نتایج جستجو برای: radiofrequency rf

تعداد نتایج: 49059  

Journal: :Journal of magnetic resonance imaging : JMRI 2000
D J Larkman A H Herlihy G A Coutts J V Hajnal

Foldover artifacts arise when the same imaging frequency occurs both at a desired location within a slice and at another location within the sensitive region of the radiofrequency (RF) coil. Foldover artifacts can be caused by nonlinearity in the gradient system and by inhomogeneity in B(0). This study investigates an approach in which an extra RF receiver coil and a postprocessing method are u...

2012
Chung Hoon Park Yoon Woo Lee Yong Chan Kim Joo Hwa Moon Jong Bum Choi

Trigger point injection treatment is an effective and widely applied treatment for myofascial pain syndrome. The trapezius muscle frequently causes myofascial pain in neck area. We herein report a case in which direct pulsed radiofrequency (RF) treatment was applied to the trapezius muscle. We observed that the RF treatment produced continuous pain relief when the effective duration of trigger ...

Journal: :Thermal Medicine(Japanese Journal of Hyperthermic Oncology) 1990

Journal: :Journal of atrial fibrillation 2010
Pawan K Arora James C Hansen Adam D Price Josef Koblish Boaz Avitall

The ablation of atrial fibrillation (AF) is an area of intense research in cardiac electrophysiology. In this review, we discuss the development of catheter-based interventions for AF ablation. We outline the pathophysiologic and anatomic bases for ablative lesion sets and the evolution of various catheter designs for the delivery of radiofrequency (RF), cryothermal, and other ablative energy s...

2007
Linda Moulton

Just over a decade ago, the advent of tip temperature monitoring during radiofrequency (RF) energy delivery marked the beginning of a second generation of ablation catheter technology and furthered the success of catheter ablation as a therapeutic tool. RF generators were designed with a closed-loop feedback system to automatically adjust power output to avoid temperatures that would cause coag...

2015
Jongju Na Zhenlong Zheng Christopher Dannaker Sang Eun Lee Jin-Soo Kang Sung Bin Cho

Radiofrequency (RF) energy can be emitted into the skin, either non- or invasively, via a monopolar mode that utilizes an active electrode and a grounded electrode or via a bipolar mode that employs two active electrodes. In this experimental study of RF tissue reactions, bipolar RF energy was emitted in vivo to micropig skin at varying microneedle penetration depths, signal amplitudes, and con...

Journal: :Journal of cosmetic and laser therapy : official publication of the European Society for Laser Dermatology 2005
Seema N Doshi Tina S Alster

PURPOSE As the demand for noninvasive procedures to address cutaneous aging issues has increased, novel nonablative lasers and radiofrequency (RF) devices have recently emerged. The objective of this study was to evaluate the safety and efficacy of a combination RF/diode laser device designed to target both skin laxity and facial rhytides. Materials and methods. Twenty patients (skin phototypes...

Journal: :Indian journal of physiology and pharmacology 2023

Objectives: Radiofrequency electromagnetic radiation (RF-EMR) from mobile phones is known to produce a stress response because of its effect on hypothalamus. Mobile have become an integral part our lives with increasing usage not only in terms number users but also increase talk time. The present study aimed the phone radiofrequency radiations oxidative and feeding behaviour assessment Sprague ...

Journal: :Journal of magnetic resonance 1998
B J Dardzinski S Li C M Collins G D Williams M B Smith

The design and performance of an inductively fed low-pass birdcage radiofrequency (RF) coil for applications at 9.4 T are described where tuning is accomplished by mechanically moving a concentric RF shield about the longitudinal axis of an RF coil. Moving the shield about the RF coil effectively changes the mutual inductance of the system, providing a mechanism for adjusting the resonant frequ...

Journal: :journal of medical signals and sensors 0
fereshteh yousefi rizi seyed kamaledin setarehdan hamid behnam

quantification of arterial elasticity and its dependency to age is considered in this paper. we use radiofrequency (rf) signals fromcarotid artery ultasonography to evaluate this dependency. blood pressure, blood flow, and tethering to surrounding tissue are the maincauses of the motion of the carotid wall. tracking carotid artery wall motion from a series of ultrasound b‑mode images is challen...

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