In high and ultrahigh field magnetic resonance imaging (MRI) research, computational electromagnetic techniques are now taking an important role in the design and evaluation of MRI radiofrequency (RF) coils. This paper focuses on the RF power requirements and specific absorption rate (SAR) associated with the MRI operation at different field strength. This paper also presents new techniques for...

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...

Background: Drug resistance is widely believed to be an increasingly serious threat to global public health. We have previously reported that short term exposure of microorganisms to diagnostic ultrasound waves could significantly alter their sensitivity to antibiotics. In our previous studies, Klebsiella pneumoniae showed major differences in the sensitivity to antibiotics in exposed and non-e...

Introduction: Halitosis and foreign body sensation are two common and disturbing symptoms of chronic caseous tonsillitis (CCT). The aim of this study was to compare the efficacy and safety of temperature-controlled radiofrequency (TC-RF) tonsil ablation with CO2-laser cryptolysis (CO2-LC) in the treatment of patients with halitosis caused by CCT.   Materials and Methods: Sixty-two patients who ...

The performance of multidimensional spatially selective radiofrequency (RF) pulses is often limited by their long duration. In this article, high-order, nonlinear gradients are exploited to reduce multidimensional RF pulse length. Specifically, by leveraging the multidimensional spatial dependence of second-order gradients, a two-dimensional spatial-spectral RF pulse is designed to achieve thre...

Recent studies have shown that radiofrequency (RF) ablation therapy is a safe, feasible, and effective procedure for hepatic hemangiomas, even huge hepatic hemangiomas. RF ablation has the following advantages in the treatment of hepatic hemangiomas: minimal invasiveness, definite efficacy, high safety, fast recovery, relatively simple operation, and wide applicability. It is necessary to formu...

The increasing use of mobile phones has raised public concern about the possible biological effects of radiofrequency electromagnetic field (RF-EMF) exposure on the human brain. To investigate the potential effect of RF-EMF exposure on the brain, we examined the behaviors and hippocampal morphology of C57BL/6 mice after sub-chronic exposure to RF-EMFs with a relatively high SAR level (5.0 W/kg)...

Several methods have been proposed for overcoming the effects of radiofrequency (RF) magnetic field inhomogeneity in high-field MRI. Some of these methods rely at least in part on the ability to independently control magnitude and phase of different drives in either one multielement RF coil or in different RF coils in a transmit array. The adjustment of these drive magnitudes and phases alone t...

Introduction Substrate-based radiofrequency (RF) ablation of scar-related ventricular tachycardia (VT) has become standard practice, often in addition to an intracardiac cardioverter-defibrillator. VT procedures without identified substrate are particularly challenging cases, especially when VT is noninducible. An intramural focus is often challenging to ablate using conventional RF ablation, a...

Complex regional pain syndrome (CRPS) is characterized by a combination of sensory, motor, vasomotor, pseudomotor dysfunctions and trophic signs. We describe the use of radiofrequency (RF) ablation of Stellate ganglion (SG) under fluoroscopy, for long-term suppression of sympathetic nervous system, in a patient having CRPS-not otherwise specified. Although the effects of thermal RF neurolysis m...