Near-infrared laser irradiation of a multilayer agar-gel tissue phantom to induce thermal effect of traditional moxibustion

Cho, Jiyong; Prasad, Bibin; Kim, Jung Kyung

doi:10.1142/s1793545818500335

Cited by 15 publications

(13 citation statements)

References 26 publications

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“…There were slight differences in the determined optical properties in comparison to values published for various agar-based phantoms. Cho et al [30] reported an absorption coefficient of 0.24 cm À1 for skin and 0.52 cm À1 for fat tissue while in another study by Iizuka et al [31] values of 0.50 AE 0.04 and 0.7 AE 0.1 cm À1 for unspecified tissue samples was given. This demonstrates the concentrations and different constituents of the fabricated phantoms, which are decisive factors for their optical properties [14,31].…”

Section: Resultsmentioning

confidence: 96%

Low-cost fabrication of optical tissue phantoms for use in biomedical imaging

Ntombela

Adeleye

Chetty

2020

Heliyon

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The rapid development of new optical imaging techniques is dependent on the availability of low-cost and easily reproducible standards for technique validation. This work describes a low-cost fabrication process of an agar gelbased phantom that may accurately simulate the optical properties of different human tissues at 532 and 630nm wavelengths. It was designed to match the optical properties of the brain, bladder wall, and lung tissues. These low-cost phantoms use agar powders dissolved in water as the bulk matrix. The latter is loaded with varying amounts of India ink, and aluminium oxide Al 2 O 3 particles for optical absorption and scattering targets. The optical properties (absorption and scattering coefficients), the primary design factor and critical parameters of these phantoms were deduced from measurements of the total attenuation coefficients ðμ t Þ.It is anticipated that the constructed tissue phantoms have the potential to be used as a reference standard since it's possible to preserve the optical properties in a period exceeding two years, under ideal storage conditions.

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Section: Resultsmentioning

confidence: 96%

Low-cost fabrication of optical tissue phantoms for use in biomedical imaging

Ntombela

Adeleye

Chetty

2020

Heliyon

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“…Agar in different concentrations is widely used for fabricating tissue phantoms [ 46 , 49 ]. For a concentration range of agar from 2.5% to 3.5%, the thermal properties of the agar-based phantom are similar to the thermal properties of many soft tissues [ 46 ]. In this condition, when the temperature reaches around 60 °C to 62 °C, the phase change from solid to liquid occurs.…”

Section: Methodsmentioning

confidence: 99%

“…These phantoms usually require constituent materials whose physical properties accurately represent key tissue characteristics such as the capacity to absorb and transfer the heat [ 45 ]. In particular, agar-based phantoms have been selected thanks to their thermal properties similar to the ones of biological tissue [ 46 , 47 , 48 , 49 , 50 ]. The main advantage of using tissue-mimicking phantoms is that tissue models can be constructed with well-defined physical properties and dimensions.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation of Radiation Response and Thermal Properties of NPs-Loaded Tissues-Mimicking Phantoms

Asadi

Korganbayev

et al. 2022

Nanomaterials

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Many efforts have recently concentrated on constructing and developing nanoparticles (NPs) as promising thermal agent for optical hyperthermia and photothermal therapy. However, thermal energy transfer in biological tissue is a complex process involving different mechanisms such as conduction, convection, radiation. Therefore, having information about thermal properties of tissue especially when NPs are embedded in is a necessity for predicting the heat transfer during hyperthermia. In this work, the thermal properties of solid phantom based on agar in the presence of three different nanoparticles (BPSi, tNAs, GNRs) and alone were measured and reported as a function of temperature (ranging from 22 to 62 °C). The thermal response of these NPs to an 808 nm laser beam with three different powers were studied in the water comparatively. Agar and tNAs have almost constant thermal properties in the considered range. Among the three NPs, gold has the highest conductivity and diffusivity. At 62 °C BPSi NPs have the similar amount of increase for the diffusivity. The thermal parameters reported in this paper can be useful for the mathematical modeling. Irradiation of the NPs-loaded water phantom displayed the highest radiosensitivity of gold among the three mentioned NPs. However, for the higher power of irradiation, BPSi and tNAs NPs showed the increased absorption of heat during shorter time and the increased temperature gradient slope for the initial 15 s after the irradiation started. The three NPs showed different thermal and irradiation response behavior; however, this comparison study notes the worth of having information about thermal parameters of NPs-loaded tissue for pre-clinical planning.

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“…At first, we used a 3% agar gel phantom mimicking the thermal properties of the biological tissue (Fig. 3(a)) [26]. The homogeneity of the phantom makes it suitable for a preliminary analysis of our data-assimilation Bayesian framework.…”

Section: G Experimental Setupmentioning

confidence: 99%

Model-Based Thermometry for Laser Ablation Procedure Using Kalman Filters and Sparse Temperature Measurements

Schulmann

Soltani-Sarvestani

Landro

et al. 2022

IEEE Trans. Biomed. Eng.

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We implement a data-assimilation Bayesian framework for the reconstruction of the spatiotemporal profile of the tissue temperature during laser irradiation. The predictions of a physical model simulating the heat transfer in the tissue are associated with sparse temperature measurements, using an Unscented Kalman Filter. Methods: We compare a standard state-estimation filtering procedure with a joint-estimation (state and parameters) approach: whereas in the state-estimation only the temperature is evaluated, in the joint-estimation the filter corrects also uncertain model parameters (i.e., the medium thermal diffusivity, and laser beam properties). We have tested the method on synthetic temperature data, and on the temperature measured on agar-gel phantom and porcine liver with fiber optic sensors. Results: The joint-estimation allows retrieving an accurate estimate of the temperature distribution with a maximal error < 1.5 °C in both synthetic and liver 1D data, and < 2 °C in phantom 2D data. Our approach allows also suggesting a strategy for optimizing the temperature estimation based on the positions of the sensors. Under the constraint of using only two sensors, optimal temperature estimation is obtained when one sensor is placed in proximity of the source, and the other one is non-symmetrical. Conclusion: The joint-estimation significantly improves the predictive capability of the physical model. Significance: This work opens new perspectives on the benefit of data-assimilation frameworks for laser therapy monitoring.

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Near-infrared laser irradiation of a multilayer agar-gel tissue phantom to induce thermal effect of traditional moxibustion

Cited by 15 publications

References 26 publications

Low-cost fabrication of optical tissue phantoms for use in biomedical imaging

Low-cost fabrication of optical tissue phantoms for use in biomedical imaging

Experimental Evaluation of Radiation Response and Thermal Properties of NPs-Loaded Tissues-Mimicking Phantoms

Model-Based Thermometry for Laser Ablation Procedure Using Kalman Filters and Sparse Temperature Measurements

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