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Relevant bibliographies by topics / High-frequency hyperthermia

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Academic literature on the topic 'High-frequency hyperthermia'

Author: Grafiati

Published: 30 May 2022

Last updated: 31 May 2022

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Journal articles on the topic "High-frequency hyperthermia"

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Tapper, Simon, Joseph J. Nocera, and Gary Burness. "Experimental evidence that hyperthermia limits offspring provisioning in a temperate-breeding bird." Royal Society Open Science 7, no. 10 (October 2020): 201589. http://dx.doi.org/10.1098/rsos.201589.

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In many vertebrates, parental care can require long bouts of daily exercise that can span several weeks. Exercise, especially in the heat, raises body temperature, and can lead to hyperthermia. Typical strategies for regulating body temperature during endurance exercise include modifying performance to avoid hyperthermia (anticipatory regulation) and allowing body temperature to rise above normothermic levels for brief periods of time (facultative hyperthermia). Facultative hyperthermia is commonly employed by desert birds to economize on water, but this strategy may also be important for chick-rearing birds to avoid reducing offspring provisioning when thermoregulatory demands are high. In this study, we tested how chick-rearing birds balance their own body temperature against the need to provision dependent offspring. We experimentally increased the heat dissipation capacity of breeding female tree swallows ( Tachycineta bicolor ) by trimming their ventral feathers and remotely monitored provisioning rates, body temperature and the probability of hyperthermia. Birds with an experimentally increased capacity to dissipate heat (i.e. trimmed treatment) maintained higher feeding rates than controls at high ambient temperatures (greater than or equal to 25°C), while maintaining lower body temperatures. However, at the highest temperatures (greater than or equal to 25°C), trimmed individuals became hyperthermic. These results provide evidence that chick-rearing tree swallows use both anticipatory regulation and facultative hyperthermia during endurance performance. With rising global temperatures, individuals may need to increase their frequency of facultative hyperthermia to maintain nestling provisioning, and thereby maximize reproductive success.

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Barker, WJ, JT Amsterdam, SA Syverud, JR Hedges, and JS Huff. "High-frequency jet ventilation cooling in a canine hyperthermia model." Annals of Emergency Medicine 14, no. 5 (May 1985): 501–2. http://dx.doi.org/10.1016/s0196-0644(85)80367-x.

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Barker, William J., James T. Amsterdam, Scott A. Syverud, Jerris R. Hedges, and J. Stephen Huff. "High-frequency jet ventilation cooling in a canine hyperthermia model." Annals of Emergency Medicine 15, no. 6 (June 1986): 680–84. http://dx.doi.org/10.1016/s0196-0644(86)80425-5.

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Nomura, Shinichi, and Takanori Isobe. "Design Study on High-Frequency Magnets for Magnetic Hyperthermia Applications." IEEE Transactions on Applied Superconductivity 28, no. 3 (April 2018): 1–7. http://dx.doi.org/10.1109/tasc.2018.2800056.

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Kobayashi, Katsuhiro, Iori Ohmori, Keiichiro Hayashi, Yuichiro Kitagawa, Mamoru Ouchida, Takushi Inoue, and Yoko Ohtsuka. "High-frequency EEG oscillations in hyperthermia-induced seizures of Scn1a mutant rats." Epilepsy Research 103, no. 2-3 (February 2013): 161–66. http://dx.doi.org/10.1016/j.eplepsyres.2012.07.020.

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Zeinoun, Michael, Diego Serrano, Pablo Tezanos Medina, Oscar Garcia, Miroslav Vasic, and Jose Javier Serrano-Olmedo. "Configurable High-Frequency Alternating Magnetic Field Generator for Nanomedical Magnetic Hyperthermia Applications." IEEE Access 9 (2021): 105805–16. http://dx.doi.org/10.1109/access.2021.3099428.

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Caizer, Costica. "Optimization Study on Specific Loss Power in Superparamagnetic Hyperthermia with Magnetite Nanoparticles for High Efficiency in Alternative Cancer Therapy." Nanomaterials 11, no. 1 (December 26, 2020): 40. http://dx.doi.org/10.3390/nano11010040.

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The cancer therapy with the lowest possible toxicity is today an issue that raises major difficulties in treating malignant tumors because chemo- and radiotherapy currently used in this field have a high degree of toxicity and in many cases are ineffective. Therefore, alternative solutions are rapidly being sought in cancer therapy, in order to increase efficacy and a reduce or even eliminate toxicity to the body. One of the alternative methods that researchers believe may be the method of the future in cancer therapy is superparamagnetic hyperthermia (SPMHT), because it can be effective in completely destroying tumors while maintaining low toxicity or even without toxicity on the healthy tissues. Superparamagnetic hyperthermia uses the natural thermal effect in the destruction of cancer cells, obtained as a result of the phenomenon of superparamagnetic relaxation of the magnetic nanoparticles (SPMNPs) introduced into the tumor; SPMNPs can heat the cancer cells to 42–43 °C under the action of an external alternating magnetic field with frequency in the range of hundreds of kHz. However, the effectiveness of this alternative method depends very much on finding the optimal conditions in which this method must be applied during the treatment of cancer. In addition to the type of magnetic nanoparticles and the biocompatibility with the biological tissue or nanoparticles biofunctionalization that must be appropriate for the intended purpose a key parameter is the size of the nanoparticles. Also, establishing the appropriate parameters for the external alternating magnetic field (AMF), respectively the amplitude and frequency of the magnetic field are very important in the efficiency and effectiveness of the magnetic hyperthermia method. This paper presents a 3D computational study on specific loss power (Ps) and heating temperature (ΔT) which allows establishing the optimal conditions that lead to efficient heating of Fe3O4 nanoparticles, which were found to be the most suitable for use in superparamagnetic hyperthermia (SPMHT), as a non-invasive and alternative technique to chemo- and radiotherapy. The size (diameter) of the nanoparticles (D), the amplitude of the magnetic field (H) and the frequency (f) of AMF were established in order to obtain maximum efficiency in SPMHT and rapid heating of magnetic nanoparticles at the required temperature of 42–43 °C for irreversible destruction of tumors, without affecting healthy tissues. Also, an analysis on the amplitude of the AMF is presented, and how its amplitude influences the power loss and, implicitly, the heating temperature, observables necessary in SPMHT for the efficient destruction of tumor cells. Following our 3D study, we found for Fe3O4 nanoparticles the optimal diameter of ~16 nm, the optimal range for the amplitude of the magnetic field of 10–25 kA/m and the optimal frequency within the biologically permissible limit in the range of 200–500 kHz. Under the optimal conditions determined for the nanoparticle diameter of 16.3 nm, the magnetic field of 15 kA/m and the frequency of 334 kHz, the magnetite nanoparticles can be quickly heated to obtain the maximum hyperthermic effect on the tumor cells: in only 4.1–4.3 s the temperature reaches 42–43 °C, required in magnetic hyperthermia, with major benefits in practical application in vitro and in vivo, and later in clinical trials.

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Gkanas, Evangelos. "In vitro magnetic hyperthermia response of iron oxide MNP’s incorporated in DA3, MCF-7 and HeLa cancer cell lines." Open Chemistry 11, no. 7 (July 1, 2013): 1042–54. http://dx.doi.org/10.2478/s11532-013-0246-z.

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AbstractIn the current work, iron oxide magnetic nanoparticles (MNP’s) were synthesized by thermal decomposition of Fe(acac)3-(iron acetylacetonate) compounds in high-boiling organic solvents containing stabilizing surfactants and examined as possible agents for magnetic hyperthermia treatment, according to their structural, magnetic and heating properties. Three different cancer cell lines (DA3, MCF-7 and HeLa cell lines) were used to assess the suitability of the MNP’s. The experimental results proved that the synthesized MNPs are non-toxic and the uptake efficiency was extremely good. Further, from in vitro hyperthermia results, very fast thermal response was observed (reaching hyperthermia levels in less than 200 s), which minimize the duration of the cell and human body exposure in a high frequency AC external magnetic field.

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Xu, Hang, Shinichi Nomura, and Takanori Isobe. "Design and Development of a High-Frequency Magnet Prototype for Magnetic Hyperthermia Applications." IEEE Transactions on Applied Superconductivity 30, no. 4 (June 2020): 1–6. http://dx.doi.org/10.1109/tasc.2020.2978791.

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Ibarra M, Carlos A., Shiwen Wu, Kumiko Murayama, Narihiro Minami, Yasuko Ichihara, Hirosato Kikuchi, Satoru Noguchi, Yukiko K. Hayashi, Ryoichi Ochiai, and Ichizo Nishino. "Malignant Hyperthermia in Japan." Anesthesiology 104, no. 6 (June 1, 2006): 1146–54. http://dx.doi.org/10.1097/00000542-200606000-00008.

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Background Malignant hyperthermia (MH) is a disorder of calcium homeostasis in skeletal muscle triggered by volatile anesthetics or succinylcholine in susceptible persons. More than 100 mutations in the ryanodine receptor type 1 gene (RYR1) have been associated with MH susceptibility, central core disease, or both. RYR1 mutations may account for up to 70% of MH-susceptible cases. The authors aimed to determine the frequency and distribution of RYR1 mutations in the Japanese MH-susceptible population. Methods The authors selected 58 unrelated Japanese diagnosed as MH-susceptible for having an enhanced Ca-induced Ca release rate from the sarcoplasmic reticulum on chemically skinned muscle fibers. They sequenced the entire RYR1 coding region from genomic DNA. Muscle pathology was also characterized. Results Seven previously reported and 26 unknown RYR1 potentially pathogenic sequence variations were identified in 33 patients (56.9%). Of these patients, 48% had cores on muscle biopsy. The mutation detection rate was higher in patients with clear enhancement of Ca-induced Ca release rate (72.4%), whereas all patients with central core disease had RYR1 mutations. Six patients harbored potentially causative compound heterozygous sequence variations. Conclusions Distribution and frequency of RYR1 mutations differed markedly from those of the North American and European MH-susceptible population. Comprehensive screening of the RYR1 gene is recommended for molecular investigations in MH-susceptible individuals, because many mutations are located outside the "hot spots." Based on the observed occurrence of compound heterozygous state, the prevalence of a possibly predisposing phenotype in the Japanese population might be as high as 1 in 2,000 people.

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Dissertations / Theses on the topic "High-frequency hyperthermia"

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Pothecary, N. M. "The interaction of high frequency fields with physical objects and the resultant thermal response." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385685.

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Сокол, Евгений Иванович, Л. А. Поспелов, Константин Васильевич Колесник, and Юрий Петрович Федоренко. "Повышение эффективности гипертермического медицинского комплекса с помощью криогенной системы термостабилизации." Thesis, Политехпериодика, 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/32439.

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Проанализированы достоинства криогенной системы хладагента для ВЧ-гипертермии в сравнении с аналогичной системой, использующей фреоновый генератор холода.
Advantages of the cryogenic system refrigerant for HF hyperthermia in comparison with a similar system that uses freon generator cold are analyzed.

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Sessel, Gareth Kevin. "A technique for the production of a high amplitude, high frequency, concentrated magnetic field for use in hyperthermia applications." Thesis, 2013. http://hdl.handle.net/10539/12404.

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Cancer of the liver is a common disease with a relatively poor prognosis. Hyperthermia is an exciting treatment that is under investigation. One modality of hyperthermia therapy makes use of an external magnetic field to produce losses in magnetic particles that have been supplied to the tumour. The losses result in the heating of the tumour cells thereby causing cell destruction. There exists a limit in the product of magnetic field intensity and frequency, above which eddy currents reach levels capable of causing thermal damage in healthy tissue. This limit is well documented in the literature and, due to the seriousness of the disease, can be increased to 5 x 109 A/ms. The magnetic field used by most researchers is produced by simple coils. Using these simple coils, it is very difficult to produce sufficient heating throughout the tumour cells without exceeding the safety limit in healthy tissue. This research provides a machine that is capable of producing a magnetic field of sufficient energy to cause therapeutic heating within the tumour region whilst remaining within the safety limit elsewhere. A design methodology for this machine is demonstrated. A prototype machine is built and tested in order to validate the design procedure. The results from the prototype experiment are in good agreement with those predicted by the theory. The idea of “focussing” a magnetic field in distances far smaller than the wavelength of the field is a novel concept. This fundamentally new research has the potential to assist in the development of a treatment for tumour sufferers.

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Books on the topic "High-frequency hyperthermia"

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Bruggmoser, G., W. Hinkelbein, R. Engelhardt, and M. Wannenmacher, eds. Locoregional High-Frequency Hyperthermia and Temperature Measurement. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82530-9.

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1948-, Bruggmoser G., ed. Locoregional high-frequency hyperthermia and temperature measurement. Berlin: Springer-Verlag, 1986.

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Bruggmoser, G. Locoregional High-Frequency Hyperthermia and Temperature Measurement. Springer-Verlag, 2011.

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Book chapters on the topic "High-frequency hyperthermia"

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Gentilal, Nichal, Ricardo Salvador, and Pedro Cavaleiro Miranda. "A Thermal Study of Tumor-Treating Fields for Glioblastoma Therapy." In Brain and Human Body Modeling 2020, 37–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_3.

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AbstractTumor-treating fields (TTFields) is an antimitotic cancer treatment technique used for glioblastoma multiforme (GBM) and malignant pleural mesothelioma. Although the frequency used is not as high as in hyperthermia, temperature increases due to the Joule effect might be meaningful given the necessary time that these fields should be applied for. Post hoc analysis of the EF-11 clinical trial showed higher median overall survival in patients whose compliance was at least 18 h per day. To quantify these temperature increases and predict the thermal impact of TTFields delivery to the head, we used a realistic model created from MR images segmented in five tissues: scalp, skull, CSF, gray matter (GM), and white matter (WM). Through COMSOL Multiphysics, we solved Laplace’s equation for the electric field and Pennes’ equation for the temperature distribution. To mimic the therapy as realistically as possible, we also considered complete current shutdown whenever any transducer reached 41 °C to allow transducers and tissues’ temperature to decrease. Our results indicate an intermittent operation of Optune due to this necessary current shutdown. Localized temperature increases were seen, especially underneath the regions where the transducers were placed. Maximum temperature values were around 41.5 °C on the scalp and 38 °C on the brain. According to the literature, significant thermal impact is only predicted for the brain where the rise in temperature may lead to an increased BBB permeability and variation in the blood flow and neurotransmitter concentration. Additionally, our results showed that if the injected current is reduced by around 25% compared to Optune’s standard way of operating, then uninterrupted treatment might be attainable. These predictions might be used to improve TTFields delivery in real patients and to increase awareness regarding possible thermal effects not yet reported elsewhere.

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Telling, Neil. "High-Frequency Magnetic Response and Hyperthermia From Nanoparticles in Cellular Environments." In Nanomaterials for Magnetic and Optical Hyperthermia Applications, 173–97. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-12-813928-8.00007-7.

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Puri, Ajay K., and Melissa A. McGuire. "He Went Wee, Wee, Wee All Night Long." In Pediatric Medical Emergencies, 159–68. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780190946678.003.0017.

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Hyperosmolar hyperglycemic syndrome is a condition occurring with increasing frequency in the pediatric population that carries a high mortality rate. Obese males of African American descent are most at risk. Diagnosis requires a high degree of suspicion as patients often present with nonspecific symptoms. A fingerstick glucose sample and laboratory testing are primary identifiers of type 2 diabetes mellitus. The hallmark of management of these patients involves aggressive fluid resuscitation and close management of their electrolytes. Patients may present with features of diabetic ketoacidosis, which presents a unique challenge to treatment. Complications such as rhabdomyolysis, malignant hyperthermia, and cerebral edema need to be identified early and managed promptly.

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Conference papers on the topic "High-frequency hyperthermia"

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Sarnago, H., O. Lucia, and J. M. Burdio. "High frequency and power density gallium nitride based inverter for magneto fluid hyperthermia." In IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society. IEEE, 2016. http://dx.doi.org/10.1109/iecon.2016.7793076.

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Jiang, Junfeng, Ruoyu Hong, Xiaohui Zhang, and Hongzhong Li. "On the in Vitro Hyperthermia of Magnetic Fluid in AC Magnetic Field." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18547.

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Hyperthermia therapy for cancer has attracted much attention nowadays. The study on the heat transfer in the magnetic fluid and the tumor is crucial for the successful application of magnetic fluid hyperthermia (MFH). Water-based Fe3O4 magnetic fluid is expected to be a most appropriate candidate for MFH due to the good biocompatibility, high saturation magnetization, super-paramagnetization and high chemical stability. In this paper, we explore the heat generation and transfer in magnetic fluid which is placed under an AC magnetic field. It is found that the amplitude and the frequency of alternating magnetic field, particle size and volume fraction have a pronounce influence on maximum temperature of hyperthermia.

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Nowak, G., Athanase-Jorge A. Terzis, O. Rentzsch, and H. Arnold. "Induced hyperthermia in brain tissue: comparison between contact Nd:YAG laser system and automatically controlled high-frequency current." In OE/LASE '90, 14-19 Jan., Los Angeles, CA, edited by Stephen N. Joffe and Kazuhiko Atsumi. SPIE, 1990. http://dx.doi.org/10.1117/12.17432.

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Li, B. Q., C. Mi, C. Liu, G. Cheng, M. Fu, and G. Meadow. "Nanoparticle Heat Transfer and Its Application to Laser Hyperthermia." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43083.

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Nanoparticles-enabled laser hyperthermia holds a great promise as a new therapeutic treatment for cancer patients. This paper presents some preliminary data on the frequency tenability of nanostructures and on the heat transfer aspect of this process that results from the interaction between high frequency electromagnetic field and nanostructures. Maxwell equations are solved to predict heat generation from the surface plasma resonance excitation of a nano-sized particle or structure by a laser beam. An experimental system has also been setup to validate the concept of heat generation through particle-laser interaction. Results obtained on both model tissues and on mice are consistent with the model predictions. Experiments further show that concentrated local heating can be generated in cancerous cells for a thermal kill.

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Gordon, Danica, and Chandrasekhar Thamire. "Ultrasound Hyperthermia: Dose Estimation and Device Design." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87790.

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As a cancer treatment modality, thermal ablation offers the advantages of being less invasive and posing fewer post-procedural complications compared to traditional cancer therapies. It involves destroying cancerous cells by subjecting them to the appropriate amount of heat dose. In the present study, high frequency ultrasound (US) ablation is theoretically examined for effectiveness as a treatment modality for intraluminal and extracorporeal cancer treatment. Objectives of this study are to 1) develop thermal-damage correlations for a variety of cancer cells and 2) design US treatment devices, based on thermal damage correlations developed, and treatment planning protocols. To achieve these goals, thermal damage information for different cell types is first determined from earlier studies or pilot experiments. Required US doses for specific tissues are determined next through numerical experiments. Device design and estimation of thermal coagulation contours is then performed by comparing temperature-history data against the thermal-damage data for a range of device parameters. Treatment protocols are finally developed based on the analysis of the results for a range of applicable device parameters. Results are presented in terms of correlations for the volume and location of ablated tissue corresponding to a range of operating parameter values.

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Echeverria, Esteban, and Chandrasekhar Thamire. "Development of an Ultrasound Hyperthermia Simulator for Therapeutic Applications." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64205.

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In recent times, Ultrasound for therapeutic applications is becoming increasingly popular due to its high practicality and efficiency. However, determination of adequate dosages presents a great challenge due to the difficulty of measuring tissue temperatures during the process. Further, accurate calculation of temperature field induced by ultrasound within the tissue is difficult to develop because of the time-scale differences between pressure and temperature analyses. In order to overcome this issue, practical and accurate methods to couple both analyses are needed. In the present study, Westervelt’s nonlinear wave equation is used to simulate ultrasonic propagation driven by an unfocused piston source in an axisymmetric biological tissue phantom. Using the Finite Difference Time Domain (FDTD) method, a pressure field was calculated for different sinusoidal bursts, frequencies, and source pressures. Average heat generation fields were calculated from the pressure field within an adequate time range for practical purposes. The Pennes bioheat transfer equation with the calculated heat generation fields were used to acquire transient temperature distributions. Effect of source pressure, frequency, source radius, and trial duration on the temperature profiles was examined. It can be observed from the simulations that continuous wave signals increase temperature at a focus in shorter times, while discrete pulses with adequate duty factors can be useful in maintaining required temperatures constant while diffusing heat along the tissue. The methodology presented here can be of use in many applications such as increasing necrotic volume for tissue ablation purposes.

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Gordon, Danica, and Chandrasekhar Thamire. "Ultrasound Hyperthermia: Dose Estimation and Device Design for Intraluminal and External Delivery." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80345.

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Thermal ablation in the context of this study refers to destroying cancer cells by heating them to supraphysiological temperatures for appropriate times. Once the tumor cells and a small layer of surrounding tissue cells are killed, they are absorbed by the body over time. Compared to open surgery, radiation, and chemotherapy, thermal therapy can be less expensive and pose less risk of harmful post-procedural complications, while possessing the potential to be effective [1]. Currently microwave and radiofrequency ablation are in use for local hyperthermia; however, they lack the ability to focus heat into the target zones effectively or treat larger tumors without affecting the surrounding healthy tissue. In the current study, high frequency ultrasound (US) ablation is examined as a treatment modality because of its ability to focus and control heat effectively. Objectives of this study are to 1) develop thermal-damage correlations for US thermal therapy and 2) design delivery devices and associated treatment planning protocols. To achieve these goals, thermal damage information is first evaluated for a variety of cells and tissues from published data or pilot experiments. Required US dose levels are determined next through numerical experiments, followed by device design and estimation of thermal coagulation contours by comparing the temperature-history data against the thermal-damage data. Based on the analysis of the results for a range of parameters, namely, the applicator power, geometry, frequency, coolant parameters, treatment time, and tissue perfusion, treatment protocols are developed. Intraluminal, external, and interstitial modes of delivery are considered for focal sites in a variety of target areas. In the following sections, methods followed and sample results obtained are presented.

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Grosh, Karl, John M. Dodson, and Yuan Lin. "Finite Element Methods for the Radiation of Ultrasonic Phased Arrays Into an Acoustic Medium." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-3840.

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Abstract In this paper, the dynamic response of a piezoelectric transducer in contact with an acoustic media is formulated. This serves as a model problem for an ultrasonic phased array in contact with the human body. These arrays may be used for hyperthermia or ablation surgery; the focus of this paper, however, is the efficient numerical formulation for modeling the array problem. Efficient numerical methods will provide a useful design tool and allow for the investigation of structural–acoustic phenomena. A finite element formulation based on Galerkin and Galerkin Least Squares (GLS) methods is presented. The benefits of the GLS method over the standard Galerkin method are demonstrated through numerical experiments of the dynamic response of a multi–element array. The methods under development can be applied to any fluid structure interaction problem and point strongly to the advantage of GLS methods for mid– and high–frequency applications. The accuracy of approximate versus exact non–reflecting, truncation boundary conditions is discussed.

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Zhu, Yiying I., Timothy L. Hall, and Oliver D. Kripfgans. "Programmable Ultrasound Phased Array Therapy System." In 2017 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dmd2017-3370.

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There has been an emerging interest in high intensity focused ultrasound (HIFU) for therapeutic applications. By means of its thermal or mechanical effects, HIFU is able to serve as a direct tool for tissue ablation, or an indirect moderating medium to manipulate microbubbles or perform heating (hyperthermia) for the purpose of targeted drug delivery. The development and testing of HIFU based phased arrays is favorable as their elements allow for individual phasing to steer and focus the beam. While FDA has already approved tissue ablation by HIFU for the treatment of uterine fibroids (2004) and pain from bone metastases (2012), development continues on other possible applications that are less forgiving of incomplete treatment, such as thermal necrosis of malignant masses. Ideally, each element, of such an array must have its own fully programmable electrical driving channel, which allows the control of delay, phase, and amplitude of the output from each element. To enable full control, each channel needs a waveform generator, an amplification device, and an impedance matching circuit between driver and acoustic element. Similar projects utilizing this approach to drive therapeutic arrays include a 512-channel therapy system which was built at the University of Michigan using low cost Field-Programmable Gate Arrays (FPGA) microcontroller and highly efficient MOSFET switching amplifiers [1]. However, this system lacks the ability to drive both, continuous wave (CW) and transient short duty-cycle high power pulses. This paper presents a hybrid system, which is able to perform CW and transient short duty-cycle high power excitation. In the following we will describe the design, programming, fabrication, and evaluation of this radiofrequency (RF) driver system as used in our laboratory for a 1.5 MHz center frequency, 298-element array (Imasonic SA, Besancon, France) [2], FPGA-controlled amplifier boards and matching circuitry. Advantages of our design include: 1. Inexpensive components (<$15/channel); 2. Ability to program/drive individual output channels independently; 3. Sufficient time and amplitude resolution for various acoustic pattern design; 4. Capability of hybrid switching between low power CW and short duty cycle, high instantaneous power.

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Nelson, David A., Allen R. Curran, Eric A. Marttila, Sylvain Charbonnel, and Dusan Fiala. "Thermoregulation in Humans: Results From an Anatomically-Based, High-Resolution Voxelized Model." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176527.

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The ability to predict local surface and internal temperatures in humans subjected to various environmental and direct thermal loads has applications which include assessment of human exposure to radio frequency radiation (RFR) from mobile phones [1], medical imaging technologies [2] and mild-temperature hyperthermia (MTH) treatment for some cancers [3].

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