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Proceedings Paper

Effect of vacuum and thermal shock on laser treatment of Trichophyton rubrum (toenail fungus)
Author(s): Guillermo Aguilar; Feng Sun; Pierre Carlier; Erica Young; David Hennings; F. Javier González
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Paper Abstract

The eradication of Trichophyton rubrum has been attempted via laser irradiation because it could result advantageous relative to current clinical therapies. Anticipating that the necessary thermal effects could unintentionally damage the underlying toe dermal layer, we have explored two auxiliary approaches: (a) laser irradiation under vacuum pressure, with and without water dousing and, (b) cooling followed by laser heating (thermal shock). The rationale is that at low pressures, the temperature necessary to achieve water evaporation/boiling is significantly reduced, thus requiring lower fluences. Similarly, a thermal shock induced by cooling followed by laser irradiation may require lower fluences to achieve fungus necrosis. For all experiments presented we use a Cooltouch, model CT3 plus, 1320 nm laser to irradiate fungi colonies. The vacuum pressure experiments exposed fungi colonies to a subatmospheric pressure of 84.7 kPa (25 inHg) with and without water dousing for 5 min, followed by irradiation with 4.0 J/cm2 fluence and 40-90 J total energies. The thermal shock experiments consisted of three sections at 4.8 J/cm2: cooling the fungus to 0 °C at 0.39 °C/min and then irradiating to 45-60 °C; cooling to -20 °C at 1.075 °C/min and irradiating to 45 °C; and cooling to -20 °C at 21.5 °C/min and irradiating to 45 °C. Fungus growth rate over a 1-week period assessed the feasibility of these procedures. Results indicated both approaches hamper the growth rate of fungi colonies relative to untreated control samples, especially water dousing under vacuum conditions and slow cooling rate preceding irradiation for thermal shock effect.

Paper Details

Date Published: 2 March 2010
PDF: 9 pages
Proc. SPIE 7548, Photonic Therapeutics and Diagnostics VI, 754805 (2 March 2010); doi: 10.1117/12.841056
Show Author Affiliations
Guillermo Aguilar, Univ. of California, Riverside (United States)
Feng Sun, Univ. of California, Riverside (United States)
Pierre Carlier, Ecole Nationale Supérieure D'Ingénieurs de Caen & Ctr. de Recherche (United States)
Erica Young, Univ. of California, Riverside (United States)
David Hennings, CoolTouch, Inc. (United States)
F. Javier González, CIACyT, Univ. Autónoma de San Luis Potosí (Mexico)

Published in SPIE Proceedings Vol. 7548:
Photonic Therapeutics and Diagnostics VI
Anita Mahadevan-Jansen; Andreas Mandelis; Brian Jet-Fei Wong; Nikiforos Kollias; Henry Hirschberg; Kenton W. Gregory; Reza S. Malek; E. Duco Jansen; Guillermo J. Tearney; Steen J. Madsen; Bernard Choi; Justus F. R. Ilgner; Haishan Zeng; Laura Marcu, Editor(s)

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