1. |
Gambin B.J., Kruglenko E., Tymkiewicz R., Litniewski J., Heating efficiency of agarose samples doped with magnetic nanoparticles subjected to ultrasonic and magnetic field,
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, ISSN: 0017-9310, DOI: 10.1016/j.ijheatmasstransfer.2024.125467, Vol.226, No.125467, pp.1-10, 2024Abstract: Recently, magneto-ultrasound heating of tissue in the presence of magnetic nanoparticles (NPs) has been studied due to its high potential for use in oncological hyperthermia. It has been published that a synergistic effect, generation of additional heat caused by magneto-ultrasonic coupling, was observed in a tissue-mimicking material (TMM) enriched with magnetic NPs. The specific absorption rate (SAR) was determined from the temperature rise measurements in a focus of the ultrasound beam. It is important to use precise measurement methods when considering medical applications, for which there are limitations to the power of each field, resulting from the prevention of biological phenomena dangerous to the patient. This study demonstrates that in magneto-ultrasonic heating SAR can be measured much more accurately if the ultrasonic field is almost uniform. Measurements were performed on TMM containing Fe3O4 NPs with a diameter of approximately 8 nm and superparamagnetic properties. Both, the measurement and simulation results showed that the errors resulting from the inaccuracy of placing the temperature probe are smaller than in the case of the focused ultrasound. At the same time, the temperature increase caused by the ultrasonic field is almost linear and the influence of heat convection on the SAR determination is negligible. The measurements showed that magneto-ultrasonic hyperthermia can provide the desired thermal effect at lower ultrasound powers and magnetic fields compared to ultrasonic or magnetic hyperthermia used alone. No synergy effect was recorded. Keywords: Magnetic nanoparticle-mediated hyperthermia,Dual-mode ultrasonic-magnetic hyperthermia,Specific absorption rate,Hyperthermia efficiency Affiliations:
Gambin B.J. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Tymkiewicz R. | - | IPPT PAN | Litniewski J. | - | IPPT PAN |
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2. |
Byra M., Klimonda Z., Kruglenko E., Gambin B., Unsupervised deep learning based approach to temperature monitoring in focused ultrasound treatment,
Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2022.106689, Vol.122, pp.106689-1-7, 2022Abstract: Temperature monitoring in ultrasound (US) imaging is important for various medical treatments, such as high-intensity focused US (HIFU) therapy or hyperthermia. In this work, we present a deep learning based approach to temperature monitoring based on radio-frequency (RF) US data. We used Siamese neural networks in an unsupervised way to spatially compare RF data collected at different time points of the heating process. The Siamese model consisted of two identical networks initially trained on a large set of simulated RF data to assess tissue backscattering properties. To illustrate our approach, we experimented with a tissue-mimicking phantom and an ex-vivo tissue sample, which were both heated with a HIFU transducer. During the experiments, we collected RF data with a regular US scanner. To determine spatiotemporal variations in temperature distribution within the samples, we extracted small 2D patches of RF data and compared them with the Siamese network. Our method achieved good performance in determining the spatiotemporal distribution of temperature during heating. Compared with the temperature monitoring based on the change in radio-frequency signal backscattered energy parameter, our method provided more smooth spatial parametric maps and did not generate ripple artifacts. The proposed approach, when fully developed, might be used for US based temperature. Keywords: temperature monitoring, high intensity ultrasound, deep learning, transfer learning, ultrasound imaging Affiliations:
Byra M. | - | IPPT PAN | Klimonda Z. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Gambin B. | - | IPPT PAN |
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3. |
Gambin B., Korczak-Ciegielska I.♦, Secomski W., Kruglenko E., Nowicki A., Ultrasonic Experimental Evaluation of the Numerical Model of the Internal Fluid Flow in the Kidney Cooling Jacket,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2022.142004, Vol.47, No.3, pp.389-397, 2022Abstract: Kidney Cooling Jacket (KCJ) preserves the kidney graft, wrapped in the jacket, against the too fast time of temperature rise during the operation of connecting a cooled transplant to the patient’s bloodstream. The efficiency of KCJ depends on the stationarity of the fluid flow and its spatial uniformity. In this paper, the fluid velocity field inside the three different KCJ prototypes has been measured using the 20 MHz ultrasonic Doppler flowmeter. The simplified 2D geometrical model of the prototypes has been presented using COMSOL-Multiphysics to simulate the fluid flow assuming the laminar flow model. By comparing the numerical results with experimental data, the simplified 2D model is shown to be accurate enough to predict the flow distribution of the internal fluid velocity field within the KCJ. The discrepancy between the average velocity measured using the 20 MHz Doppler and numerical results was mainly related to the sensitivity of the velocity measurements to a change of the direction of the local fluid flow stream. Flux direction and average velocity were additionally confirmed by using ommercial colour Doppler imaging scanner. The current approach showed nearly 90% agreement of the experimental results and numerical simulations. It was important for justifying the use of numerical modelling in designing the baffles distribution (internal walls in the flow space) for obtaining the
most spatially uniform field of flow velocity. Keywords: multi-canal system; fluid flow prediction; cooling jacket; flow Doppler measurement Affiliations:
Gambin B. | - | IPPT PAN | Korczak-Ciegielska I. | - | other affiliation | Secomski W. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Nowicki A. | - | IPPT PAN |
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4. |
Gambin B., Melnikova P.♦, Kruglenko E., Strzałkowski R., Krajewski M., Impact of the agarose ferrogel fine structure on magnetic heating efficiency,
Journal of Magnetism and Magnetic Materials, ISSN: 0304-8853, DOI: 10.1016/j.jmmm.2021.169000, No.1690000, 169423, pp.1-10, 2022Abstract: Magnetic nanoparticles-mediated hyperthermia was widely studied in the last decades as applicable in cancer therapy. The majority of magnetic hyperthermia research was devoted to improvement of heating efficiency by application of various nanomaterials. The influence of biocompatibility, magnetic properties, sizes, composition, and concentration of magnetic nanoparticles (MNPs) on hyperthermia efficiency was extensively studied. Also, the limits preserving biological safety and the chemical stability of MNPs delivered to the tissue were established. However, much less research concerned the impact of the physical interactions between the closest MNPs on the hyperthermia efficiency. Our goal was to demonstrate the relationships between the internal structure of soft tissue containing MNPs, and the thermal effects of an alternating magnetic field. Because agarose-based gel exhibits a tissue-like internal structure, we performed hyperthermia experiments in two types of such gel containing bare and polyethylene glycol-coated Fe3O4 nanoparticles. We described the structural difference and we estimated the ferrogels specific absorption rate coefficients (SAR) from calorimetric experiments. Magnetic measurements showed 11% lower magnetic saturation of PEG-coated MNPs than of the bare MNPs. While the SAR of ferrogel with PEG-coated MNPs was 15% greater than bare MNPs. The structural characteristics calculated from TEM and SEM images were significantly different. Particularly, we observed the nanoparticle agglomeration in the gel with bare MNPs. The bare MNPs uniformly packed and located inside agarose double helices were observed for the first time. The distribution of MNPs and their spatial configuration in gel influenced strongly the strength of bonds blocking the movement of MNPs and determined the ferrogels heating efficiency. As the tissues to which we delivered MNPs were composed of agarose gel-like structures, our results may be useful in further research on hyperthermia in vivo. 10.1016/j.jmmm.2021.169000, 10.1016/j.jmmm.2022.169423 Keywords: nanoparticle-mediated magnetic hyperthermia, ferrogel, nanoparticles distribution, double helices structure Affiliations:
Gambin B. | - | IPPT PAN | Melnikova P. | - | Warsaw University of Technology (PL) | Kruglenko E. | - | IPPT PAN | Strzałkowski R. | - | IPPT PAN | Krajewski M. | - | IPPT PAN |
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5. |
Miklewska A., Tymkiewicz R., Kruglenko E., Krajewski M., Gambin B., Comparison of the influence of superparamagnetic nanoparticles concentration and coverage on the alternating magnetic field thermal effect,
Journal of Magnetism and Magnetic Materials, ISSN: 0304-8853, DOI: 10.1016/j.jmmm.2021.168918, Vol.550, pp.168918-1-6, 2022Abstract: Magnetic nanoparticles (MNP)s of Fe3O4 were synthesized in the co-precipitation reaction of iron chlorides dissolved in water and ammonia water. To produce polyethylene glycol (PEG) coatings of the NMPs, we added PEG to the ammonia water during the fabrication process. Magnetic fluids, ferrofluids, for research were prepared as oleic acid suspension of bare and PEG-coated nanoparticles at four concentrations. The results of the conducted calorimetric experiments confirmed that the efficiency of heating ferrofluids strongly depends on the concentration of nanoparticles in fluids. The results also indicate that the ferrofluids containing PEG-coated NPs heat up more than ferrofluids with bare nanoparticles. They are characterized by a higher specific absorption rate (SAR) value calculated from the initial slope of temperature versus time curve during heating. 10.1016/j.jmmm.2021.168918, 10.1016/j.jmmm.2022.169422 Keywords: nanoparticle fluid hyperthermia, magnetite nanoparticles, PEG-coated nanoparticles, hyperthermia Affiliations:
Miklewska A. | - | IPPT PAN | Tymkiewicz R. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Krajewski M. | - | IPPT PAN | Gambin B. | - | IPPT PAN |
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6. |
Gambin B., Kruglenko E., Ultrasonic specific absorption rate in nanoparticle-mediated moderate hyperthermia,
BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2021.137053, Vol.69, No.3, pp.e137053-1-18, 2021Abstract: Magnetic nanoparticle’s different applications in nanomedicine, due to their unique physical properties and biocompatibility, were intensively investigated. Recently, Fe3O4 nanoparticles, are confirmed to be the best sonosensitizers to enhance the performance of HIFU (high intensity focused ultrasound). They are also used as thermo-sensitizers in magnetic hyperthermia. A new idea of dual, magneto-ultrasound, coupled hyperthermia allows the ultrasound intensity to be reduced from the high to a moderate level. Our goal is to evaluate the enhancement of thermal effects of focused ultrasound of moderate intensity due to the presence of nanoparticles. We combine experimental results with numerical analysis. Experiments are performed on tissue-mimicking materials made of the 5% agar gel and gel samples containing Fe3O4 nanoparticles with φ = 100 nm with two fractions of 0.76 and 1.53% w/w. Thermocouples registered curves of temperature rising during heating by focused ultrasound transducer with acoustic powers of the range from 1 to 4 W. The theoretical model of ultrasound-thermal coupling is solved in COMSOL Multiphysics. We compared the changes between the specific absorption rates (SAR) coefficients determined from the experimental and numerical temperature rise curves depending on the nanoparticle fractions and applied acoustic powers.We confirmed that the significant role of nanoparticles in enhancing the thermal effect is qualitatively similarly estimated, based on experimental and numerical results. So that we demonstrated the usefulness of the FEM linear acoustic model in the planning of efficiency of nanoparticle-mediated moderate hyperthermia. Keywords: ultrasonic hyperthermia, agar-based tissue mimicking phantom, magnetic nanoparticles, temperature, specific absorption rate (SAR) Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN |
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7. |
Korczak I., Romowicz A.♦, Gambin B., Palko T.♦, Kruglenko E., Dobruch-Sobczak K., Numerical prediction of breast skin temperature based on thermographic and ultrasonographic data in healthy and cancerous breasts,
Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2020.10.007, Vol.40, pp.1680-1692, 2020Abstract: Breast cancer is one of the most common women's cancers, so an available diagnostic modality, particularly non-invasive, is important. Infrared thermography (IRT) is a supporting diagnostic modality. Until now, many finite element methods (FEM) numerical models have been constructed to evaluate IRT's diagnostic value and to relate breast skin temperature characteristics with breast structural disorder presence, particularly to distinguish between cancerous types and normal structures. However, most of the models were not based on any clinical data, except for several papers based on clinical magnetic resonance imaging (MRI) data, wherein a three-dimensional (3D) breast model was studied. In our paper, we propose a very simplified numerical two-dimensional FEM model constructed based on clinical ultrasound data of breasts, which is much cheaper and available in realtime as opposed to MRI data. We show that our numerical simulations enabled us to distinguish between types of healthy breasts in agreement with the clinical classification and with thermographic results. The numerical breast models predicted the possibility of differentiation of cancerous breasts from healthy breasts by significantly different skin temperature variation ranges. The thermal variations of cancerous breasts were in the range of 0.5 8C–3.0 8C depending on the distance of the tumor from the skin surface, its size, and the cancer type. The proposed model, due to its simplicity and the fact that it was constructed based on clinical ultrasonographic data, can compete with the more sophisticated 3D models based on MRI. Keywords: non-invasive cancer detection, Pennes' bioheat transfer equation, finite element method, breast thermography, ultrasonography Affiliations:
Korczak I. | - | IPPT PAN | Romowicz A. | - | other affiliation | Gambin B. | - | IPPT PAN | Palko T. | - | other affiliation | Kruglenko E. | - | IPPT PAN | Dobruch-Sobczak K. | - | IPPT PAN |
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8. |
Gambin B., Kruglenko E., Tymkiewicz R., Litniewski J., Ultrasound assessment of the conversion of sound energy into heat in tissue phantoms enriched with magnetic micro- and nanoparticles,
Medical Physics, ISSN: 0094-2405, DOI: 10.1002/mp.13742, Vol.46, No.10, pp.4361-4370, 2019Abstract: Purpose: Nowadays, the improvement of ultrasonic hyperthermia therapy is often achieved by adding hard particles to the sonicated medium in order to increase the heating efficiency. The explanation of the phenomenon of ultrasonic heating still requires testing on tissue mimicking materials (TMMs), enriched with particles of different sizes and physical properties. Our goal was to determine, by comparing their quantitative acoustic properties, which TMMs, with magnetic micro- or nanoparticles, convert more ultrasonic energy into heat or which of the particles embedded in the agar gel act as more effective thermal sonosensitizers. Methods: We manufactured a pure agar gel and an agar gel with the addition of magnetic micro- or nanoparticles in two proportions of 8 and 16 mg/ml. Ultrasound quantitative techniques, the broadband reflection substitution technique and backscattered spectrum analysis were used to characterize the samples by speed of sound (SOS), frequency-dependent attenuation, and backscattering coefficients. The integrated backscattering coefficients were also calculated. The quantitative parameters, scattering, and attenuation coefficients of ultrasound in phantoms with micro- and nanoparticles were estimated. Based on the attenuation and scattering of ultrasound in the samples, the ultrasonic energy absorption, which determines the heating efficiency, was evaluated. Additionally, the temperature increase during sonication of the phantoms by an ultrasonic beam was directly measured using thermocouples. Results: The density of the materials with nanoparticles was higher than for the materials with microparticles with the same fractions of particles. The SOS for all materials ranged from 1489 to 1499 m/s. The attenuation in the whole frequency range (3–8 MHz) was higher for the materials with nanoparticles than for the materials with microparticles. For the materials with the lower content (8 mg/ml) of particles, the attenuation coefficient was 0.2 dB/(MHz cm). For the 16 mg/ml concentration of nanoparticles and microparticles, the attenuation coefficients were 0.66 and 0.45 dB/(MHz cm), resectively. The value of backscattering coefficient in the whole frequency range was greater for the materials with microparticles than for the materials with nanoparticles. The values of the integrated backscattering coefficient were 0.05 and 0.08 1/m for the materials with nanoparticles and 0.46 and 0.82 1/m for the materials with microparticles and concentrations of 8 and 16 mg/ml, respectively. The rates of temperature increase in the first 3 s due to ultrasonic heating were higher for the materials with nanoparticles than for the materials with microparticles. Conclusions: Based on acoustical measurements, we confirmed that all materials can be used as tissue phantoms in the study of ultrasonic hyperthermia, as their properties were in the range of soft tissue properties. We found that the nanoparticle-doped materials had greater attenuation and smaller scattering of ultrasound than the materials with microparticles, so absorption in these materials is greater. Thus, the TMMs with nanoparticles convert more acoustic energy into heat and we conclude that magnetic nanoparticles are more effective thermal sonosensitizers than microparticles. This conclusion is confirmed by direct measurement of the temperature increase in the samples subjected to sonification. Keywords: backscattering coefficient, frequency-dependent attenuation, hyperthermia TMM, magnetic particles, ultrasound absorption Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Tymkiewicz R. | - | IPPT PAN | Litniewski J. | - | IPPT PAN |
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9. |
Byra M., Kruglenko E., Gambin B., Nowicki A., Temperature Monitoring during Focused Ultrasound Treatment by Means of the Homodyned K Distribution,
ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.131.1525, Vol.131, No.6, pp.1525-1528, 2017Abstract: Temperature monitoring is essential for various medical treatments. In this work, we investigate the impact of temperature on backscattered ultrasound echo statistics during a high intensity focused ultrasound treatment. A tissue mimicking phantom was heated with a spherical ultrasonic transducer up to 56 _C in order to imitate tissue necrosis. During the heating, an imaging scanner was used to acquire backscattered echoes from the heated region. These data was then modeled with the homodyned K distribution. We found that the best temperature indicator can be obtained by combining two parameters of the model, namely the backscattered echo mean intensity and the effective number of scatterers per resolution cell. Next, ultrasonic thermometer was designed and used to create a map of the temperature induced within the tissue phantom during the treatment Keywords: Temperature monitoring, homodyned K distribution, focused ultrasound Affiliations:
Byra M. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Gambin B. | - | IPPT PAN | Nowicki A. | - | IPPT PAN |
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10. |
Gambin B., Byra M., Kruglenko E., Doubrovina O.♦, Nowicki A., Ultrasonic Measurement of Temperature Rise in Breast Cyst and in Neighbouring Tissues as a Method of Tissue Differentiation,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.1515/aoa-2016-0076, Vol.41, No.4, pp.791-798, 2016Abstract: Texture of ultrasound images contain information about the properties of examined tissues. The analysis of statistical properties of backscattered ultrasonic echoes has been recently successfully applied to differentiate healthy breast tissue from the benign and malignant lesions. We propose a novel procedure of tissue characterization based on acquiring backscattered echoes from the heated breast. We have proved that the temperature increase inside the breast modifies the intensity, spectrum of the backscattered signals and the probability density function of envelope samples. We discuss the differences in probability density functions in two types of tissue regions, e.g. cysts and the surrounding glandular tissue regions. Independently, Pennes bioheat equation in heterogeneous breast tissue was used to describe the heating process. We applied the finite element method to solve this equation. Results have been compared with the ultrasonic predictions of the temperature distribution. The results confirm the possibility of distinguishing the differences in thermal and acoustical properties of breast cyst and surrounding glandular tissues. Keywords: medical ultrasound, temperature changes in vivo, breast tissue, ultrasonic temperature measurement Affiliations:
Gambin B. | - | IPPT PAN | Byra M. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Doubrovina O. | - | Belarussian State University (BY) | Nowicki A. | - | IPPT PAN |
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11. |
Gambin B., Kruglenko E., Byra M., Relationships between Acoustical Properties and Stiffness of Soft Tissue Phantoms,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.19, pp.111-120, 2016Abstract: Polyvinyl-alcohol cryogel is commonly used for soft tissue phantom manufacture. The gel formation from an aqueous solution of polyvinyl-alcohol takes place during the freezing and thawing cycle. The aim of this work was to assess the degree of gel solidification, hence the material stiffness, by means of quantitative ultrasound. We manufactured three phantoms which differed in the number of freezing/thawing cycles. First, tissue phantoms were examined with an elastography technique. Next, we measured the speed of sound and the attenuation coefficient. What is more, the inter structure variations in phantoms were assessed with the Nakagami imaging which quantifies the scattering properties of the backscattered ultrasound echo. Obtained results confirmed the connection between the number of freezing/thawing cycles and the solidification process. We defined the boundary layer as a region which has a different structure than the sample interior. Next, for each phantom this layer was extracted based on a Nakagami parameter map. We calculated that the thickness of the boundary layer was lower in samples which were subjected to a larger number of freezing/thawing cycles. Keywords: soft tissue phantoms, elastography, ultrasound attenuation, speed of sound, Nakagami maps, stiffness Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Byra M. | - | IPPT PAN |
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12. |
Gambin B., Kruglenko E., Temperature Measurement by Statistical Parameters of Ultrasound Signal Backscattered from Tissue Samples,
ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.128.A-72, Vol.128, No.1-A, pp.A-72-78, 2015Abstract: A novel estimation of temperature changes inside soft tissues has been proposed in sub-ablation range, i.e. 20°C-48°C. This estimation has been obtained by studying statistical properties of backscattered ultrasonic signals. Two different procedures of heating/cooling have been performed in which the RF echoes have been registered from soft tissue phantom in the first procedure, and from soft tissue in vitro in the second one. Calculated envelopes of signals registered in time points during heating/cooling experiments have been treated as a statistical sample drawn from a random variable with three different distributions, namely the Rayleigh distribution, the Nakagami distribution, and the K-distribution. The histograms obtained in subsequent time moments have been fitted to the three distributions. Dependencies of their shape and scale parameters on temperature have been calculated. It is concluded that the shape parameter of the K-distribution can be chosen as the best marker of temperature changes in both experiments. The choice of the marker has been made by analysis of temperature dependencies of all calculated parameters and by comparing the quality of fitting all histograms to the considered distributions. Besides, the chosen marker as a function of temperature exhibits the closest shape to temperature/time function experimentally measured. Keywords: therapeutic applications, ultrasonics, medical imaging Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN |
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13. |
Gambin B., Kruglenko E., Gałka A.A.♦, Wojnar R., Macroscopic thermal properties of quasi-linear cellular medium on example of the liver tissue,
COMPUTER ASSISTED METHODS IN ENGINEERING AND SCIENCE, ISSN: 2299-3649, Vol.22, No.4, pp.329-346, 2015Abstract: There are two main topics of this research: (i) one topic considers overall properties of a nonlinear cellular composite, treated as a model of the liver tissue, and (ii) the other topic concerns the propagation of heat in the nonlinear medium described by the homogenised coefficient of thermal conductivity.
For (i) we give a method and find the effective thermal conductivity for the model of the liver tissue, and for the point (ii) we present numerical and analytical treatment of the problem, and indicate the principal difference of heat propagation in linear and nonlinear media. In linear media, as it is well known, the range of the heat field is infinite for all times t > 0, and in nonlinear media it is finite.
Pennes’ equation, which should characterize the heat propagation in the living tissue, is in general a quasi-nonlinear partial differential equation, and consists of three terms, one of which describes Fourier’s heat diffusion with conductivity being a function of temperature T. This term is just a point of our analysis.
We show that a nonlinear character of the medium (heat conductivity dependent on the temperature) changes in qualitative manner the nature of heat transfer. It is proved that for the heat source concentrated initially (t = 0) at the space point, the range of heated region (for t > 0) is finite. The proof is analytical, and illustrated by a numerical experiment. Keywords: heat transport, asymptotic homogenisation, effective heat conductivity Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Gałka A.A. | - | other affiliation | Wojnar R. | - | IPPT PAN |
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14. |
Gambin B., Kruglenko E., Wójcik J., Relationship between thermal and ultrasound fields in breast tissue in vivo,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.18, pp.53-58, 2015Abstract: The study shows the direct relationship between the temperature field and the parallel changes that are taking place in backscattered ultrasonic signals from the breast tissue in vivo when heated to the temperature of approximately 42 o C. The non-uniform temperature field inside the heating tissue was determined by the numerical model using FEM. It is shown that the spatial distribution of intensities of the backscattered signals coincides with the temperature distribution field predicted by the numerical model in some areas. The result indicates the possibility of the indirect measurement of the temperature rise in the breast tissue in vivo by measuring the intensity variations of the ultrasound echo. Keywords: temperature field, backscattered ultrasonic signals, breast tissue in vivo, FEM model Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Wójcik J. | - | IPPT PAN |
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15. |
Kujawska T., Secomski W., Kruglenko E., Krawczyk K., Nowicki A., Determination of Tissue Thermal Conductivity by Measuring and Modeling Temperature Rise Induced in Tissue by Pulsed Focused Ultrasound,
PLOS ONE, ISSN: 1932-6203, DOI: 10.1371/journal.pone.0094929, Vol.9, No.4, pp.e94929-1-8, 2014Abstract: A tissue thermal conductivity (Ks) is an important parameter which knowledge is essential whenever thermal fields induced in selected organs are predicted. The main objective of this study was to develop an alternative ultrasonic method for determining Ks of tissues in vitro suitable for living tissues. First, the method involves measuring of temperature-time T(t) rises induced in a tested tissue sample by a pulsed focused ultrasound with measured acoustic properties using thermocouples located on the acoustic beam axis. Measurements were performed for 20-cycle tone bursts with a 2 MHz frequency, 0.2 duty-cycle and 3 different initial pressures corresponding to average acoustic powers equal to 0.7 W, 1.4 W and 2.1 W generated from a circular focused transducer with a diameter of 15 mm and f-number of 1.7 in a two-layer system of media: water/beef liver. Measurement results allowed to determine position of maximum heating located inside the beef liver. It was found that this position is at the same axial distance from the source as the maximum peak-peak pressure calculated for each nonlinear beam produced in the two-layer system of media. Then, the method involves modeling of T(t) at the point of maximum heating and fitting it to the experimental data by adjusting Ks. The averaged value of Ks determined by the proposed method was found to be 0.5±0.02 W/(m·°C) being in good agreement with values determined by other methods. The proposed method is suitable for determining Ks of some animal tissues in vivo (for example a rat liver). Keywords: Acoustics, Sound pressure, Beef, Thermal conductivity, Thermocouples, Nonlinear systems, Sound waves, Bioacoustics Affiliations:
Kujawska T. | - | IPPT PAN | Secomski W. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Krawczyk K. | - | IPPT PAN | Nowicki A. | - | IPPT PAN |
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16. |
Kruglenko E., Gambin B., RF signal amplitude statistics during temperature changes in tissue phantoms,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.17, pp.115-122, 2014Abstract: Two heating protocols for soft tissue phantoms have been performed. An Agar-Gel-Oil (AGO) mixture has been heated locally by applying ultrasonic beams and a Poly Vinyl Alcohol-cryogel (PVA-c) has been heated “globally” by a water bath with a controlled temperature rise. The RF signals were collected during heating by an ultrasound transducer to ensure no interference from waves from the heating transducer. Independently, the thermocouples' measurement has been used to obtain temperature as a function of time in the AGO case. At first, a compensation of attenuation was performed and normalized envelopes of signals were used as data for statistical analysis. It is shown that random the values of the backscattered amplitude are close to Rayleigh and K-distributed random variables for AGO and PVA-c, respectively. Temperature is linked to the scale parameter of Rayleigh distribution for the AGO, and the shape parameter of K-distribution for PVA-c were calculated and discussed in the context of their suitability for the acoustic measurement of temperature. Keywords: Agar-Gel_Oil soft tissue phantom, K-distribution shape parameter, temperaturę measurements Affiliations:
Kruglenko E. | - | IPPT PAN | Gambin B. | - | IPPT PAN |
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17. |
Doubrovina O.♦, Gambin B., Kruglenko E., Temperature level and properties of wavelet approximations of back scattered ultrasound,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.17, pp.37-46, 2014Abstract: The aim of the paper is to find links between the dynamics of changes of statistical parameters and changes in spectral properties of the signal envelope of backscattered RF signals during the thermal process. We have shown previously that by using wavelet approximations these tendencies are better recognized in the case of the heating of a phantom sample than in the parallel analysis performed for a full signal envelope. Here we are currently expanding this statement to the case of heating a soft tissue sample in vitro. The shape parameter of the K- distributed random variable is considered as a statistical marker of temperature level changes. Additionally, the spectral properties of different levels of wavelet approximations are calculated and their sensitivity to temperature increase and decrease is demonstrated. Both approaches registering changes in temperature, are used in the case of the pork loin tissue sample in vitro, heated by an ultrasound beam with a different power. Keywords: ultrasound echoes, soft tissue sample in vitro, statistical marker of temperaturę rise Affiliations:
Doubrovina O. | - | Belarussian State University (BY) | Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN |
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18. |
Kruglenko E., Gambin B., Cieślik L., Soft Tissue-Mimicking Materials With Various Number of Scatterers and Their Acoustical Characteristics,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.16, pp.121-128, 2013Abstract: For the study of the temperature increase in the soft tissues irradiated by a low-power ultrasound [1], soft tissue-mimicking materials can be used. The phantoms have been produced based on an aqueous solution of agar, oil, and glass beads microparticles. The RF signals collected in the experiments enabled evaluation of the acoustic properties of phantoms with different number of strong scatterers (concentration varied from 0 to 30 pcs/mm3). Speed of sound (SOS) determined for the phantoms was similar to the value typical of soft tissue (about 1540 m/s). To determine attenuation coefficient the semi-transmission method has been used. Attenuation coefficient value varied from 0.5 to 1.1 dB/(MHz cm), depending on the number of scatterers. It was shown that the phantoms stored for 6 months preserved their acoustical properties and were usable for further experiments. It was found that within the total attenuation, the part corresponding to scattering can be distinguished. Keywords: acoustical characteristics, soft tissue mimicking material, scatterers number Affiliations:
Kruglenko E. | - | IPPT PAN | Gambin B. | - | IPPT PAN | Cieślik L. | - | IPPT PAN |
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19. |
Kruglenko E., Wpływ zmienności właściwości fizycznych tkanki na rozkład temperatury w tkance przy terapeutycznym oddziaływaniu ultradźwięków,
INŻYNIERIA BIOMEDYCZNA/BIOMEDICAL ENGINEERING, ISSN: 1234-5563, Vol.18, No.4, pp.250-254, 2012Abstract: Artykuł dotyczy numerycznego wyznaczania in vivo przestrzennego i czasowego rozkładu temperatury po oddziaływaniu na tkankę zogniskowaną wiązką ultradźwiękową małej mocy. Celem pracy jest analiza wpływu parametrów fizycznych tkanki na rozkład temperatury oraz przedstawienie wyników obliczeń dla modelu wątroby szczura, w którym uwzględniono zależność parametrów fizycznych tkanki od temperatury. Wykazano, że przewidywana temperatura tkanki po 20-minutowym oddziaływaniu w większym stopniu zależy od zmiany przewodnictwa cieplnego tkanki niż od jej ciepła właściwego. Parametry materiałowe wody i tkanki wątroby przyjęto na podstawie danych z literatury. Założono, że geometria modelu numerycznego odpowiada rzeczywistemu położeniu obszaru oddziaływania względem głowicy emitującej zogniskowaną wiązkę ultradźwiękową. Keywords: wiązka ultradźwiękowa małej mocy, rozkład temperatury, tkanka miękka, przewodność cieplna, ciepło właściwe Affiliations:
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Gambin B., Kruglenko E., Kujawska T., Michajłow M.♦, Modeling of tissues in vivo heating induced by exposure to therapeutic ultrasound,
ACTA PHYSICA POLONICA A, ISSN: 0587-4246, Vol.119, pp.950-956, 2011Abstract: The aim of this work is mathematical modeling and numerical calculation in space and time of temperature fields induced by low power focused ultrasound beams in soft tissue in vivo after few minutes exposure time. These numerical predictions are indispensable for planning of various ultrasound therapeutic applications. Both, the acoustic pressure distribution and power density of heat sources induced in tissue, were calculated using the numerical solution to the second order nonlinear differential wave equation describing propagation of the high intensity acoustic wave in three-layer structure of nonlinear attenuating media. The problem of the heat transfer in living tissues is modelled by the Pennes equation, which accounts for the effects of heat diffusion, blood perfusion losses and metabolism rate. Boundary conditions and geometry are chosen according to the anatomical dimensions of a rat liver. The obtained results are compared with those calculated previously and verified experimentally for temperature elevations induced by ultrasound in liver samples in vitro. The analysis of the results emphasizes the value of the blood perfusion and the values of heat conductivity on the temperature growth rate. The numerical calculations of temperature fields were performed using the ABAQUS FEM software package. The thermal and acoustic properties of the liver and water being the input parameters to the numerical model were taken from the published data in cited references. The range of thermal conductivity coefficient of living tissue is obtained from the model of two-phase composite medium with given microstructure. The first component is a “solid” tissue and the second one corresponds to blood vessels area. The circular focused ultrasonic transducer with a diameter of 15 mm, focal length of 25 mm and resonance frequency of 2 MHz has been used to generate the pulsed ultrasonic beam in a very introductory experiment in vivo, which has been performed. Numerical prediction confirms qualitatively its results. Keywords: focused ultrasound, soft tissues, local thermal fields, numerical modelling Affiliations:
Gambin B. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Kujawska T. | - | IPPT PAN | Michajłow M. | - | other affiliation |
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Kruglenko E., Gambin B., Some aspects of numerical modeling of temperature increase due to ultrasound beam irradiation of rat liver,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.14, pp.99-110, 2011Abstract: Some aspects of FEM modeling of hyperthermia, the procedure of tissue temperature rise above 37 oC inside the living organism, as a treatment modality, are studied. Low intensity focused ultrasound (LIFU) beam has been used as a source of temperature rise in the liver tissue during performed experiments in vitro. The comparison of the FEM model of the corresponding heating process and the experimental results has been presented in [1]. In the paper, the FEM model of heating scheme of the rat liver tissue in vivo irradiated by the same ultrasound transducer is formulated. At first, the existence of blood perfusion is taken into account in the model equation. Secondly, the thermal and acoustical properties, which are the input parameters of the numerical model, are taken from the published data in literature. Here, the size and the intensity of heat sources are modeled in two ways on the basis of acoustic nonlinear equation solutions in 3 layers attenuating medium. We demonstrate how the results of FEM model in the case of in vitro and in vivo heating, depend on the assumed power density of heat sources, as well as on the size of the heated area. The results are compared and discussed. The influence of different models on temperature rise profiles are demonstrated. Affiliations:
Kruglenko E. | - | IPPT PAN | Gambin B. | - | IPPT PAN |
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Gambin B., Kujawska T., Kruglenko E., Mizera A., Nowicki A., Temperature fields induced by low power focused ultrasound during gene therapy. Numerical predictions and experimental results,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.34, No.4, pp.445-460, 2009Abstract: The aim of this work is twofold. Firstly, to verify a theoretical model which is capable of predicting temperature fields appearing in soft tissues during their ultrasound treatment. Secondly, to analyze some aspects of the dynamics of Heat Shock Response induced by the heating process in the context of therapeutic treatment. The theoretical investigations and quantitive analysis of temperature increments at any field point versus time of heating process, depending on the heat source power, spatial distribution and duration as well as on the tissue thermal properties, has been carried out by Finite Element Method (FEM). The validation of the numerical model has been performed by comparison of the calculation results with the experimental data obtained by measuring in vitro of the 3D temperature increments induced in samples of the turkey and veal liver by the circular focused transducer with the diameter of 15 mm, focal length of 25 mm and resonance frequency of 2 MHz. Various ultrasonic regimes were considered. They were controlled by adjusting ultrasound power and exposure time. The heat shock proteins (HSP) and misfolded proteins (MFP) levels during the proposed cyclic sonification are presented. Keywords: heat-responsive gene therapy, temperature field, low-power focused ultrasound, soft tissues, ultrasonic regime control, heat sources distribution, heat shock proteins Affiliations:
Gambin B. | - | IPPT PAN | Kujawska T. | - | IPPT PAN | Kruglenko E. | - | IPPT PAN | Mizera A. | - | IPPT PAN | Nowicki A. | - | IPPT PAN |
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Bielski W.♦, Kruglenko E., Telega J.J., Young measures and their applications in micromechanics and optimization. I. Mathematical principles.,
Mathematica Applicanda (Matematyka Stosowana), ISSN: 1730-2668, DOI: 10.14708/ma.v31i45/04.1914, Vol.31, No.45/04, pp.90-138, 2003Abstract: The paper is a review of modern mathematical methods for the analysis of continuous problems of nonlinear mechanics and magnetism. The bibliography contains 175 items. The second part of the paper deals with mechanical problems described by nonconvex density energy functions and with numerical methods to solve such problems. Affiliations:
Bielski W. | - | Institute of Geophysics (PL) | Kruglenko E. | - | IPPT PAN | Telega J.J. | - | IPPT PAN |
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