In-vitro study of the temperature dependence of the optoacoustic conversion efficiency in biological tissues

Nikitin, S. M.; Khokhlova, Tanya D.; Pelivanov, Ivan

doi:10.1070/qe2012v042n03abeh014674

Cited by 4 publications

(15 citation statements)

References 27 publications

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“…Table 4 shows mean value and SD of phase transition characteristic temperatures averaged over 10 fat samples studied by each measurement technique [AR, spectral OCT (S-OCT), and AR/time-domain OCT (AR/TD-OCT)] and comparison with the independent measurements done for 10 samples using optoacoustic technique. 65,66 It is worth noting that data presented in Table 4 for all 30 samples studied in this paper demonstrate existence of the very-low-temperature transitions for 29 samples in the range from 22.3°C to 26.5°C detected by all three measurement techniques (AR, S-OCT, and AR/TD-OCT, respectively). The lowtemperature transitions in the range from 30.6°C to 35.2°C were also detected by all techniques for 27 samples, whereas the middle-temperature range transitions between ð39.5 AE 1.9Þ°C and ð44.4 AE 0.6Þ°C were found only for AR measurements, for nine and six samples from studied 10, respectively.…”

Section: Resultssupporting

confidence: 51%

“…9)] agrees well with the results obtained by optoacoustic measurements for ex vivo samples of porcine fat (the right column of Table 4). 65,66 Data received for both techniques have a similar trend and high correlation index (Spearman's rank correlation coefficient between the OCT and the optoacoustic measurements was 0.958; between the refractometry and the optoacoustic measurements was 0.958). Unfortunately, we could not compare the second high-temperature transition of porcine fat found in optoacoustic measurements at ð65 AE 2Þ°C (Table 4) and (b) the phase transition is defined as a change in the relative slope of the temperature dependence of the RI.…”

Section: Resultsmentioning

confidence: 86%

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Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry

et al. 2018

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Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis.

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Section: Resultssupporting

confidence: 51%

Section: Resultsmentioning

confidence: 86%

Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry

et al. 2018

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“…The absorbed laser energy is too small to bring about significant temperature changes, so that the temperature of the medium is controlled by that of its immediate surroundings. A representative sample of the relevant literature is conveyed in (Esenaliev et al, 2000;Larin et al, 2005;Nikitin et al, 2012a;Nikitin et al, 2012b;Petrova et al, 2013;Shah et al, 2009;Pramanik & Wang, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Among these studies, a number of significant differences in instrumentation, laser wavelength, irradiated medium, and acoustic results was encountered. In (Nikitin et al, 2012a;Nikitin et al, 2012b), a 1064-nm laser beam was rotated by 90 o to enable the sound-detecting piezoelectric transducer to be positioned upstream of the irradiated specimen. The specimens, all biological, were positioned in a heated water bath.…”

Section: Introductionmentioning

confidence: 99%

“…The test specimen was canine liver, and the acoustic signal, produced from a 355-nm laser beam, also increased with increasing temperature. However, the positioning of the piezoelectric sensor differed for the two aforementioned experiments, either upstream (Nikitin et al, 2012a;Nikitin et al, 2012b) or downstream of the test specimen (Larin et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Temperature Determination by Means of Optoacoustic Measurements

Gorman¹,

Sparrow²,

Abraham³

2014

SET

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The capabilities of the optoacoustic principle as a means of temperature measurement have been explored by means of experiments. In the experiments, a tissue test specimen, biological muscle sample, was positioned in a precisely temperature-controlled environment and irradiated with 532-nm laser light. The absorbed radiation gave rise to thermal expansion whose induced stresses created a sound field which was detected by a piezoelectric sensor. During the course of the experiments, the temperature of the water bath was systematically varied, with ample time being allowed to enable the test specimen to achieve thermal equilibrium. The temperature variation encompassed both increasing and decreasing protocols. Replicate samples were tested to ensure accuracy. It was found that temperature increases gave rise to decreasing acoustic amplitudes. An opposite trend was observed when the temperature was decreased. This outcome, when compared with the published literature, suggested that accurate use of the photoacoustic effect as a means of temperature measurement requires great care in the setup and execution of the experiment.

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Dual-wavelength photoacoustic technique for monitoring tissue status during thermal treatments

2013

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Photoacoustic (PA) techniques have been exploited for monitoring thermal treatments. However, PA signals depend not only on tissue temperature but also on tissue optical properties which indicate tissue status (e.g., native or coagulated). The changes in temperature and tissue status often occur simultaneously during thermal treatments, so both effects cause changes to PA signals. A new dual-wavelength PA technique to monitor tissue status independent of temperature is performed. By dividing the PA signal intensities obtained at two wavelengths at the same temperature, a ratio, which only depends on tissue optical properties, is obtained. Experiments were performed with two experimental groups, one with untreated tissue samples and the other with high-intensity focused ultrasound treated tissue samples including thermal coagulated lesion, using ex vivo porcine myocardium specimens to test the technique. The ratio of PA signal intensities obtained at 700 and 800 nm was constant for both groups from 25 to 43°C, but with distinct values for the two groups. Tissue alteration during thermal treatment was then studied using water bath heating of tissue samples from 35 to 60°C. We found that the ratio stayed constant before it exhibited a marked increase at around 55°C, indicating tissue changes at this temperature.

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In-vitro study of the temperature dependence of the optoacoustic conversion efficiency in biological tissues

Cited by 4 publications

References 27 publications

Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry

Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry

Temperature Determination by Means of Optoacoustic Measurements

Dual-wavelength photoacoustic technique for monitoring tissue status during thermal treatments

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