TY - JOUR
T1 - Noninvasive optoacoustic online retinal temperature determination during continuous-wave laser irradiation
AU - Kandulla, Jochen
AU - Elsner, Hanno
AU - Birngruber, Reginald
AU - Brinkmann, Ralf
N1 - Funding Information:
This project was supported by grants from the German Ministry of Education and Research, BMBF (grant number 01EZ0311). The authors are grateful to the diploma students Carolin Hartert and Markus Hilmes for their experimental contributions to the project.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2006/7
Y1 - 2006/7
N2 - The therapeutic effect of most retinal laser treatments is initiated by a transient temperature increase. Although crucial to the effectiveness of the treatment, the temperature course is not exactly known due to individually different tissue properties. We develop an optoacoustic method to determine the retinal temperature increase in real time during continuous-wave (cw) laser irradiation, and perform temperature calculations to interpret the results exemplary for transpupillary thermotherapy (TTT). Porcine globes ex vivo and rabbit eyes in vivo are irradiated with a diode laser (λ=810nm, P≤3W, φ =2 mm) for 60 s. Simultaneously, pulses from a N2-laser pumped dye laser (λ = 500 nm, t=3.5 ns, E = 5 μ) are applied on the retina. Following its absorption, an ultrasonic pressure wave is emitted, which is detected by a transducer embedded in a contact lens. Using the previously measured temperature-dependent Grüneisen coefficient of chorioretinal tissue, a temperature raise in porcine eyes of 5.8 °C/(W/cm2) after 60 s is observed and confirmed by simultaneous measurements with an inserted thermocouple. In a rabbit, we find 1.4 °C/(W/cm2) with, and 2.2 °C/(W/cm2) without perfusion at the same location. Coagulation of the rabbit's retina occurs at AT =21 °C after 40 s. In conclusion, this optoacoustic method seems feasible for an in vivo real-time determination of temperature, opening the possibility for feedback control retinal laser treatments.
AB - The therapeutic effect of most retinal laser treatments is initiated by a transient temperature increase. Although crucial to the effectiveness of the treatment, the temperature course is not exactly known due to individually different tissue properties. We develop an optoacoustic method to determine the retinal temperature increase in real time during continuous-wave (cw) laser irradiation, and perform temperature calculations to interpret the results exemplary for transpupillary thermotherapy (TTT). Porcine globes ex vivo and rabbit eyes in vivo are irradiated with a diode laser (λ=810nm, P≤3W, φ =2 mm) for 60 s. Simultaneously, pulses from a N2-laser pumped dye laser (λ = 500 nm, t=3.5 ns, E = 5 μ) are applied on the retina. Following its absorption, an ultrasonic pressure wave is emitted, which is detected by a transducer embedded in a contact lens. Using the previously measured temperature-dependent Grüneisen coefficient of chorioretinal tissue, a temperature raise in porcine eyes of 5.8 °C/(W/cm2) after 60 s is observed and confirmed by simultaneous measurements with an inserted thermocouple. In a rabbit, we find 1.4 °C/(W/cm2) with, and 2.2 °C/(W/cm2) without perfusion at the same location. Coagulation of the rabbit's retina occurs at AT =21 °C after 40 s. In conclusion, this optoacoustic method seems feasible for an in vivo real-time determination of temperature, opening the possibility for feedback control retinal laser treatments.
UR - http://www.scopus.com/inward/record.url?scp=33751368145&partnerID=8YFLogxK
U2 - 10.1117/1.2236301
DO - 10.1117/1.2236301
M3 - Journal articles
C2 - 16965139
AN - SCOPUS:33751368145
SN - 1083-3668
VL - 11
JO - Journal of Biomedical Optics
JF - Journal of Biomedical Optics
IS - 4
M1 - 041111
ER -
