Noninvasive optoacoustic temperature determination at the fundus of the eye during laser irradiation

Schuele, Georg and Huttmann, Gereon and Framme, Carsten and Roider, Johann and Brinkmann, Ralf (2004) Noninvasive optoacoustic temperature determination at the fundus of the eye during laser irradiation. JOURNAL OF BIOMEDICAL OPTICS, 9 (1). pp. 173-179. ISSN 1083-3668, 1560-2281

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Abstract

In all fundus laser treatments of the eye, the temperature increase is not exactly known. In order to optimize treatments, an online temperature determination is preferable. We investigated a noninvasive optoacoustic method to monitor the fundus temperature during pulsed laser irradiation. When laser pulses are applied to the fundus, thermoelastic pressure waves are emitted, due to thermal expansion of the heated tissue. Using a constant pulse energy, the amplitude of the pressure wave increases linearly with an increase in the base temperature of between 30 and 80degreesC. This method was evaluated in vitro on porcine retinal pigment epithelium (RPE) cell samples and clinically during selective RPE treatment with repetitive microsecond laser pulses. During the irradiation of porcine RPE with a neodymium-doped yttrium (Nd:YLF) laser (527 nm, 1.7 mus, 500 Hz repetition rate, 160 mJ/cm(2)) an increase in the base temperature of 30+/-4degreesC after 100 pulses was found. During patient treatments, a temperature increase of 60+/-11degreesC after 100 pulses with a 500-Hz repetition rate and 7+/-1degreesC after 30 pulses with 100 Hz at 520 mJ/cm(2) was found. All measured data were in good agreement with heat diffusion calculations. Optoacoustic methods can be used to noninvasively determine retinal temperatures during pulsed laser treatment of the eye. This technique can also be adapted to continuous-wave photocoagulation, photodynamic therapy and transpupillary thermotherapy, or other fields of laser-heated tissue. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

Item Type: Article
Uncontrolled Keywords: SUBFOVEAL CHOROIDAL NEOVASCULARIZATION; MACULAR DEGENERATION; PHOTOCOAGULATION; ULTRASOUND; THERAPY; LIQUIDS; DAMAGE; RETINA; photocoagulation; retinal pigment epithelium; selective microphotocoagulation; optoacoustic; thermoelastic expansion; selective retinal pigment epithelium treatment
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Lehrstuhl für Augenheilkunde
Depositing User: Dr. Gernot Deinzer
Date Deposited: 23 Jul 2021 10:24
Last Modified: 23 Jul 2021 10:24
URI: https://pred.uni-regensburg.de/id/eprint/38183

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