Sharif Digital Repository

The aim of this study was to investigate the rate of increase in temperature of a phantom equivalent to body tissue by different groups of magnetic iron nanoparticles in the external magnetic field to kill cancer cells based on the hyperthermia method. To achieve this goal, three groups of dextran magnetic nanoparticles with different properties and reduced iron oxide-graphene oxide magnetic nanoparticles by M-rGO supercritical synthesis method were used. After XRD, FTIR, SEM, FESEM, VSM, TEM characterization tests, these materials were placed in a phantom made of agarose gel and with the same properties, in a magnetic field with fixed characteristics for all groups and during the process of... 

The main methods have been used clinically for cancer treatment are included: surgery, chemotherapy, radiation therapy and hyperthermia. Hyperthermia (heat therapy) treatment method in which by raising the temperature of the tumor it removed. Magnetic hyperthermia is known as a kind of hyperthermia that have been represent appropriate results. In this study, using iron oxide nanoparticle coated with graphene for cancer treatment under a magnetic field of the laser. In the first stage, graphene oxide nanosheets and nanoparticles Magntayt are synthesized by chemical oxidation and co-precipitation, respectively. At the end, the nanoparticles on the substrate of graphene layer is obtained... 

The purpose of this study is to estimate the temperature distribution of the internal body organs using electromagnetic waves. When the external electromagnetic field propagates in biological tissues under a process like microwave hyperthermia, the temperature of the tissue at the field concentration area increases. Due to temperature and frequency dependence of the tissue dielectric, the tissue permittivity changes; thus, the electric field scattered by the tissue changes. Therefore, by measuring the field scattered from the object, dielectric changes of the tissue structure can be calculated. Since the biological tissues’ dielectric coefficient at frequencies lower than 2GHz is linear,... 

In the method treatment of thermobrachytherapy, the method of this project, simultaneously use of two processes of thermotherapy and brachytherapy is considered, which can be a more effective treatment for the destruction of tumor tissue. In thermotherapy, the temperature of the tissue is artificially raised to a temperature that leads to cell dysfunction resulting in cell death. In brachytherapy, the destruction of defective tissue is done by placing a source in the tissue. In the present project, we supposed to consider both mechanisms simultaneously for treatment at the same time. In this project, radioactive material 125I is used as a source of radiation emission for brachytherapy. In... 

nowadays Acoustic play an important role in the treatment of various diseases, especially cancer. in 2020 cancer has been the cause of death for more than 10 million patients. High intensity focused ultrasound is a non-invasive technique that used successfully to treat Malignant cancers like liver, pancreas and prostate. One of the major problems of using acoustic waves is the absorption of high frequency waves by the tissue before reaching the target area. in this study, a finite element model used to find the relation between frequency and acoustic pressure of transducer and focal region intensity. the results show, the maximum intensity in focal region linearly proportional to frequency... 

Hyperthermia (also called thermal therapy or thermotherapy) is defined as a type of cancer treatment in which body tissue is exposed to high temperatures, to damage and kill cancer cells, or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. The temperature increase required by hyperthermia can be achieved via different heat sources, such as electromagnetic radiation waves (radiofrequency or microwave, ultrasound waves and electrical current. These techniques have shown good results, however, the major problem with present conventional methods is reaching homogenous heat distribution and therapeutic temperatures in the deep region of the tumor to be... 

Cancer treatment is one of the most challenging issues of recent years. Extensive researches have been conducted in various fields of medicine, pharmacy, and medical physics in this regard. Today, considering nanotechnology developments, researchers believe that full cancer treatment is possible through the use of nano-systems designed with scientific background to overcome the defects of previous methods. In this research, the main purpose is to design and synthesize multifunctional hybrid nanostructures with favorable optical and magnetic properties providing a way to combine chemotherapy and thermal treatment. Accordingly, two different structures were designed and experimentally... 

Controlled release is a crucial factor in tissue engineering and cancer-therapy applications. The main purpose of current research is to synthesis smart magnetic nanocarriers for hydrophobic drug and embedding them in a fibrous platform for anti-cancer/ tissue engineering applications. In this regard, three different drug delivery systems of magnetic nanocolloid, magnetic fibers and hydrogels were studied. In the first phase, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized and then were modified using oleic acid and thermo-sensitive polymer of pluronic F127/F68. After characterization of this composite, Response Surface Methodology (RSM) was applied to model the lower... 

Ultrasound hyperthermia is a commonly used noninvasive approach to destroy cancer tumors. High Intensity Focused Ultrasound (HIFU) is a technique based on hyperthermia. It creates short and local elevations of temperature at a focus site within the tissue of interest. The main goal of HIFU is to maintain the temperature between 50 and 100 °C for a few seconds (typically less than 10 s), in order to cause tissue necrosis. In order to predict the effects of hyperthermia, accurate and effective modeling is needed. This study considers a 3D simulation of the hyperthermia based on HIFU method in the liver tissue. Temperature distribution and lesion volume changes, with a temperature of above... 

The tumor is a collection of cells (cell mass) caused by the lack or ineffectiveness of cellular proliferation inhibitors. Many types of cancers are associated with the emergence of a tumor, a tissue with specific physiological characteristics. The tumors grow very fast so researchers try to prevent their growth and eventually destroy them. Thermal ablation by MWA(microwave ablation) is a common and minimally-invasive treatment for primary and secondary liver tumors that can not be cured by surgery. During treatment, the tissue is heated by microwaves and at a temperature higher than 50 degree Celsius, destroyed by thermal ablation. In this study, two thermal models have been used to... 

Low frequency Magnetic hyperthermia is a promising cancer treatment technique. It is based on the fact that magnetic nanoparticles (MNPs) placed in an alternating magnetic field release heat.Active research is being done to improve the specific absorption rate (SAR) of MNPs, which could permit the treatment of tumors of a smaller size and could reduce the amount of material that must be injected to treat a tumor of a given size. However, a major technical problem with hyperthermia is the difficulty of heating the targeted tumor to the desired temperature without damaging the surrounding tissues, as the electromagnetic energy must be directed from an external source and penetrates normal... 

In this research, diffraction limit is introduced as the major challenge in wave focusing. Common wave focusing techniques have been reviewed and classified into two categories: far-field and near-field techniques. Through examples that illustrate its major inherent and practical challenges, super-oscillation has been presented as a specific idea of focusing waves using remote sources. By introducing subwavelength inhomogeneities in the region of interest, we have demonstrated sub-diffraction wave focusing in a near-field approach. Using the multipole method, the effect of injecting sub-wavelength cylindrical particles on focusing electromagnetic waves has been studied. Since when there are...