Dissertations / Theses on the topic 'Hyperthermia'
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Nijhuis, Erwin. "Hyperthermia-induced apoptosis." Enschede : University of Twente [Host], 2008. http://doc.utwente.nl/59801.
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Habash, Riadh W. Y. "Non-Invasive Microwave Hyperthermia." Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/193.
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Presented in this thesis are the following theoretical investigations carried out on the non-invasive microwave hyperthermia of malignant tumours in the human body:
Fundamental concepts of electromagnetic wave propagation through a biomass and its interaction with it, are discussed. Various types of applicators used for producing hyperthermia in a biomass, are also discussed.
Propagation of a uniform plane electromagnetic wave through a human body is investigated for the general case of oblique incidence. Various models used for the human body have been discussed and the planar multilayer model has been chosen for this study. Reflection and transmission coefficients for both the parallel and perpendicular linear polarisations of the wave, have been determined. For normal incidence, power transfer ratio at the muscle has been defined and calculated at 433, 915 and 2450 MHz (ISM frequencies).
Efects of skin thickness and also of fat thickness, on the power transfer ratio at muscle, have been studied. Effects of the thickness and dielectric constant of a bolus, and also of the dielectric constant of an initial layer, on the power transfer ratio, have been studied and their optimum values obtained at the ISM frequencies. For microwave hyperthermia, 915 MHz is recommended as the frequency of operation.
Steady-state solution of the bioheat transfer equation has been obtained, assuming the biomass to be a semi-infinite homogeneous medium. Effects of various physical parameters on the temperature profile in the biomass, have been studied. Also studied is the effect of the surface temperature on the magnitude, location and the width of the temperature peak attained in the biomass. A method to determine the microwave power and the surface temperature required to produce a prescribed temperature profile in the biomass, has been developed. The transient-state solution of the bioheat transfer equation has been obtained to study the building up of the temperature profile.
Procedures for the design of an open-ended rectangular metal waveguide applicator and for estimating the total microwave power requirement to produce hyperthermia in the human body, have been developed. Performance of the applicators employing linear as well as planar arrays of open-ended rectangular metal waveguide antennas, has also been studied. In order to reduce the overall physical size of the applicators, filling up of the feed waveguide with a high dielectric constant but low loss material is suggested. A simple method of obtaining the elements of the array by partitioning a large aperture by using metal walls has been adopted. Calculation of the total microwave power required by various applicators for producing hyperthermia at various depths in a biomas, have been made and a comparison of the performance of various applicators, has been presented.
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Habash, Riadh W. Y. "Non-Invasive Microwave Hyperthermia." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/193.
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Presented in this thesis are the following theoretical investigations carried out on the non-invasive microwave hyperthermia of malignant tumours in the human body:
Fundamental concepts of electromagnetic wave propagation through a biomass and its interaction with it, are discussed. Various types of applicators used for producing hyperthermia in a biomass, are also discussed.
Propagation of a uniform plane electromagnetic wave through a human body is investigated for the general case of oblique incidence. Various models used for the human body have been discussed and the planar multilayer model has been chosen for this study. Reflection and transmission coefficients for both the parallel and perpendicular linear polarisations of the wave, have been determined. For normal incidence, power transfer ratio at the muscle has been defined and calculated at 433, 915 and 2450 MHz (ISM frequencies).
Efects of skin thickness and also of fat thickness, on the power transfer ratio at muscle, have been studied. Effects of the thickness and dielectric constant of a bolus, and also of the dielectric constant of an initial layer, on the power transfer ratio, have been studied and their optimum values obtained at the ISM frequencies. For microwave hyperthermia, 915 MHz is recommended as the frequency of operation.
Steady-state solution of the bioheat transfer equation has been obtained, assuming the biomass to be a semi-infinite homogeneous medium. Effects of various physical parameters on the temperature profile in the biomass, have been studied. Also studied is the effect of the surface temperature on the magnitude, location and the width of the temperature peak attained in the biomass. A method to determine the microwave power and the surface temperature required to produce a prescribed temperature profile in the biomass, has been developed. The transient-state solution of the bioheat transfer equation has been obtained to study the building up of the temperature profile.
Procedures for the design of an open-ended rectangular metal waveguide applicator and for estimating the total microwave power requirement to produce hyperthermia in the human body, have been developed. Performance of the applicators employing linear as well as planar arrays of open-ended rectangular metal waveguide antennas, has also been studied. In order to reduce the overall physical size of the applicators, filling up of the feed waveguide with a high dielectric constant but low loss material is suggested. A simple method of obtaining the elements of the array by partitioning a large aperture by using metal walls has been adopted. Calculation of the total microwave power required by various applicators for producing hyperthermia at various depths in a biomas, have been made and a comparison of the performance of various applicators, has been presented.
4
Duong, Lawrence. "Computational electromagnetics in microwave hyperthermia." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=83861.
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Microwave hyperthermia is a cancer treatment used in combination with radiotherapy and/or chemotherapy. Hyperthermia sensitizes cancer cells to the primary treatment by sublethal heat. An antenna array non-invasively launches electromagnetic waves, targeting cancer cells, and produces preferential heating. This thesis discusses the two-arm Archimedean spiral antenna as a possible antenna to deliver such energy.Simulations are performed on a homogeneous cylindrical numerical phantom using the finite-difference time-domain (FDTD) method. FDTD is well-suited for the analysis of the interaction between electromagnetic waves and complex media.
This thesis explores two types of input signals to the antenna array: a continuous wave and a pulse. By strategically changing the phase of the continuous wave or the delay of the pulse of individual antenna elements, spots of maximal energy deposition within the phantom can be controlled. In the case of pulse-excited antenna array, temperature distribution is also computed.
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Thomas, L. "Nanoparticle synthesis for magnetic hyperthermia." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/646236/.
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This work reports on an investigation into the synthesis, control, and stabilisation of iron oxide nanoparticles for biomedical applications using magnetic hyperthermia. A new understanding of the factors effecting nanoparticle growth in a coprecipitation methodology has been determined. This thesis challenges the highly cited Ostwald Ripening as the primary mechanism for nanoparticulate growth, and instead argues that in certain conditions, such as increasing reaction temperature, a coalescence mechanism could be favoured by the system. Whereas in a system with a slower rate of addition of the reducing agent, Ostwald ripening is the favoured mechanism. The iron oxide nanoparticles made in the study were stabilised and functionalised for the purpose of stability in physiological environments using either carboxylic acid or phosphonate functionalised ligands. It was shown that phosphonate ligands form a stronger attachment to the nanoparticle surface and promote increased stability in aqueous solutions, however, this affected the magnetic properties of the particles and made them less efficient heaters when exposed to an alternating magnetic fields. Tiopronin coated iron oxide nanoparticles were a far superior heater, being over four times more effective than the best commercially available product. Due to its strong response, experiments into the antimicrobial properties of tiopronin coated iron oxide nanoparticles were undertaken, specifically on Staphylococcus aureus, to our knowledge this is the first time magnetic hyperthermia has been used for such an application. At concentrations of 50 mg/ml the sample was capable of complete bacterial kills following exposure to the in-house magnetic hyperthermia MACH system. Aging and oxidation over a period of a month did decrease the performance of the particles to kill bacteria using MACH heating, however they were still shown to be effective in killing Staphylococcus aureus.
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Neufeld, Esra. "High resolution hyperthermia treatment planning." Konstanz Hartung-Gorre, 2008. http://d-nb.info/992327873/04.
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Flores, Glen P. "Ferroelectric hyperthermia for cancer therapy." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001113.
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Taylor, Arthur. "Engineering Carbon Encapsulated Nanomagnets towards Their Use for Magnetic Fluid Hyperthermia." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-63695.
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Magnetic fluid hyperthermia is a potential therapy for achieving interstitial hyperthermia and is currently under clinical trials. This approach is based on the instillation of magnetic nanoparticles at the tumour site, which dissipate heat when exposed to an alternating magnetic field. This procedure leads to a local increase of temperature and induction of tumour death or regression. Nanoparticles of metallic iron are potential heating agents for this therapy, but rely on the presence of a protecting coat that avoids reactions with their environment. In this work, iron nanospheres and iron nanowires with a graphite coat are explored for this purpose. From these two nanostructures, the nanospheres are shown to have a greater potential in terms of heat dissipation. The graphite shell is further investigated as an interface for conjugation with other molecules of relevance such as drugs and fluorescent probes. The effect of acidic treatments on the magnetic and surface properties of the nanospheres is systematically studied and a suitable method to generate carboxylic functionalities on the nanoparticle surface alongside with a good preservation of the magnetic properties is developed. These carboxylic groups are shown to work as a bridge for conjugation with a model molecule, methylamine, as well as with a fluorescent dye, allowing the detection of the nanoparticles in cells by means of optical methods. The carboxylic functionalities are further explored for the conjugation with the anti-cancer drug cisplatin, where the amount of drug loaded per particle is found to be dependent on the density of free carboxylic groups. The release of the drug in physiological salt solutions is time and temperature dependent, making them particularly interesting for multi-modal anti-cancer therapies, where concomitant hyperthermia and chemotherapy could be achieved. Their potential for such therapies is shown in vitro by inducing hyperthermia in cell suspensions containing these nanoparticles. These results are finally translated to a three dimensional cell culture model where the in vitro growth of tumour spheroids is inhibited. The developed nanostructures have a great potential for therapeutic approaches based on the synergistic effects of hyperthermia and chemotherapy.
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Niculaes, Dina. "Iron oxide nanocubes for magnetic hyperthermia." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/441740.
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Durant la meva tesi s’han desenvolupat tres projectes principals, centrats en l'estudi de nanosistemes basats en l'ús de nanocubs d'òxid de ferro (IONCs) per a la hipertèrmia magnètica (HM).
S’ha demostrat l'ús innovador de la configuració de HM per a l'oxidació suau de nanocubs tipus core-shell Fe1-xO/Fe3-δO4 a una única fase de Fe3O4. Atès que els valors de la taxa d'absorció específica (SAR) dels nanocubs tipus core-shell wüstita/magnetita han estat menors en comparació amb els IONCs de magnetita amb una longitud d’aresta de cub similar, el nucli de FeO s’ha oxidat mitjançant estimulació MH. Després de diversos tractaments amb HM, els valors de SAR s’han duplicat, mentre que l'estabilitat col·loïdal, la distribució de mida i la forma no s’han vist afectades. Els IONCs estimulats magnèticament han mostrat un valor de magnetització de saturació més elevat, reflectint canvis estructurals i de composició, confirmats a través d'estudis de microscòpia electrònica i de dispositius superconductors d'interferència quàntica. El tractament suau amb HM també ha fet possible l'ancoratge de molècules biològicament rellevants a la superfície dels nanocubs, preservant la seva activitat i millorant alhora el rendiment tèrmic dels IONCs.
Els valors de SAR de IONCs tipus core-shell també s'han millorat acoblant els nanocubs en estructures de tipus cadena. Inicialment, es va desenvolupar l'agregació controlada dels IONCs durant la seva transferència en aigua, permetent la formació d'agregats (clústers) amb formats hidrodinàmics mitjans entre 30 i 100 nm. Així mateix, s’ha avaluat la resposta d’hipertèrmia de nanocubs individuals envers de nanoclústers col·loïdals tous de diferents mides. Les estructures denominades "dímers" i "trímers"—2D formades amb dos i tres IONCs—han mostrat valors SAR més alts.
S’ha aconseguit la càrrega de fàrmac en dos nanosistemes dissenyats per alliberament de fàrmac quimioterapèutic desencadenat mitjançant calor. Tots dos sistemes s’han basat en IONCs de magnetita revestits amb polímers termo-responsius carregats amb doxorubicina. L'objectiu era obtenir nanotransportadors estables a la temperatura corporal que alliberessin la càrrega exclusivament sota l'aplicació d'un camp magnètic altern (AMF). D'aquesta manera, un cop obtinguts els IONCs individuals revestits amb polímer termo-responsiu amb altsTres proyectos principales se desarrollaron durante mi tesis centrada en el estudio de nanosistemas basados en el uso de nanocubos de óxido de hierro (IONCs) para la hipertermia magnética (HM). Se demostró el uso novedoso de la configuración de HM para la oxidación suave de nanocubos tipo core-shell Fe1-xO/Fe3-δO4 a una única fase de Fe3O4. Dado que los valores de la tasa de absorción específica (SAR) de los nanocubos tipo core-shell wüstita/magnetita fueron menores en comparación con los IONCs de magnetita con una longitud de borde de cubo similar, el núcleo de FeO se oxidó mediante estimulación MH. Después de varios tratamientos con HM, los valores de SAR se duplicaron, mientras que la estabilidad coloidal, la distribución del tamaño y la forma no se vieron afectadas. Los IONCs estimulados magnéticamente mostraron un valor de magnetización de saturación más elevado, reflejando cambios estructurales y de composición, confirmados a través de estudios de microscopía electrónica y de dispositivos superconductores de interferencia cuántica. El tratamiento suave con HM también hizo posible el anclaje moléculas biológicamente relevantes a la superficie de los nanocubos preservando su actividad y mejorando al mismo tiempo el rendimiento térmico de los IONCs. Los valores de SAR de IONCs tipo core-shell también se han mejorado ensamblando los nanocubos en estructuras de tipo cadena. Inicialmente, se desarrolló la agregación controlada de los IONCs durante su transferencia en agua, permitiendo la formación de agregados (clusters) con tamaños hidrodinámicos medios entre 30 y 100 nm. Asimismo, se evaluó la respuesta de hipertermia de nanocubos individuales frente a nanoclusters coloidales blandos de diferentes tamaños. Las estructuras denominadas "dímeros" y "trímeros"—2D formadas con dos y tres IONCs—mostraron valores SAR más altos. Se logró la carga de fármaco en dos nanosistemas diseñados para liberación de fármaco quimioterapéutico desencadenada mediante calor. Ambos sistemas se basaron en IONCs de magnetita revestidas con polímeros termo-responsivos cargados con doxorrubicina. El objetivo era obtener nanotransportadores estables a la temperatura corporal que liberaran la carga exclusivamente bajo la aplicación de un campo magnético alterno (AMF). De este modo, una vez obtenidos los IONCs individuales revestidos con
Three main projects were conducted during my thesis that was focused on the study of nanosystems based on iron oxide nanocubes (IONCs) for magnetic hyperthermia (MH). The novel use of MH set-up for the mild oxidization of Fe1-xO/Fe3-δO4 core-shell nanocubes to single Fe3O4 phase was demonstrated. As specific absorption rate (SAR) values of wüstite/magnetite core-shell nanocubes were lower compared to magnetite IONCs of similar cube edge length, the FeO core was oxidized by MH stimulation. After several MH treatments, the SAR values increased twice, while colloidal stability, size distribution and shape remained unaffected. The magnetically stimulated IONCs showed higher saturation magnetization, reflecting structural and compositional changes, as confirmed by electron microscopy and superconductive quantum interference device studies. The mild MH treatment also opened up the possibility of attaching biologically relevant molecules to the surface of nanocubes and preserving their activity while improving the IONCs heat performance. The SAR values of core-shell IONCs were also enhanced by clustering the nanocubes in chain like structures. Initially, the controlled clustering of the IONCs during their water transfer was developed, enabling the formation of clusters with mean hydrodynamic sizes between 30 and 100 nm. The hyperthermia response of individual nanocubes vs. soft colloidal nanoclusters of different sizes was evaluated. The so called “dimers” and “trimers”—2D structures formed with two and three IONCs—showed higher SAR values. Drug loading on two nanosystems designed for heat-triggered chemotherapeutic drug release was achieved. Both systems were based on magnetite IONCs coated with thermo-responsive polymers loaded with doxorubicin. The goal was to have stable nanocarriers at body temperature that would release the cargo exclusively upon the application of an alternating magnetic field (AMF). Once individually thermo-responsive polymer coated IONCs with high SAR values were obtained, the heat-triggered doxorubicin release under AMF—at biologically relevant field conditions—was qualitatively, but not quantitatively proven.
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Ramasamy, Manoshika. "Material analysis of wearabale hyperthermia applicator." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20371.
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Master of ScienceDepartment of Apparel, Textiles, and Interior Design
Minyoung Suh
The purpose of this study was to explore printed antennas as an alternative technique for applying hyperthermia treatment. The antenna consisted of a printed ground plane and a thin copper plate. The ground plane was made of silver conductive ink printed on a flexible substrate. The challenge of the printed ground plane was limited conductivity. Multi-layer printing was one of the ways to increase the conductivity of the printed trace. This study examined whether the multiple-layered printings on the ground plane influence the performance of the antenna. The ground plane printed on a flexible substrate was evaluated for its conductivity and capacity to handle the heat energy for the extended time duration at the elevated temperature. This research was conducted in two experimental stages. The first stage of the experiment was designed to test conductivity of the ground plane. Ground planes were printed on a 32.5 mm × 17.0 mm substrate. The thickness and resistance of up to five layers of conductive printing were tested to verify how repeated printing improved the resistance and resistivity. Results showed that the multi-layering technique reduced the resistance of the printed trace, but statistically, the ground plane had no significant improvement in resistance beyond the triple layer printing. With an increase of the thickness, resistivity rather increased after the triple layer printing. The second stage of the experiment was used to assess the performance of the entire antenna. Antennas were fabricated using ground planes with triple and quintuple layers based on resistance and resistivity measurements. The antennas showed an acceptable level of performance in terms of antenna return loss and temperature elevation. The statistical analysis of return loss, power handling capability over the time, and temperature elevation was not significant among the antennas with triple and quintuple layered ground planes. Antennas were able to achieve 42 ˚C within 10 minutes at a 2cm deep location with the return loss of -13.76 dB. Most importantly, experimental results showed that antennas were able to handle 15 watt power without degrading the antenna performance. The antenna showed a successful performance in power handling and reaching the tumor temperature.
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Zeng, Xiaozheng. "Ultrasound phased array simulations for hyperthermia." Diss., Connect to online resource - MSU authorized users, 2008.
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Foroughmand, Ali Mohammad. "Molecular genetic analysis of malignant hyperthermia." Thesis, University of Leeds, 1997. http://etheses.whiterose.ac.uk/2649/.
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Malignant hyperthermia (MH) is the most common cause of unexpected death due to general anaesthesia using common volatile anaesthetic agents. It is an autosomal dominant pharmacogenetic abnormality of skeletal muscle with a high degree of genetic and clinical variability. It is associated with elevated calcium ion levels in skeletal muscle cells. Apparently it is caused by defect in a calcium release channel, encoded by theRYRJ gene which is located on chromosome 19q. Studies show only around 50% of MH families are linked to the RYR1 gene so that heterogeneity for this abnormality is suggested. Further studies proved more genes or a candidate regions such as chromosome 7q, 3q are involved in malignant hyperthermia susceptibility. In this search for more understanding of the malignant hyperthermia disorder and for identifying the gene or genes which may be causative in MH, some UK MH families for the RYR1 gene and other candidate regions were studied. Furthermore based on reports of the correlation between MH and mutations in the RYR1 gene in 19-linked families the screening of UK MH families for three mutations from eight putative causative mutations in the RYR] gene was carried out. The ultimate goal of this MH project has been to identify individuals susceptible to MH in advance of anaesthesia. Genetic analysis by direct mutation testing or linkage analysis potentially offers an alternative non-invasive and accurate test for diagnosis of MH susceptibility. However once the linkage relationships are firmly established, they provide a sensitive, non-invasive technique for the presymptomatic diagnosis of MH.
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Chen, Zong-Ping. "Three-dimensional hyperthermia cancer treatment simulation." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184852.
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A simulation program to study the three dimensional temperature distributions produced by hyperthermia in anatomically realistic inhomogeneous tissue models has been developed. The anatomical data for the inhomogeneous tissues of the human body are entered on a digitizing tablet from serial CT scans. The program not only predicts temperature distributions in regions dominated by blood perfusion (with large number of small capillaries), but it can also predict the temperatures inside of and at the vicinity of large blood vessels. The program can be used for different power deposition patterns from various heating modalities, but they must be calculated independently. In this study, the author's attention has been focused on ferromagnetic implants. The program has been used to comparatively evaluate two and three dimensional simulations in a series of parametric calculations based on simple tissue models for both uniform power deposition and ferromagnetic implants. The conclusions drawn from these studies are that two dimensional simulations can lead to significant errors in many situations, and therefore three dimensional simulations will be necessary for accurate patient treatment planning. The conclusion from the geometrically simple model is substantiated by the results obtained using the full 3D model for actual patient anatomical simulations. The program has also been used for several parametric studies. The effect of the thermal conductivity used in the models on the temperature field has been studied, and the results show that its value in the range of 0.4 to 0.6 W/m/°C (valid for most soft tissues) has only a slight effect on the resultant temperature fields. The heating ability of the ferromagnetic implants has also been investigated for different blood perfusions. The effects of the Curie point of the ferromagnetic seeds, and seed spacing are also studied. Finally, the impact of large blood vessels on the resultant temperatures are studied, and the results show that the effect is dramatic and therefore it must be included in the simulations in order to predict accurate temperature fields. Finally, the program has been used to analyze a previously performed dog experiment, and a previously performed clinical treatment. A comparison between the predicted temperatures and the measured ones show that good agreement has been achieved for the clinical treatment, but not for the dog experiment. These results are studied in detail, and the conditions under which this program can be used as a hyperthermia patient treatment planning tool is discussed.
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Lim, Chuck Mang 1963. "Improved thermometry system for ultrasound hyperthermia." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278185.
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A thermometry system for use during ultrasound hyperthermia treatments was developed to provide fast and reliable temperature measurements such that transient temperatures from multi-sensor thermocouples could be measured. It was also intended to provide electrical isolation for patient safety when bare thermocouple sensors were used in order to reduce artifacts. The system hardware development involved fabrication of a high precision temperature measurement box which was electrically isolated from, by an opto-isolation unit, and interfaced with, an 386-20 MHz personal computer. The system software development involved a two point calibration program for each thermocouple probe to be used with the system, and a sensor locating program to rapidly identify the probe locations immediately prior to treatment. A single scan temperature reading speed of 0.2 sec for all 112 thermocouple sensors with an average accuracy of ±0.05°C under normal operating conditions (ambient temperature 22°C to 28°C) was achieved. A probe to earth ground leakage sink current of 75 μA and a leakage source current of less than 10 μA was attained.
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Bhuttacharji, Shivini Chandr. "Microvascular responses of the ileum to hyperthermia." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46964.
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Limire, Bruno. "Cold water immersion after exercise-induced hyperthermia." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27703.
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Cold water immersion (CWI) is the most effective known cooling treatment against exercise-induced hyperthermia. However, sex differences related to body composition (i.e. body fat, muscle mass, surface area, etc.) may affect core cooling rates in hyperthermic males and females.
Purpose. To determine sex related differences in core cooling rates during CWI after exercise-induced hyperthermia.
Methods. Ten male (M) and nine female (F) participants matched for body surface area to mass ratio took part in this study. Participants exercised at 65% V˙O2max at an ambient temperature of 40°C until rectal temperature (Tre) increased to 39.5°C. Following exercise, subjects were immersed in a 2°C circulated water bath until Tre decreased to 37.5°C.
Results. Females had a significantly greater core cooling rate compared to males. This was paralleled by a lower skin temperature and a shorter time to reach the exit criterion.
Conclusion. We conclude that previously hyperthermic females have a 1.7 times greater Tre cooling rate compared to males. We attribute this difference to a smaller lean body mass (expressed by the body-surface-area-to-lean-body-mass ratio) in females compared to males.
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Kok, Henny Petra. "Treatment planning for locoregional and intraluminal hyperthermia." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/46767.
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DeBease, Amy Jo 1967. "Comparison of adaptive control techniques for hyperthermia." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278270.
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This thesis investigates several different control techniques as applied to hyperthermia-based models. These control techniques are control switching, Model Reference Adaptive Control, and Self Tuning Regulators. These three techniques are compared to a conventional PI controller. The objective of each controller is to regulate three temperatures associated with models which represent a three region tissue volume using a single input. Consideration is given to different types of blood perfusion levels as well as restrictions placed on the flexibility of the input power. This thesis shows that during simulations of the hyperthermia treatments, the Self Tuning Regulator technique is more effective at regulating the temperatures.
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Patel, Anil Pravin. "Cancer hyperthermia using gold and magnetic nanoparticles." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8124/.
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An estimated 12 million people worldwide are diagnosed with cancer every year, with around 17 million cancer-related deaths per year predicted by 2030 (Thun et al. 2010). Contemporary clinical treatments include surgery, chemotherapy and radiotherapy, however all vary in success and exhibit unpleasant side effects. Localised tumour hyperthermia is a moderately new cancer treatment envisaged by researchers, which exploits exclusive tumour vulnerabilities to specific temperature profiles (42-45°C) leading to cancer cell apoptosis, whilst normal tissue cells are relatively unaffected. Hyperthermia is therefore proposed as an alternative potential therapy for cancer, by delivering localised treatment to cancer cells, without the severe side effects associated with traditional therapies. This project aimed to investigate potential hyperthermic treatment of cancer cells in vitro by adopting nanomedicine principles. Inorganic nanoparticles, such as gold or iron oxide, are both capable of generating heat when appropriately stimulated, therefore both have been suggested as candidates for inducing localised tumour heating following their internalisation into cells. In this project, both gold (GNPs) and magnetic (mNPs) were individually assessed for their potential to deliver toxic thermal energy to bone cancer cells (MG63) and breast cancer cells (MCF-7). Studies were carried out both in standard 2D monolayer and in 3D tumour spheroids. When considering use in vivo, it is essential that both GNPs and mNPs are biocompatible, therefore initial studies characterised the cell viability and metabolic activity following incubation with the NPs. The NP internalisation was subsequently verified, prior to hyperthermic studies. Following hyperthermic treatment, both GNPs and mNPs were confirmed as inducing cancer cell death. Further studies were carried out using the GNPs, to identify the cell death pathways activated, where mitochondrial stress was evident following 2D culture tests. Gene and protein expression analysis indicated that cell death occurred predominantly via several apoptotic pathways, through increased fold expression changes in apoptotic markers. Interestingly, cell protective mechanisms were simultaneously switched on, as cells were also observed to exhibit thermotolerance with a number of heat shock proteins (Hsps) being substantially increased during hyperthermic treatments.
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Connord, Vincent. "Echauffement de nanoparticules par un champ magnétique haute fréquence : Applications en cancérologie et catalyse de réaction Fischer-Tropsch." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0016/document.
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Dans le cadre du projet MultiFun par lequel cette thèse a été financée, nous avons travaillé en collaboration avec des équipes européennes de synthèse chimique pour proposer des nanoparticules d'oxydes de fer dédiées à la détection et au traitement du cancer par hyperthermie magnétique. Habituellement, l'efficacité des nanoparticules est déterminée par la valeur du SAR (Specific Absoption Rate, en W/g), mesuré par élévation de température. Nous avons développé un banc permettant la mesure de cycles d'hystérésis dans les mêmes gammes d'amplitude et de fréquence de champs magnétiques que celles utilisées habituellement en hyperthermie magnétique. Le cycle d'hystérésis fourni plus d'informations sur l'échantillon et permet par exemple d'évaluer l'importance des interactions inter-particulaires. Le projet MultiFun prévoyait également l'étude du traitement in vivo. Le LPCNO a donc développé un inducteur adapté aux expériences sur le petit animal (souris, rats). Cet électroaimant refroidit à l'air a un entrefer de 3 cm et fonctionne à un champ de 23 mT pour des temps de traitements d'une heure. Nous avons également collaboré avec le Laboratoire de Réceptologie et Ciblage Thérapeutique en Cancérologie pour effectuer des expériences d'hyperthermie magnétique in vitro au moyen de nanoparticules fonctionnalisées puis internalisées de manière spécifique dans les lysosomes. L'application d'un champ magnétique haute fréquence aux cellules contenant ces nanoparticules induit de forts pourcentages de mort cellulaire (principalement par voies apoptotique). Dans ces travaux, les nanoparticules ont de faibles SAR et sont présentes en faibles quantités dans les cellules, ce qui n'engendre pas d'élévations de températures mesurables. L'efficacité du traitement dans ces conditions pose nombre de questions quant aux mécanismes réels entrainant la mort de la cellule. Pour tenter de répondre à ces questions, nous avons conçu un système permettant d'appliquer des champs magnétiques hautes fréquences in vitro sous un microscope confocal à fluorescence couramment utilisé pour suivre des mécanismes intracellulaire à l'aide de fluorochromes. On introduit un électroaimant miniaturisé (largeur d'entrefer ≈ 400 μm) directement dans une boite de culture cellulaire. On génère ainsi un champ d'environ 60 mT à 300 kHz. Cette méthode nous permet d'observer les cellules et leurs organites durant le temps de traitement. Les niveaux de mort cellulaire atteints ici sont équivalents aux expériences précédentes, et valident ainsi l'utilisation de cet inducteur à entrefer réduit. Pour l'heure, nous avons quantifié l'apparition en temps réel des ROS (Reactive Oxygen Species) dans la cellule lors de l'application du champ. Nous avons également mis en lumière la perméabilisation lysosomale, qui peut engendrer la libération d'agents de mort cellulaires. Enfin cet outil permettra de continuer les recherches de mécanismes intracellulaires pour des échantillons soumis à un champ magnétique extérieur. Les nanoparticules soumises à un champ magnétique alternatif peuvent également être utilisées comme catalyseurs de réactions chimiques. Nous avons utilisé les nanoparticules synthétisées au LPCNO comme catalyseurs de la réaction Fischer-Tropsch. Ce procédé permet de produire industriellement des hydrocarbures à partir de monoxyde de carbone et de dihydrogène. Des caractérisations poussées des propriétés structurales, magnétiques, d'échauffement et de catalyse ont été menées sur des nanoparticules possédant un cœur de fer recouvert d'un métal catalytique (ruthénium ou cobalt). La preuve que ces nanoparticules peuvent catalyser la réaction de Fischer-Tropsch lorsqu'elles sont soumises à un champ magnétique haute-fréquence a été établie, et une bonne corrélation entre leur puissance de chauffe et leur activité catalytique a été montréeAs partners of Multifun by which this thesis was funded, we have worked with European groups of chemists to provide iron oxide nanoparticles dedicated to the detection and treatment of cancer by magnetic hyperthermia. Usually, the nanoparticles efficiency is determined by the SAR value (Specific Absoption Rate, in W / g), measured by a calorimetric method. We have developed a device for measuring hysteresis loops at the same amplitude and frequency range of magnetic fields than those usually used in magnetic hyperthermia. Hysteresis loops provide more information about the samples and allows for example to assess the importance of inter-particle interactions. Multifun project also included the study of in vivo treatments. LPCNO has developed an inductor suitable for experiments on small animals (mice, rats). The electromagnet is air-cooled, displays a gap of 3 cm and operates at a field of 23 mT during one hour. We also worked with the Laboratoire de Réceptologie et Ciblage Thérapeutique en Cancérologie, Toulouse, to perform in vitro magnetic hyperthermia experiments using functionalized nanoparticles specifically internalized into lysosomes. The application of a high frequency magnetic field to the cells containing these nanoparticles induces a significant cell death (mainly apoptotic pathways). In these studies, the nanoparticles have low SAR, and are present in small quantities in the cells. Thus no temperature rise is measured during the experiments. The efficacy of treatment in these conditions poses many questions about the actual mechanisms at the origin of cell death. To try to answer these questions, we have designed a setup permitting to apply high frequency magnetic fields under a confocal fluorescence microscope; the latter is commonly used to monitor intracellular mechanisms with fluorochromes. We introduce a miniaturized solenoid (gap width ≈ 400 µm) directly into a cell culture box. This generates a field of approximately 60 mT at 300 kHz. This method allows us to observe the cells and their organelles during the time of treatment. Infected cell death levels here are equivalent to the previous experiments, which thus validates the use of this reduced gap inductor. For now, we quantified the appearance of ROS (Reactive Oxygen Species) in real time in the cell during the application of the field. We also evidenced the lysosomal permeabilization, which can cause the release of cellular death agents. Finally this tool will serve to continue research on intracellular mechanisms in cells inside an external high-frequency magnetic field. Nanoparticles subjected to an alternating magnetic field can also be used as catalysts of chemical reactions. We used the nanoparticles synthesized LPCNO as catalysts for the Fischer-Tropsch reaction. This process allows the industrial production of hydrocarbons from carbon monoxide and hydrogen gas. Extensive characterizations of structural, magnetic, heating and catalysis properties were carried out on nanoparticles with an iron core coated with a catalytic metal (ruthenium or cobalt). Evidence that these nanoparticles catalyze the Fischer-Tropsch synthesis when subjected to a high-frequency magnetic field has been established, and a good correlation between their heating power and their catalytic activity has been shown
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Brehmer, Marianne. "Transurethral microwave thermotherapy of benign prostatic hyperplasia : mechanisms of action and clinical outcome /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3857-1/.
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Blad, Börje. "Electrical impedence tomography for temperature measurement in hyperthermia." Lund : Dept. of Electrical Measurements, Lund Institute of Technology, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39225511.html.
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Armstrong, Rachel G. "Autonomic nervous system function following exercise-induced hyperthermia." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28362.
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Exercise in the heat is associated with cardiovascular and thermoregulatory disturbances that can persist postexercise. The effect of orthostasis on autonomic nervous system function following exercise-induced hyperthermia (EIH) remains to date unclear. Insight into the mechanisms of control is beneficial to those encountering orthostatic challenges after activity-induced hyperthermia.
We evaluated the short-term postexercise cardiovascular and thermoregulatory responses to repeated orthostatic challenges performed in a hyperthermic state and the effects of EIH on autonomic nervous system function during repeated orthostatic challenges in the early and late-stages of recovery.
We conclude that following EIH, the cardiovascular system maintained arterial pressure and cardiac output during repeated 70° head-up tilts. Nonthermal baroreceptor control predominates over thermal control of cutaneous vascular conductance during postural challenges following EIH, but no effect was observed in local sweat rate. The short-term reductions in baroreceptor sensitivity and heart rate variability following EIH were re-established following a 24-h recovery period.
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Adams, Tracy Elizabeth. "An integrated circuit biosensor for hyperthermia cancer treatment." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40176.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 87-90).
by Tracy Elizabeth Adams.
M.Eng.
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Kozissnik, B. "Antibody targeted magnetic nanoparticle hyperthermia for cancer therapy." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1415747/.
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Superparamagnetic iron oxide nanoparticles (SPION) are used clinically to improve the sensitivity of magnetic resonance imaging (MRI). A less exploited property of SPION is their ability to generate heat when subjected to an alternating magnetic field, a process called magnetic alternating current hyperthermia (MACH). Hyperthermia has been shown to be a cancer effective treatment modality in the clinic when given together with radio/chemotherapy. However, delivery of sufficient heat to damage tumours without harming healthy tissue remains challenging. The central hypothesis for this thesis is that MACH activated SPION can be used to generate hyperthermia in situ and therefore will have potential to achieve localised hyperthermic cancer treatments. The aim of the thesis was to evaluate the potential of SPION to deliver localised hyperthermia by: (1) Characterization and comparison of SPION to select a lead candidate for clinical application. (2) Developing conjugation methods to confer SPION with cancer-binding properties by attachment of single chain Fv antibodies (scFv). (3) Evaluating the localisation and heating potential in vivo. SPION were characterized with regard to their hydrodynamic diameter, core size, magnetic properties, atomic iron content and heating potential for hyperthermia application. Different chemistries were evaluated to functionalize the most promising candidate using shMFEm, an scFv targeting the carcinoembryonic antigen (CEA). A CEA-non-binding scFv variant, shNFEm, was used as a negative control. Functionality of the scFv-SPIONs was assessed using quartz crystal microbalance. In vivo heating potential of the SPION was tested in a xenograft tumour model in vivo, using bespoke MACH apparatus. The results established Ferucarbotran (FX), unformulated Resovist®, an MRI contrast agent, as the most suitable candidate for hyperthermia application. Cyanogen bromide chemistry was selected to functionalise Ferucarbotran with the scFvs shMFEm. The FX-scFv conjugates were purified and analysed. Functionality was confirmed by quartz crystal microbalance, enabling the first visualisation of the interaction between a SPION-scFv conjugate and cognate antigen in real-time. The in vivo assessment of Ferucarbotran and the FX-scFv conjugates confirmed the in vitro heating potential of Ferucarbotran. In vivo analysis of heating showed that localised hyperthermia was achievable with intratumoral injection followed by MACH. Histological analysis of the tumours revealed an uneven distribution of particles within the tumours and an accumulation of the particles within the surrounding stroma indicating the future work should include study of innovative tumour delivery methods. These results support the hypothesis of a therapeutic potential for targeted magnetic nanoparticle hyperthermia and indicates the challenges that have be addressed to enable clinical application of this treatment modality.
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Kress, Reid Leonard. "Adaptive model-following control for hyperthermia treatment systems." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184430.
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The purpose of this research was to develop three real-time adaptive temperature controllers for hyperthermia heating systems. Each scheme is made adaptive by using a transient Gaussian estimation routine to estimate the tissue blood perfusion and by then using these estimated values either in an optimizing routine, or in an observer, or in both. The optimizing routine uses a steady-state Gaussian estimation technique to optimize the power distribution until the best possible match is obtained between the steady-state temperatures predicted by a treatment model and a prespecified ideal temperature distribution. The observer uses a treatment model to control unmeasured locations. The first adaptive control scheme uses the optimizing routine alone, the second uses the observer alone and the third uses both the optimzing routine and observer. The performance of each of the adaptive control schemes is compared to a standard proportional-integral-derivative (PID) control scheme for one-dimensional simulations of typical treatments. Results comparing the deviation of the controlled temperature distribution to the ideal desired temperature distribution for all locations and all times indicate that the adaptive schemes perform better than the PID scheme. It can be concluded that adaptive control yields improved performance if good a priori knowledge of the treated region tissue and perfusion region boundaries is available. While these control schemes were designed for eventual implementation on a scanned focused ultrasound hyperthermia treatment system, the techniques are applicable to any system with the capability to vary specific power with respect to location and with an unknown distributed energy sink proportional to the temperature elevation.
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Tait, Diana Mary. "A quantitative study of hyperthermia in human tumours." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/19336.
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Dremann, David Michael. "Pluronic Activity in Hyperthermia-induced Cancer Cell Death." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1247425426.
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Akyürekli, Ufuk (Ufuk Dennis) Carleton University Dissertation Physics. "The Effects of hyperthermia on tissue blood flow." Ottawa, 1995.
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Liauh, Chihng-Tsung. "Parameter estimation in reconstructing temperature fields during hyperthermia." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185613.
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In this dissertation, a state and parameter estimation algorithm is implemented and modified to predict the blood perfusions and thus the complete steady-state temperature fields based on input from a limited number of temperature measurements taken during simulated hyperthermia treatments. Several fundamental phenomena related to this inverse problem are investigated from simple direct models. The general conditions under which these multiple minima occur are shown to be solely due to the existence of symmetries in the inverse problem formulation. Both an adjoint formulation and a sensitivity equation method are derived and used to determine the elements in the Jacobian matrix associated with the inverse problem of estimating the blood perfusion and temperature fields during hyperthermia cancer treatments. These methods and a previously developed influence coefficient method for obtaining that matrix are comparatively evaluated by solving a set of numerically simulated inverse hyperthermia problems. An improved state and parameter estimation algorithm has been developed to reduce the total computational time required. If the change of the unknown perfusion parameters is small a linear approximation scheme is implemented in which the old Jacobian matrix (or sensitivity matrix) is used, instead of recalculating the new Jacobian matrix for the next iteration. Results show that if the temperature is approximated as a linear (or quasi-linear) function of the blood perfusion, the linearizing approach considerably reduces the CPU time required to accurately reconstruct the temperature field. One of the model mismatch problems between the actual tumor and the simulated models is selected and investigated for the one-dimensional case. The model mismatch present in this dissertation is caused by the discretization of a perfusion field into several discrete zones. It is our attempt to understand the effects of the model mismatch problems from a simple model, and then generalize to more complicated three-dimensional cases which could occur during hyperthermia treatments. To simulate the ultrasound hyperthermia treatments, a scanned focussed ultrasound power field is generated and then used to create the transient power-on data and the steady-state temperature field. The feasibility of using the transient power-on data to estimate the attenuation coefficient and the blood perfusion and thus reconstruct the steady-state temperature field is presented.
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Potocki, Jon Kyle. "Application of control theory to the hyperthermia problem." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185999.
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The objective of a hyperthermia cancer treatment is to heat the tumor tissue to a therapeutic level while limiting the detrimental effects experienced by the surrounding normal tissue. To achieve an optimal treatment requires knowledge of the resulting temperature response and an understanding of the complex interaction between the thermal response, the applied power, and the blood flow in the target tissue region. This dissertation considers model reduction to overcome the large dimensions associated with thermal modelling, extended Kalman filtering to estimate both the unmeasured temperature states and the unknown blood perfusion magnitudes, optimization of the applied power to achieve the best thermal response, and optimal servomechanism control to attain the desired regulated output tracking. A controller methodology that combines thermal estimation, applied power optimization, and optimal servomechanism control with a simple expert system shell is examined. This controller methodology is analyzed for a simulated scanned focussed ultrasound system (SFUS) based upon the bioheat transfer equation (BHTE) model of the thermal response in the target region. The results of the presented studies illustrate the following important points. First, open-loop reduced-order models based on the balanced transformation provide drastic model reduction for controller design purposes. Second, the success of thermal estimation depends on the number and the location of the thermal sensors, and the accuracy of the modelled blood perfusion profile. Third, multiple modelling in estimation provides an alternate technique for overcoming model mismatch associated with the modelling of the blood perfusion pattern. Fourth, the choice of the set points for the optimal servomechanism controller play a crucial role in the resulting tissue temperatures. Fifth, the scan parameter sets that result in optimal SFUS power profiles need to be changed on-line during a treatment as the blood perfusion magnitude and pattern are estimated. Finally, to fully automate a hyperthermia treatment requires that the expertise of the clinician be incorporated into the controller design. Hierarchical control provides a means of incorporating the expert system shell at the higher levels of the controller, while maintaining optimal servomechanism control at the lower levels.
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Buchanan, Mark Thomas 1967. "An ultrasound phased array system for intracavitary hyperthermia." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278159.
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Intracavitary ultrasound hyperthermia applicators have the potential to better heat certain tumor sites, especially in the pelvic region, than external techniques. To allow deep, controlled heating, an intracavitary phased array has been developed. The hardware required to drive the array was also developed; including amplifiers, phase shifters, power meters and matching circuits. The entire system is computer controlled and capable of driving up to 64 individual ultrasound transducers. This system was used to conduct acoustic field measurements and in vivo perfused kidney experiments with the phased arrays. These results show that these arrays focus as predicted, and are capable of controlling the heating field by electrically controlling the position of the focus.
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Coffel, Joel. "Implementation and modeling of in situ magnetic hyperthermia." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2058.
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Health-care associated infections (HAIs) on medical implant surfaces present a unique challenge to physicians due to their existence in the biofilm phenotype which defends the pathogen from antibiotics and the host’s own immune system. A 2004 study in the U.S. showed that 2 to 4% of implanted devices become infected and must be treated via surgical explantation—a process that is both expensive and dangerous for the patient. A potential, alternative strategy to antibiotics and surgery is to use heat delivered wirelessly by a magnetic coating. This thermal treatment strategy has the potential to kill these HAIs directly on the implanted surface and without the patient requiring surgery.
This thesis introduces an iron oxide nanoparticle composite coating that is wirelessly heated using energy converted from an alternating magnetic field. Iron oxide nanoparticle composites are demonstrated to be remotely heated in both hydrophilic and hydrophobic polymer composites. In designing the composite coating, multiple parameters were investigated for how they impact the normalized heating rate of the material. Specifically, the amount of iron in the coating, the coating thickness, the polymer type, and the orientation of the coating relative to the applied magnetic field were investigated. Power output was shown to increase proportionally with iron loading whereas nearly two times the amount of power output was observed for the same coatings positioned parallel to magnetic field lines versus those positioned perpendicular—a result believed to be due to magnetic shielding from neighboring particles.
Microscope slides coated with 226 µm of composite delivered up to 10.9 W cm⁻² of power when loaded with 30.0% Fe and positioned parallel in a 2.3 kA m⁻¹AMF. Pseudomonas aeruginosa biofilms were grown directly on these coatings and heated for times ranging from 1 to 30 min and temperatures from 50 to 80 °C. Less than one order of magnitude of cell death was observed for temperatures less than 60 °C and heat shock times less than 5 min. Up to six orders of magnitude reduction in viable bacteria were observed for the most extreme heat shock (80 °C for 30 min).
Introducing this wirelessly heated composite into the body has the potential to kill harmful bacteria but at the risk of thermally damaging the surrounding tissue and organs if the treatment is not designed and predicted intelligently. Thermal energy will propagate differently depending on the surrounding heat sink, with convective heat sinks (i.e. those due to blood flow) requiring much more power to reach the same surface temperature than a conduction-only heat sink. To study how heat is transferred in biological tissues, a robust, poly(vinyl alcohol) tissue phantom was developed that can be poured to accommodate any geometry, is volume stable in water and under thermal stress, and can be modified with inert particle fillers to adjust its thermal conductivity from 0.475 to 0.795 W m⁻¹°C⁻¹. In vitro heat transfer was measured through this hydrogel tissue phantom with at least 10 °C of temperature rise, penetrating 5 mm of tissue in less than 120 sec for an 80 °C boundary condition.
A computational model was used to solve three-dimensional energy transfer through a combined fluid mimic/tissue mimic heat sink spanning the same surface boundary condition. The model was validated with experimental models using a custom designed heat transfer station. This scenario is applicable in the instance where the same coating is subject to starkly different heat sinks: half subject to convective heat loss, half to conductive heat loss. Based on these conditions, a magnetic coating would need to be designed that has a power gradient up to 15 times larger on the fluid half versus the other.
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MAMELI, VALENTINA. "Colloidal CoFe2O4-based nanoparticles for Magnetic Fluid Hyperthermia." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266766.
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In the field of biomedicine, important issues to address are the early-stage diagnosis and targeted therapies. Since the last two decades, magnetic nanoparticles have been proposed as potentially powerful due to their unique chemical-physical properties. Magnetic nanoparticles can be applied in a wide variety of biomedical fields from the magnetic separation and Magnetic Resonance Imaging (MRI) to drug delivery and Magnetic Fluid Hyperthermia (MFH).1 In particular, MFH is based on the heat released by magnetic nanoparticles subjected to an alternate external magnetic field. Among the different material features affecting the hyperthermic efficiency, the magnetic properties are clearly the most important. Therefore, the optimisation of the magnetic properties, aimed to increase the heating ability and to reduce the magnetic material dose to be inserted in the human body, is still an active research field. In 2013 alone, 682 works have been published in the literature on the topic of magnetic hyperthermia.2
Despite cobalt toxicity, cobalt-containing materials and especially cobalt ferrite nanoparticles have been proposed as promising heat mediators due to its high anisotropy.3–13
In this thesis, the results obtained on two different systems, designed with the idea of studying the effect on the hyperthermic properties of proper tuning of the magnetic properties, are presented. Both the sets of samples are based on cobalt ferrite nanoparticles. The first strategy consists on the substitution of cobalt ions with zinc ones with the aim of tuning the magnetic properties of the system and, at the same time, decrease the toxicity of the material. The second way is on the contrary represented by the coating of cobalt ferrite cores by means of biocompatible or less toxic isostructural phases (i.e. magnetite/maghemite or manganese ferrite).
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Stege, Gerardus Johannes Jozef. "Hyperthermia and protein aggregation role of heat shock proteins /." [S.l. : [Groningen] : s.n.] ; [University Library Groningen] [Host], 1995. http://irs.ub.rug.nl/ppn/138287325.
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Guibert, Clément. "Etude des propriétés d'hyperthermie de nanoparticules dispersées dans des systèmes complexes." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066386/document.
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L'hyperthermie magnétique est une technique de traitement de cancers en plein essor. Cette conversion d'une énergie électromagnétique en énergie thermique par des nanoparticules soumises à une excitation magnétique oscillant à haute fréquence est étudiée depuis près de deux décennies mais elle est encore mal décrite pour des systèmes complexes.Le travail présenté ici s'attache à compléter la connaissance de ce phénomène en reliant l'état de dispersion de nanoparticules à leurs propriétés d'hyperthermie.Tout d'abord sont présentés la caractérisation et le contrôle de dispersions dans des milieux complexes tels qu'un liquide ionique ou une matrice polymère.En effet, l'obtention d'une dispersion colloïdalement stable dans un liquide ionique soulève de nombreux défis. Une étude approfondie du rôle de la charge de surface des particules, contrôlée à l'aide du pH dans un liquide ionique protique, a permis de mieux comprendre le rôle du solvant et la nature des interactions dans ce type de milieu.En outre, disperser finement des nanoparticules hydrophiles dans une matrice hydrophobe telle qu'une matrice siliconée est également une tâche délicate et une méthode nouvelle d'évaporation d'émulsion ferrofluide-dans-matrice polymère est présentée ici, ainsi que l'étude des dispersions ainsi obtenues.Enfin est exposée une étude du pouvoir chauffant de nanoparticules dans des états de dispersion variés, faisant notamment intervenir une méthode de mesure développée dans le cadre de cette thèse. Ces résultats soulignent l'influence de l'agrégation des particules qui provoque une baisse significative de leur échauffement ainsi que le rôle clef de la compacité des agrégats formésMagnetic hyperthermia is a promising therapeutic technique against cancer. It consists in turning electromagnetic energy into heat thanks to nanoparticles that are excited by a radiofrequency oscillating magnetic field. Although this phenomenon has been studied for more than two decades, it remains poorly described. This work aims at filling the gap of knowledge about magnetic hyperthermia through the study of the correlations between the dispersion state and the heating efficiency of the particles. The characterisation and the control of dispersions in complex media such as ionic liquids or a polymer matrix is dealt with in the first part. Obtaining a colloidally stable dispersion in an ionic liquid proves indeed a challenging task. The particles surface charge can be controlled in a protic ionic liquid by tuning the pH. A thorough study of the influence of this parameter allowed a better insight into the role of the solvent and the nature of the interactions. Furthermore, the formation of a fine dispersion of hydrophilic nanoparticles in a hydrophobic silicon matrix is also a ticklish task. A new method is presented here, that consists in the evaporation of a ferrofluid-in-polymer matrix emulsion. The dispersion state of the resulting materials is then characterised.The heating efficiency of particles showing different dispersion states is studied in the last part. It includes results obtained with a new measurement method developed in the scope of this thesis. These results highlight that the particles aggregation causes a decrease of their heating properties. They also evidence the key role of the aggregates compactness in this respect
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Fullerton, Graham. "Hyperthermia as a Cancer Treatment- From Theory to Practice." Scholarship @ Claremont, 2018. http://scholarship.claremont.edu/cmc_theses/1824.
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Using iron super-paramagnetic and ferromagnetic nanoparticles composed of Fe3O4 molecules, scientists analyze the effectiveness and practicality of this new treatment theory, hyperthermia. The problems of magnetic particle density, isothermal barriers/cellular cooling thresholds, and nanoparticle specific targeting are addressed in this review.
Iron magnetic nanoparticles were chosen due to their relatively low biological reactivates and lack of subsequent cellular toxicity. However, there are significant heating problems associated with these magnetic nanoparticles due to their relative size and short thermal time constants or thermal half-lives. Effectively, these aforementioned issues create a phenomenon where cancerous cells, surrounded by unheated healthy tissue, exhibit properties similar to those of an isothermal barrier. As a result, target cells experience limited gross heating, which is localized to the area directly surrounding the active magnetic nanoparticle within the cytoplasm. The effects of isothermal barriers and HSP up regulation on particle-based hypothermia are profound and prevent therapeutic temperatures from being achieved in single cell heating limiting the applications for Fe3O4 magnetic nanoparticle hyperthermia applications.
It has been shown that reaching a certain magnetic nanoparticle density within the cell can result in a larger heating capacity, though this effect is also dependent on the particle dispersion pattern within cytoplasm. It has yet to be concluded whether ferromagnetic particles or super-paramagnetic particles are superior or more practical for hyperthermic treatments as they each have distinct benefits, and further study is needed.
Finally, the popular targeting mechanism associated with magnetic nanoparticle research, monoclonal antibodies, require that they have an organic coating (such as starch) as a means of both providing an organic binding point and as camouflage for avoiding host filtration pathways. Forgoing this organic coating could lead to increased particle density within the cell and the adoption of a more specific targeting mechanism such as virus like particles (VLPs) altered to target HSP’s could lead to an increase in yield. Furthermore the up regulation of HSPs in response to therapeutic temperature is problematic for the therapies practically.
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Bhatia, Nimmi. "Mitigation of hyperthermia in outdoor environments for the elderly." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24443.pdf.
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Fatehi, Daryoush. "Technical Quality of Deep Hyperthermia Using the BSD-2000." [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2007. http://hdl.handle.net/1765/10546.
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Paulides, Margarethus Marius. "Development of a clinical head and neck hyperthermia applicator." [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2007. http://hdl.handle.net/1765/10599.
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Linnane, Denise M. "Physiological responses to hyperthermia during short term maximal exercise." Thesis, Coventry University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424485.
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Friesen, Brian J. "Whole-Body Cooling Following Exercise-Induced Hyperthermia: Biophysical Considerations." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30510.
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This thesis examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (2°C, CWI) and temperate water immersion (26°C, TWI) following exercise-induced hyperthermia (end-exercise rectal temperature of 40°C). Individuals with a High AD/LBM (315 cm2/kg) had a ~1.7-fold greater overall rectal cooling rate relative to those with Low AD/LBM (275 cm2/kg) during both CWI and TWI. Further, overall rectal cooling rates during CWI were ~2.7-fold greater than during TWI for both the High and Low AD/LBM groups. Study findings show that AD/LBM must be considered when determining the duration of the immersion period. However, CWI provides the most effective cooling treatment for EHS patients irrespective of physical differences between individuals.
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Vieira, Raquel Nadine Cadete. "Coating of magnetite nanoparticles with chitosan for magnetic hyperthermia." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21895.
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Mestrado em Materiais e Dispositivos BiomédicosO cancro é uma das doenças com maior ocorrência na população mundial e com uma elevada taxa de mortalidade. Os principais problemas na luta contra o cancro prendem-se com a dificuldade de diagnóstico precoce, a citotoxicidade associada aos fármacos anticancerígenos usados em quimioterapia convencional e a falta de tratamentos mais eficazes. Com o advento da nanotecnologia, tem havido um crescente interesse na aplicação de nanopartículas e nanoestruturas, nas mais diversas áreas da ciência, nomeadamente em aplicações biomédicas. Neste contexto em particular, as nanopartículas magnéticas apresentam propriedades interessantes, por exemplo, em sistemas de libertação controlada de fármaco e em hipertermia. A sua aplicação em áreas relacionadas com a saúde, como o tratamento de cancro por hipertermia magnética, passa necessariamente por uma boa caracterização das suas propriedades e pela correta avaliação das suas capacidades de libertação de energia sob a forma de calor por indução magnética. Nesse sentido, este trabalho teve como objetivo a síntese de nanopartículas de magnetite devido a sua compatibilidade com o organismo humano e propriedades magnéticas. No entanto, devido ao seu elevado grau de agregação assim como facilidade de oxidação em meios aquosos existe uma necessidade de revestir estas partículas. Para tal, foi utilizado um biopolímero: a quitosana. A ligação do revestimento da quitosana ao núcleo do óxido de ferro foi realizada através de dois tipos de ancoragem: através da dopamina, conhecida pela sua grande afinidade aos grupos aminas e através do ácido cafeico, por apresentar uma similaridade estrutural à dopamina. Para a caracterização estrutural e morfológica das partículas recorreu-se à difração de raios-X (DRX), à espetroscopia de infravermelhos com transformada de Fourier (FTIR), à dispersão dinâmica da luz (DLS), ao Potencial Zeta e à microscopia eletrónica de transmissão (TEM). As propriedades magnéticas foram medidas por magnetometria de SQUID (Superconducting Quantum Interferance Device). Por fim foi avaliada a capacidade das partículas sintetizadas para aplicação em hipertermia magnética.
Cancer is a disease with high incidence in the world population and equally with a high mortality rate. The main problems in the fight against cancer are linked to the difficulty of early diagnosis, the cytotoxicity associated with anticancer drugs used in conventional chemotherapy and the lack of more effective treatments. With the advent of nanotechnology, there has been increasing interest in the application of nanoparticles and nanostructures, in several areas of science, such as biomedicine. In this context, the magnetic nanoparticles have interesting properties in controlled drug release systems and hyperthermia. Its application in areas related to health, such as the treatment of cancer by magnetic hyperthermia, necessarily requires a good characterization of their properties and the correct assessment of their ability to release energy in the form of heat by magnetic induction. Therefore, this study aimed the synthesis of nanoparticles of magnetite due to their biocompatibility and magnetic properties. However, due to their high degree of aggregation as well as facile oxidation in aqueous media there is a need to coat these particles. For this purpose, a biopolymer was used: chitosan. The binding of the coat to the core of the iron oxide was accomplishment through two types of anchorages molecules: dopamine, knowing for their great affinity with amine groups and through caffeic acid due to structural similarity to dopamine. The structural and morphological characterization was performed using X-ray diffraction (DRX), Fourier transformed infrared spectroscopy (FTIR), dynamic light scattering (DLS), Zeta Potential; thermalgravimetric analysis and transmission electron microscopy (TEM). The magnetic properties were studied using a Superconducting Quantum Interference Device (SQUID) magnetometer. Finally, we evaluated the ability of some of the synthesized NPs for use in magnetic hyperthermia.
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Nemati, Porshokouh Zohreh. "Novel Magnetic Nanostructures for Enhanced Magnetic Hyperthermia Cancer Therapy." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6548.
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In this dissertation, I present the results of a systematic study on novel multifunctional nanostructure systems for magnetic hyperthermia applications. All the samples have been synthesized, structurally/magnetically characterized, and tested for magnetic hyperthermia treatment at the Functional Materials Laboratory of the University South Florida. This work includes studies on four different systems: (i) Core/shell Fe/γ-Fe2O3 nanoparticles; (ii) Spherical and cubic exchange coupled FeO/Fe3O4 nanoparticles; (iii) Fe3O4 nano-octopods with different sizes; (iv) High aspect ratio FeCo nanowires and Fe3O4 nanorods.
In particular, we demonstrated the enhancement of the heating efficiency of these nanostructures by creating monodisperse and highly crystalline nanoparticles, and tuning their magnetic properties, mainly their saturation magnetization (MS) and effective anisotropy, in controlled ways. In addition, we studied the influence of other parameters, such as the size and concentration of the nanoparticles, the magnitude of the applied AC magnetic field, or different media (agar vs. water), on the final heating efficiency of these nanoparticles.
For the core/shell Fe/γ-Fe2O3 nanoparticles, a modest heating efficiency has been obtained, resulting mainly from the strong reduction in MS caused by the shrinkage of the core with time. However, for sizes above 14 nm, the shrinkage process is much slower and the obtained heating efficiency is better than the one exhibited by conventional solid nanoparticles of the same size.
In the case of the exchange-coupled FeO/Fe3O4 nanoparticles, we successfully created two sets of comparable particles: spheres with 1.5 times larger MS than the cubes, and cubes with 1.5 times larger effective anisotropy than the spheres, while keeping the other parameters the same. Our results show that increasing the effective anisotropy of the nanoparticles gives rise to a greater heating efficiency than increasing their MS.
The Fe3O4 nano-octopods, with enhanced surface anisotropy, present better heating efficiency than their spherical and cubic nanoparticles, especially in the high field region, and we have shown that by tuning their size and the effective anisotropy, we can optimize their heating response to the applied AC magnetic field. For magnetic fields, smaller than 300−400 Oe we found that the smallest nano-octopods give the best heating efficiency. Yet if we increase the AC field value, the bigger octopods show an increased heating efficiency and become more effective.
Finally, the FeCo nanowires and Fe3O4 nanorods exhibit enhanced heating efficiency with increasing aspect ratio when aligned in the direction of the applied AC magnetic field, due to the combined effect of shape anisotropy and dipolar interactions. Of all the studied systems, these 1D high aspect ratio nanostructures have displayed the highest heating rates.
All of these findings point toward an important fact that tuning the structural and magnetic parameters in general, and the effective anisotropy in particular, of the nanoparticles is a very promising approach for improving the heating efficiency of magnetic nanostructures for enhanced hyperthermia.
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Abrego, peris Iñaki. "Antenna with medical applications for tumour cancer: hyperthermia function." Thesis, Högskolan i Gävle, Elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-24719.
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The idea is to improve or help the treatments that exist in the market in the medical field. Treatments such as mammography or radiotherapy make use of X-rays. X-rays are electromagnetic radiation in a high frequency band, this type of electromagnetic is dangerous to health because ionizing radiation is used, ionized atoms interact with matter. For this reason, in our work we give alternative solution to these treatments without any risk to health. This project consists in the use of non-harmful frequencies such as microwave. In this way, we will make an antenna with medical applications whose frequency range will be between 300 MHz and 30 GHz, specifically between 950MHz and 2.45GHz (medical range). The first step will be the detection of the tumour and classification of this, but our work is about another technique called hyperthermia. This technique consists in increase the temperature with a value of 40-43 degrees in the tumour area. Tumour resistance decreases when heat is applied to this. When combining a treatment with oncologic hyperthermia, the effect of radiotherapy is most effective (between 1.5-5 times). The most important part is study antenna in body tissues characteristics as SAR, depth penetration and antenna size; this theory part is essential to know the best parameters and what case use this. In work development we will choose and design antennas for the different parts of the body in some specific frequencies and choose circular antennas in frequencies of 915 MHz and 1.8 GHz. Finally, we will take measurements about temperature increase with meat and say some conclusions.
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Akyürekli, Ufuk (Ufuk Dennis) Carleton University Dissertation Physics. "Simulation of ultrasound hyperthermia using the finite element method." Ottawa, 1988.
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Kaytar, Doru Carleton University Dissertation Physics. "Hyperthermia generated with array of interstitial ultrasound waveguide applicators." Ottawa, 1995.
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Merritt, Alan. "Functional characterisation of genetic variants associated with malignant hyperthermia." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/4951/.
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Mutations in the skeletal muscle sarcoplasmic reticulum calcium release channel (RYR1) have been identified in association with malignant hyperthermia(MH)and exertional heat stroke(EHS). MH is a pharmacogenetic disorder in which hypermetabolism is triggered upon exposure to volatile anaesthetics. MH has long been linked with EHS, a life threatening increase in body temperature caused by strenuous exercise in warm climates with both conditions being caused by a deregulation of skeletal muscle calcium homeostasis. The availability of genetic testing in MH is limited to variants that have been proven to alter calcium handling in vitro. In this thesis, data on the functional consequences of seven RYR1 variants found in association with MH are presented, one of which has also been identified in an EHS patient. Site-directed mutagenesis was used to introduce the variants into a human RYR1 cDNA clone before expressing wild type and mutant constructs in HEK293 cells. Six of the variants, including the EHS mutation, were found to have an increased sensitivity to caffeine as evidenced through a significant decrease in EC50 as well as exaggerated calcium release at low doses of caffeine as compared to wild type controls. For one variant, p.D3986E, an increase in RYR1 expression was required before the phenotype resembled the other RYR1 variants, hinting at a more complicated role in MH for this variant. The functional data presented in this thesis is supportive of the addition of six RYR1 variants onto the genetic diagnostic panel for MH, increasing the availability of initial genetic testing by 19%. Furthermore, the work presented further supports the link between MH and EHS through the presence of a common RYR1 variant proven to alter calcium handling. Finally, data obtained for the p.D3986E variant lays the foundation for future studies aiming to identify genetic modifiers of the MH phenotype.
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Hallin, Anders. "Transurethral microwave thermotherapy of benign prostatic hyperplasia : a clinical and methodological evaluation /." Stockholm, 1997. http://diss.kib.ki.se/1997/91-628-2727-8.
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Chen, Guoyan. "Dielectric characterizations, ex vivo experiments and multiphysics simulations of microwave hyperthermia of biological tissues." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066289/document.
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La recherche et développement de dispositifs médicaux avec diverses applications en diagnostiques et en thérapie ont été réalisés. Actuellement, tous les systèmes micro-ondes disponibles d'hyperthermie proposent uniquement des traitements avec une puissance élevée de micro-ondes. Dans cette thèse, un nouveau système d'hyperthermie micro-ondes est étudié pour le bénéfice des fonctions de diagnostic et de thérapie. L'utilisation d'un applicateur avec un niveau très faible et inoffensif de puissance micro-ondes permet de faire le premier diagnostic. Le traitement thérapeutique thermique sera effectué en utilisant le même applicateur avec une puissance micro-ondes élevée et adaptée sur la partie pathologique. Des caractérisations micro-ondes large bande de cinq tissus biologiques différents ont été effectuées à différentes températures avec une méthode de sonde coaxiale ouverte et le modèle de ligne virtuelle. Les expérimentations ex vivo d'hyperthermie micro-ondes avec des puissances de quelques watts à 2,45GHz ont été réalisées sur ces tissus d'épaisseurs variées. L'évolution de la température des tissus a été mesurée en utilisant un capteur infrarouge. Les simulations électromagnétiques et thermiques pour les expérimentations ex vivo d'hyperthermie micro-ondes ont été effectuées en utilisant COMSOL Multiphysics avec la méthode des éléments finis et la symétrie axiale 2D en considérant les tissus variés de différentes épaisseurs et puissances micro-onde incidente. Les simulations du modèle correspondent bien aux mesures. Cette recherche illustre la possibilité d'avoir un câble coaxial souple et adapté à la fois au diagnostic et au traitement pour une thérapie mini invasiveResearch and development of medical devices with various diagnostic and therapeutic applications have been carried out in different countries because of the great advances in electronic and electromagnetic devices during recent decades. However, at present, all of available existing microwave hyperthermia system can just offer treatment, by using high microwave power. In this thesis, a new microwave hyperemia system is researched which could have both diagnostic and therapeutic functions. One single applicator is used to measure dielectric properties of tissue with a very low harmless microwave power for diagnosis first. Then thermal therapeutic treatment will be carried out by using the same applicator with higher and adapted microwave power. Microwave broad band characterization of five different biological tissues at different temperatures with an open–ended coaxial probe method and the virtual line model has been carried out. Ex vivo microwave hyperthermia experiments using microwave power of a few Watts at 2.45GHz have been carried out on five tissues of various thicknesses. Temperature evolution of the biological tissues has been measured by using an infra-red senor. Electromagnetic and thermal simulations for ex vivo microwave hyperthermia experiment have also been achieved by using COMSOL Multiphysics software with 2D axisymmetrical finite–element method and considering different tissues of various thicknesses and incident microwave powers. Simulation results correlate well with the experimental ones. This research, illustrates the possibility to have a flexible and feasible coaxial cable for both diagnosis and treatment for a minimally invasive therapy