Application of the photoacoustic technique for temperature measurements during hyperthermia

Alaeian, Mohsen; Orlande, Helcio R. B.; Lamien, Bernard

doi:10.1080/17415977.2018.1516767

Cited by 5 publications

(15 citation statements)

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“…The thermophysical properties of the mucosa, such as the thermal expansion coefficient and the Gruneisen parameter, were not found in the literature. Therefore, the thermophysical properties of muscle, presented by Table , are also used for the mucosa in the numerical simulations. The variation of the Gruneisen parameter with temperature used in this work is given by

normalΓ ((), x, y, T) = 0.0086 T ((), {}^{normalo}{normalC}) + 0.112

…”

Section: Resultsmentioning

confidence: 99%

“…The photoacoustic problem in biological tissues is considered in the two‐dimensional rectangular region ( W ‐ width and H ‐ height) illustrated by Figure . The mathematical model for the pressure wave, p , inside the domain is given by

((), \nabla^{2} - \frac{1}{{v_{s}}^{2}} \frac{\partial^{2}}{\partial t^{2}}) p ((), x, y, t) = - \frac{β}{c_{p}} \frac{\partial H_{h} ((), x, y, t)}{\partial t} in - \frac{W}{2} < x < \frac{W}{2}, - \frac{H}{2} < y < \frac{H}{2}, for t > 0

with v s is the speed of sound, β is the coefficient of thermal expansion, and c p is the specific heat.…”

Section: Physical Problem and Mathematical Formulationmentioning

confidence: 99%

“…These techniques rely on the generation of pressure waves from the absorption of light energy of a laser pulse. The amplitude of the resulting acoustic wave is proportional to the Gruneisen parameter that includes the local sound velocity, thermal expansion coefficient, and specific heat . As a consequence that the Gruneisen parameter is temperature dependent, the amplitude of the photoacoustic wave is proportional to the local temperature.…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence that the Gruneisen parameter is temperature dependent, the amplitude of the photoacoustic wave is proportional to the local temperature. The application of photoacoustic techniques for temperature measurements in biological tissues has been recently studied by different groups . Intrusive temperature measurements have been used as references for the correlation between the Gruneisen parameter and temperature in previous studies .…”

Section: Introductionmentioning

confidence: 99%

“…The results obtained with simulated measurements and the Markov chain Monte Carlo (MCMC) method revealed the capabilities of the proposed technique for parameter and temperature estimation. Our previous work was then extended to a two‐dimensional case related to the hyperthermia cancer treatment, where the spatial variation of the temperature was estimated as an indirect measurement of the spatial variation of the Gruneisen parameter …”

Section: Introductionmentioning

confidence: 99%

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Temperature estimation of inflamed bowel by the photoacoustic inverse approach

Alaeian¹,

Orlande²,

Machado

2020

Numer Methods Biomed Eng

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Local temperature increase is one of the five classical signs of regions with inflammations. This work is focused on the application of the photoacoustic technique for the estimation of the temperature field in the colon, as the solution of an inverse problem, for the detection of inflamed regions. Two‐dimensional cases are examined here involving a cross section of the bowel, which characterize either the inflammation of the whole mucosa layer, or three small inflamed regions. The inverse problem is solved for a rotating laser inside the intestine lumen, which imposes pulses for the generation of the acoustic waves. One single ultrasound detector, also located at the laser rotating shaft, provides the simulated measurements for the inverse analysis. The inverse problem is solved here with the minimization of the maximum a posteriori objective function. Results show that the proposed technique can be applied for accurate estimations of the temperature distribution in the region of interest, which might be used for the diagnosis of inflammatory bowel diseases (IBD).

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