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

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

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

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

The technique of anterolateral cordotomy for relief of pain was first performed by Spiller and Martin (1912). It was accepted as the best available method for long-term relief despite its disadvantages. It has been well documented that the procedure often caused weakness of an extremity or the loss of sphincter control and respietory impairment associated with high surgical cervical cordotomy. In 1963, Mullan et al. devised an approach to the cervical spinal cord by inserting a needle through the neck under roentgenologic control. They introduced a radioactive needle (Strontium90) to produce a lesion interrupting the lateral spinothalamic tract. Mullan and Rosomoff et al. (1965) later simplified the produce by using an electrical current to produce the lesion. The percutaneous method has considerable advantages. The mortality and morbidity are very small and the technique can be used on any patient including even the terminal state. If the required level is not attained on the first attempt, or if the level subsequently drops, the procedure is easily repeated. Most patients can be discharged early after this type of cordotomy. Authors have reviewed 46 cordotomies on 35 patients with intractable pain carried out by the percutaneous radiofrequency procedure at the Neurosurgery Department of Yonsei University from 1972 to 1975:36 cases were treated by a modification of the Rosomoffs technique, 10 cases by Lin's technique. Intractable pain has been a continuing problem in neurosurgery and many methods have been employed in its treatment. The function of lateral spinothalamic tract was described by Spiller and Martin in 1912. and they described the posterior approach to the spinal cord which has been widely used for cordotomy in the 50 years since. However, in elderly or debilitated patients, this method has proved to have many complications and is poorly tolerated and has a morbidity and mortality rate. In 1963, Sean Mullan, using a Strontium90 electrode accomplished a lateral spinothalamic cordotomy by stereotaxic surgery under local anesthesia (Mullan, et al., 1963; 1965; 1965). Later, in 1965, Rosomoff (Rosomoff,et al., 1965; Rosomoff, et al., 1966) developed an improved technique using UHF radio waves, which achieved wide popularity. Using radiological equipment and measuring the impedance of various portions of the spinal cord with electrodes, the exact area of the lateral spinothalamic tract to be destroyed could be located. Utilizing localizing electrodes and the above method, complications from destruction of the tracts near the lateral spinothalamic tract which formerly resulted in hemiparesis, respiratory difficulty, urinary difficulties and other surgical difficulties could be minimized much more effectively than with open surgical approaches (Mullan and Hosobuchi, 1968). In bilateral, high cervical cordotomy the complication of sleep induced apnea may be a cause of death. Belmusto (Belmusto, et al., 1963; Belmusto; et al., 1965) indicated that the respiratory fibers are very near the lateral spinothalamic tract in the C-1 to C-3 spinal region. The respiratory fibers are located in the anterior one fourth of the spinal cord, extending from the median fissure 3~3.5 mm lateral wards towards the region of the median part of the lateral spinothalamic tract. (Mullan and Mosobuchi, 1968; Nathan, 1963; Hitchcock and Lee ce, 1967; Crosby, et al., 1962). In 1966, Lin (Lin, et al., 1966), developed a low cervical anterior approach, in order to avoid damage to the respiratory tract, and found that respiratory tract damage was actually decreased, and also found that regional analgesia was easily accomplished. Over the last three years, the authors, applying a percutaneous cervical cordotomy technique, have studied 46 patients, recording the present illness, method of surgery, postoperative analgesic area and its change with time, and complications. This material was analyzed and conclusions drawn.
Adult ; Aged ; Cordotomy/methods* ; Female ; Human ; Male ; Middle Age ; Pain, Intractable/surgery* ; Radio Waves*