Introduction In high field MRI, the increased interactions between the electromagnetic waves and the biological tissues may give rise to heat and thermal hazards. This is clearly apparent for multi-transmit array applications where the electromagnetic fields are heavily manipulated in the subject to be imaged. In this work we provide complete 3D predictions of the B1 + fields, MRI images, energ...

The safety of the barewire loopless catheter antenna in transmit mode is addressed with respect to radiofrequency (RF) heating. Analytical expressions for electric field and specific absorption rate (SAR) distributions surrounding the antenna are postulated and experimentally verified. Limiting RF transmit power to 40-70 mW time-averaged power, depending on the specific antenna design, will ens...

Specific Absorption Rate (SAR) constitutes a key issue for mobile phones. Indeed, SAR which represents the power per unit mass delivered in biological tissues must comply with existing standards. The averaged SAR required by standards can be deduced from the measurement of E-field distribution in a volume of biological phantoms, filled with a tissue equivalent liquid. Such a standard procedure ...

The management of local and global power deposition in human subjects (specific absorption rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in ...

The finite difference time domain (FDTD) method in combination with a well established frequency scaling method was used to calculate the internal fields and current densities induced in a simple model of a pregnant woman and her foetus, when exposed to hand-held metal detectors. The pregnant woman and foetus were modelled using a simple semi-heterogeneous model in 10 mm resolution, consisting ...

Preliminary communication The aim of this investigation is to analyse the effects of hand on electromagnetic (EM) absorption and antenna performances. The EM absorption is evaluated by using the specific absorption rate (SAR) in the human head and total absorbed power by the user in this paper. The antenna performance’s parameters comprising radiation efficiency, total efficiency, gain and band...

Parallel transmission has gained considerable interest during the last few years [1,2]. The use of multiple individual RF transmit coils have been introduced to overcome B1 homogeneity limitations and to improve multi-dimensional RF pulses by shortening their duration. Of special concern in all these transmit applications is the specific absorption rate (SAR), which has to be kept below certain...

The purpose of this paper is to calculate the specific absorption rate (SAR) reduction in muscle cube with metamaterial attachment. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in a realistic anatomically based model of the muscle cube. We design the single negative metamaterials from periodic arrangement of split ring resonators (SRRS). By properly designin...

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...

An in-depth approach towards the design of PIFA has been taken. After discussing the essential parameters involved in the design procedure and introduction of a design algorithm, a miniaturized dual-band PIFA is introduced. Different specifications of the proposed antenna are measured both through computer simulation and fabricated PIFA. Also, the Specific Absorption Rate (SAR) is introduced an...