Browsing by Subject "Magnetic Fluid Hyperthermia"

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Open Access
Focused RF ablation using magnetic fluids
(2006) Taşçı, T. Onur
In most developed countries, cancer is presently responsible for about 25% of all deaths. Heat therapies like hyperthermia and thermoablation are very promising approaches in the treatment of the cancer. Since these are physical treatment methods they have fewer side affects compared to chemo- and radio-therapy. Currently, various types of heat treatment modalities are available like microwave, ultrasound, RF capacitance hyperthermia, RF probe hyperthermia, magnetic fluid hyperthermia, but non of these methods have the ability to accurately deliver high heat energy to deeply seated tumors without damaging the healthy surrounding tissues. In this thesis, a novel RF ablation system was developed capable of focusing the heat in to very small areas in the order of millimeters, which will allow heating of the tumors without destroying collateral normal tissues. Generally, in this system the tumor ablation is achieved via coupling RF energy on the magnetic fluids which are previously dispersed in to the tumor tissue. By considering the human safety limits (nerve stimulation and tissue eddy current heating safeties) optimum treatment parameters like particle size of the magnetic fluids, frequency and strength of the applied RF field are obtained. The utilization of the optimum parameters may lead to the very effective operation of the ablation system where treatments can be done with very small amounts of fluid injections, in short durations. We believe that by the studies conducted in this thesis, magnetic fluid hyperthermia (tumor ablations using magnetic fluids) can be a much more effective method so that it can be used as the one of the most important tumor treatment techniques in future.
Open Access
Targeted photosensitizers and controlled singlet oxygen generation for therapeutic applications
(2018-12) Uçar, Esma
Photodynamic therapy of cancer plays a pivotal role due to its many superior features and potential. Considering the pathways for improving the practice of PDT of cancer is gradually increasing, enhancing the selectivity of photodynamic action is an obvious choice. Being the source of reactive oxygen species in the body, mitochondrion is one of the most proper organelles to target. There is plethora of findings suggesting that triphenlyphosphonium cation is a very favorable mitochondria targeting agent. Another aspect of PDT requires creation of smart molecules which respond to either the increased temperature or ion concentrations in order to release 1O2. Cyclic endoperoxides of naphthalene and anthracene could help in achieving the desired objective of storing 1O2 and regenerating it again when appropriate conditions meet. The half-life cycloreversion of 1,4-Dimethylnaphthalene could be changed at least 100-fold when 2-position of the naphthalene is sterically hindered. Taking advantage of the fact that fluoride ions’ silicophile nature, a novel perspective for drug design can be proposed. In the final project, a certain level magnetic hyperthermia, large enough to cause endoperoxide cycloreversion, but not large enough to cause necrotic death, is being sought after. Controlled generation singlet oxygen by the application of tissue penetrating alternating magnetic fields is the ultimate goal for that project.