This paper explored the feasibility of using ultrasonic Nakagami statistic parameter imaging to evaluate the thermal lesion induced by microwave ablation (MWA) in porcine models. In this paper, thermal lesions were induced in livers and kidneys in 5 swines using a clinical MWA system. During this treatment progress, ultrasonic radiofrequency (RF) data were collected. The dynamic changes of Nakagami parameter in the thermal lesion were calculated, and the ultrasonic B-mode images and Nakagami images were reconstructed simultaneously. The contrast-to-noise ratio (CNR) between the thermal lesion and the surrounding normal tissue was calculated over the MWA procedure. After MWA, a bright hyperechoic region appeared in the ultrasonic Nakagami image as an indicator of the thermal lesion and this bright spot enlarged with lesion development during MWA exposure. The mean value of Nakagami parameter in the liver and kidney increased from 0.78 and 0.79 before treatment to 0.91 and 0.92 after treatment, respectively. During MWA exposure, the mean values of CNR calculated from the Nakagami parameter increased from 0.49 to 1.13 in the porcine liver and increased from 0.51 to 0.85 in the kidney, which were both higher than those calculated from the B-mode images. This study on porcine models suggested that the ultrasonic Nakagami imaging may provide an alternative modality for monitoring MWA treatment.
Animals ; Kidney ; diagnostic imaging ; Liver ; diagnostic imaging ; Microwaves ; Radio Waves ; Radiofrequency Ablation ; Swine ; Ultrasonography

In this article, an introduction is given on the structure of RF subsystem, its main parameters and impact on the performance of MRI and RF techniques and its development. Furthermore, pivotal parameters provided by different suppliers are quoted and compared in functionality aspect.
Magnetic Resonance Imaging ; instrumentation ; methods ; Radio Waves

This paper reviews the basic principles and calculation methods of MR specific absorption rate, discusses the clinical application of MR specific absorption rate.
Humans ; Magnetic Resonance Imaging ; Radio Waves

OBJECTIVETo Compare the therapeutic effects of cryocareTM cryoablation, radiofrequency ablation(RFA), and and microwave coagulation (MCT) in rabbits with VX(2) liver cancer.

METHODSForty-five rabbits with VX(2) liver cancer were randomly and equally allocated into 5 groups to receive treatment with cryocare cryoablation (group A), radiofrequency ablation (group B), microwave coagulation (group C), surgical resection (group D) and control group (group E), respectively. The residual tumor tissues and metastasis (intrahepatic, lung, abdominal lymphoid node, and abdominal implantation) were observed after the treatments, with also detection of soluble interleukin-2 receptor ( sIL-2R) and recording of the survival time of the rabbits.

RESULTSSignificant differences were found in the occurrence of tumor residue (chi(2)=20.700, P=0.0000), intrahepatic metastasis (chi(2)=15.652, P=0.0004), and abdominal implantation tumor (chi(2)=13.894, P=0.0008) between the 5 groups, but not in lung and abdominal lymph node metastasis. sIL-2R levels differed significantly only after but not before the treatments (F=31.58, P=0.000) between groups A to D and group E (t=10.119, P=0.000). The treatments in groups A to D all resulted in prolonged survival of the rabbits as compared with the control (F=73.084, P=0.000), and cryocareTM cryoablation and surgical resection showed similarly better effect than RFA and MCT.

CONCLUSIONCryocare cryoablation can be more effective than RFA and MCT in reducing tumor residue and metastasis and prolonging the survival time of rabbits with VX(2) liver cancer, and RFA and MCT are comparable for their therapeutic effects.

Ablation Techniques ; methods ; Animals ; Cryosurgery ; Female ; Liver Neoplasms ; metabolism ; surgery ; Male ; Microwaves ; Rabbits ; Radio Waves ; Receptors, Interleukin-2 ; metabolism ; Survival Rate

In this paper, an overview is given on the optimization methods of designing RF coil array. Advantages and disadvantages are also discussed.
Equipment Design ; Magnetic Resonance Imaging ; instrumentation ; methods ; Radio Waves

Persistent light reaction, actinic reticuloid, photosensitive eczema are three chronic photodermatoses with a feature of clinical, histological, and photobiologieal characteristics in common. These conditions were given the name of chronic persistent photosensitivity. Chronic persistent photosensitivity with the feature of photosensitive eczema developed in a 68-year-old male patient who had experienced persisited dermatitis. On phototesting the patient showed extremely severe photosensitivity to the short wave UVB. A skin biopsy showed microscopic finding of eczematous dermatitis.
Actins ; Aged ; Biopsy ; Dermatitis ; Eczema ; Humans ; Male ; Radio Waves ; Skin

Aiming at the increasing application of RFID technology in the medical environment, this study introduces the foreign requirements for RFID immunity test of medical devices, compares them with the current immunity test requirements of medical devices in China, and puts forward the necessity of establishing relevant test specifications in China.
Radio Frequency Identification Device ; Electromagnetic Fields ; Radio Waves ; Equipment Safety ; Technology

The extensive use of mobile phones causes increasing public concern on health effects of exposure to radiofrequency (RF) electromagnetic fields. Conflicting results are found in publications on the mutagenic, carcinogenic and teratogenic effects of RF electromagnetic fields. The overwhelming findings do not support the assumption that RF exposure may induce mutagenic, carcinogenic or teratogenic effects. However, health effects from low level RF exposure need to be further studied.
Animals ; Cell Phone ; Congenital Abnormalities ; etiology ; Dose-Response Relationship, Radiation ; Electromagnetic Fields ; adverse effects ; Female ; Fetal Diseases ; etiology ; Humans ; Male ; Microwaves ; adverse effects ; Neoplasms ; etiology ; Occupational Exposure ; Pregnancy ; Radio Waves ; adverse effects

Radio frequency identification sensor network, which is a product of integrating radio frequency identification (RFID) with wireless sensor network (WSN), is introduced in this paper. The principle of radio frequency identification sensor is analyzed, and the importance of the antenna is emphasized. Then three kinds of common antennae, namely coil antenna, dipole antenna and microstrip antenna, are discussed. Subsequently, according to requirement, we have designed a microstrip antenna in a wireless temperature-monitoring and controlling system. The measurement of factual effect showed the requirement was fulfilled.
Body Temperature ; Computer Communication Networks ; Humans ; Monitoring, Physiologic ; instrumentation ; Radio Frequency Identification Device ; methods ; Radio Waves ; Telemetry ; instrumentation ; methods ; Transducers

In the design of RF receiver of the digital MRI spectrometer console, a digital demodulation and filtering algorithm is presented in this thesis. The MR signals are firstly converted to digital signals by the A/D converter, and then quadrature-demodulated from high frequency carrier wave. The CIC filter, half-band filter and linear phase FIR filter are designed to process the cascaded filtering and decimation of the demodulated signals. This method achieves a satisfying processing speed and filtering effect, and also reduces the data size obviously. The experiment based on the permanent magnetism resonance imaging system proves its effectiveness and practicability.
Algorithms ; Magnetic Resonance Imaging ; instrumentation ; methods ; Radio Waves ; Signal Processing, Computer-Assisted ; instrumentation ; Software