Nanosecond, high‐intensity pulsed laser ablation of myocardium tissue at the ultraviolet, visible, and near‐infrared wavelengths: In‐vitro study

Abstract

At the laser intensity of approximately 2 GW/cm(2), ablation characteristics were drastically changed for the different laser wavelengths. The results indicated that for 266, 355, and 532 nm, the tissue removal was achieved mainly through a photothermal process, but for 266 nm the intense laser-induced plasma formation would result in a reduced laser energy coupling to the tissue. For 1064 nm, a photodisruption was most probable as a dominant tissue removal process. Because of the high ablation rate and limited thermal denaturation, the 355- and 1064-nm lasers could be potential laser sources for TMLR, although further investigation is needed to discuss the clinical issues.

Experimental study of laser–cheese interaction for making of thin cheese slices with complex shapes

“…Frequency-tripled or quadrupled Nd:YAG lasers at wavelengths of 355 and 266 nm have been used with ablation of different materials in the medical and biological applications (Diaz, Aguilar, Lavernia, & Wong, 2001;Katsura, Hirano, Matsuzawa, Yoshikawa, & Mizuno, 1998;Kilmer & Garden, 2000;Massicotte, Stewart, & Poppas, 1998;Sato, Ashida, et al, 2000;Sato, Ogura, et al, 2001). However, little study has been performed to understand the interaction between UV laser and cheese.…”

Modeling of Skin Tissue Ablation by Nanosecond Pulses From Ultraviolet to Near-Infrared and Comparison With Experimental Results

“…None of the photothermal and photochemical models, however, considers the possibility of ionization due to the light absorption by chromophores. The necessity of including chromophores ionization in the modeling of tissue ablation by nanosecond pulses is manifested from the very large rise in the local temperature within a chromophore that can be estimated from (11). Using the values of calculated irradiance thresholds and other parameters listed in Table I, one finds that the magnitude of is between to K from UV to NIR, much higher than the vaporization temperature of water under ambient pressure and thus the possibility of ionization must be taken into account.…”

“…For a single nanosecond laser pulse starting at , the energy deposited into a chromophore is determined by the laser fluence given by the time integral of the irradiance . Neglecting the temperature dependence of and , justified under the condition of inertial confinement, the local temperature within an illuminated chromophore can be found to be (11) where K is the ambient temperature. Combining, we find (12) One can observe that the wavelength dependence of the laser-induced chromophore ionization originates from that of the tissue absorption coefficient .…”

“…However, a clear understanding of the ablation mechanism for tissue ablation with nanosecond pulses of wavelengths ranging from UV to NIR can provide insights on the laser-tissue interaction in the strong field regime and may lead to new methods of tissue or pigment breakdown inside the tissue for the relatively large penetration depth afforded in the visible and NIR regions. [9] Recently, experimental studies have been published on soft tissue ablation by nanosecond laser pulses at multiple wavelengths from 1064 to 213 nm [10], [11].…”

A Novel Nanoparticle-Enhanced Photoacoustic Stimulus for Bone Tissue Engineering

“…The 10 min stimulation time per day was chosen based on other optical and ultrasound stimulation work reported in the literature. [24][25][26][27][28] The cells are held in a fixture approximately 20 cm above the optical table containing the laser. A 45°reflecting mirror below the fixture redirects the horizontal laser beam vertically upward, where it enters the bottom of the well.…”