Nonionizing electromagnetic fields (EMF) have photon energy less than 10eV, a level not sufficient to produce ions by ejection of orbital electrons from atoms. The biological effects of two types of nonionizing electromagnetic fields are being studies intensely: extremely-lowfrequency (ELF) electromagnetic field and radiofrequency radiation. Extremely-low-frequency EMF covers the frequency rang...

BACKGROUND Radiofrequency ablation is extensively used to achieve pulmonary veins isolation for the cure of atrial fibrillation. Luminal esophageal temperature can be monitored by means of suitable probes to prevent the onset of lesions. OBJECTIVE To compute the thermal field generated by the ablation, to investigate the interaction between the electromagnetic field and the probe sensors, and...

At high magnetic field strengths (≥ 3T), the radiofrequency wavelength used in MRI is of the same order of magnitude of (or smaller than) the typical sample size, making transmit magnetic field (B1+) inhomogeneities more prominent. Methods such as radiofrequency-shimming and transmit SENSE have been proposed to mitigate these undesirable effects. A prerequisite for such approaches is an accurat...

Miranda-Filho et al. in their recently published paper entitled “Cancers of the brain and CNS: global patterns and trends in incidence” provided a global status report of the geographic and temporal variations in the incidence of brain and CNS cancers in different countries across continents worldwide. While the authors confirm the role of genetic risk factors and ionizing radiation exposur...

BACKGROUND Radiofrequency surgery is a method of utilizing high frequency (3.8 to 4MHz) radio wave energy to incise, excise, or coagulate tissues. Radiofrequency (RF) is a relatively new modality that is being used for ano-rectal surgeries with increasing frequency. As the RF energy is applied, frictional heating of tissues results, with cell death occurring at temperatures between 60 and 100 d...

Introduction: Parallel transmission techniques in MRI have sparked new interest in measuring the B1+ field, the component of the radiofrequency field concerned with spin excitation. A precise measurement over a large range of B1+ values can be performed by fitting a function to data acquired with different flip angles [1]. However a large number of support points are necessary, making this meas...

Carr-Purcell-Meiboom-Gill train of radiofrequency pulses applied to spins in the constant magnetic field gradient is an efficient variant of the modulated magnetic field gradient spin echo method, which provides information about molecular diffusion in the frequency-domain instead in the time-domain as with the two-pulse gradient spin echo. The frequency range of novel technique is broad enough...

BACKGROUND The lethal isotherm for radiofrequency catheter ablation of cardiac myocardium is widely accepted to be 50°C, but this has not been directly measured. The purpose of this study was to directly measure the tissue temperature at the edge of radiofrequency lesions in real time using infrared thermal imaging. METHODS AND RESULTS Fifteen radiofrequency lesions of 6 to 240 seconds in dur...