In this study, a double-negative triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The spe...

When using a transmit array at high field, it is well established that high local specific absorption rate (SAR) values can occur [1]. In order to guarantee patient safety without harsh limitations to in-vivo transmit-SENSE [2] applications, subtle SAR monitoring is therefore necessary. In the recent past, a comprehensive solution involving pre-calculated B1-field-maps and local pickup-coils wa...

NOVEL TECHNIQUES REGARDING SPECIFIC ABSORPTION RATE AND FIELD OF VIEW REDUCTION IN MAGNETIC RESONANCE IMAGING Emre Kopanoglu Ph.D. in Electrical and Electronics Engineering Supervisors: Prof. Dr. Ergin Atalar Assoc. Prof. Dr. Vakur B. Ertürk September, 2012 In this dissertation, novel strategies regarding the reduction of the specific absorption rate (SAR) and the reduction of the total scan ti...

PURPOSE To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. METHODS We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of...

A promising route to cancer treatment is hyperthermia, facilitated by superparamagnetic iron oxide nanoparticles (SPIONs). After exposure to an alternating external magnetic field, SPIONs generate heat, quantified by their specific absorption rate (SAR, in W g(-1) Fe). However, without surface functionalization, commercially available, high SAR SPIONs (EMG 308, Ferrotec, USA) aggregate in aqueo...

The numerical calculation of the Specific Absorption Rate (SAR) averaged over a certain tissue mass is a common practice when evaluating the potential health risk due to the human exposure to electromagnetic sources. Nevertheless, SAR values are strongly influenced by many factors such as, for instance, the shape of the volume containing the reference mass, the spatial discretization step, or t...

Recently, there has been increasing concern regarding the safety of exposure to RF electromagnetic fields in pregnant females and their fetuses. In this study, we acquired fetal magnetic resonance imaging at 20 26 and 29 weeks from a healthy volunteer of pregnancy and developed the pregnant female models at those weeks of pregnancy by combining the fetal models constructed on the basis of the f...

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PURPOSE To investigate the behavior of whole-head and local specific absorption rate (SAR) as a function of trajectory acceleration factor and target excitation pattern due to the parallel transmission (pTX) of spatially tailored excitations at 7T. MATERIALS AND METHODS Finite-difference time domain (FDTD) simulations in a multitissue head model were used to obtain B(1) (+) and electric field...