Extended photoacoustic transport model for characterization of red blood cell morphology in microchannel flow

Uluc, Nasire; Ünlü, Mehmet; Gülşen, Gültekin; Erkol, Hakan

doi:10.1364/boe.9.002785

Cited by 5 publications

(4 citation statements)

References 97 publications

(151 reference statements)

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“…The change in the normalized photoacoustic pressure waves (p/p0) with respect to normalized time (vs t/R) is also observed for different positions as shown in figure 2. The photoacoustic waves are obtained at radial positions r = 100, 150, 200 μm, respectively where the pulse duration of the laser is taken as τ = 5 ns (Uluc et al 2018) in figure 2. Similar results are also presented for the applications of ultra-short laser pulses in figure 3 where the pulse duration is taken as τ = 5 fs.…”

Section: Resultsmentioning

confidence: 99%

“…In their studies, the temporal and the spatial profiles were represented by the Dirac delta and Gaussian functions (Tabaru et al 2019;Tabaru, Hayber, Saracoglu 2018). In another study, Uluc et al (2018) described the photoacoustic signal resulted from red blood cells moving in a microfluidic channel and presented a transport model for the characterization of red blood cells.…”

Section: Introductionmentioning

confidence: 99%

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An Analytical Expression Of The Photoacoustic Signal For A Pulsed Laser With A Sinusoidal Radial Profile

Erkol¹

2021

European Journal of Science and Technology

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Photoacoustic signal depends on several laser factors, particularly the pulse duration, energy, wavelength, beam-width and repetition rate of the pulsed laser. Although these dependencies are well tested through experiments, they can also be investigated via theoretical approaches for the research into photoacoustic signal generation in parallel to advances in laser technologies. In this study, the photoacustic signal is presented analytically by solving the photoacoustic wave equation for an optical absorber heated up by a pulsed laser. The spatial and temporal parts of the pulsed laser are modeled by a sampling (sinc) function and a Gaussian function, respectively. The radial profile obtained experimentally by using a spatial light modulator can be modeled accurately with a sampling function. Pulsed lasers can lead to nonlinear effects. This nonlinear mechanism has various advantageous for the photoacoustic imaging. These shortpulsed lasers have a close-to-sinusoidal variation in the central pulse region so that the spatial part of the laser is modeled by a sampling function in this work. For the photoacoustic wave, a detailed expression is obtained analytically in terms of the pulse duration and beamwidth. The photoacoustic signal is observed in terms of time for various detector positions. Moreover, a detailed analysis is conducted to obtain a correlation between the photoacoustic signal and the laser factors. Therefore, the resulting quantification of the physical laser factors can offer a useful theoretical guide for the applications of photoacoustics. The sampling modeling presented by this study can also be helpful for the understanding of the nonlinear mechanism in photoacoustics.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Analytical Expression Of The Photoacoustic Signal For A Pulsed Laser With A Sinusoidal Radial Profile

Erkol¹

2021

European Journal of Science and Technology

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“…Extensions of the standard wave model in PAT have also been considered and are presented in [6][7][8], for example.…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic inversion formulas using mixed data on finite time intervals*

Dreier

Haltmeier

2022

Inverse Problems

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We study the inverse source problem in photoacoustic tomography (PAT) for mixed data, which denote a weighted linear combination of the acoustic pressure and its normal derivative on an observation surface. We consider in particular the case where the data are only available on finite time intervals, which accounts for real-world usage of PAT where data are only feasible within a certain time interval. Extending our previous work, we derive explicit formulas up to a smoothing integral on convex domains with a smooth boundary, yielding exact reconstruction for circular or elliptical domains. We also present numerical reconstructions of our new exact inversion formulas on finite time intervals and compare them with the reconstructions of our previous formulas for unlimited time wave measurements.

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“…The photoacoustic effect, which Alexander Graham Bell first presented in 1880, can be described as the formation of acoustic pressure waves resulting from the interaction of the short pulsed laser with a medium [1,2]. Developments in laser and ultrasonic transducer technologies have made Photoacoustic Imaging (PI) very popular in the last decades [2][3][4][5][6][7][8][9][10][11][12]. In PI, a very short pulsed laser with a pulse duration typically on the order of nanoseconds (or shorter) is sent to a sample to be imaged.…”

Section: Introductionmentioning

confidence: 99%

An analytical model to calculate the primary and secondary acoustic forces acting on microbubbles due to a short pulsed laser excitation

Erkol¹

2022

Phys. Scr.

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This work presents a comprehensive analytical approach to describe photoacoustic waves resulting from a pulsed laser excitation. The spatial part of the laser is modeled by a zeroth-order Bessel function of the first kind, which has a wide range of applications in optics and medical physics, such as optical trapping and nonlinear effects resulting from the interaction of a pulsed laser with tissue in photoacoustic imaging. The temporal part of the laser is described by a Gaussian function, which is a pretty realistic approximation since the interaction of the laser with the medium is instantaneous. The photoacoustic wave equation is solved analytically using the Fourier transform and the Greens’ function methods. The solution of the photoacoustic wave equation depends explicitly on position, time, pulse duration, and beam-width of the pulsed laser. The effects of these dependencies on the photoacoustic wave are investigated. Later, the primary and secondary radiation forces acting on microbubbles Albunex and Quantison are calculated using the magnitude of the photoacoustic pressure wave. The primary and secondary radiation forces decrease considerably with the distance from the photoacoustic absorber. These forces increase as the beam-width increases while they decrease as the pulse duration gets longer. The primary radiation forces on the microbubbles are on the order of nanonewtons. The force at this scale can be used to manipulate microbubbles. The secondary radiation force between identical microbubbles is in the range of piconewtons. Hence, this force can be used to determine the viscoelastic properties of microbubbles even though it is very small compared to the primary radiation force. The radiation forces determined by this work are also compared with those calculated by another study describing the laser’s spatial profile with a Gaussian function. The forces obtained by this work are larger than the forces determined by the Gaussian function approximation at the positions near the source. The forces obtained by the two approaches show similar behaviors, and they decrease remarkably with the distance from the source. Thus, the model presented in this work can be used to study the nonlinear mechanism in photoacoustics, such as enhancing image contrast and determining the tissue temperature. It can also be helpful for the applications of microbubbles in medical imaging and drug delivery as carriers.

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Extended photoacoustic transport model for characterization of red blood cell morphology in microchannel flow

Cited by 5 publications

References 97 publications

An Analytical Expression Of The Photoacoustic Signal For A Pulsed Laser With A Sinusoidal Radial Profile

An Analytical Expression Of The Photoacoustic Signal For A Pulsed Laser With A Sinusoidal Radial Profile

Photoacoustic inversion formulas using mixed data on finite time intervals*

An analytical model to calculate the primary and secondary acoustic forces acting on microbubbles due to a short pulsed laser excitation

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