Penetrating effect of high-intensity infrared laser pulses through body tissue

Han, Danhong; Xu, Jingjing; Wang, Zhenhai; Yang, Nana; Li, Xunzhou; Qian, Yufeng; Li, Ge; Dai, Rujun; Xu, Shengyong

doi:10.1039/c8ra05285a

Cited by 26 publications

(35 citation statements)

References 78 publications

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“…Further, transmittance of both high and LF type pulsed lasers passing through chicken samples are also about 2-times greater than through beef samples. This observation corroborates with the trend of increased transmission as one moves from mainly muscular tissue to mainly fatty tissue [31].…”

Section: Discussionsupporting

confidence: 87%

Higher pulse frequency of near-infrared laser irradiation increases penetration depth for novel biomedical applications

et al. 2021

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Background The clinical efficiency of laser treatments is limited by the low penetration of visible light used in certain procedures like photodynamic therapy (PDT). Second Harmonic Generation (SHG) PDT is an innovative technique to overcome this limitation that enables the use of Near Infrared (NIR) light instead of visible light. NIR frequency bands present an optical window for deeper penetration into biological tissue. In this research, we compare the penetration depths of 405 and 808 nm continuous wave (CW) lasers and 808 nm pulsed wave (PW) laser in two different modes (high and low frequency). Methods Increasing thicknesses of beef and chicken tissue samples were irradiated under CW and PW lasers to determine penetration depths. Results The 808 nm CW laser penetrates 2.3 and 2.4 times deeper than the 405 nm CW laser in beef and chicken samples, respectively. 808 nm PW (pulse frequency—500 Hz) penetrates deeper than CW laser at the same wavelength. Further, increasing the pulse frequency achieves higher penetration depths. High frequency 808 nm PW (pulse frequency—71.4 MHz) penetrates 7.4- and 6.0-times deeper than 405 nm CW laser in chicken and beef, respectively. Conclusions The results demonstrate the higher penetration depths of high frequency PW laser compared to low frequency PW laser, CW laser of the same wavelength and CW laser with half the wavelength. The results indicate that integrating SHG in the PDT process along with pulsed NIR light may allow the treatment of 6–7 times bigger tumours than conventional PDT using blue light.

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Section: Discussionsupporting

confidence: 87%

Higher pulse frequency of near-infrared laser irradiation increases penetration depth for novel biomedical applications

et al. 2021

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“…Figure 2c shows our Pd-Cr TFTC devices made on a 400-nm-thick freestanding Si 3 N 4 thin film window. The Pd-Cr TFTC made with the same process parameter of Pt-Cr TFTC was used to measure the Medical laser by our teammates, instead of Pt-Cr TFTC, and significant results were referred here to confirm the high temperature reliability of this type device [47]. With irradiation at the focal point of a 79 mW (power), 785 nm (wavelength) laser for 2 s, two Pd-Cr junctions were burnt (highlighted with white arrows).…”

Section: Resultsmentioning

confidence: 99%

Measurement and Evaluation of Local Surface Temperature Induced by Irradiation of Nanoscaled or Microscaled Electron Beams

et al. 2019

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Electron beams (e-beams) have been applied as detecting probes and clean energy sources in many applications. In this work, we investigated several approaches for measurement and estimation of the range and distribution of local temperatures on a subject surface under irradiation of nano-microscale e-beams. We showed that a high-intensity e-beam with current density of 105-6 A/cm2 could result in vaporization of solid Si and Au materials in seconds, with a local surface temperature higher than 3000 K. With a lower beam intensity to 103-4 A/cm2, e-beams could introduce local surface temperature in the range of 1000–2000 K shortly, causing local melting in metallic nanowires and Cr, Pt, and Pd thin films, and phase transition in metallic Mg-B films. We demonstrated that thin film thermocouples on a freestanding Si3N4 window were capable of detecting peaked local surface temperatures up to 2000 K and stable, and temperatures in a lower range with a high precision. We discussed the distribution of surface temperatures under e-beams, thermal dissipation of thick substrate, and a small converting ratio from the high kinetic energy of e-beam to the surface heat. The results may offer some clues for novel applications of e-beams.

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“…The etching was performed at 40 °C in a water bath via the floating technique [65,66]. The total etching period took around 65 min for the sword-shaped probes to thoroughly separate from the substrate.…”

Section: Methodsmentioning

confidence: 99%

Multifunctional Freestanding Microprobes for Potential Biological Applications

Yang

Wang

et al. 2019

Sensors

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Deep-level sensors for detecting the local temperatures of inner organs and tissues of an animal are rarely reported. In this paper, we present a method to fabricate multifunctional micro-probes with standard cleanroom procedures, using a piece of stainless-steel foil as the substrate. On each of the as-fabricated micro-probes, arrays of thermocouples made of Pd–Cr thin-film stripes with reliable thermal sensing functions were built, together with Pd electrode openings for detecting electrical signals. The as-fabricated sword-shaped freestanding microprobes with length up to 30 mm showed excellent mechanical strength and elastic properties when they were inserted into the brain and muscle tissues of live rats, as well as suitable electrochemical properties and, therefore, are promising for potential biological applications.

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Penetrating effect of high-intensity infrared laser pulses through body tissue

Abstract: Researchers have utilized infrared (IR) lasers as energy sources in laser therapy for curing skin diseases and skin injuries with remarkable effects.

Cited by 26 publications

References 78 publications

Higher pulse frequency of near-infrared laser irradiation increases penetration depth for novel biomedical applications

Higher pulse frequency of near-infrared laser irradiation increases penetration depth for novel biomedical applications

Measurement and Evaluation of Local Surface Temperature Induced by Irradiation of Nanoscaled or Microscaled Electron Beams

Multifunctional Freestanding Microprobes for Potential Biological Applications

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