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...

Abstract A helicon plasma source has been designed using annular permanent magnets to produce the required DC magnetic field (B-field). With the discharge tube located in the remote field, rather than the internal field of the magnet rings, the plasma can be injected into a processing chamber containing the substrate to be treated. The discharge tube, radiofrequency (RF) antenna and magnet size...

Pulsed radiofrequency, in which short bursts of radiofrequency energy are applied to nervous tissue, has been recently described as an alternative technique devoid of nerve injury, a subsequent side effect of thermal lesions created by continuous radiofrequency lesioning. Yet the mechanism of this effect remains unclear. In this study we compared the acute effects of pulsed versus continuous ra...

The 7-tesla acquisitions, facilitated by the use of a customized radiofrequency coil configuration and cardiac gating, achieved isotropic resolution of 6 mm, reported researchers from the Berlin Ultrahigh Field Facility (BUFF) in Berlin, along with co-authors from other institutions including Charité University Medicine in Berlin, the German Cancer Research Center in Berlin, and the University ...

During MR procedures majority of the radiofrequency (RF) power transmitted for imaging or spectroscopy is transformed into heat within the patient’s tissue as a result of resistive losses. In this work we evaluate the effect of a wide variety of receive-only insert geometry including cylinders and helmets with different trace widths on spin excitation field and SAR of a 7T TEM transmit coil.

transcatheter ablation of atrioventricular accessory pathway is the therapy of choice in symptomatic patients. the ablation of posteroseptal accessory pathways thas some important points due to its anatomical location. catheter ablation of posteroseptal accessory pathways via left side approach is time consuming with low success rate and higher complications. we performed successful transcathet...

Radiofrequency ablation (RFA) has been widely used for the treatment of various solid organ malignancies. Over the last decade, endosonographers have gradually shifted the application of RFA from porcine models to humans to treat a spectrum of diseases. RFA is performed in patients with pancreatic carcinoma who are not candidates for surgery. In this paper, we will discuss various indications f...