Measurement of temperature-dependent specific heat of biological tissues

Haemmerich, Dieter; Schutt, David J.; Santos, Ícaro dos; Webster, John G.; Mahvi, David M.

doi:10.1088/0967-3334/26/1/006

Cited by 45 publications

(33 citation statements)

References 6 publications

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“…0.3 Wm −1 K −1 and thermal diffusivity approx. 1.31 × 10 −7 m 2 s −1 ) [17,18] are similar to those of tissue (thermal conductivity 0.6 Wm −1 K −1 and thermal diffusivity 1.58 × 10 −7 m 2 s −1 ) [19,20]. Figure 2 shows a schematic of the analytic model for a single µ-ILED in the tissue.…”

Section: Thermal Analysis For a Single Inorganic Light-emitting Diodementioning

confidence: 90%

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Thermal analysis of injectable, cellular-scale optoelectronics with pulsed power

Shi

Song

et al. 2013

Proc. R. Soc. A.

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An ability to insert electronic/optoelectronic systems into precise locations of biological tissues provides powerful capabilities, especially in neuroscience such as optogenetics where light can activate/deactivate critical cellular signalling and neural systems. In such cases, engineered thermal management is essential, to avoid adverse effects of heating on normal biological processes. Here, an analytic model of heat conduction is developed for microscale, inorganic light-emitting diodes (μ-ILEDs) in a pulsed operation in biological tissues. The analytic solutions agree well with both three-dimensional finite-element analysis and experiments. A simple scaling law for the maximum temperature increase is presented in terms of material (e.g. thermal diffusivity), geometric (e.g. μ-ILED size) and loading parameters (e.g. pulsed peak power, duty cycle and frequency). These results provide useful design guidelines not only for injectable μ-ILED systems, but also for other similar classes of electronic and optoelectronic components.

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Section: Thermal Analysis For a Single Inorganic Light-emitting Diodementioning

confidence: 90%

“….45 µm and t 0 = 0.33 s) [13,20]. Equation (2.12) and figure 3 clearly suggest that small peak power Q 0 , duty cycle D, period t 0 , and large surface area A of µ-ILED are effective to reduce the maximum temperature increase.…”

Section: Thermal Analysis For a Single Inorganic Light-emitting Diodementioning

confidence: 94%

Thermal analysis of injectable, cellular-scale optoelectronics with pulsed power

Shi

Song

et al. 2013

Proc. R. Soc. A.

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“…Based upon agar measurements performed in Haemmerich et al (2005), experimental error is under 3.1%. For each phantom, we performed three specific heat measurements.…”

Section: Methodsmentioning

confidence: 99%

Measurement of the specific heat capacity of liver phantom

Prakash¹,

Converse²,

Mahvi³

et al. 2006

Physiol. Meas.

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Phantoms are often used to simulate tissue during the development, testing and calibration of medical devices. In order to infer the specific absorption rate (SAR) and resistive heating in phantoms from temperature measurements, the specific heat capacity and density of the phantom are needed. Stauffer et al (2003 Int. J. Hyperth. 19 89-101) developed several phantoms that mimic dielectric properties of liver tissue at 915 MHz. However, thermal properties of the phantoms were not presented. We have measured specific heat capacities and densities for these phantoms. We also present dielectric properties for these phantoms measured from 0.7 to 20 GHz, including 2.45 GHz-a commonly used frequency for microwave hyperthermia and ablation.

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“…During the experiment, we filled the cavity with deionized water and immersed the ultrasonic probe in the water without direct contact with the agar layer. Because the agar jelly had similar thermal conductivity and heat capacity to that of water [21,22], by simple calculation, it would take more than 10 minutes for the overall sample temperature to rise by 1 degree even if all the laser light energy was absorbed and became heat. Combining our previous experimental result with this calculation, we believe that the base temperature of the sample did not change much when imaging, thereby eliminating the effect from the varied Gruneisen parameter on the 2nd order beating signals.…”

Section: Application-nonlinear Photoacoustic Microscopymentioning

confidence: 99%

Nonlinear photoacoustic microscopy via a loss modulation technique: from detection to imaging

Lai¹,

Lee²,

Chang³

et al. 2014

Opt. Express

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Abstract:In order to achieve high-resolution deep-tissue imaging, multiphoton fluorescence microscopy and photoacoustic tomography had been proposed in the past two decades. However, combining the advantages of these two imaging systems to achieve optical-spatial resolution with an ultrasonic-penetration depth is still a field with challenges. In this paper, we investigate the detection of the two-photon photoacoustic ultrasound, and first demonstrate background-free two-photon photoacoustic imaging in a phantom sample. To generate the background-free two-photon photoacoustic signals, we used a high-repetition rate femtosecond laser to induce narrowband excitation. Combining a loss modulation technique, we successfully created a beating on the light intensity, which not only provides pure sinusoidal modulation, but also ensures the spectrum sensitivity and frequency selectivity. By using the lock-in detection, the power dependency experiment validates our methodology to frequencyselect the source of the nonlinearity. This ensures our capability of measuring the background-free two-photon photoacoustic waves by detecting the 2nd order beating signal directly. Furthermore, by mixing the nanoparticles and fluorescence dyes as contrast agents, the two-photon photoacoustic signal was found to be enhanced and detected. In the end, we demonstrate subsurface two-photon photoacoustic bio-imaging based on the optical scanning mechanism inside phantom samples.

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Measurement of temperature-dependent specific heat of biological tissues

Cited by 45 publications

References 6 publications

Thermal analysis of injectable, cellular-scale optoelectronics with pulsed power

Thermal analysis of injectable, cellular-scale optoelectronics with pulsed power

Measurement of the specific heat capacity of liver phantom

Nonlinear photoacoustic microscopy via a loss modulation technique: from detection to imaging

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