam.
关键词： borate,single pulse,aluminosilicate,scanning electron microscopy,crystal structure,nanohole morphology,femtosecond laser ablation,nanostructuring
更新于2025-09-23 15:19:57
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Iron Oxide Nanopowders Obtained via Pulsed Laser Ablation, for Supercapacitors
摘要： Nano-sized magnetite powders with addition of iron nitrides were synthesized via pulsed laser ablation (PLA) of an iron target in atmospheric air. A series of iron oxide nanopowders with various phase compositions (ranging from magnetite to hematite) and structures (from 2D lamellas and spherical nanoparticles to continuous 3D structures) were prepared via heat treatment of the initial (as-synthesized) powder at temperatures in the range 200–500°C. The powders were introduced into the composition of carbon paste electrodes (CPEs). The capacitive characteristics of the electrodes prepared were studied in comparison to a commercial electroexplosive iron oxide powder. The capacitances of electrodes were matched to the structural characteristics of the materials and their phase compositions. With the chosen electrode-preparation method, the powder heat-treated at 500°С (sample Fe/500) showed the highest capacitance. The potential of the studied ultrafine materials based on ablative iron oxide was shown for use in electrodes for supercapacitors.
关键词： supercapacitor,specific capacitance,pulsed laser ablation,iron oxides,nanopowder
更新于2025-09-23 15:19:57
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Advantages and Limitations of Laser-Assisted Mass Spectrometry for the Local Determination of the Trace Element Composition of Fluid Inclusions in Quarzites in the Bural-Sardyk Deposit (Vostochny Sayan, Buryatia)
摘要： The effect of laser radiation on the surface and volume of natural quartz of the Bural-Sardyk deposit (East Sayan, Buryatia) is studied. The influence of the main parameters of laser radiation with a wavelength of 213 nm (prefix NWR-213) and the properties of the sample on the results of elemental mass spectrometric analysis with inductively coupled plasma are established. The features of laser ablation of various microinclusions in quartz are considered. The main problems arising from the laser evaporation of fluid inclusions in quartzites for the quantitative determination of their chemical composition are indicated.
关键词： superquartzite,fluid inclusions,LA-ICP-MS,inductively coupled plasma mass spectrometry,laser ablation,quartz
更新于2025-09-23 15:19:57
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Preparation of Silver Nanoparticles Dispersed in Almond Oil Using Laser Ablation Technique
摘要： Nanoparticle production by pulsed laser ablation (PLA) is a process that can generate pure nanoparticles (NPs) straight from a varied range of bulk substances and compounds. Silver nanoparticles (Ag NPs) are probably one of the most attractive noble metal nanostructures because of their unique and interesting physical and chemical properties. In this study, laser ablation of pure silver plate immersed in almond oil was carried out for Ag NPs production. Nd: Yag laser of wavelength 1064 nm, was used for the ablation of the Ag plate at different laser energies and ablation times. The almond oil permitted the formation of Ag NPs with a stable and homogeneity particle diameter in a reasonable time. The size distribution of the NPs was examined by High-Resolution Transmission Electron Microscopy (HRTEM). The particle sizes of the produced Ag NPs at laser energy 200 mJ in the solution at 10,15 and 20-min ablation times were 4.82, 3.11 and 1.82 nm respectively. The particle sizes of Ag NPs produced at different laser energies 150,200 and 250 mJ and at ablation time 10 min inside the solution were 5.39,4.82 and 1.92 nm respectively. The absorption peaks of the produced nanoparticles have been characterized using a UV-Vis spectrophotometer.
关键词： Laser ablation,almond oil,metal nanoparticle
更新于2025-09-23 15:19:57
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Progress in Endovenous Pulsed Laser Ablation
摘要： Continuous-wave (CW) lasers have been commonly used for endovenous laser ablation (EVLA). However, as some undesired side effects such as postoperative pain and bruising occasionally happens, longer laser wavelength and specially-fabricated laser fibers have been developed. On the other hand, the pulsed-wave (PW) laser, which has a heat production control by thermal relaxation, is independently developed for EVLA. This article discusses the implication of PW laser in EVLA from a theoretical point of view and a newly-developed micropulsation (MP) is introduced as a new concept. Since the MP yields adequate blood and vein wall heat degeneration by microseconds laser emission, efficacy and safety are improved compared with CW laser or conventional PW laser. Initial clinical outcome is favorable and promising for painless EVLA using inexpensive bare fiber.
关键词： varicose vein,thermal relaxation time,micropulsation,endovenous laser ablation,clear tip mode
更新于2025-09-23 15:19:57
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Structural Analysis of Nanoparticles Formed via Laser Ablation of Porous Silicon and Silicon Microparticles in Water
摘要： Silicon nanoparticles with sizes of 50–300 nm have been formed via picosecond laser ablation of porous silicon and silicon microparticles in water using various targets. Raman spectroscopy has revealed the presence of a low amount of the amorphous phase in the obtained particles (10–12%) prepared from micro- and mesoporous silicon layers and almost a zero degree of crystallinity in the case of laser fragmentation of silicon micropowders in water. The results are promising for further application of the nanoparticles in photonics and biomedicine.
关键词： silicon nanoparticles,laser ablation,Raman scattering
更新于2025-09-23 15:19:57