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Sample records for monopolar radiofrequency energy

  1. Comparison between bipolar pulsed radiofrequency and monopolar pulsed radiofrequency in chronic lumbosacral radicular pain

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    Chang, Min Cheol; Cho, Yun Woo; Ahn, Sang Ho

    2017-01-01

    Abstract Background: Chronic lumbosacral radicular pain is a challenging medical problem with respect to therapeutic management. Many patients with lumbosacral radicular pain complain of persistent leg pain after transforaminal epidural steroid injection. Nowadays, pulsed radiofrequency (PRF) stimulation on the dorsal root ganglion (DRG) is widely used for controlling lumbosacral radicular pain. Methods: We evaluated the effect of bipolar PRF on the DRG for the management of lumbosacral radicular pain. In addition, we compared the effect of bipolar PRF to monopolar PRF. Fifty patients with chronic lumbosacral radicular pain were included in the study and randomly assigned to 1 of 2 groups, the bipolar or monopolar PRF group (n = 25 per group). Pain intensity was evaluated using a numeric rating scale (NRS) at pretreatment, and 1, 2, and 3 months after treatment. Results: When compared to the pretreatment NRS scores, patients in both groups showed a significant decrease in NRS scores at 1, 2, and 3 months after treatment. Reductions in the NRS scores over time were significantly larger in the bipolar PRF group. Three months after treatment, 19 patients (76.0%) in the bipolar PRF group and 12 patients (48.0%) in the monopolar PRF group reported successful pain relief (pain relief of ≥50%). Conclusion: The use of bipolar PRF on the DRG can be an effective and safe interventional technique for chronic refractory lumbosacral radiculopathy, particularly in patients whose pain are refractory to epidural steroid injection or monopolar PRF stimulation. PMID:28248888

  2. Monopolar radiofrequency ablation using a dual-switching system and a separable clustered electrode: Evaluation of the in vivo efficiency

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    Yoon, Jeong Hee; Lee, Jeong Min; Hwang, Eui Jin; Hwang, In Pyung; Beak, Jee Hyun; Han, Joon Koo; Choi, Byung Ihn [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-04-15

    To determine the in vivo efficiency of monopolar radiofrequency ablation (RFA) using a dual-switching (DS) system and a separable clustered (SC) electrode to create coagulation in swine liver. Thirty-three ablation zones were created in nine pigs using a DS system and an SC electrode in the switching monopolar mode. The pigs were divided into two groups for two experiments: 1) preliminary experiments (n = 3) to identify the optimal inter-electrode distances (IEDs) for dual-switching monopolar (DSM)-RFA, and 2) main experiments (n = 6) to compare the in vivo efficiency of DSM-RFA with that of a single-switching monopolar (SSM)-RFA. RF energy was alternatively applied to one of the three electrodes (SSM-RFA) or concurrently applied to a pair of electrodes (DSM-RFA) for 12 minutes in in vivo porcine livers. The delivered RFA energy and the shapes and dimensions of the coagulation areas were compared between the two groups. No pig died during RFA. The ideal IEDs for creating round or oval coagulation area using the DSM-RFA were 2.0 and 2.5 cm. DSM-RFA allowed more efficient RF energy delivery than SSM-RFA at the given time (23.0 ± 4.0 kcal vs. 16.92 ± 2.0 kcal, respectively; p 0.0005). DSM-RFA created a significantly larger coagulation volume than SSM-RFA (40.4 ± 16.4 cm{sup 3} vs. 20.8 ± 10.7 cm{sup 3}; p < 0.001). Both groups showed similar circularity of the ablation zones (p = 0.29). Dual-switching monopolar-radiofrequency ablation using an SC electrode is feasible and can create larger ablation zones than SSM-RFA as it allows more RF energy delivery at a given time.

  3. Comparison of the Outcomes of Monopolar and Bipolar Radiofrequency Ablation in Surgical Treatment of Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    Wei-zhao Huang; Ying-meng Wu; Hong-yu Ye; Hai-ming Jiang

    2014-01-01

    Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency (RF) ablation used during cardiac surgery to treat atrial fibrillation. Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011. Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation, respectively. The sinus rhythm restoration rate, the procedural duration, the frequency of severe perioperative complications, and mortality were compared between the two groups. Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months (P=0.199). The frequencies of severe perioperative complications and mortality were also similar in the two groups. The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation (19.7±4.6 minutes vs. 28.1±8.5 minutes, P Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery, but bipolar RF ablation is more convenient in practice.

  4. Osteoid osteoma of the spine: CT-guided monopolar radiofrequency ablation

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    Martel, Jose [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain)], E-mail: jmartel@fhalcorcon.es; Bueno, Angel [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain); Nieto-Morales, M Luisa [Servicio de Radiologia, Hospital Universitario de Tenerife (Spain); Ortiz, Eduardo J. [Departamento de Cirugia Ortopedica, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain)

    2009-09-15

    CT-guided percutaneous radiofrequency ablation and laser photocoagulation have become the methods of choice for the treatment of all osteoid osteomas except those in contact with neural structures. We report 10 patients with spinal osteoid osteoma adjacent to the neural elements treated with 12 sessions of CT-guided monopolar radiofrequency ablation. The size range of the lesion was 3-14 mm (mean, 7.5 mm) and the distance between the nidus and the adjacent spinal cord or nerve root was 2-12 mm (mean, 5 mm). No intact cortex between the tumor and the spinal cord or nerve roots constituted an exclusion criterion because of a higher risk of undesirable neurotoxic effects. Patients were under general anesthesia. After location of the lesion, a 11G-bone biopsy was introduced into the nidus. The radiofrequency electrode was inserted through the biopsy needle and heated at 90 deg. C for 4 min. Primary success was obtained in eight patients. At follow-up (mean, 19.5 months; range, 6-24 months), pain persisted in two patients after 2 months. Both of them were re-treated. All patients are currently pain-free and complications were not detected. In our opinion, radiofrequency ablation can also be considered the treatment of choice for spinal osteoid osteoma.

  5. COMPARATIVE STUDY OF FISTULECTOMY BY CORING TECHNIQUE IN FISTULA IN ANO, USING RADIOFREQUENCY CAUTERY AND MONOPOLAR CAUTERY

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    Madhura M

    2015-12-01

    Full Text Available Fistula in ano is common condition in perineal region. Anorectal fistulas are divided into four distinct types according to the Parks’ classification: intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric.1 The ultimate goal of fistula surgery is to eradicate it without disturbing or disturbing minimally the anal sphincter mechanism. The radiofrequency scalpel is an innovative instrument, which allows cutting and coagulating tissues in an atraumatic manner and which facilitates in accelerating and improving the surgical procedure conversely to the electric scalpel.2 This prospective study which will be conducted in a single centre and in this study we are comparing use of monopolar cautery and radiofrequency cautery units for the patients with fistula in ano operated during the period of February 2012 to February 2015. All fistulas will be treated by fistulectomy using coring technique. Results will be analyzed on following points like intraoperative bleeding, clearance of visual field, intra- and post-operative odema, and time required for every procedure, recurrence. AIMS AND OBJECTIVES OF STUDY 1. To compare intraoperative bleeding during surgery using both the units (cautery/RF cautery during surgery. 2. To assess clearance of field of vision intraoperatively. 3. To see for intraoperative and post-operative edema. 4. To assess time required for the procedure. 5. Final results in terms of recurrence. CONCLUSION Radiofrequency ablation is better method for fistulectomy compared to monopolar cautery in terms of intraoperative blood loss, post-operative pain, oedema, and healing period. But if procedure is better taken care of recurrence is avoidable. Operative time required for monopolar cautery exceeds radiofrequency cautery.

  6. Treatment of facial skin laxity by a new monopolar radiofrequency device

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    Uwe Wollina

    2011-01-01

    Full Text Available Background : Acquired facial skin laxity seems to be a result of the combination of intrinsic and extrinsic processes. For treatment of facial ageing, non-invasive procedures have become popular. Aim : We wanted to investigate the effect of a new 2.2-MHz radiofrequency (RF device on acquired facial skin laxity. Setting : Outpatient clinic associated with an academic teaching hospital. Materials and Methods : We performed an open trial with the RF-ReFacing™ device (Meyer-Haake Medical Innovations, Wehrheim/ Germany in the monopolar mode with a power of 8-12 W, two passes per session and repetition three times after 2 weeks without treatment. Results : A total of 20 Caucasian female patients were included (age range, 34-73 years. The procedure was performed without any analgesia. We did not see any adverse effect. The procedure was scored as most convenient or convenient by all patients. Improvement in skin laxity and fine wrinkles was seen after the second treatment in 19 of the 20 patients and after the third treatment in 100% of the patients. On a scale from 0 to 3, improvement in the lower lid, Crow′s feet and jowl line was scored 2.6±0.7 by the patients; improvement in the overall appearance of the face was scored 2.3±0.5. Blinded assessment of the photographs rated the improvement as good or better in 15 of the 20 patients, moderate in 3 patients, no change in 1 patient. Conclusions : RF-ReFacing™ treatment was effective in improvement in skin laxity. Patients′ satisfaction was high. Although RF-ReFacing™ treatment cannot substitute surgical procedure, it might prolong the time to the first surgical facial lift. The number of patients treated was small, and no quantitative measurements or histopathology was performed. Hence further studies with greater number of patients are necessary.

  7. Comparison of thermal damage of the internal thoracic artery using ultra high radiofrequency and monopolar diathermy.

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    Bulat, Cristijan; Pešutić-Pisac, Valdi; Capkun, Vesna; Marović, Zlatko; Pogorelić, Zenon; Družijanić, Nikica

    2014-10-01

    The internal thoracic artery (ITA) has been accepted worldwide as a first choice conduit for myocardial revascularisation. It still remains questionable what is the best method for ITA harvesting in a skeletonized fashion according to structural integrity of artery, as a risk factor of early and late graft failure. The purpose of this study was to determine the impact of the ultra-high radiofrequency energy used for ITA harvesting on arterial structural integrity, in particular on the endothelial layer. Seventy-four ITA specimens were divided into two groups depending on device used for harvesting (radiofrequency-knife (RF) or electrocauter (EC)). Thermal damage on arterial structural integrity was measured using light microscope, morphometric imaging analysis and immunohistochemical methods. Thermal damage of endothelium was 2.8 times higher in EC than in RF group (p = 0.041) and 5 times higher in patients older than 66 years of age (p = 0.002). Extent of endothelial damage (graded from 0 to 3) was significantly higher in EC group (p = 0.03). Also, in EC group, in patients older than 66 years of age higher proportion of extent of endothelial damage was found (p = 0.027). The endothelial damage was more often in EC than in RF group as in the patients older than 66 years of age. Demonstrated results suggest that the radiosurgery in comparison to conventional electrocautery is safe and effective method, and significantly reduces thermal damage to endothelial layer of artery. Copyright © 2013 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

  8. Monopolar Radiofrequency Ablation for Medium-sized Hepatocellular Carcinoma: Preliminary Experience with Single-Electrode Overlapping Ablation and Multiple-Electrode Switching System

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    Shen-Yung Wang

    2015-03-01

    Conclusions: Medium-sized hepatocellular carcinoma can be effectively ablated with monopolar radiofrequency ablation by either single-electrode overlapping ablation or a multiple-electrode switching system. Regarding mid-term treatment responses, both RFA approaches can achieve similar treatment effectiveness, local tumor progression rate, and survival probabilities. Multiple-electrode switching RFA can treat larger medium-sized HCC with comparable mid-term efficacy as smaller medium-sized HCC treated with single-electrode overlapping RFA.

  9. Ultrasonic energy device versus monopolar energy device in laparoscopic transabdominal preperitoneal (TAPP) inguinal hernia repair.

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    Otsuka, Shimpei; Kaneoka, Yuji; Maeda, Atsuyuki; Takayama, Yuichi; Fukami, Yasuyuki; Onoe, Shunsuke

    2017-03-01

    Laparoscopic transabdominal preperitoneal (TAPP) is gaining popularity as an approach to repairing of inguinal hernia. In many institutions, a disposable ultrasonic energy device is used in the TAPP repair procedure. However, the benefit and necessity of an ultrasonic device are unclear. We have switched to use of a reusable monopolar energy device, and we conducted a retrospective study comparing the surgical results obtained with each of the energy devices. Our study group comprised 241 adults who underwent TAPP repair for inguinal hernia between November 2012 and December 2014. We compared clinical characteristics, and surgical outcomes between patients in whom a disposable ultrasonic energy device was used (n = 116, U group) and those in whom a reusable monopolar energy device (n = 125, M group) was used. There was no statistically significant difference between the 2 groups in age, sex, body mass index, or hernia type. In cases of unilateral hernia, operation time was significantly longer in the U group than in the M group (71.4 vs. 59.4 min, respectively, p energy device lead us to conclude that the ultrasonic energy device is unnecessary for simple TAPP repair.

  10. No-touch radiofrequency ablation: A comparison of switching bipolar and switching monopolar ablation in Ex Vivo bovine liver

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    Chang, Won; Lee, Jeong Min; Lee, Sang Min; Hank, Joon Koo [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-04-15

    To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers. A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups. Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases. The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries.

  11. No-Touch Radiofrequency Ablation: A Comparison of Switching Bipolar and Switching Monopolar Ablation in Ex Vivo Bovine Liver

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    Chang, Won; Lee, Sang Min; Han, Joon Koo

    2017-01-01

    Objective To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers. Materials and Methods A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups. Results Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases. Conclusion The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries.

  12. Surgical complications specific to monopolar electrosurgical energy: engineering changes that have made electrosurgery safer.

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    Odell, Roger C

    2013-01-01

    Monopolar electrosurgical energy is the most commonly used energy source during laparotomic and laparoscopic surgery. The clinical application of monopolar energy is not without risk. Monopolar electrosurgical energy was introduced into surgical practice at the turn of the 20th century. Alternate site burns during laparotomic application were the most common complication for the first half century (i.e., ground point burns and dispersive electrode burns [1920-1970]). The aims of this article were to discuss historic design flaws associated with the most common alternate site burns, ground point burns, and dispersive electrode burns and the technological advancements introduced to mitigate these risks to the patient and to discuss current design flaws associated with stray energy burns during laparoscopy because of insulation failure and capacitive coupling and the technological advancements introduced to eliminate these risks to the patient. Today, insulation failure and capacitive coupling are the most common reasons for electrosurgical injury during laparocopic procedures. There is a need for advanced technology such as active electrode monitoring to address these invisible risks to the surgeon and their patients. In addition, the laparoscopic surgeon should be encouraged to study the basic biophysics involved in electrosurgery.

  13. Influence of the Dermis Thickness on the Results of the Skin Treatment with Monopolar and Bipolar Radiofrequency Currents

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    Ilja L. Kruglikov

    2016-01-01

    Full Text Available Electrically layered tissue structure significantly modifies distribution of radiofrequency (RF current in the dermis and in the subcutaneous adipose tissue comparing to that in a homogeneous medium. On the basis of the simple model of RF current distribution in a two-layer skin containing dermis and subcutis, we assess the influence of the dermal thickness on the current density in different skin layers. Under other equal conditions, current density in the dermis is higher for the skin having thinner dermis. This contradicts the main paradigm of the RF theory stating that treatment results are mainly dependent on the maximal temperature reached in a target tissue, since the best short- and long-term clinical results of RF application to the skin were reported in the areas having thicker dermis. To resolve this contradiction, it is proposed that the long-term effect of RF can be realized through a structural modification of the subcutaneous fat depot adjacent to the treated skin area. Stimulation of these cells located near the interface dermis/subcutis will demand the concentration of applied RF energy in this area and will require the optimal arrangement of RF electrodes on the skin surface.

  14. Dissection by Ultrasonic Energy Versus Monopolar Electrosurgical Energy in Laparoscopic Cholecystectomy

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    2010-01-01

    Introduction: Laparoscopic cholecystectomy is the gold standard for management of symptomatic gallstones. Electrocautery remains the main energy form used during laparoscopic dissection. However, due to its risks, search is continuous for safer and more efficient forms of energy. This review assesses the effects of dissection using ultrasonic energy compared with monopolar electrocautery during laparoscopic cholecystectomy. Methods: A literature search of the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE, and EMBASE was performed. Studies included were trials that prospectively randomized adult patients with symptomatic gallstone disease to either ultrasonic or monopolar electrocautery dissection during laparoscopic cholecystectomy. Data were collected regarding the characteristics and methodological quality of each trial. Outcome measures included operating time, gallbladder perforation rate, bleeding, bile leak, conversion rate, length of hospital stay and sick leave, postoperative pain and nausea scores, and influence on systemic immune and inflammatory responses. For metaanalysis, the statistical package RevMan version 4.2 was used. For continuous data, Weighted Mean Difference (WMD) was calculated with 95% confidence interval (CI) using the fixed effects model. For Categorical data, the Odds Ratio (OR) was calculated with 95% confidence interval using fixed effects model. Results: Seven trials were included in this review, with a total number of 695 patients randomized to 2 dissection methods: 340 in the electrocautery group and 355 in the ultrasonic group. No mortality was recorded in any of the trials. With ultrasonic dissection, operating time is significantly shorter in elective surgery (WMD −8.19, 95% CI −10.36 to −6.02, P>0.0001), acute cholecystitis (WMD −17, 95% CI −28.68 to −5.32, P=0.004), complicated cases (WMD −15, 95% CI −28.15 to −1.85, P=0.03), or if surgery was performed by trainee

  15. The science of conventional and water-cooled monopolar lumbar radiofrequency rhizotomy: an electrical engineering point of view.

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    Ball, Richard D

    2014-01-01

    Radiofrequency ablation (RFA) is a safe and effective pain therapy used to create sensory dysfunction in appropriate nerves via thermal damage. While commonly viewed as a simple process, RF heating is actually quite complex from an electrical engineering standpoint, and it is difficult for the non-electrical engineer to achieve a thorough understanding of the events that occur. RFA is highly influenced by the configuration and properties of the peri-electrode tissues. To rationally discuss the science of RFA requires that examples be procedure-specific, and lumbar RFA is the procedure selected for this review. Adequate heating of the lumbar medial branch has many potential failure points, and the underlying science is discussed with recommendations to reduce the frequency of failure in heating target tissues. Important technical details of the procedure that are not generally appreciated are discussed, and the status quo is challenged on several aspects of accepted technique. The rationale underlying electrode placement and the limitations of RF heating are, for the most part, commonly misunderstood, and there may even need to be significant changes in how lumbar radiofrequency rhizotomy (RFR) is performed. A new paradigm for heating target tissue may be of value. Foremost in developing best practices for this procedure is avoiding pitfalls. Good RF heating and medial branch lesioning are the rewards for understanding how the process functions, attention to detail, and meticulous attention to electrode positioning.

  16. Ocular effects of radiofrequency energy.

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    Elder, J A

    2003-01-01

    Radiofrequency (RF) energy has been reported to cause a variety of ocular effects, primarily cataracts but also effects on the retina, cornea, and other ocular systems. Cataracts have been observed in experimental animals when one eye was exposed to a localized, very high RF field and the other eye was the unexposed control. The results show that 2450 MHz exposures for >or=30 min at power densities causing extremely high dose rates (>or=150 W/kg) and temperatures (>or=41 degrees C) in or near the lens caused cataracts in the rabbit eye. However, cataracts were not observed in the monkey eye exposed to similar exposure conditions, reflecting the different patterns of energy absorption (SAR, specific absorption rate) distribution, due to their different facial structure. Since the monkey head is similar in structure to the human head, the nonhuman primate study showed that the incident power density levels causing cataracts in rabbits and other laboratory animals cannot be directly extrapolated to primates, including human beings. It is reasonable to assume that an SAR that would induce temperatures >or=41 degrees C in or near the lens in the human eye would produce cataracts by the same mechanism (heating) that caused cataracts in the rabbit lens; however, such an exposure would greatly exceed the currently allowable limits for human exposure and would be expected to cause unacceptable effects in other parts of the eye and face. Other ocular effects including corneal lesions, retinal effects, and changes in vascular permeability, have been observed after localized exposure of the eye of laboratory animals to both continuous wave (CW) and pulsed wave (PW) exposures, but the inconsistencies in these results, the failure to independently confirm corneal lesions after CW exposure, the failure to independently confirm retinal effects after PW exposure, and the absence of functional changes in vision are reasons why these ocular effects are not useful in defining an

  17. Tratamiento quirúrgico curativo de la fibrilación atrial mediante técnica de ablación con radiofrecuencia monopolar irrigada: resultados a corto y mediano plazo Surgical treatment of atrial fibrillation through irrigated ablation with monopolar radiofrequency: results to short and midterm

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    Sergio Franco

    2007-02-01

    irrigated monopolar radiofrequency to short and midterm, through clinical follow-up, electrocardiogram and echocardiogram. Methods: 70 patients with diagnosis of atrial fibrillation and some other heart pathology that required surgery were evaluated between September 2003 and October 2005, in a prospective way. An ablation though monopolar radiofrequency (Cardioblate® Medtronic, Inc was performed. Results were analyzed with the SPSS version 11, 0 statistical package. Results: 70 patients, 52% females and 48% males with mean age 54 years and preoperatory ejection fraction of 47% had mitral insufficiency (49% and mitral stenosis (26% as their main cause for primary heart surgery. 87% patients were evaluated at 18 months (3 to 25 months. Sinus rhythm was achieved in 88%. Residual arrhythmias in this group were atrial fibrillation (6% and atrial flutter (6%. 80% of post-operatory arrhythmias were found in the first 15 days after surgery, being atrial fibrillation and atrial flutter the most common ones. Anticoagulation and anti-arrhythmic medication was suspended in 89% and 90% of the patients, respectively. The surgical technique had no inherent complications. Conclusions: this investigation demonstrated that the surgical ablation of atrial fibrillation with irrigated monopolar radiofrequency is easily reproducible, highly effective and safe for the patient.

  18. Radiofrequency energy in surgery: state of the art.

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    Ihnát, Peter; Ihnát Rudinská, Lucia; Zonča, Pavel

    2014-06-01

    Over a period of more than 100 years, radiofrequency energy has been introduced in many fields and applications in medicine. At present, radiofrequency constitutes the basis of numerous medical devices employed in almost all medical specialties. It is particularly applicable and valuable in various minimally invasive procedures for its locally focused effects. Radiofrequency energy is a technical term established to describe high-frequency alternating electrical currents (with a frequency ranging from 300 kHz to 3 MHz) and their impact on biological tissue. The application of RF energy causes controlled tissue heating with consequent cell protein denaturation and desiccation, which leads to cell death and tissue destruction. The primary principle of radiofrequency is that the generated heat can be used to cut, coagulate or induce metabolic processes in the target tissue. The authors of this paper offer a comprehensive and compact review of the definition, history, physics, biological principles and applications of radiofrequency energy in current surgery.

  19. Comparative study of the safety and efficacy of liquid and dry monopolar electrocoagulation in experimental canine bleeding ulcers using computerized energy monitoring.

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    Swain, C P; Mills, T N; Dark, J M; Lewin, M R; Bown, S G; Northfield, T C; O'Sullivan, J P; Salmon, P R

    1984-01-01

    The drawbacks of monopolar electrocoagulation in the control of gastrointestinal bleeding include tissue adherence, unpredictable energy deposition, and a high incidence of tissue damage. Introduction of a conductive interfacial film of liquid between the monopolar electrode and the bleeding point during electrocoagulation may overcome these drawbacks. A prospective, controlled study was undertaken to evaluate the efficacy and safety of a monopolar electrode in liquid and dry modes when used to coagulate experimental canine bleeding ulcers. All experiments were done in open fashion via a gastrotomy with hand-held electrodes. An analog computer, which could be connected between a standard electrosurgical generator and the electrode, was designed and built to monitor and control the energy delivered to the tissue. Both liquid and dry electrodes were highly effective in stopping bleeding. The liquid electrode was found to be superior to the dry electrode in that tissue adherence was eliminated and energy deposition was more predictable, varying less with angle of incidence. The liquid electrode caused less macroscopic serosal damage and less full-thickness histologic damage if the total energy or number of pulses was limited; however, both caused microscopic full-thickness damage in one-half of the experimental ulcers treated, although no perforations occurred.

  20. Arthroscopic gluteal muscle contracture release with radiofrequency energy.

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    Liu, Yu-Jie; Wang, Yan; Xue, Jing; Lui, Pauline Po-Yee; Chan, Kai-Ming

    2009-03-01

    Gluteal muscle contracture is common after repeated intramuscular injections and sometimes is sufficiently debilitating to require open surgery. We asked whether arthroscopic release of gluteal muscle contracture using radiofrequency energy would decrease complications with clinically acceptable results. We retrospectively reviewed 108 patients with bilateral gluteal muscle contractures (57 males, 51 females; mean age, 23.7 years). We used inferior, anterosuperior, and posterosuperior portals. With the patient lying laterally, we developed and enlarged a potential space between the gluteal muscle group and the subcutaneous fat using blunt dissection. Under arthroscopic guidance through the inferior portal, we débrided and removed fatty tissue overlying the contractile band of the gluteal muscle group using a motorized shaver introduced through the superior portal. Radiofrequency then was introduced through the superior portal to gradually excise the contracted bands from superior to inferior. Finally, hemostasis was ensured using radiofrequency. Patients were followed a minimum of 7 months (mean, 17.4 months; range, 7-42 months). At last followup, the adduction and flexion ranges of the hip were 45.3 degrees +/- 8.7 degrees and 110.2 degrees +/- 11.9 degrees, compared with 10.4 degrees +/- 7.2 degrees and 44.8 degrees +/- 14.1 degrees before surgery. No hip abductor contracture recurred and no patient had residual hip pain or gluteal muscle wasting. We found gluteal muscle contracture could be released effectively with radiofrequency energy.

  1. Arthroscopic Gluteal Muscle Contracture Release With Radiofrequency Energy

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    LIU Yu-jie; Wang, Yan; Xue, Jing; Lui, Pauline Po-Yee; Chan, Kai-Ming

    2008-01-01

    Gluteal muscle contracture is common after repeated intramuscular injections and sometimes is sufficiently debilitating to require open surgery. We asked whether arthroscopic release of gluteal muscle contracture using radiofrequency energy would decrease complications with clinically acceptable results. We retrospectively reviewed 108 patients with bilateral gluteal muscle contractures (57 males, 51 females; mean age, 23.7 years). We used inferior, anterosuperior, and posterosuperior portals...

  2. Radio-frequency energy harvesting for wearable sensors.

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    Borges, Luís M; Chávez-Santiago, Raul; Barroca, Norberto; Velez, Fernando José; Balasingham, Ilangko

    2015-02-01

    The use of wearable biomedical sensors for the continuous monitoring of physiological signals will facilitate the involvement of the patients in the prevention and management of chronic diseases. The fabrication of small biomedical sensors transmitting physiological data wirelessly is possible as a result of the tremendous advances in ultra-low power electronics and radio communications. However, the widespread adoption of these devices depends very much on their ability to operate for long periods of time without the need to frequently change, recharge or even use batteries. In this context, energy harvesting (EH) is the disruptive technology that can pave the road towards the massive utilisation of wireless wearable sensors for patient self-monitoring and daily healthcare. Radio-frequency (RF) transmissions from commercial telecommunication networks represent reliable ambient energy that can be harvested as they are ubiquitous in urban and suburban areas. The state-of-the-art in RF EH for wearable biomedical sensors specifically targeting the global system of mobile 900/1800 cellular and 700 MHz digital terrestrial television networks as ambient RF energy sources are showcased. Furthermore, guidelines for the choice of the number of stages for the RF energy harvester are presented, depending on the requirements from the embedded system to power supply, which is useful for other researchers that work in the same area. The present authors' recent advances towards the development of an efficient RF energy harvester and storing system are presented and thoroughly discussed too.

  3. Energy Saving Glass Lamination via Selective Radio-Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly S.; Allan, Shawn M.

    2009-11-11

    This Inventions and Innovations program supported the technical and commercial research and development needed to elevate Ceralink's energy saving process for flat glass lamination from bench scale to a self-supporting technology with significant potential for growth. Radio-frequency heating was any un-explored option for laminating glass prior to this program. With significant commercial success through time and energy savings in the wood, paper, and plastics industries, RF heating was found to have significant promise for the energy intensive glass lamination industry. A major technical goal of the program was to demonstrate RF lamination across a wide range of laminate sizes and materials. This was successfully accomplished, dispelling many skeptics' concerns about the abilities of the technology. Ceralink laminated panels up to 2 ft x 3 ft, with four sets processed simultaneously, in a 3 minute cycle. All major categories of interlayer materials were found to work with RF lamination. In addition to laminating glass, other materials including photovoltaic silicon solar cells, light emitting diodes, metallized glass, plastics (acrylic and polycarbonate), and ceramics (alumina) were found compatible with the RF process. This opens up a wide range of commercial opportunities beyond the initially targeted automotive industry. The dramatic energy savings reported for RF lamination at the bench scale were found to be maintained through the scale up of the process. Even at 2 ft x 3 ft panel sizes, energy savings are estimated to be at least 90% compared to autoclaving or vacuum lamination. With targeted promotion through conference presentations, press releases and internet presence, RF lamination has gained significant attention, drawing large audiences at American Ceramic Society meetings. The commercialization success of the project includes the establishment of a revenue-generating business model for providing process development and demonstrations for

  4. 单双极射频加热组织对皮肤收紧的疗效和安全性观察%Therapeutic effect and safety on skin tightening by monopolar and bipolar radiofrequency technology

    Institute of Scientific and Technical Information of China (English)

    刘志飞; 崔雅宁; 李薇薇; 朱琳; 王智; 王晓军

    2010-01-01

    目的 探讨单双极射频加热组织对于皮肤自体老化和形态改善的效果和安全性,观察和总结黄种人治疗的参数和疗程.方法 选择28例健康的志愿者,接受Accent Pro射频系统治疗,共治疗4次,每隔2周治疗1次,治疗结束后1个月观察疗效.通过治疗前后的照片对比和志愿者的主观满意度评估疗效和安全性.结果 治疗过程中没有任何水泡、皮肤烫伤、色素沉着和瘢痕形成,医师评估满意率达到85%,患者满意率达到90%.结论 无创射频技术通过对组织的深度加热,对于皮肤收紧有很好疗效,治疗过程安全,是一种新型的收紧皮肤治疗技术.%Objective To evaluate the efficacy and safety in the treatment for gravitation wrinkles and unsatisfied shape with raonopolar and bipolar radiofrequency (RF) technique. Methods 28 patients were enrolled in this study. Every patient was treated for four times with an interval of 14 days by Accent Pro radiofrequency electric device (Alma Lasers Ltd). The clinical photographs were taken before and after the treatment, and the parameters were recorded during the treatment. The clinical efficacy and safety was evaluated 1 month after the treatment by comparing photographs and patients' satisfaction. Results Satisfactory rates were as follows: 85 % in doctor side, and 90 % in patients' side. No blister, scald, pigmentation and scar were observed during the treatment. Conclusion High frequency electric technique can be effective for the treatment of gravitation wrinkles and skin tightening by heating tissue deeply and non-invasively. Our clinical study shows that RF is an effective, non-invasive treatment with less pain and low side effects.

  5. Radiofrequency energy exposure from the Trilliant smart meter.

    Science.gov (United States)

    Foster, Kenneth R; Tell, Richard A

    2013-08-01

    This paper reviews radiofrequency (RF) field levels produced by electric utility meters equipped with RF transceivers (so-called Smart Meters), focusing on meters from one manufacturer (Trilliant, Redwood City, CA, USA, and Granby, QC, Canada). The RF transmission levels are summarized based on publicly available data submitted to the U.S. Federal Communications Commission supplemented by limited independent measurements. As with other Smart Meters, this meter incorporates a low powered radiofrequency transceiver used for a neighborhood mesh network, in the present case using ZigBee-compliant physical and medium access layers, operating in the 2.45 GHz unlicensed band but with a proprietary network architecture. Simple calculations based on a free space propagation model indicate that peak RF field intensities are in the range of 10 mW m or less at a distance of more than 1-2 m from the meters. However, the duty cycle of transmission from the meters is very low (Smart Meter technology. The RF transmitters in wireless-equipped Smart Meters operate at similar power levels and in similar frequency ranges as many other digital communications devices in common use, and their exposure levels are very far below U.S. and international exposure limits.

  6. Postoperative Adhesion Formation in a Rabbit Model: Monopolar Electrosurgery Versus Ultrasonic Scalpel

    Science.gov (United States)

    Lazarou, George; Apostol, Radu; Khullar, Poonam; Okonkwo, Linda; Nezhat, Farr

    2015-01-01

    Background and Objectives: To determine if surgery using ultrasonic energy for dissection results in less adhesion formation than monopolar electrosurgical energy in the late (8 weeks) postoperative period. Methods: Injuries were induced in rabbits by using ultrasonic energy on one uterine horn and the adjacent pelvic sidewall and using monopolar energy on the opposite side. Eight weeks postoperatively, the rabbits underwent autopsy and clinical and pathologic scoring of adhesions was performed by blinded investigators. Results: There was no significant difference in clinical adhesion scores between the two modalities. The mean clinical score for monopolar cautery was 1.00 versus 0.88 for the Harmonic device (Ethicon Endo-Surgery, Cincinnati, Ohio) (P = .71). Furthermore, there was no significant difference found in the pathologic adhesion scores between the ultrasonic scalpel and monopolar energy. The mean pathologic score for monopolar electrosurgery was 4.35 versus 3.65 for the Harmonic scalpel (P = .30). Conclusion: Neither monopolar electrosurgery nor ultrasonic dissection is superior in the prevention of adhesion formation in the late postoperative period. PMID:26005316

  7. Painless, safe, and efficacious noninvasive skin tightening, body contouring, and cellulite reduction using multisource 3DEEP radiofrequency.

    Science.gov (United States)

    Harth, Yoram

    2015-03-01

    In the last decade, Radiofrequency (RF) energy has proven to be safe and highly efficacious for face and neck skin tightening, body contouring, and cellulite reduction. In contrast to first-generation Monopolar/Bipolar and "X -Polar" RF systems which use one RF generator connected to one or more skin electrodes, multisource radiofrequency devices use six independent RF generators allowing efficient dermal heating to 52-55°C, with no pain or risk of other side effects. In this review, the basic science and clinical results of body contouring and cellulite treatment using multisource radiofrequency system (Endymed PRO, Endymed, Cesarea, Israel) will be discussed and analyzed. © 2015 Wiley Periodicals, Inc.

  8. Complementary Effects of Negative-Pressure Wound Therapy and Pulsed Radiofrequency Energy on Cutaneous Wound Healing in Diabetic Mice.

    Science.gov (United States)

    Chen, Bin; Kao, Huang-Kai; Dong, Ziqing; Jiang, Zhaohua; Guo, Lifei

    2017-01-01

    Negative-pressure wound therapy and pulsed radiofrequency energy are two clinical modalities used to treat soft-tissue wounds. They are purported to affect healing differently. The aim of this experimental study was to contrast the two modalities at a mechanistic level and to investigate whether their combined therapy could achieve additive and complementary effects on wound healing. Full-thickness dorsal cutaneous wounds of diabetic, db/db, mice were treated with either negative-pressure wound therapy, pulsed radiofrequency energy, or combined therapies. Macroscopic healing kinetics were examined. Epidermal regeneration (proliferation rate and length of reepithelialization) and neovascularization (blood vessel density) were investigated. Messenger RNA levels indicative of angiogenic (basic fibroblast growth factor), profibrotic (transforming growth factor-β), epidermal proliferative (keratinocyte growth factor), and extracellular matrix remodeling (collagen 1) processes were measured in wound tissues. All three treatment groups displayed faster wound healing. The negative-pressure wound therapy/pulsed radiofrequency energy combined therapy led to significantly faster healing than either the negative-pressure wound therapy or pulsed radiofrequency energy therapy alone. Epidermal regeneration and neovascularization were enhanced in all three groups. The two negative-pressure wound therapy groups (alone and combined with pulsed radiofrequency energy) demonstrated more significant increases in expression of all assayed growth factors than the pulsed radiofrequency energy group. Furthermore, the combined therapy exhibited a more profound elevation in collagen 1 expression than either of the two therapies alone. Combining the negative-pressure wound therapy and pulsed radiofrequency energy modalities can achieve additive benefits in cutaneous healing, and the two therapies can be easily used together to complement each other in clinical wound treatments.

  9. Insights into energy delivery to myocardial tissue during radiofrequency ablation through application of the first law of thermodynamics.

    Science.gov (United States)

    Bunch, T Jared; Day, John D; Packer, Douglas L

    2009-04-01

    The approach to catheter-based radiofrequency ablation of atrial fibrillation has evolved, and as a consequence, more energy is delivered in the posterior left atrium, exposing neighboring tissue to untoward thermal injury. Simultaneously, catheter technology has advanced to allow more efficient energy delivery into the myocardium, which compounds the likelihood of collateral injury. This review focuses on the basic principles of thermodynamics as they apply to energy delivery during radiofrequency ablation. These principles can be used to titrate energy delivery and plan ablative approaches in an effort to minimize complications during the procedure.

  10. Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

    2012-10-08

    A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

  11. Repeat procedure using radiofrequency energy for recurrence of atrial fibrillation after initial cryoballoon ablation: a 2-year follow-up

    NARCIS (Netherlands)

    Conte, G.; Chierchia, G.B.; Sieira, J.; Levinstein, M.; Casado-Arroyo, R.; Asmundis, C. de; Sarkozy, A.; Rodriguez-Manero, M.; Giovanni, G.; Baltogiannis, G.; Wauters, K.; Brugada, P.

    2013-01-01

    AIMS: The ideal energy source needed to perform 're-isolation' of the pulmonary veins (PVs) during a repeat procedure for recurrence of paroxysmal atrial fibrillation (AF) has not been established yet. In this study we analysed the outcome of repeat procedure using radiofrequency (RF) energy after i

  12. Monopolar diathermy used for correction of ankyloglossia

    Directory of Open Access Journals (Sweden)

    Tuli A

    2010-06-01

    Full Text Available Tongue tie, also known as ankyloglossia or ankyloglossia inferior, is a relatively common finding in pediatric surgical outpatient clinics. It occurs as a result of a short, tight, lingual frenum causing tethering of the tongue tip. It is a common oral finding in infants and children, which is often neglected. Although most cases resolve or are asymptomatic, some patients develop articulation problems and other concerns related to poor tongue-tip mobility. In this article, we report on a 5-year old girl with a tongue tie, who underwent frenectomy using monopolar diathermy under local anesthesia without any postoperative complication.

  13. Implementation of Radio-Frequency Deflecting Devices for Comprehensive High-Energy Electron Beam Diagnosis

    Science.gov (United States)

    Craievich, Paolo; Petronio, Marco; Biedron, Sandra G.; Castronovo, Davide; Dal Forno, Massimo; Di Mitri, Simone; Faure, Nicolas; La Civita, Daniele; Penco, Giuseppe; Rumiz, Luca; Sturari, Luca; Vescovo, Roberto; Wang, Defa

    2015-02-01

    In next-generation light sources, high-brightness electron beams are used in a free-electron laser configuration to produce light for use by scientists and engineers in numerous fields of research. High-brightness beams are described for such light sources as having low transverse and longitudinal emittances, high peak currents, and low slice emittance and energy spread. The optimal generation and preservation of such high-brightness electron beams during the acceleration process and propagation to and through the photon-producing element is imperative to the quality and performance of the light source. To understand the electron beam's phase space in the accelerating section of a next-generation light source machine, we employed radio-frequency cavities operating in a deflecting mode in conjunction with a magnetic spectrometer and imaging system for both low (250 MeV) and high (1.2 GeV) electron energies. This high-resolution, high-energy system is an essential diagnostic for the optimization and control of the electron beam in the FERMI light source generating fully transversely and longitudinally coherent light in the VUV to soft x-ray wavelength regimes. This device is located at the end of the linear accelerator in order to provide the longitudinal phase space nearest to the entrance of the photon-producing beam-lines. Here, we describe the design, fabrication, characterization, commissioning, and operational implementation of this transverse deflecting cavity structure diagnostic system for the high-energy (1.2 GeV) regime.

  14. Monopolar intracochlear pulse trains selectively activate the inferior colliculus.

    Science.gov (United States)

    Schoenecker, Matthew C; Bonham, Ben H; Stakhovskaya, Olga A; Snyder, Russell L; Leake, Patricia A

    2012-10-01

    Previous cochlear implant studies using isolated electrical stimulus pulses in animal models have reported that intracochlear monopolar stimulus configurations elicit broad extents of neuronal activation within the central auditory system-much broader than the activation patterns produced by bipolar electrode pairs or acoustic tones. However, psychophysical and speech reception studies that use sustained pulse trains do not show clear performance differences for monopolar versus bipolar configurations. To test whether monopolar intracochlear stimulation can produce selective activation of the inferior colliculus, we measured activation widths along the tonotopic axis of the inferior colliculus for acoustic tones and 1,000-pulse/s electrical pulse trains in guinea pigs and cats. Electrical pulse trains were presented using an array of 6-12 stimulating electrodes distributed longitudinally on a space-filling silicone carrier positioned in the scala tympani of the cochlea. We found that for monopolar, bipolar, and acoustic stimuli, activation widths were significantly narrower for sustained responses than for the transient response to the stimulus onset. Furthermore, monopolar and bipolar stimuli elicited similar activation widths when compared at stimulus levels that produced similar peak spike rates. Surprisingly, we found that in guinea pigs, monopolar and bipolar stimuli produced narrower sustained activation than 60 dB sound pressure level acoustic tones when compared at stimulus levels that produced similar peak spike rates. Therefore, we conclude that intracochlear electrical stimulation using monopolar pulse trains can produce activation patterns that are at least as selective as bipolar or acoustic stimulation.

  15. Effects of radiofrequency energy on human chondromalacic cartilage: an assessment of insulation material properties.

    Science.gov (United States)

    Meyer, Marie L; Lu, Yan; Markel, Mark D

    2005-04-01

    The objective of this study was to establish guidelines for the selection of an insulation material used to surround the electrode of radiofrequency energy (RFE) probes used for thermal chondroplasty. These guidelines were established by identifying which insulation materials resulted in the least amount of chondrocyte death while smoothing the surface of chondromalacic cartilage. RFE causes electrolyte oscillation and molecular friction in the tissue to heat it and subsequently smooth the surface. Material properties investigated included the coefficient of thermal expansion (CTE), thermal conductivity (TC), and volume resistivity (VR). Fresh human chondromalacic cartilage samples of Outerbridge grades II and III were obtained from patients undergoing total knee arthroplasty. Stiffness measurements were taken pretreatment and posttreatment. RFE was applied to a 1-cm2 area for 15 s in a paintbrush treatment pattern. The insulation materials evaluated included Macor (decrease CTE, decrease TC, increase VR; in relation to CTE = 10 x 10(-6)/degrees C at 20 degrees C, TC = 3 W/mK, VR=1 x 10(14) ohm x cm), zirconia toughened alumina (ZTA) and 99.5% alumina (decrease CTE, increase TC, increase VR), aluminum nitride (decrease CTE, increase TC, decrease VR), Teflon (PTFE) (increase CTE, decrease TC, increase VR), partially stabilized zirconia (YTZP) (decrease CTE, decrease TC, decrease VR), and Ultem (increase CTE, decrease TC, decrease VR). There were no significant differences between pretreatment and posttreatment stiffness of the cartilage for any material investigated. Subjectively scored scanning electron microscopy (SEM) images revealed that the surfaces of all samples treated with RFE were relatively smooth with melted fronds. Prototype probes made with Macor, 99.5% alumina, and ZTA had TC or = 1 x 10(14) ohm x cm and resulted in a mean 37% less cell death than aluminum nitride or YTZP. There was no apparent relationship between CTE and the depth of chondrocyte

  16. Method of destruction of the pathological excitation sources in the heart by original monopolar electrode

    Directory of Open Access Journals (Sweden)

    M. M. Sychyk

    2016-06-01

    Full Text Available Purpose. This work is devoted to the study of destruction of the pathological excitation sources in the heart by the original monopolar electrode and the high-frequency electrosurgical generator Erbe VIO-100 S (Germany in the coagulation mode in order to optimize technology of their using in surgical practice for Maze surgery. Methodology. Experimental study of the effect of electric current on the myocardium were performed in the laboratory on the endocardial part of four remote pig hearts in the cold hibernation state. Temperature evaluation of myocardial contact with the electrode was carried out using mathematical modeling of temperature fields of radio frequency current interaction with the tissue in the program Comsol Multiphysics. Results. Safe and effective destruction size, nature of histological and temperature changes in the interaction region of myocardial tissue with a source of electrical current depending on the duration and power application to stop the spread of pathological excitation sources in the heart were defined. Originality. The recommendations on the choice of the optimal parameters for the application of the generator Erbe and the original monopolar electrode were developed and adapted to radiofrequency ablation of myocardial tissue in the open heart for the arrhythmias treatment in order to reduce the total duration of surgery with cardiopulmonary bypass. Practical value. The results have been introduced in surgical practice of the State Institution «M. M. Amosov National Institute of Cardiovascular Surgery Ukraine NAMS of Ukraine». The work has great practical importance, because the expanding of the functional range of generator Erbe VIO-100 S (Germany applications and reducing of the cost of radio frequency ablation procedure in comparison with the use of specialized disposable bipolar electrodes.

  17. Evaluation of stray radiofrequency radiation emitted by electrosurgical devices.

    Science.gov (United States)

    De Marco, M; Maggi, S

    2006-07-21

    Electrosurgery refers to the passage of a high-frequency, high-voltage electrical current through the body to achieve the desired surgical effects. At the same time, these procedures are accompanied by a general increase of the electromagnetic field in an operating room that may expose both patients and personnel to relatively high levels of radiofrequency radiation. In the first part of this study, we have taken into account the radiation emitted by different monopolar electrosurgical devices, evaluating the electromagnetic field strength delivered by an electrosurgical handle and straying from units and other electrosurgical accessories. As a summary, in the worst case a surgeon's hands are exposed to a continuous and pulsed RF wave whose magnetic field strength is 0.75 A m(-1) (E-field 400 V m(-1)). Occasionally stray radiation may exceed ICNIRP's occupational exposure guidelines, especially close to the patient return plate. In the second part of this paper, we have analysed areas of particular concern to prevent electromagnetic interference with some life-support devices (ventilators and electrocardiographic devices), which have failed to operate correctly. Most clinically relevant interference occurred when an electrosurgery device was used within 0.3 m of medical equipment. In the appendix, we suggest some practical recommendations intended to minimize the potential for electromagnetic hazards due to therapeutic application of RF energy.

  18. Evaluation of stray radiofrequency radiation emitted by electrosurgical devices

    Science.gov (United States)

    DeMarco, M.; Maggi, S.

    2006-07-01

    Electrosurgery refers to the passage of a high-frequency, high-voltage electrical current through the body to achieve the desired surgical effects. At the same time, these procedures are accompanied by a general increase of the electromagnetic field in an operating room that may expose both patients and personnel to relatively high levels of radiofrequency radiation. In the first part of this study, we have taken into account the radiation emitted by different monopolar electrosurgical devices, evaluating the electromagnetic field strength delivered by an electrosurgical handle and straying from units and other electrosurgical accessories. As a summary, in the worst case a surgeon's hands are exposed to a continuous and pulsed RF wave whose magnetic field strength is 0.75 A m-1 (E-field 400 V m-1). Occasionally stray radiation may exceed ICNIRP's occupational exposure guidelines, especially close to the patient return plate. In the second part of this paper, we have analysed areas of particular concern to prevent electromagnetic interference with some life-support devices (ventilators and electrocardiographic devices), which have failed to operate correctly. Most clinically relevant interference occurred when an electrosurgery device was used within 0.3 m of medical equipment. In the appendix, we suggest some practical recommendations intended to minimize the potential for electromagnetic hazards due to therapeutic application of RF energy.

  19. Evaluation of stray radiofrequency radiation emitted by electrosurgical devices

    Energy Technology Data Exchange (ETDEWEB)

    De Marco, M; Maggi, S [Department of Medical Physics, Ospedali Riuniti di Ancona, Ancona, 60021 (Italy)

    2006-07-21

    Electrosurgery refers to the passage of a high-frequency, high-voltage electrical current through the body to achieve the desired surgical effects. At the same time, these procedures are accompanied by a general increase of the electromagnetic field in an operating room that may expose both patients and personnel to relatively high levels of radiofrequency radiation. In the first part of this study, we have taken into account the radiation emitted by different monopolar electrosurgical devices, evaluating the electromagnetic field strength delivered by an electrosurgical handle and straying from units and other electrosurgical accessories. As a summary, in the worst case a surgeon's hands are exposed to a continuous and pulsed RF wave whose magnetic field strength is 0.75 A m{sup -1} (E-field 400 V m{sup -1}). Occasionally stray radiation may exceed ICNIRP's occupational exposure guidelines, especially close to the patient return plate. In the second part of this paper, we have analysed areas of particular concern to prevent electromagnetic interference with some life-support devices (ventilators and electrocardiographic devices), which have failed to operate correctly. Most clinically relevant interference occurred when an electrosurgery device was used within 0.3 m of medical equipment. In the appendix, we suggest some practical recommendations intended to minimize the potential for electromagnetic hazards due to therapeutic application of RF energy.

  20. A novel method for real-time skin impedance measurement during radiofrequency skin tightening treatments.

    Science.gov (United States)

    Harth, Yoram; Lischinsky, Daniel

    2011-03-01

    The thermal effects of monopolar and bipolar radiofrequency (RF) have been proven to be beneficial in skin tightening. Nevertheless, these effects were frequently partial or unpredictable because of the uncontrolled nature of monopolar or unipolar RF and the superficial nature of energy flow for bipolar or tripolar configurations. One of the hypotheses for lack or predictability of efficacy of the first-generation RF therapy skin tightening systems is lack of adaptation of delivered power to differences in individual skin impedance. A novel multisource phase-controlled system was used (1 MHz, power range 0-65 W) for treatment and real-time skin impedance measurements in 24 patients (EndyMed PRO™; EndyMed, Cesarea, Israel). This system allows continuous real-time measurement of skin impedance delivering constant energy to the patient skin independent of changes in its impedance. More than 6000 unique skin impedance measurements on 22 patients showed an average session impedance range was 215-584 Ohm with an average of 369 Ohm (standard deviation of 49 Ohm). Analyzing individual pulses (total of 600 readings) showed a significant decrease in impedance during the pulse. These findings validate the expected differences in skin impedance between individual patients and in the same patients during the treatment pulse. Clinical study on 30 patients with facial skin aging using the device has shown high predictability of efficacy (86.7% of patients had good results or better at 3 months' follow-up [decrease of 2 or more grades in Fitzpatrick's wrinkle scale]). The real-time customization of energy according to skin impedance allows a significantly more accurate and safe method of nonablative skin tightening with more consistent and predictable results. © 2011 Wiley Periodicals, Inc.

  1. Radiofrequency Energy in Hepatic Bed during Partial Cystectomy for Hydatid Liver Disease: Standing Out from the Usual Conservative Surgical Management.

    Science.gov (United States)

    Mantonakis, Eleftherios; Papalampros, Alexandros; Moris, Demetrios; Dimitrokallis, Nikolaos; Sakarellos, Panagiotis; Griniatsos, John; Felekouras, Evangelos

    2016-01-01

    Background. Surgical treatment of hydatid liver disease (HLD) is divided into conservative and radical procedures. While conservative techniques are easier and faster to perform, there is an emerging need to reduce their morbidity and recurrence rates. Our aim was to present and evaluate the efficiency and safety of the application of radiofrequency energy (TissueLink® and Aquamantys® systems) in hepatic bed during partial cystectomy. Materials and Methods. Eighteen consecutive patients with hydatid liver cysts were referred to our department between April 2006 and June 2014. Data about demographics, mortality, morbidity, and recurrence rate were obtained and analyzed retrospectively. Results. The mean follow-up was 38 months (range: 4-84 months). The postoperative course of most patients was uneventful. One case of recurrence was found in our series in a patient with 4 cysts in the right lobe, 3 years after initial treatment. He was reoperated on with the same method. Conclusions. Saline-linked RF energy seems to be an effective means to be employed in conservative surgical procedures of HLD, with satisfactory postoperative morbidity. Recurrence rates appear to be low, but further follow-up is needed in order to draw safer conclusions.

  2. Day care monopolar transurethral resection of prostate: Is it feasible?

    Directory of Open Access Journals (Sweden)

    Altaf Khan

    2014-01-01

    Full Text Available Introduction: Benign prostatic hyperplasia is a common disease accounting for 30% of our OPD cases and about 25% of our surgery cases. Various treatment options are now available for more efficient care and early return to work. We wanted to determine the safety and feasibility of day care monopolar transurethral resection of prostate (m-TURP, by admitting the patients on the day of surgery and discharging the patient without catheter on the same day. We also compared the morbidity associated with conventional TURP where in the catheter is removed after 24-48 h of surgery and day care TURP where in the catheter is removed on the day of surgery. Materials and Methods: A total of 120 patients who fulfilled the criteria were included in the study which was conducted between November 2008 and December 2010. A total of 60 patients were assigned for day care and 60 for conventional monopolar TURP. There was no significant difference in age, prostatic volume or IPSS score. Day care patients were admitted on day of surgery and discharged the same day after the removal of catheter. Results: Both the groups were comparable in outcome. Stricture rate was less with day care TURP. Mean catheterization time was similar to laser TURP. Conclusion: Monopolar TURP is still the gold standard of care for BPH. If cases are selected properly and surgery performed diligently it remains the option of choice for small and medium sized glands and patients can be back to routine work early.

  3. Clinical evaluation of the efficacy and safety of combined bipolar radiofrequency and optical energies vs. optical energy alone for the treatment of aging hands.

    Science.gov (United States)

    Verner, Ines; Kutscher, Tuvia Dror

    2017-08-01

    Different treatment modalities are used for the treatment and esthetic improvement of aging hands. This study evaluated the efficacy and safety of a novel technology, which combines bipolar radio frequency (RF) and optical energies for the cosmetic treatment of aging hands. The objective of the study was to assess the efficacy, safety, tolerability, and patient satisfaction of combined bipolar radiofrequency and optical energies vs. optical energy alone for the treatment of aging hands. Thirteen female patients with solar lentigines on the back of the hands were enrolled. Participants received three treatments: combined RF and intense pulsed light (IPL) on one hand and IPL treatment alone on the other. Standardized clinical photographs were taken, and patient and investigator improvement assessment (Global Esthetic Improvement (GAI) scale), patient satisfaction, and tolerability were evaluated. At the 1 and 3 months follow-up, skin laxity and pigmentation, investigator and patient improvement assessments, and satisfaction were significantly better in the hand treated with combined bipolar RF and IPL. This study demonstrates the safety and efficacy of combining RF and optical energies for the esthetic improvement of aging hands. Combined RF and IPL treatment was more efficient than IPL alone in improving skin pigmentation, skin laxity, and texture.

  4. Percutaneous bipolar radiofrequency thermocoagulation for the treatment of lumbar disc herniation.

    Science.gov (United States)

    Zeng, Zhenhua; Yan, Min; Dai, Yi; Qiu, Weidong; Deng, Shuo; Gu, Xinzhu

    2016-08-01

    Lumbar disc herniation is usually managed with conservative treatment or surgery. However, conservative therapy seldom yields good results, and surgery is associated with multiple complications. This study aimed to assess bipolar radiofrequency thermocoagulation for the treatment of lumbar disc herniation. A total of 168 patients with lumbar disc herniation suitable for radiofrequency thermocoagulation were enrolled and randomized to monopolar radiofrequency thermocoagulation (control group, n=84) or bipolar radiofrequency thermocoagulation (experimental group, n=84) treatment groups. Ablation sites were targeted under CT scan guidance, and consecutive radiofrequency therapy was used. One and two probes were used for monopolar and bipolar thermocoagulation, respectively. Thermocoagulation was achieved at 50°C, 60°C, and 70°C for 60s each, 80°C for 90s, and 92°C for 100s. Symptoms and complications were evaluated using the modified Macnab criteria and Visual Analog Scale at 7, 30, and 180days postoperatively. At 180days, a significantly higher efficacy rate was obtained in the experimental group compared with control patients (91.6% versus 79.7%, Plumbar disc herniation treatment, and should be further explored for broad clinical application.

  5. Perceptual Interactions Between Electrodes Using Focused and Monopolar Cochlear Stimulation

    DEFF Research Database (Denmark)

    Marozeau, Jeremy; McDermott, Hugh J.; Swanson, Brett A.;

    2015-01-01

    to implement an all-polar (AP) stimulation mode designed to create a focused electrical field. The goal of this experiment was to study the potential benefits of this all-polar mode for reducing uncontrolled electrode interactions compared with the monopolar mode. The five participants who took part......-matched sequential and simultaneous stimuli composed of 2 spatially separated pulse trains was measured as function of the electrode separation. Results indicated a strong current-summation interaction for simultaneous stimuli in the MP mode for separations up to at least 4.8 mm. No significant interaction was found...

  6. High versus moderate energy use of bipolar fractional radiofrequency in the treatment of acne scars: a split-face double-blinded randomized control trial pilot study.

    Science.gov (United States)

    Phothong, Weeranut; Wanitphakdeedecha, Rungsima; Sathaworawong, Angkana; Manuskiatti, Woraphong

    2016-02-01

    Bipolar fractional radiofrequency (FRF) device was firstly FDA-approved for treating atrophic acne scar in 2008 through the process of dermal coagulation and minimal epidermal ablation. The average energy at 60 mJ/pin was widely used to treat atrophic acne scars. However, the higher energy was delivered, the deeper ablation and coagulation were found. At present, the new generation of a device with bipolar FRF technology with electrode-pin tip was developed to maximize ability to deliver energy up to 100 mJ/pin. The objective of the study was to explore and compare the efficacy of utilizing high energy (100 mJ/pin) and moderate energy (60 mJ/pin) of bipolar fractional radiofrequency in treatment of atrophic acne scar in Asians. This is a split-face, double-blinded, randomized control trial, pilot study by using parallel group design technique. Thirty healthy subjects with Fitzpatrick skin phototype III-IV diagnosed as atrophic acne scares were enrolled. All subjects received four monthly sessions of bipolar FRF treatment. Left and right facial sides of individual patients were randomly assigned for different energy (high energy at 100 mJ/pin versus moderate energy at 60 mJ/pin). Acne scars improvement was blinded graded by dermatologist using global acne scarring score (GASS) which was subjectively evaluated at baseline, 1-, 3-, and 6-month follow-up. Objective scar analysis was also done using UVA-light video camera to measure scar volume, skin smoothness, and wrinkle at baseline, 3-, and 6-month follow-up after the last treatment. Side effects including pain, erythema, swelling, and crusting were also recorded. Thirty subjects completed the study with full 4-treatment course. The mean GASS of high energy side and moderate energy side was significantly reduced at 1-, 3-, and 6-month follow-up visits. At 1 month follow-visit, high energy side demonstrated significant improvement compared with moderate energy side (p = 0.03). Postinflammatory hyperpigmentation

  7. Part-body and multibody effects on absorption of radio-frequency electromagnetic energy by animals and by models of man

    Science.gov (United States)

    Gandhi, O. P.; Hagmann, M. J.; Dandrea, J. A.

    1979-01-01

    Fine structure in the whole-body resonant curve for radio-frequency energy deposition in man can be attributed to part-body resonances. As for head resonance, which occurs near 350 MHz in man, the absorptive cross section is nearly three times the physical cross section of the head. The arm has a prominent resonance at 150 MHz. Numerical solutions, antenna theory, and experimental results on animals have shown that whole-body energy deposition may be increased by 50 percent or more because of multiple bodies that are strategically located in the field. Empirical equations for SARs are also presented along with test data for several species of laboratory animals. Barbiturate anesthesia is sufficiently disruptive of thermoregulation that delta Ts of colonic temperature yield energy dose values in several mammals that compare quite favorably with those based on whole-body calorimetry.

  8. Membrane module and process development for monopolar and bipolar membrane electrodialysis

    OpenAIRE

    Balster, Jörg Henning

    2006-01-01

    This thesis aims to develop more efficient monopolar and bipolar membrane electrodialysis processes. Three main topics have been investigated: 1. Membrane selectivity 2. Concentration polarisation 3. Membrane scaling and fouling

  9. Stability and phase separation in mixed monopolar lipid/bolalipid layers.

    Science.gov (United States)

    Longo, Gabriel S; Thompson, David H; Szleifer, I

    2007-10-15

    The phase stability of a fluid lipid layer that is a mixture of conventional monopolar lipids and C20 bipolar bolalipids was studied using a mean field theory that explicitly includes molecular details and configurational properties of the lipid molecules. The effect of changing the fraction of bolalipids, as well as the length of the hydrocarbon chain of the monopolar lipids, was probed. A phase separation between two liquid lipid phases was found when a mismatch exists in the optimal hydrophobic thicknesses of the pure bolalipid and monopolar lipid layers. The lipid mixture phase separates into a thin bolalipid-rich layer and a thicker monopolar-rich layer. The thin membrane phase is mainly composed of transmembrane bolalipid molecules whose polar heads are positioned at opposite membrane-water interfaces. In the monopolar lipid-rich phase, bolalipids are the minor component and most of them assume a looping configuration where both headgroups are present at the same membrane-water interface. For mixed layers that form a single lipid phase across all bolalipid concentrations, the hairpin-transmembrane ratio strongly depends on the hydrocarbon chain length of the monopolar lipid and the bolalipid concentration. The C-D bond order parameters of the different species have been calculated. Our findings suggest that the concentration-dependent phase transition should be experimentally observable by measuring of the order parameters through quadrupolar splitting experiments. The driving force for the phase separation in the monopolar lipid/bolalipid mixture is the packing mismatch between hydrophobic regions of the monopolar lipid hydrocarbon chains and the membrane-spanning bolalipid chains. The results from the molecular theory may be useful in the design of stable lipid layers for integral membrane protein sensing.

  10. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  11. The radio-frequency quadrupole

    CERN Document Server

    Vretenar, Maurizio

    2013-01-01

    Radio-frequency quadrupole (RFQ) linear accelerators appeared on the accelerator scene in the late 1970s and have since revolutionized the domain of low-energy proton and ion acceleration. The RFQ makes the reliable production of unprecedented ion beam intensities possible within a compact radio-frequency (RF) resonator which concentrates the three main functions of the low-energy linac section: focusing, bunching and accelerating. Its sophisticated electrode structure and strict beam dynamics and RF requirements, however, impose severe constraints on the mechanical and RF layout, making the construction of RFQs particularly challenging. This lecture will introduce the main beam optics, RF and mechanical features of a RFQ emphasizing how these three aspects are interrelated and how they contribute to the final performance of the RFQ.

  12. Pulsed radiofrequency ablation for treatment of severe pain after shoulder arthroplasty (case report

    Directory of Open Access Journals (Sweden)

    D. V. Zabolotsky

    2015-01-01

    Full Text Available A case of refractory neuropathic pain syndrome in patient who underwent monopolar shoulder replacement is presented. The patient had right lung tumor metastasis in the right humeral head. Severe neuropathic pain syndrome, not responding to 6-months conservative treatment, developed in post-operative period. Pulsed radiofrequency ablation of C4-C6 nerve roots via interscalene access was performed. The procedure allowed the patient to stop taking painkillers and improved his quality of life. The patient was monitored for 2 months.

  13. Evaluation of the In Vivo Efficiency and Safety of Hepatic Radiofrequency Ablation Using a 15-G Octopus® in Pig Liver

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sun [Department of Radiology, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lee, Jeong Min [Department of Radiology, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Kim, Kyung Won [Department of Radiology, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lee, In Joon [National Cancer Center, Seoul 410-769 (Korea, Republic of); Han, Joon Koo; Choi, Byung Ihn [Department of Radiology, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of)

    2013-07-01

    To determine in vivo efficacy of radiofrequency ablation (RFA) in porcine liver by using 15-gauge Octopus® (15-G Octopus®) electrodes to create a large coagulation. A total of 18 coagulations were created by using a 180-W generator and 15-G Octopus® electrodes during laparotomy, performed in 14 pigs. Coagulation necrosis was created in the pig livers by the use of one of three RFA protocols: 1) group A, monopolar RFA using a 15-G Octopus® electrode with a 5-mm inter-electrode distance (n = 4); 2) group B, monopolar RFA using a 15-G Octopus® electrode with a 10-mm inter-electrode distance (n = 6); and 3) group C, switching monopolar RFA using two 15-G Octopus® electrodes (n = 8). The energy efficiency, shape, maximum and minimum diameters (Dmx and Dmi), and the volume of the coagulation volume were measured in each group. The Summary statistics were obtained and Mann-Whitney test was were performed. The mean ablated volume of each group was 49.23 cm{sup 3} in A, 64.11 cm{sup 3} in B, and 72.35 cm{sup 3} in C. The mean Dmx and Dmi values were 5.68 cm and 4.58 cm in A and 5.97 cm and 4.97 cm in B, respectively. In group C, the mean diameters of Dmx and Dmi were 6.80 cm and 5.11 cm, respectively. The mean ratios of Dmi/Dmx were 1.25, 1.20, and 1.35 in groups A, B, and C, respectively. There was one animal death during the RFA procedure, the cause of which could not be subsequently determined. However, there were no other significant, procedure-related complications during the seven-hour-delayed CT scans. RFA procedures using 15-G Octopus® electrodes are useful and safe for creating a large ablation in a single electrode model as well as in the multiple electrodes model.

  14. Antenna coupling--a novel mechanism of radiofrequency electrosurgery complication: practical implications.

    Science.gov (United States)

    Robinson, Thomas N; Barnes, Kelli S; Govekar, Henry R; Stiegmann, Greg V; Dunn, Christina L; McGreevy, Francis T

    2012-08-01

    (1) To determine if antenna coupling occurs in common operating room scenarios. (2) To define modifiable clinical variables that reduce the magnitude of antenna coupling. Mechanisms of electrosurgical burns where monitoring devices contact the surgical patient are unclear. Antenna coupling occurs when the "bovie" active electrode (electrically active transmitting antenna) emits energy, which is captured by a nonelectrically active wire (electrically inactive receiving antenna) in close proximity without direct contact. Monopolar radiofrequency energy was delivered to a laparoscopic instrument (electrically active transmitting antenna), whereas other nonelectrically active wires (electrically inactive receiving antenna) including electrocardiogram (EKG) lead, nonactive "bovie" pencil, and nerve electrode monitor were placed in proximity. Temperature changes of tissue placed adjacent to the electrically inactive receiving antennae were measured. Nonelectrically active wires (receiving antenna) increase tissue temperature when lying parallel to the active electrode cord: EKG pad 2.4°C ± 1.2°C (P = 0.002), "bovie" pencil tip 90°C ± 9°C (P antenna coupling included the following: increasing angulation between transmitting and receiving antennae (parallel = 90°C ± 9°C; 45° angle = 53°C ± 10°C; perpendicular = 35°C ± 11°C; P antenna (Antenna coupling occurs in common operating room scenarios. Simple, practical measures by the surgeon, such as orienting the receiving antenna at a greater angle and with greater separation to the active electrode cord, or lowering the generator power setting reduce antenna coupling.

  15. Technological advances in transurethral resection of the prostate: bipolar versus monopolar TURP.

    Science.gov (United States)

    Issa, Muta M

    2008-08-01

    One of the most significant recent advancements in transurethral resection of the prostate (TURP) is the incorporation of bipolar technology. Bipolar circuitry allows TURP to be performed in a normal saline environment, which addresses a fundamental concern of conventional monopolar TURP (i.e., the use of hypo-osmolar irrigation). As a result, the risks of dilutional hyponatremia and transurethral resection (TUR) syndrome are eliminated, allowing for longer and safer resection. This review discusses the principles and applications of electrosurgery in conventional monopolar as well as new bipolar saline-based TURP systems. This review also addresses the positive impact on patient safety and resident training.

  16. Radiofrequency ablation in dermatology

    Directory of Open Access Journals (Sweden)

    Sachdeva Silonie

    2007-01-01

    Full Text Available Radiofreqeuency ablation is a versatile dermatosurgical procedure used for surgical management of skin lesions by using various forms of alternating current at an ultra high frequency. The major modalities in radiofrequency are electrosection, electrocoagulation, electrodessication and fulguration. The use of radiofrequency ablation in dermatosurgical practice has gained importance in recent years as it can be used to treat most of the skin lesions with ease in less time with clean surgical field due to adequate hemostasis and with minimal side effects and complications. This article focuses on the major tissue effects and factors influencing radiofrequency ablation and its application for various dermatological conditions.

  17. Angular momentum dynamics and the intrinsic drift of monopolar vortices on a rotating sphere

    NARCIS (Netherlands)

    Van der Toorn, R.; Zimmerman, J.T.F.

    2010-01-01

    On the basis of the angular momentum equation for a fluid shell on a rotating planet, we analyze the intrinsic drift of a monopolar vortex in the shell. Central is the development of a general angular momentum equation for Eulerian fluid mechanics based on coordinate-free, general tensorial

  18. Angular momentum dynamics and the intrinsic drift of monopolar vortices on a rotating sphere

    NARCIS (Netherlands)

    Van der Toorn, R.; Zimmerman, J.T.F.

    2010-01-01

    On the basis of the angular momentum equation for a fluid shell on a rotating planet, we analyze the intrinsic drift of a monopolar vortex in the shell. Central is the development of a general angular momentum equation for Eulerian fluid mechanics based on coordinate-free, general tensorial represen

  19. Behavioral pattern of a monopolar passive direct methanol fuel cell stack

    Science.gov (United States)

    Kim, Young-Jin; Bae, Byungchan; Scibioh, M. Aulice; Cho, EunAe; Ha, Heung Yong

    A passive, air-breathing, monopolar, liquid feed direct methanol fuel cell (DMFC) stack consisting of six unit cells with no external pump, fan or auxiliary devices to feed the reactants has been designed and fabricated for its possible employment as a portable power source. The configurations of the stack of monopolar passive feed DMFCs are different from those of bipolar active feed DMFCs and therefore its operational characteristics completely vary from the active ones. Our present investigation primarily focuses on understanding the unique behavioral patterns of monopolar stack under the influence of certain operating conditions, such as temperature, methanol concentration and reactants feeding methods. With passive reactants supply, the temperature of the stack and open circuit voltage (OCV) undergo changes over time due to a decrease in concentration of methanol in the reservoir as the reaction proceeds. Variations in performance and temperature of the stack are mainly influenced by the concentration of methanol. Continuous operation of the passive stack is influenced by the supply of methanol rather than air supply or water accumulation at the cathode. The monopolar stack made up of six unit cells exhibits a total power of 1000 mW (37 mW cm -2) with 4 M methanol under ambient conditions.

  20. A Seven-year Experience for The Surgical Radiofrequency Ablation in Patients With Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    Bin XIE; Hui-ming GUO; Ruo-bin WU; Cong LU

    2009-01-01

    Objective A 7-year experience for the treatment strategy using mono- and bi-polar radiofrequency (RF) ablation procedures in a heterogeneous group of patients was reported. Methods Between July 2003 and May 2009, the data of 314 consecutive patients aged 13 -75 (48. 70 + 11.09)undergone the radiofrequency ablation procedure for atrial fibrillation (AF) associated with concomitant cardiac surgery were analyzed. Monopolar was used for 91 patients; Medtronic bi-polar RF ablation procedure for 92 patients and Atricure RF ablation procedure for 131 patients. All patients were combined with valve surgery. Regular follow-ups were performed at 3, 6 month after surgery. Results Hospital mortality after combined open heart and surgical RF ablation was 0 %. The success rates for sinus rhythm con-version with monopolar RF were 73.6 % immediately, 74. 7 % at 3 months, 79. 1% at 6 months; with Medtronic bi-polar RF, the rates were 78.3 % immediately, 82. 8 % at 3 months, 84 % at 6 months; with Atricure bi-polar RF, the rates were 82. 4 % immediately, 84. 1% at 3 months, 83.9 % at 6 months. Conclusions The use of RF ablation pro-cedures is a safe and efficient option to cure AF during open heart surgery in a selective group of patients.

  1. MONOPOLAR ELECTROCAUTERY VS SURGICAL CLIPS IN CONTROL OF CYSTIC ARTERY IN LAPAROSCOPIC CHOLECYSTECTOMY: A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Ridipta Sekha

    2016-04-01

    Full Text Available BACKGROUND Laparoscopic cholecystectomy has been extensively accepted since Mouret first successfully introduced the procedure in 1987. During this procedure the cystic artery can be controlled using surgical clips, harmonic scalpel and ligature or monopolar cautery. The extensive use of surgical clips in laparoscopic surgery has led to a variety of complications. Monopolar electrocoagulation can be used to control the cystic artery as it is cheap and universally available. Hence in this study, we compared monopolar electrocautery with clip application for securing haemostasis and to identify the safest and least complicated way for haemostasis of the cystic artery in laparoscopic cholecystectomy. METHODS A retrospective analysis of 201 patients were done who were planned for laparoscopic cholecystectomy. Among them 3 were converted to open cholecystectomy due to intraoperative bleeding. The rest 198 patients underwent successful laparoscopic cholecystectomy. In 42 patients the cystic artery was ligated using Ligaclip 300, while in 156 patients the artery was coagulated using monopolar cautery with hook. The patients were observed for any incidences of post-operative haemorrhage and bile leak, difference in length of hospital stay and post-operative complications. RESULTS The mean age was 40.26 years with M:F ratio 1:4. About 86% (135 and 88% (37 patients, respectively in electrocautery and Ligaclip group were discharged on the first post-operative day itself. Only 3 (1.5% patients, 2 in electrocautery and 1 in Ligaclip group developed post-operative port site infection. These differences were not statistically significant. CONCLUSION We conclude that monopolar electrocautery can be used as a safer alternative to surgical clips in control of cystic artery, especially in developing countries.

  2. Radiofrequency coblation tonsillectomy.

    Science.gov (United States)

    Grobler, Alethea; Carney, A Simon

    2006-06-01

    Radiofrequency coblation is a new technology that is finding favour as a method for performing tonsillectomy. Its benefits include reduced pain and postoperative morbidity but there is controversy regarding possible increased postoperative haemorrhage rates.

  3. Bilateral vision loss associated with radiofrequency exposure

    Directory of Open Access Journals (Sweden)

    Liu D

    2012-12-01

    Full Text Available Dianna Liu, Franz Marie Cruz, Prem S SubramanianWilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USAAbstract: A 57-year-old otherwise healthy woman presented with painless binocular vision loss 1 week after direct application of radiofrequency energy to her orbits. She had no light perception bilaterally. Pupils were dilated and not reactive to light. Fundoscopic exam initially showed optic disc swelling in the right eye and a normal-appearing disc in the left eye. Magnetic resonance imaging of the brain and orbits showed gadolinium enhancement of both intraorbital optic nerves. She underwent a course of high-dose steroid treatment without recovery of vision. Optic discs were pale 11 weeks after injury. With exclusion of other possible causes, this represents a unique case of irreversible binocular optic nerve damage and blindness secondary to radiofrequency exposure.Keywords: optic neuropathy, blindness, radiofrequency, vision loss

  4. The acute effect of bipolar radiofrequency energy thermal chondroplasty on intrinsic biomechanical properties and thickness of chondromalacic human articular cartilage.

    Science.gov (United States)

    Dutcheshen, Nicholas; Maerz, Tristan; Rabban, Patrick; Haut, Roger C; Button, Keith D; Baker, Kevin C; Guettler, Joseph

    2012-08-01

    Radio frequency energy (RFE) thermal chondroplasty has been a widely-utilized method of cartilage debridement in the past. Little is known regarding its effect on tissue mechanics. This study investigated the acute biomechanical effects of bipolar RFE treatment on human chondromalacic cartilage. Articular cartilage specimens were extracted (n = 50) from femoral condyle samples of patients undergoing total knee arthroplasty. Chondromalacia was graded with the Outerbridge classification system. Tissue thicknesses were measured using a needle punch test. Specimens underwent pretreatment load-relaxation testing using a spherical indenter. Bipolar RFE treatment was applied for 45 s and the indentation protocol was repeated. Structural properties were derived from the force-time data. Mechanical properties were derived using a fibril-reinforced biphasic cartilage model. Statistics were performed using repeated measures ANOVA. Cartilage thickness decreased after RFE treatment from a mean of 2.61 mm to 2.20 mm in Grade II, II-III, and III specimens (P resistance to shear and tension could be compromised due to removal of the superficial layer and decreased fibril modulus, RFE treatment increases matrix modulus and decreases tissue permeability which may restore the load- bearing capacity of the cartilage.

  5. Design of an 81.25 MHz continuous-wave radio-frequency quadrupole accelerator for Low Energy Accelerator Facility

    Science.gov (United States)

    Ma, Wei; Lu, Liang; Xu, Xianbo; Sun, Liepeng; Zhang, Zhouli; Dou, Weiping; Li, Chenxing; Shi, Longbo; He, Yuan; Zhao, Hongwei

    2017-03-01

    An 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been designed for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). In the CW operating mode, the proposed RFQ design adopted the conventional four-vane structure. The main design goals are providing high shunt impendence with low power losses. In the electromagnetic (EM) design, the π-mode stabilizing loops (PISLs) were optimized to produce a good mode separation. The tuners were also designed and optimized to tune the frequency and field flatness of the operating mode. The vane undercuts were optimized to provide a flat field along the RFQ cavity. Additionally, a full length model with modulations was set up for the final EM simulations. Following the EM design, thermal analysis of the structure was carried out. In this paper, detailed EM design and thermal simulations of the LEAF-RFQ will be presented and discussed. Structure error analysis was also studied.

  6. Radiofrequency ablation of osteoid osteoma

    NARCIS (Netherlands)

    Vanderschueren, Geert Maria Joris Michael

    2009-01-01

    The main purpose of this thesis was to evaluate the effectiveness and safety of CT-guided radiofrequency ablation for the treatment of spinal and non-spinal osteoid osteomas. Furthermore, the technical requirements needed for safe radiofrequency ablation and the clinical outcome after radiofrequency

  7. Interaction of monopolar and dipolar vortices with a shear flow: a numerical study

    Science.gov (United States)

    Kamp, Leon; Marques Rosas Fernandes, Vitor; van Heijst, Gert-Jan; Clercx, Herman

    2014-11-01

    Interaction of large-scale flows with vortices is of fundamental and widespread importance in geophysical fluid dynamics and also, more recently for the dynamics of fusion plasma. More specifically the interplay between two-dimensional turbulence constituted by a collection of unsteady eddies and so-called zonal flows has gained considerable interest because of the relevance for transport and associated barriers. We present numerical results on the interaction of individual monopolar and dipolar vortices with typical sheared channel flows (Couette and Poiseuille). Contrary to monopolar vortices, dipolar ones tend to retain their compactness while propagating through the shear flow along curved pathways without much distortion. Simulations on the interaction of a driven turbulent field with mentioned channel flows are used to explore the suppression of turbulence and turbulent transport and the pronounced role played by the boundaries on these.

  8. [Bipolar versus monopolar transurethral resection of the prostate: a prospective randomized study].

    Science.gov (United States)

    Ghozzi, S; Ghorbel, J; Ben Ali, M; Dridi, M; Maarouf, J; Khiari, R; Ben Rais, N

    2014-02-01

    To compare bipolar with standard monopolar transurethral resection of the prostate (TURP). A prospectively randomized study was conducted between January 2010 and September 2011. Primary end points studied were efficacy (maximum flow rate [Qmax], International Prostate Symptom Score) and safety (adverse events, decline in postoperative serum sodium [Na+] and haemoglobin [Hb] levels). Secondary end points were operation time and duration of irrigation, catheterization, and hospitalization. Sixty consecutive patients were randomized and completed the study, with 29 patients in the monopolar TURP group and 31 in the TURIS group. At baseline, the two groups were comparable in age, prostate volume, mean prostate-specific antigen value, International Prostate Symptom Score, and they had at least 12 months of follow-up. Declines in the mean postoperative serum Na+ for bipolar and monopolar TURP groups were 1.2 and 8.7 mmol/L, respectively. However, there was no statistical difference in the decline in postoperative Hb between the two groups. The mean catheterization time was 26.6 and 52 hours in the bipolar and standard groups, respectively. This difference was statistically significant as was the difference in the time to hospital discharge. The IPSS and Qmax improvements were comparable between the two groups at 12 months of follow-up. No clinically relevant differences in short-term efficacy are existed between the two techniques, but bipolar TURP is preferable due to a more favorable safety profile and shorter catheterization duration. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  9. Effectiveness of electrocoagulation process in removing organic compounds from slaughterhouse wastewater using monopolar and bipolar electrolytic cells.

    Science.gov (United States)

    Asselin, Mélanie; Drogui, Patrick; Benmoussa, Hamel; Blais, Jean-François

    2008-08-01

    Slaughterhouse wastewaters contain varied and high amounts of organic matter (e.g., proteins, blood, fat). In order to produce an effluent suitable for stream discharge, electrochemical techniques have been particularly explored at the laboratory pilot scale for organic compounds removal from poultry slaughterhouse (PS) effluent. Electrocoagulation (EC) process was tested using either mild steel or aluminium electrodes arranged in bipolar (BP) or monopolar configuration system. Results showed that the best performance was obtained using mild steel BP electrode system operated at a current intensity of 0.3A, through 60 or 90 min of treatment. Under these conditions, removals of 86+/-1% and 99+/-1% were measured for BOD and oil and grease, respectively, whereas soluble COD and total COD were removed by 50+/-4% and 82+/-2%, respectively. EC is also efficient for decolorization (red-color) and clarification of the PS effluent. Removals of 89+/-4% and 90+/-4% have been measured for total suspended solids and turbidity, respectively. Electrochemical coagulation operated under the optimal conditions involves a total cost of 0.71 USD $ per cubic meter of treated PS effluent. This cost includes energy and electrode consumptions, chemicals, and sludge disposal.

  10. Evaluation of the efficiency of monopolar and bipolar BDD electrodes for electrochemical oxidation of anthraquinone textile synthetic effluent for reuse.

    Science.gov (United States)

    Abdessamad, NourElHouda; Akrout, Hanene; Hamdaoui, Ghaith; Elghniji, Kais; Ksibi, Mohamed; Bousselmi, Latifa

    2013-10-01

    The efficiency of the electrochemical degradation of synthetic wastewater containing an anthraquinone dye has been comparatively studied in two electrolytic cells with a synthetic boron-doped diamond (Si/BDD) as an anode. The first is an individual cell (Cell 1) with monopolar electrode BDD and the second (Cell 2) has two bipolar electrodes BDD self-polarized. The bulk electrolysis was performed at the same initial operating conditions in order to quantify the influence of the initial pH and current density on dye discoloration and global mineralization removal. The current efficiency and the consumption energy were also evaluated. When the same solutions have been comparatively treated with the two cells, a quite good mineralization is found in Cell 2. This result supposed more fraction of the applied current is used for the electrocombustion reaction on Cell 2 if compared to Cell 1 and small amount rest for the side reaction of oxygen evolution. The HPLC analyses confirmed this hypothesis and showed that the concentration trend of intermediates (sulfanilic acid, phthalate acid and salicylic acid) with electrolysis time was different on two cells. Phototoxicity tests show that the electrochemical oxidation with BDD electrodes could be useful as a pretreatment technique for reducing hazardous wastewater toxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Ventricular fibrillation induced by a radiofrequency energy delivery for idiopathic premature ventricular contractions arising from the left ventricular anterior papillary muscle.

    Science.gov (United States)

    Yamada, Takumi; McElderry, H Thomas; Allred, James D; Doppalapudi, Harish; Kay, G Neal

    2009-08-01

    A 73-year-old man with idiopathic premature ventricular contractions (PVCs) underwent electrophysiological testing. Left ventricular activation mapping revealed a focal mechanism of the PVCs with the earliest activation on the anterior papillary muscle (APM). Irrigated radiofrequency (RF) current delivered at that site induced a cluster of non-sustained ventricular tachycardia episodes with the same QRS morphology as the PVCs, followed by ventricular fibrillation (VF). The APM might have served as an abnormal automatic trigger and driver for the VF occurrence. Ventricular fibrillation may occur as a complication during RF catheter ablation of papillary muscle ventricular arrhythmias even if the clinical arrhythmia is limited to PVCs.

  12. Quasi-monopolar stimulation: a novel electrode design configuration for performance optimization of a retinal neuroprosthesis.

    Directory of Open Access Journals (Sweden)

    Gita Khalili Moghadam

    Full Text Available In retinal neuroprostheses, spatial interaction between electric fields from various electrodes - electric crosstalk - may occur in multielectrode arrays during simultaneous stimulation of the retina. Depending on the electrode design and placement, this crosstalk can either enhance or degrade the functional characteristics of a visual prosthesis. To optimize the device performance, a balance must be satisfied between the constructive interference of crosstalk on dynamic range and power consumption and its negative effect on artificial visual acuity. In the present computational modeling study, we have examined the trade-off in these positive and negative effects using a range of currently available electrode array configurations, compared to a recently proposed stimulation strategy - the quasi monopolar (QMP configuration - in which the return current is shared between local bipolar guards and a distant monopolar electrode. We evaluate the performance of the QMP configuration with respect to the implantation site and electrode geometry parameters. Our simulation results demonstrate that the beneficial effects of QMP are only significant at electrode-to-cell distances greater than the electrode dimensions. Possessing a relatively lower activation threshold, QMP was found to be superior to the bipolar configuration in terms of providing a relatively higher visual acuity. However, the threshold for QMP was more sensitive to the topological location of the electrode in the array, which may need to be considered when programming the manner in which electrode are simultaneously activated. This drawback can be offset with a wider dynamic range and lower power consumption of QMP. Furthermore, the ratio of monopolar return current to total return can be used to adjust the functional performance of QMP for a given implantation site and electrode parameters. We conclude that the QMP configuration can be used to improve visual information

  13. Monopolar Electro-Coagulation Process for Azo Dye C.I. Acid Red 18 Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Ghasem Azarian

    2014-12-01

    Full Text Available The discharge of wastewaters containing an untreated dye results in aesthetic problems and an increase in gases solubility, which causes light transmission inhibition into water bodies. In spite of advantages of physicochemical and biological methods, these processes produce huge amounts of sludge, toxic by-products and require several oxidant chemicals. By contrast, electrochemical processes because of their high versatility, high efficiency and eco-friendly properties are more acceptable. In the present study, the removal of azo dye Acid Red 18 and chemical oxygen demand (COD from synthetic wastewater by monopolar (EC process was investigated and key parameters such as operating time, current density (CD, initial pH and energy, and electrode consumption were optimized. It was found that the process had a very good efficiency in the removal of both COD and color; for the iron electrode, the maximum amounts of color and COD removal were 99.5% and 59.0%, respectively. An operating time of 45 min, pH of 7 and CD of 1.2 mA/cm2 was selected as the optimized condition. The optimization of variables is extremely crucial as it results in a decrease in costs, energy and electrode consumption. Overall, the iron electrode used less energy than the aluminum electrode and was more acceptable for use in this process due to economical reasons. The findings of UV/vis spectra illustrated that the structures of this dye were removed by the process. In comparison with traditional methods such as aerobic and anaerobic systems, the EC process is a suitable alternative for the treatment of wastewaters containing dye pollutants.

  14. Thermal and histological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model

    Science.gov (United States)

    Ko, Raymond; Chew, Ben H.; Tan, Andrew H. H.; Rowe, Elaine; Razvi, Hassan

    2007-02-01

    Bipolar transurethral resection (TUR) is an alternative to monopolar TUR in the treatment of benign prostatic hyperplasia and offers the major advantage of utilizing 0.9% sodium chloride for irrigation. Claims have been made that bipolar electrosurgery in clinical use causes less thermal damage to adjacent tissues. We sought to assess tissue thermometry and histopathologic thermal effects of a bipolar system in comparison to standard monopolar TUR in an animal model. Eight male beagles were studied. A lower midline incision was used to access the prostate. Fiber-optic thermosensors were placed within the prostate. A midline cystotomy was used to perform antegrade resection of the prostate using a bipolar TUR system (VISTA CTR) with normal saline or a monopolar device using glycine. Resection of a 1cm cavity was performed in each lateral lobe. Animals were sacrificed acutely and the prostates excised for histopathological assessment of thermal damage. In both groups, prostatic temperature rises were transient and fell with increasing distance from the resection site. The greatest temperature increase occurred in the monopolar group (24.2 +/- 3.9°C) compared to the bipolar group (6.8 +/- 1.8°C, p<0.0001). The depth of thermal damage was greatest in the monopolar group (0.59 +/- 0.27mm vs 0.15 +/-0.02mm in the bipolar arm, p<0.0001). Bipolar TUR generated significantly less heat and produced less histopathological thermal damage compared to monopolar prostatic resection in a canine model. The clinical benefits of these findings remain to be determined.

  15. Reducing Postoperative Pain from Tonsillectomy Using Monopolar Electrocautery by Cooling the Oropharynx

    Science.gov (United States)

    Vieira, Lucas; Nissen, Leonardo; Sela, Gustavo; Amara, Yara; Fonseca, Vinicius

    2014-01-01

    Objective Evaluate intraoperative cooling of the oropharynx to reduce postoperative pain in tonsillectomy using monopolar electrocautery. Methods Sixty-six patients, age 1 to 12 years, were selected for the study, 33 in the control group and 33 in the experimental group. After randomization, patients underwent subcapsular dissection and hemostasis with monopolar electrocautery. Patients in the experimental group had the oropharynx cooled after tonsil dissection and hemostasis for 10 minutes. The procedure was done through the oral cavity by irrigation with 500 mL of 0.9% saline, in temperatures between 5°C and 10°C, for 5 minutes. The evaluation of postoperative pain was made with the pain visual analog scale (VAS) for 10 days. As complementary data on the evaluation of pain, we recorded daily use of ketoprofen for pain relief. Results Pain after tonsillectomy assessed by VAS was significantly lower in the experimental group at days 0, 5, and 6 (p < 0.05). There were no differences in the use of ketoprofen between the groups. Conclusion Cooling of the oropharynx after tonsillectomy promotes clinically significant reduction in postoperative pain, without additional complications. PMID:25992083

  16. Reducing Postoperative Pain from Tonsillectomy Using Monopolar Electrocautery by Cooling the Oropharynx

    Directory of Open Access Journals (Sweden)

    Vieira, Lucas

    2014-01-01

    Full Text Available Objective Evaluate intraoperative cooling of the oropharynx to reduce postoperative pain in tonsillectomy using monopolar electrocautery. Methods Sixty-six patients, age 1 to 12 years, were selected for the study, 33 in the control group and 33 in the experimental group. After randomization, patients underwent subcapsular dissection and hemostasis with monopolar electrocautery. Patients in the experimental group had the oropharynx cooled after tonsil dissection and hemostasis for 10 minutes. The procedure was done through the oral cavity by irrigation with 500 mL of 0.9% saline, in temperatures between 5°C and 10°C, for 5 minutes. The evaluation of postoperative pain was made with the pain visual analog scale (VAS for 10 days. As complementary data on the evaluation of pain, we recorded daily use of ketoprofen for pain relief. Results Pain after tonsillectomy assessed by VAS was significantly lower in the experimental group at days 0, 5, and 6 (p < 0.05. There were no differences in the use of ketoprofen between the groups. Conclusion Cooling of the oropharynx after tonsillectomy promotes clinically significant reduction in postoperative pain, without additional complications.

  17. CT-guided radiofrequency (RF) ablation of osteoid osteoma. Clinical long-term results; CT-gesteuerte Radiofrequenz(RF)-Ablation von Osteoidosteomen. Klinische Langzeitergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Diethard; Clasen, S.; Schaefer, J.F.; Rempp, H.; Koenig, C.W.; Claussen, C.D. [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Duda, S.; Truebenbach, J. [Juedisches Krankenhaus, Berlin (Germany). Radiologen Praxis; Erdtmann, B. [Radiologie Zentrum Stuttgart, Bad Cannstatt (Germany). Praxis; Pereira, P.L. [SLK-Kliniken, Heilbronn (Germany). Klinik fuer Radiologie, Minimal-Invasive Therapien und Nuklearmedizin

    2011-04-15

    Purpose: To evaluate CT-guided radiofrequency (RF) ablation of osteoid osteoma using internally cooled monopolar RF electrodes for technical success, complications and clinical long-term success. Materials and Methods: Between April 1999 and July 2009, 23 patients were treated under general anesthesia with CT-guided RF ablation using an internally cooled monopolar single RF electrode (Cool-tip, Valleylab, TycoHealthcare, Boulder, USA; active tip: 10 mm). For the removal of the nidus, we used either a manual or an automated drill. The technical success was evaluated by a CT scan (MSCT, Siemens Medical Solutions, Forchheim). The clinical long-term success was investigated by questioning patients prior to discharge, and after 6, 12 and 18 months. After 18 months, patients were interviewed on an annual basis. Results: The technical success rate was 100 %. The nidus was located in n = 19 cases at the lower extremity and in n = 4 cases at the upper extremity. Minor complications were observed for n = 2 patients. The mean hospitalization time was 1.5 d (1-2 d). The mean follow-up was 75.9 months (18-120 months) for n = 23 patients. No local recurrence was observed. One patient had intermediate pain one week after RF ablation without recurrent symptoms. Conclusion: CT-guided RF ablation using an internally cooled monopolar single RF electrode is an effective and safe minimally invasive method for the treatment of osteoid osteoma with excellent clinical long-term success. (orig.)

  18. Estimation Using an Enhancement Factor on Non Local Thermodynamic Equilibrium Behavior of High-lying Energy Levels of Neutral Atom in Argon Radio-Frequency Inductively-Coupled Plasma.

    Science.gov (United States)

    Wagatsuma, Kazuaki; Satoh, Kozue

    2016-01-01

    This paper describes a plasma-diagnostic method using an enhancement factor on the Boltzmann distribution among emission lines of iron atom in an argon radio-frequency inductively-coupled plasma (ICP). It indicated that Boltzmann plots of the atomic lines having lower excitation energies (3.4 to 4.8 eV) were well fitted on a straight line while those having more than 5.5 eV deviated upwards from a linear relationship. This observation could be explained by the fact that ICP is not in a complete thermodynamic equilibrium between direct excitation to energy levels of iron atom, ionization of iron atom, and radiative decay processes to the ground state. Especially, the recombination of iron ion with captured electron should accompany cascade de-excitations between closely-spaced excited levels just below the ionization limit, the rates of which become slower as a whole; as a result, these high-lying levels might be more populated than the low-lying levels as if a different LTE condition coexists on the high energy side. This overpopulation could be quantitatively estimated using an enhancement factor (EF), which was a ratio of the observed intensity to the expected value extrapolated from the normal distribution on the low energy side. The EFs were generally small (less than 3); therefore, the cascade de-excitation process would slightly contribute to the population of these excited levels. It could be considered from variations of the EF that the overpopulation proceeded to a larger extent at lower radio-frequency forward powers, at higher flow rates of the carrier gas, or at higher observation heights. The reason for this is that the kinetic energy of energetic particles, such as electrons, becomes reduced under all of these plasma conditions, thus enabling the high-lying levels to be more populated by cascade de-excitation processes from iron ion rather than by collisional excitation processes with the energetic particles. A similar Boltzmann analysis using the EF

  19. Ultrasonically activated scalpel versus monopolar electrocautery shovel in laparoscopic total mesorectal excision for rectal cancer

    Institute of Scientific and Technical Information of China (English)

    Bao-Jun Zhou; Wei-Qing Song; Qing-Hui Yan; Jian-Hui Cai; Feng-An Wang; Jin Liu; Guo-Jian Zhang; Guo-Qiang Duan; Zhan-Xue Zhang

    2008-01-01

    AIM: To investigate the feasibility and safety of monopolar electrocautery shovel (ES) in laparoscopic total mesorectal excision (TME) with anal sphincter preservation for rectal cancer in order to reduce the cost of the laparoscopic operation, and to compare ES with the ultrasonically activated scalpel (US).METHODS: Forty patients with rectal cancer, who underwent laparoscopic TME with anal sphincter preservation from June 2005 to June 2007, were randomly divided into ultrasonic scalpel group and monopolar ES group, prospectively. White blood cells (WBC) were measured before and after operation, operative time, blood loss, pelvic volume of drainage, time of anal exhaust, visual analogue scales (VAS) and surgery-related complications were recorded.RESULTS: All the operations were successful; no one was converted to open procedure. No significant differences were observed in terms of preoperative and postoperative d1 and d3 WBC counts (P=0.493, P=0.375, P=0.559), operation time (P=0.235), blood loss (P=0.296), anal exhaust time (P=0.431), pelvic drainage volume and VAS in postoperative d1 (P=0.431, P=0.426) and d3 (P=0.844, P=0.617) between ES group and US group. The occurrence of surgery-related complications such as anastomotic leakage and woundinfection was the same in the two groups.CONCLUSION: ES is a safe and feasible tool as same as US used in laparoscopic TME with anal sphincter preservation for rectal cancer on the basis of the skillful laparoscopic technique and the complete understanding of laparoscopic pelvic anatomy. Application of ES can not only reduce the operation costs but also benefit the popularization of laparoscopic operation for rectal cancer patients.

  20. Radiofrequency Ablation in Barrett's Esophagus

    Directory of Open Access Journals (Sweden)

    Vani J.A. Konda

    2014-01-01

    Full Text Available Radiofrequency ablation (RFA is an endoscopic modality used in the treatment of Barrett's esophagus. RFA may be performed using a balloon-based catheter or using one of the probe catheters that attaches to the distal end of the endoscope. Here we demonstrate step-by-step instruction in using radiofrequency ablation in the treatment of Barrett's esophagus and highlight key concepts in the technique.

  1. Application of a Z-Shaped Umbilical Incision and a Saline-Cooled Radiofrequency Device to Single-Incision Laparoscopic Surgery for a Huge Liver Cyst: Report of a Case.

    Science.gov (United States)

    Igami, Tsuyoshi; Tsuchiya, Tomonori; Ebata, Tomoki; Yokoyama, Yukihiro; Sugawara, Gen; Mizuno, Takashi; Nagino, Masato

    2015-06-01

    When compared with other diseases, few authors have reported on single-incision laparoscopic surgery (SILS) for liver cysts. We herein describe our experience with SILS for a huge liver cyst with the application of an umbilical Z-shaped incision using a gel port and a high-density monopolar saline-cooled radiofrequency device with a successful outcome. An 80-old-year woman was diagnosed with a huge liver cyst with abdominal pain. She underwent percutaneous drainage of the liver cyst and injection of both absolute ethanol and an antimicrobial agent into the liver cyst at the previous hospital. Because of re-expansion of the liver cyst and symptom recurrence, we performed SILS for the liver cyst. An umbilical Z-shaped incision was made for gel port placement. After aspiration of the cystic fluid and dissection of the thin cystic wall by laparoscopic coagulating shears, the thick cystic wall was divided using an endoscopic linear stapler to avoid bleeding and bile leakage. After wide fenestration, a high-density monopolar saline-cooled radiofrequency device was applied for the ablation of the remnant membrane of the cystic wall. All maneuvers could be performed only through the gel port. The patient was discharged 4 days after surgery and was satisfied with the cosmetic results. This case shows that the application of an umbilical Z-shaped incision using a gel port and a high-density monopolar saline-cooled radiofrequency device is useful for the accomplishment of SILS for a huge liver cyst.

  2. Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA of the Pancreas in a Porcine Model

    Directory of Open Access Journals (Sweden)

    Monica Gaidhane

    2012-01-01

    Full Text Available Backgrounds. Limited effective palliative treatments exist for pancreatic cancer which includes surgery or chemotherapy. Radiofrequency ablation (RFA uses high frequency alternating current to ablate diseased tissue and has been used to treat various tumors. In this study, we evaluated a prototype probe adjusted to the EUS-needle to perform EUS-RFA to permit coagulative necrosis in the pancreas. Methods. Five Yucatan pigs underwent EUS-guided radiofrequency ablation of the head of their pancreas. Using an EUS-needle, RFA was applied with 6 mm and then 10 mm of the probe exposed at specific wattage for preset durations. Results. Only one pig showed moderate levels of pancreatitis (20% proximal pancreatitis. The other animals showed much lower areas of tissue damage. In 3 of the 5 pigs, the proximal pancreas showed greater levels of tissue injury than the distal pancreas, consistent with the proximity of the tissue to the procedure site. In 1 pig, both proximal and distal pancreas showed minimal pancreatitis (1%. There was minimal evidence of fat necrosis in intra-pancreatic and/or extra-pancreatic adipose tissue. Conclusion. EUS-guided RFA of the pancreatic head with the monopolar probe through a 19-gauge needle was well tolerated in 5 Yucatan pigs and with minimal amount of pancreatitis.

  3. Fluoroscopy-guided Bipolar Radiofrequency Thermocoagulation Treatment for Discogenic Low Back Pain

    Institute of Scientific and Technical Information of China (English)

    Li Zhang; Xin-Li Ding; Xu-Li Zhao; Jun-Nan Wang; Yan-Ping Li; Ming Tian

    2016-01-01

    Background:The efficacy of percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) for the treatment of discogenic low back pain (LBP) remains controversial.However,all the PIRFT studies utilized monopolar radiofrequency thermocoagulation (RFTC).The aim of this study was to investigate the safety and efficacy of bipolar RFTC for the treatment of discogenic LBP.Methods:A total of 23 patients with discogenic LBP were treated with single-level bipolar RFTC.The patients were assessed before the procedure and at 1 week,1 month,3 months,6 months,and 1 year after the procedure.The primary outcome included the visual analog scale (VAS) score and the Oswestry Disability Index (ODI) score.The secondary outcome included pain relief,reduction of analgesic dose,and patient satisfaction.Results:The VAS and ODI scores were significantly decreased after bipolar RFTC treatment at all time points of follow-up (P < 0.05).Bipolar RFTC treatment also resulted in a significant change in all secondary measures,such as pain relief,reduction of analgesic dose,and patient satisfaction.No serious complications or neurological sequelae were observed in any of the patients.Conclusions:Bipolar RFTC treatment can significantly attenuate pain and improve the function of patients with discogenic LBP.

  4. Treatment of acne vulgaris with fractional radiofrequency microneedling.

    Science.gov (United States)

    Kim, Sang Tae; Lee, Kang Hoon; Sim, Hyung Jun; Suh, Kee Suck; Jang, Min Soo

    2014-07-01

    Fractional radiofrequency microneedling is a novel radiofrequency technique that uses insulated microneedles to deliver energy to the deep dermis at the point of penetration without destruction of the epidermis. It has been used for the treatment of various dermatological conditions including wrinkles, atrophic scars and hypertrophic scars. There have been few studies evaluating the efficacy of fractional radiofrequency microneedling in the treatment of acne, and none measuring objective parameters like the number of inflammatory and non-inflammatory acne lesions or sebum excretion levels. The safety and efficacy of fractional radiofrequency microneedling in the treatment of acne vulgaris was investigated. In a prospective clinical trial, 25 patients with moderate to severe acne were treated with fractional radiofrequency microneedling. The procedure was carried out three times at 1-month intervals. Acne lesion count, subjective satisfaction score, sebum excretion level and adverse effects were assessed at baseline and at 4, 8 and 12 weeks after the first treatment as well as 4, 8 and 12 weeks after the last treatment. Number of acne lesions (inflammatory and non-inflammatory) decreased. Sebum excretion and subjective satisfaction were more favorable at every time point compared with the baseline values (P acne vulgaris.

  5. Comparative randomized study on the efficaciousness of endoscopic bipolar prostate resection versus monopolar resection technique. 3 year follow-up

    OpenAIRE

    Roberto Giulianelli; Luca Albanesi; Francesco Attisani; Barbara Cristina Gentile; Giorgio Vincenti; Francesco Pisanti; Teuta Shestani; Luca Mavilla; David Granata; Manlio Schettini

    2013-01-01

    Objective: Transurethral resection of the prostate (TURP) is the current optimal thera- py for the relief of bladder outflow obstruction, with subjective and objective success rate of 85 to 90%. Aim of this study was to evaluate efficacy and safety of Plasmakinetic ener- gy (Gyrus electro surgical system), which produces vaporization of tissue immersed in isotonic saline against standard monopolar transurethral resection of the prostate. Methods: From January 2002 to April 2002, 160 consecuti...

  6. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  7. Multiple monopolar outflows driven by massive protostars in IRAS 18162-2048

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-López, M. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Girart, J. M. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain); Curiel, S.; Fonfría, J. P. [Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 70-264, 04510 México, DF (Mexico); Zapata, L. A. [Centro de Radioastronomía y Astrofísica, UNAM, Apartado Postal 3-72, Morelia, Michoacán 58089 (Mexico); Qiu, K., E-mail: manferna@illinois.edu, E-mail: girart@ieec.cat [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2013-11-20

    In this article, we present Combined Array for Research in Millimeter-wave Astronomy (CARMA) 3.5 mm observations and SubMillimeter Array (SMA) 870 μm observations toward the high-mass star-forming region IRAS 18162-2048, which is the core of the HH 80/81/80N system. Molecular emission from HCN, HCO{sup +}, and SiO traces two molecular outflows (the so-called northeast and northwest outflows). These outflows have their origin in a region close to the position of MM2, a millimeter source known to harbor two protostars. For the first time we estimate the physical characteristics of these molecular outflows, which are similar to those of 10{sup 3}-5 × 10{sup 3} L {sub ☉} protostars, and suggest that MM2 harbors high-mass protostars. High-angular resolution CO observations show an additional outflow due southeast. Also for the first time, we identify its driving source, MM2(E), and see evidence of precession. All three outflows have a monopolar appearance, but we link the NW and SE lobes, and explain their asymmetric shape as being a consequence of possible deflection.

  8. Efficacy of monopolar dielectric transmission radio frequency in panniculus adiposus and cellulite reduction.

    Science.gov (United States)

    Albornoz-Cabello, Manuel; Ibáñez-Vera, Alfonso Javier; De la Cruz-Torres, Blanca

    2017-07-05

    Despite high incidence rate of cellulite, there are few studies regarding its treatment. Most of them present non-validated evaluation tools. Radio frequency is a focused treatment very used in aesthetics to reduce it. To know the efficacy of Monopolar Dielectric Radio frequency (MDR) treatment in dynamic applications to reduce cellulite, panniculus adiposus and gluteal and posterior thigh regions. Experimental study consisting of inferior members of nine women. They received 10 sessions based on dynamic applications of MDR. Variables included the following: Cellulite Severity Scale (CSS), appearance of the cutaneous area, flaccidity and ultrasound measurement of the panniculus adiposus. The final CSS score of the leg treated reflects statistically significative differences (p = 0.023) when compared with control leg (p = 0.622). Significant reductions of body perimeters at the level of the great trochanter (p = 0.02), the gluteal region (p = 0.03) and the midpoint of the posterior thigh (p = 0.01) are found. The reduction of the panniculus adiposus measured using ultrasound techniques shows significant changes in the midpoint of the posterior thigh (p = 0.028) as well as in the gluteal region (p = 0.03). The dynamic application of MDR seems to be effective in order to reduce not only the thickness of panniculus adiposus but also gluteal and posterior thigh perimeters.

  9. Multiple monopolar outflows driven by massive protostars in IRAS 18162-2048

    CERN Document Server

    Fernández-López, Manuel; Curiel, Salvador; Zapata, Luis Alberto; Fonfría, Jose Pablo; Qiu, Keping

    2013-01-01

    In this paper we present Combined Array for Research in Millimeter-wave Astronomy (CARMA) 3.5 mm observations and SubMillimeter Array (SMA) 870 microns observations toward the high-mass star-forming region IRAS 1816-2048, the core of the HH 80/81/80N system. Molecular emission from HCN, HCO+ and SiO is tracing two molecular outflows (the so-called Northeast and Northwest outflows). These outflows have their origin in a region close to the position of MM2, a millimeter source known to harbor a couple protostars. We estimate for the first time the physical characteristics of these molecular outflows, which are similar to those of 1000-5000 Lo protostars, suggesting that MM2 harbors high-mass protostars. High-angular resolution CO observations show an additional outflow due southeast. We identify for the first time its driving source, MM2(E), and see evidence of precession. All three outflows have a monopolar appearance, but we link the NW and SE lobes, explaining their asymmetric shape as a consequence of possi...

  10. Radiofrequency fields and teratogenesis.

    Science.gov (United States)

    Heynick, Louis N; Merritt, James H

    2003-01-01

    Experimental studies that sought teratologic effects or developmental abnormalities from exposure to radiofrequency electromagnetic fields (RFEMF) in the range 3 kHz-300 GHz are critically reviewed for their possible consequences on human health. Those studies were conducted on beetles, birds, rodents, and nonhuman primates. Collectively, those experimental studies indicate that teratologic effects can occur only from exposure levels that cause biologically detrimental increases in body temperature. No reliable experimental evidence was found for nonthermal teratologic effects; rodents, mouse fetuses, and perinatal mice are more susceptible to such effects than rats. The primary confirmed effect in rats at high RFEMF levels was initial weight deficits in fetuses and neonates that decreased with infant growth. More generally from findings with pregnant mammals, exposures at RFEMF levels far higher than those permitted under the IEEE human exposure guidelines are necessary to reach or exceed cited experimental thresholds for maternal temperature increases. Some results indicated that the levels necessary to cause such effects in pregnant mammals could exceed those lethal to the dams. In a behavioral study of squirrel monkeys, no effects were observed on usual dam-offspring interactions or EEGs, but unexpected deaths of a number of offspring had occurred. However, this finding was not confirmed in a study solely on infant death using a larger number of subjects for greater statistical validity. Also reviewed were epidemiologic studies of various human populations considered to have been chronically exposed to environmental levels of RFEMF. Early studies on the incidence of congenital anomalies yielded no credible evidence that chronic exposure of pregnant women or of fathers exposed to RFEMF from nearby sources at levels below those guidelines would cause any anomalies in their offspring. The findings of studies on pregnancy outcomes of female physiotherapists

  11. Radiofrequency ablation of atrial fibrillation

    NARCIS (Netherlands)

    Wiesfeld, ACP; Tan, ES; Van Veldhuisen, DJ; Crijns, HJGM; Van Gelder, IC

    2004-01-01

    Twenty-five patients (16 males, mean age 46 years.) underwent radiofrequency ablation because of either paroxysmal (13 patients) or persistent atrial fibrillation (12 patients). Ablation aimed at earliest activation of spontaneous and catheter-induced repetitive ectopy in left and right atria and ap

  12. LEP radio-frequency cavity

    CERN Multimedia

    1991-01-01

    One of the copper radio-frequency accelerating cavities installed for the first phase of LEP (1989-1995). Bunches of electrons and positrons circulated in LEP in opposite directions and were accelerated in eight different sets of 16 cavities (situated on either side of the four experiments), gaining 400 million volts of accelerating power per turn.

  13. Time-course of corticospinal excitability and autonomic function interplay during and following monopolar tDCS

    Directory of Open Access Journals (Sweden)

    Emiliano eSantarnecchi

    2014-07-01

    Full Text Available While polarity-specific after-effects of monopolar transcranial direct current stimulation (tDCS on cortico-spinal excitability are well-documented, modulation of vital parameters due to current spread through the brainstem is still a matter of debate, raising potential concerns about its use through the general public, as well as for neurorehabilitation purposes. We monitored online and after-effects of monopolar tDCS (primary motor cortex in ten healthy subjects by adopting a neuronavigated transcranial magnetic stimulation (TMS/tDCS combined protocol. Motor evoked potentials (MEPs together with vital parameters (e.g. blood pressure, heart-rate variability and sympathovagal balance were recorded and monitored before, during and after anodal, cathodal or sham tDCS. Ten MEPs every 2.5-minute time windows were recorded from the right First Dorsal Interosseus (FDI, while 5-minute epochs were used to record vital parameters. The protocol included 15 minutes of pre-tDCS and of online-tDCS, (anodal, cathodal or sham. After effects were recorded for 30 minutes. We showed a polarity-independent stabilization of cortical excitability level, a polarity-specific after-effects for cathodal and anodal stimulation, and an absence of persistent excitability changes during online stimulation. No significant effects on vital parameters emerged both during and after tDCS, while a linear increase in systolic/diastolic blood pressure and heart-rate variability was observed during each tDCS condition, as a possible unspecific response to experimental demands. Taken together, current findings provide new insights on the safety of monopolar tDCS, promoting its application both in research and clinical settings.

  14. Comparative randomized study on the efficaciousness of endoscopic bipolar prostate resection versus monopolar resection technique. 3 year follow-up

    Directory of Open Access Journals (Sweden)

    Roberto Giulianelli

    2013-06-01

    Full Text Available Objective: Transurethral resection of the prostate (TURP is the current optimal thera- py for the relief of bladder outflow obstruction, with subjective and objective success rate of 85 to 90%. Aim of this study was to evaluate efficacy and safety of Plasmakinetic ener- gy (Gyrus electro surgical system, which produces vaporization of tissue immersed in isotonic saline against standard monopolar transurethral resection of the prostate. Methods: From January 2002 to April 2002, 160 consecutive patients, who had low urinary tract symptoms (LUTS of benign prostatic hyperplasia (BPH were enrolled in this study. Patients were randomised to undergo bipolar TURP (80 patients or monopolar TURP (80 patients. Preoperative work-up was assessed by administering IPSS, IIEF-5 and Qol questionnaires. All patients were submitted to uroflowmetry, transrectal ultrasound (TRUS, post-voidal residual urine measurement and PSA determination. In the two groups, IPSS, IIEF-5 and Qol, uroflowme- try, TRUS, post-voidal residual urine measurement, PSA determination and number of reopera- tions were evaluated at 1, 3, 6, 12, 18, 24, 30 and 36 months follow up, and then every year. Furthermore, in both groups operative time, resected tissue weight and perioperative complica- tions were analysed. Total postoperative catheter time, total post-operative hospital stay, haemo- globin loss were also recorded in the two groups. Results: Comparative data on IPSS symptom score, IIEF-5, Qol, PSA, peak urinary flow rate and post-void residual urine volume were similar in the two groups but showed a significant improve- ment respect to baseline values. The postoperative haemoglobin levels, postoperative catheteri- zation time, hospital stay and 3-year overall surgical re-treatment-free rate were significantly better in the bipolar group. Conclusions: Bipolar TURP has a comparable outcome to standard monopolar TURP at short and medium term regard to subjective and objective outcome

  15. Radiofrequency interstitial tumor ablation: dry electrode.

    Science.gov (United States)

    Johnson, D Brooke; Cadeddu, Jeffrey A

    2003-10-01

    With the shift in the treatment of small renal tumors from radical extirpative surgery to nephron-sparing approaches, dry-electrode radiofrequency ablation (RFA) has emerged as one potential modality. This application of RF energy leads to the production of heat within the treatment zone secondary to the native impedance of living tissue. Animal studies and human clinical series have demonstrated that RFA can create controlled, targeted, reproducible, and lethal lesions. Most clinical series have reported promising results, although some authors question the totality of tumor destruction by RFA. With time, the efficacy of RFA, as measured by patient survival, will be determined. Once this is known, RFA may be compared with other therapeutic modalities for small renal tumors to determine its place.

  16. One and Two Photon Excitation of Radiofrequency Trapped Ca+

    Institute of Scientific and Technical Information of China (English)

    C. Zumsteg; C. Champenois; D. Guyomarc'h; G. Hagel; M. Houssin; M. Knoop

    2009-01-01

    Radiofrequency (rf) trapped ions are versatile candidates for a large panel of applications ranging from quantum information to the creation of cold molecules. Sample size can range from a single to 106 ions, and the internal and external energy states of the atoms can be controlled with high precision. In the experiment, we focus on different protocols related to frequency metrology using rf trapped Ca+.

  17. Comparative evaluation of transmembrane ion transport due to monopolar and bipolar nanosecond, high-intensity electroporation pulses based on full three-dimensional analyses

    Science.gov (United States)

    Hu, Q.; Joshi, R. P.

    2017-07-01

    Electric pulse driven membrane poration finds applications in the fields of biomedical engineering and drug/gene delivery. Here we focus on nanosecond, high-intensity electroporation and probe the role of pulse shape (e.g., monopolar-vs-bipolar), multiple electrode scenarios, and serial-versus-simultaneous pulsing, based on a three-dimensional time-dependent continuum model in a systematic fashion. Our results indicate that monopolar pulsing always leads to higher and stronger cellular uptake. This prediction is in agreement with experimental reports and observations. It is also demonstrated that multi-pronged electrode configurations influence and increase the degree of cellular uptake.

  18. Monopolar high-frequency language mapping: can it help in the surgical management of gliomas? A comparative clinical study.

    Science.gov (United States)

    Riva, Marco; Fava, Enrica; Gallucci, Marcello; Comi, Alessandro; Casarotti, Alessandra; Alfiero, Tommaso; Raneri, Fabio A; Pessina, Federico; Bello, Lorenzo

    2016-05-01

    OBJECT Intraoperative language mapping is traditionally performed with low-frequency bipolar stimulation (LFBS). High-frequency train-of-five stimulation delivered by a monopolar probe (HFMS) is an alternative technique for motor mapping, with a lower reported seizure incidence. The application of HFMS in language mapping is still limited. Authors of this study assessed the efficacy and safety of HFMS for language mapping during awake surgery, exploring its clinical impact compared with that of LFBS. METHODS Fifty-nine patients underwent awake surgery with neuropsychological testing, and LFBS and HFMS were compared. Frequency, type, and site of evoked interference were recorded. Language was scored preoperatively and 1 week and 3 months after surgery. Extent of resection was calculated as well. RESULTS High-frequency monopolar stimulation induced a language disturbance when the repetition rate was set at 3 Hz. Interference with counting (p = 0.17) and naming (p = 0.228) did not vary between HFMS and LFBS. These results held true when preoperative tumor volume, lesion site, histology, and recurrent surgery were considered. Intraoperative responses (1603) in all patients were compared. The error rate for both modalities differed from baseline values (p language errors (articulatory, anomia, paraphasia) did not differ between the 2 stimulation methods (p = 0.279). CONCLUSIONS With proper setting adjustments, HFMS is a safe and effective technique for language mapping.

  19. Influence of layered skin structure on the distribution of radiofrequency currents in dermis and subcutaneous fat

    Science.gov (United States)

    Kruglikov, Ilja L.

    2015-12-01

    The layered structure of skin with multiple interfaces separating the skin layers having very different electrical characteristics significantly modifies the spatial distribution of radiofrequency (RF) current in the skin compared to that in a homogeneous medium. In this study we present the analytical solutions of Laplace's equation describing the current densities for a two-layer skin model with homogeneous single layers for the monopolar and bipolar configurations of RF electrodes. Then we analyze analytically and numerically the optimal distances between the RF electrodes providing the maximal current concentration in a given depth or in a given depths' interval under the skin surface. It is demonstrated that two main parameters which significantly define the optimization condition are the thickness of the dermis and the reflection coefficient of the current at the dermis/subcutis interface. According to this model, under physiological conditions, the surface under RF electrode collecting 50% of the current entering subcutis is 184 times larger than in homogeneous medium. Such redistribution of RF current will significantly reduce the local density of the current entering the fat tissue reducing the effect of its selective heating.

  20. Probabilistic finite element analysis of radiofrequency liver ablation using the unscented transform

    Energy Technology Data Exchange (ETDEWEB)

    Dos Santos, Icaro; Da Rocha, Adson Ferreira; Menezes, Leonardo Rax [Department of Electrical Engineering, University of Brasilia, Brasilia, DF 70910-900 (Brazil); Haemmerich, Dieter; Schutt, David [Division of Pediatric Cardiology, Medical University of South Carolina, 165 Ashley Ave., Charleston, SC 29425 (United States)], E-mail: icaro@ieee.org

    2009-02-07

    The main limitation of radiofrequency (RF) ablation numerical simulations reported in the literature is their failure to provide statistical results based on the statistical variability of tissue thermal-electrical parameters. This work developed an efficient probabilistic approach to hepatic RF ablation in order to statistically evaluate the effect of four thermal-electrical properties of liver tissue on the uncertainty of the ablation zone dimensions: thermal conductivity, specific heat, blood perfusion and electrical conductivity. A deterministic thermal-electrical finite element model of a monopolar electrode inserted in the liver was coupled with the unscented transform method in order to obtain coagulation zone confidence intervals, probability and cumulative density functions. The coagulation zone volume, diameter and length were 10.96 cm{sup 3}, 2.17 cm and 4.08 cm, respectively (P < 0.01). Furthermore, a probabilistic sensitivity analysis showed that perfusion and thermal conductivity account for >95% of the variability in coagulation zone volume, diameter and length.

  1. Radiofrequency ablation: basic principles, techniques and challenges; Radiofrequenzablation: Grundlagen, Techniken und Herausforderungen

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, P.L.; Truebenbach, J.; Schmidt, D. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany)

    2003-01-01

    Radiofrequency (RF) thermal ablation is a promising and rapidly evolving technique for the minimal invasive treatment of liver malignancies. Until a few years ago, conventional RF treatment performed with a single monopolar electrode produced thermal necrosis lesions not exceeding 1.6 cm in diameter. Substantial improvements in the RF technique included the development of high-power generators (up to 250 watts) combined with open-perfused electrodes, internally cooled-tip electrodes or expandable electrode needles, capable of ablating an area of over 5 cm in diameter. Moreover, angiographically and pharmacologically assisted strategies were introduced for expanding the volume of RF-induced coagulation necrosis. This article presents a synopsis of current RF techniques and reviews the basic principles of RF ablation with the goal of providing guidance for optimal results. (orig.) [German] Die Radiofrequenzablation ist eine vielversprechende und sich schnell weiterentwickelnde Technik zur minimal invasiven Therapie von Lebermalignomen. Bis vor einigen Jahren war der limitierende Faktor dieses Verfahrens der unter Verwendung der zur Verfuegung stehenden Ablationssonden maximal erzeugbare Laesionsdurchmesser von 1,6 cm. Entscheidende Fortschritte erfuhr dieses Verfahren durch die Entwicklung leistungsfaehigerer Generatoren (bis 250 Watt) in Kombination mit offen oder geschlossen gekuehlten Ablationssonden bzw. expandierbaren Ablationssonden. Hiermit sind nunmehr Ablationsareale mit Durchmessern bis ueber 5 cm in-vivo moeglich. Weiterhin konnte mit angiographischen bzw. pharmakologischen Strategien eine weitere Vergroesserung der Ablationsvolumina erzielt werden. In diesem Artikel werden die grundlegenden Prinzipien der RF-Ablation sowie die aktuellsten RF-Systeme im Hinblick auf die Ablationscharakteristika dargestellt. (orig.)

  2. Therapy of HCC-radiofrequency ablation.

    Science.gov (United States)

    Buscarini, L; Buscarini, E

    2001-01-01

    Radiofrequency interstitial hyperthermia has been used for percutaneous ablation of hepatocellular carcinoma, under ultrasound guidance in local anesthesia. Conventional needle electrodes require a mean number of 3 sessions to treat tumors of diameter hemotorax in one case; a fluid collection in the site of ablated tumor in one patient treated by combination of transcatheter arterial embolization and radiofrequency application.

  3. 1-year follow-up after radiofrequency tonsillotomy and laser tonsillotomy in children: a prospective, double-blind, clinical study.

    Science.gov (United States)

    Stelter, Klaus; Ihrler, Stephan; Siedek, Vanessa; Patscheider, Martin; Braun, Thomas; Ledderose, Georg

    2012-02-01

    In the last decade, tonsillotomy has come into vogue again, whereas the number of tonsillectomies is decreasing rapidly. In a previous study, the tonsillotomy with laser or radiofrequency therapy proved as a safe and effective procedure with minimal pain and hemorrhage. This follow-up study determines which method is more effective with respect to long-term outcome, recurrence of tonsillar hyperplasia and recurrence of tonsillitis. A prospective, randomised, double-blinded controlled clinical study was conducted at the Department of Otorhinolaryngology of the Ludwig-Maximilians-University, Munich, Germany. Twenty-six children with tonsillar hypertrophy were included. Tonsillotomy was performed on one side with monopolar radiofrequency and on the other side with a carbon dioxide laser. Exactly 1 year after the procedure, all 26 patients were documented by digital photography to define a possible recurrence of tonsillar hyperplasia. All parents were asked for occurring tonsillitis and fulfilled the Glasgow Children's Benefit Inventory (GCBI) for health-related quality of life after surgical procedures. In seven children, a slightly visible recurrence of the tonsillar hyperplasia occurred, without any symptoms or correlation to the different methods and sides. One child with recurrent tonsillitis and hyperplasia had to be tonsillectomized 8 months after the initial tonsillotomy procedure. The specimen showed open crypts with bacterial infection in the deep. The GCBI resulted in highly significant benefits of the surgery in all categories and subcategories. In conclusion, both methods, the laser tonsillotomy and the radiofrequency method, were equal concerning the effectiveness and safety after 1 year. Further investigations have to aim at the long-term outcome after tonsillotomy in patients with recurrent infections.

  4. Near-field radiofrequency electromagnetic exposure assessment.

    Science.gov (United States)

    Rubtsova, Nina; Perov, Sergey; Belaya, Olga; Kuster, Niels; Balzano, Quirino

    2015-09-01

    Personal wireless telecommunication devices, such as radiofrequency (RF) electromagnetic field (EMF) sources operated in vicinity of human body, have possible adverse health effects. Therefore, the correct EMF assessment is necessary in their near field. According to international near-field measurement criteria, the specific absorption rate (SAR) is used for absorbed energy distribution assessment in tissue simulating liquid phantoms. The aim of this investigation is to validate the relationship between the H-field of incident EMF and absorbed energy in phantoms. Three typical wireless telecommunication system frequencies are considered (900, 1800 and 2450 MHz). The EMF source at each frequency is an appropriate half-wave dipole antenna and the absorbing medium is a flat phantom filled with the suitable tissue simulating liquid. Two methods for SAR estimation have been used: standard procedure based on E-field measured in tissue simulating medium and a proposed evaluation by measuring the incident H-field. Compared SAR estimations were performed for various distances between sources and phantom. Also, these research data were compared with simulation results, obtained by using finite-difference time-domain method. The acquired data help to determine the source near-field space characterized by the smallest deviation between SAR estimation methods. So, this region near the RF source is suitable for correct RF energy absorption assessment using the magnetic component of the RF fields.

  5. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiofrequency lesion probe. 882.4725 Section 882...) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4725 Radiofrequency lesion probe. (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF...

  6. Radiofrequency field surveys in hospitals.

    Science.gov (United States)

    Foster, K R; Soltys, M; Arnofsky, S; Doshi, P; Hanover, D; Mercado, R; Schleck, D

    1996-01-01

    The authors surveyed levels of radiofrequency (RF) fields in the frequency range 0.1-1,000 MHz in four hospitals in the Philadelphia area, to obtain background information related to the possible interference of radiofrequency fields with medical equipment. Two large center-city hospitals, a regional county hospital, and two suburban hospitals were surveyed. Measurements were made at six to 12 sites in each hospital, in each of the three frequency bands. More limited additional measurements were conducted in a fifth hospital as well. Sites were selected to include areas where strong RF signals from transmitting antennas might be expected to be present (e.g., locations close to windows in upper stories of buildings near paging antennas) as well as other representative sites in the hospital. The median RF field strengths were quite low (0.1-0.5 V/m), but at specific locations the RF signals from broadcast sources exceeded 1 V/m. Much stronger fields were recorded close to electrosurgical units and hand-held transmitters (cellular telephones and UHF transceivers).

  7. Monopolar fuel cell stack coupled together without use of top or bottom cover plates or tie rods

    Science.gov (United States)

    Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor)

    2009-01-01

    A monopolar fuel cell stack comprises a plurality of sealed unit cells coupled together. Each unit cell comprises two outer cathodes adjacent to corresponding membrane electrode assemblies and a center anode plate. An inlet and outlet manifold are coupled to the anode plate and communicate with a channel therein. Fuel flows from the inlet manifold through the channel in contact with the anode plate and flows out through the outlet manifold. The inlet and outlet manifolds are arranged to couple to the inlet and outlet manifolds respectively of an adjacent one of the plurality of unit cells to permit fuel flow in common into all of the inlet manifolds of the plurality of the unit cells when coupled together in a stack and out of all of the outlet manifolds of the plurality of unit cells when coupled together in a stack.

  8. Subsurface Laser and Radiofrequency for Face and Body Rejuvenation.

    Science.gov (United States)

    DiBernardo, Barry E; DiBernardo, Gabriella; Pozner, Jason N

    2016-07-01

    Minimally invasive devices are a departure from standard laser therapies, because energy is delivered directly below the skin through a 1-mm incision. Lasers can affect such tissues as fat for enhanced disruption, coagulation of small blood vessels, and skin tightening at the right temperatures. Minimally invasive radiofrequency devices can tighten skin but can also improve neck muscle laxity. These devices can achieve results not possible with traditional external devices and, because the skin is not penetrated with energy, a much improved healing profile is seen as well. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Cutaneous remodeling and photorejuvenation using radiofrequency devices

    Directory of Open Access Journals (Sweden)

    Elsaie Mohamed

    2009-01-01

    Full Text Available Radio frequency (RF is electromagnetic radiation in the frequency range of 3-300GHz. The primary effects of RF energy on living tissue are considered to be thermal. The goal of the new devices based on these frequency ranges is to heat specific layers of the skin. The directed use of RF can induce dermal heating and cause collagen degeneration. Wound healing mechanisms promote the remodeling of collagen and wound contraction, which ultimately clinically enhances the appearance of mild to moderate skin laxity. Preliminary studies have reported efficacy in the treatment of laxity that involves the periorbital area and jowls. Because RF energy is not dependent on specific chromophore interaction, epidermal melanin is not at risk of destruction and treatment of all skin types is possible. As such, radiofrequency-based systems have been used successfully for nonablative skin rejuvenation, atrophic scar revision and treatment of unwanted hair, vascular lesions and inflammatory acne. The use of RF is becoming more popular, although a misunderstanding exists regarding the mechanisms and limitations of its actions. This concise review serves as an introduction and guide to many aspects of RF in the non ablative rejuvenation of skin.

  10. Trigeminal Neuralgia and Radiofrequency Lesioning

    Directory of Open Access Journals (Sweden)

    Andy R. Eugene

    2015-12-01

    Full Text Available Trigeminal Neuralgia is a disorder that is characterized with electrical-type shocking pain in the face and jaw. This pain may either present as sharp unbearable pain unilateral or bilaterally. There is no definite etiology for this condition. There are various treatment methods that are currently being used to relieve the pain. One of the pharmacological treatments is Carbamazepine and the most prevalent surgical treatments include Gamma Knife Surgery (GKS, Microvascular Decompression (MVD and Radiofrequency Lesioning (RFL. Although, MVD is the most used surgical method it is not an option for all the patients due to the intensity of the procedure. RFL is used when MVD is not suitable. In this paper we present the various treatments and Monte-Carlo based pharmacokinetic simulations of Carbamazepine in treatment of Trigeminal Neuralgia.

  11. Radiofrequency tissue ablation with cooled-tip electrodes:an experimental study in a bovine liver model on variables influencing lesion size

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hyun Young [Eulgy Univ. Hospital, Seoul (Korea, Republic of); Lee, Jeong Min; Kim, Chong Soo [Chonbuk National Univ. Hospital, Chonju (Korea, Republic of)

    2001-03-01

    The purpose of this study was to determine the influence of various factors on the extent of thermal coagulation necrosis after radiofrequency (RF) tissue ablation using a cooled-tip electrode in bovine liver. RF ablation was induced by a monopolar 500 KHz-RF generator (CC-1; Radionics, Burlington, Mass., U.S.A.) and an 18-G cooled-tip with single or clustered electrodes. The ablation protocol involved a combination of varying current, ablation time, power output, gradual or abrupt increase of this out-put, and pulsed radiofrequency techniques. The maximum diameter of all thermal lesions which showed a color change was measured perpendicular to the electrode axis by two observers who reached their decisions by consensus. Twenty representative lesions were pathologically examined. With increasing current lesion diameter also increased, but above 1500 mA no further increase was induced. Extending the ablation time to 9 minutes for a single electrode and 15 minutes for a clustered electrode increased lesion diameter until a steady state was reached. Higher power levels caused larger lesions, but above 100 W no increase was observed. Ample exposure time coupled with a stepwise increase in power level induced a lesion larger than that resulting from an abrupt increase. Continuous pulsed RF with a high current led to increased coagulation necrosis diameter. These experimental findings may be useful thermotherapy. The data suggest that all involved factors significantly affect lesion size:if the factors are better understood, cancer thermotherapy can be better controlled.

  12. Experimental and clinical studies with radiofrequency-induced thermal endometrial ablation for functional menorrhagia

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, J.H.; Lewis, B.V.; Prior, M.V.; Roberts, T. (Watford General Hospital, Herts (England))

    1990-11-01

    A method of ablating the endometrium has been introduced into clinical practice that uses radiofrequency electromagnetic energy to heat the endometrium, using a probe inserted through the cervix. Preliminary studies suggest that over 80% of patients treated will develop either amenorrhea or a significant reduction in flow. The advantages of radiofrequency endometrial ablation over laser ablation or resection are the avoidance of intravascular fluid absorption, simplicity (no special operative hysteroscopic skills are required), speed of operation, and reduced cost compared with the Nd:YAG laser. In this paper, we describe the experimental studies performed during development of this new technique.

  13. Thermistor guided radiofrequency ablation of atrial insertion sites in patients with accessory pathways.

    Science.gov (United States)

    Tracy, C M; Moore, H J; Solomon, A J; Rodak, D J; Fletcher, R D

    1995-11-01

    Radiofrequency ablation has gained acceptance in the treatment of patients with symptomatic Wolff-Parkinson-White syndrome. The purpose of this study was to characterize the relation between temperature and other electroconductive parameters in patients undergoing atrial insertion accessory pathway ablation utilizing a thermistor equipped catheter. The mean temperature and power at sites of atrial insertion ablation are lower than has been previously associated with creation of radiofrequency lesions in the ventricle. While high cavitary blood flow in the atrium may result in cooling, the thinner atrial tissue may require less energy to achieve adequate heating than ventricular myocardium.

  14. Radiofrequency-assisted Liposuction for Arm Contouring: Technique under Local Anesthesia

    Directory of Open Access Journals (Sweden)

    Spero Theodorou, MD

    2013-08-01

    Conclusions: In appropriately selected patients, RFAL arm contouring under local anesthesia represents an alternative procedure with acceptably low morbidity and high patient satisfaction. To achieve consistent results while minimizing complications, consideration to anatomic details, infiltration of the local anesthetic, and application of the radiofrequency energy must be given.

  15. An Immunomodulatory Protein (Ling Zhi-8 from a Ganoderma lucidum Induced Acceleration of Wound Healing in Rat Liver Tissues after Monopolar Electrosurgery

    Directory of Open Access Journals (Sweden)

    Hao-Jan Lin

    2014-01-01

    Full Text Available The purpose of this study was to investigate the effect of an immunomodulatory protein (Ling Zhi-8, LZ-8 on wound healing in rat liver tissues after monopolar electrosurgery. Animals were sacrificed for evaluations at 0, 3, 7, and 28 days postoperatively. It was found that the wound with the LZ-8 treatment significantly increases wound healing. Western blot analysis clearly indicated that the expression of NF-κB was decreased at 3, 7, and 28 days when liver tissues were treated with LZ-8. Moreover, caspase-3 activity of the liver tissue also significantly decreases at 7 and 28 days, respectively. DAPI staining and TUNEL assays revealed that only a minimal dispersion of NF-κB was found on the liver tissue treated with LZ-8 at day 7 as compared with day 3 and tissues without LZ-8 treatment. Similarly, apoptosis was decreased on liver tissues treated with LZ-8 at 7 days when compared to the control (monopolar electrosurgery tissues. Therefore, the analytical results demonstrated that LZ-8 induced acceleration of wound healing in rat liver tissues after monopolar electrosurgery.

  16. Mechanochemical endovenous Ablation versus RADiOfrequeNcy Ablation in the treatment of primary great saphenous vein incompetence (MARADONA) : study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    van Eekeren, Ramon R. J. P.; Boersma, Doeke; Holewijn, Suzanne; Vahl, Anco; de Vries, Jean Paul P. M.; Zeebregts, Clark J.; Reijnen, Michel M. P. J.

    2014-01-01

    Background: Radiofrequency ablation (RFA) is associated with an excellent outcome in the treatment of great saphenous vein (GSV) incompetence. The use of thermal energy as a treatment source requires the instillation of tumescence anesthesia. Mechanochemical endovenous ablation (MOCA) combines

  17. Mechanochemical endovenous Ablation versus RADiOfrequeNcy Ablation in the treatment of primary great saphenous vein incompetence (MARADONA) : study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    van Eekeren, Ramon R. J. P.; Boersma, Doeke; Holewijn, Suzanne; Vahl, Anco; de Vries, Jean Paul P. M.; Zeebregts, Clark J.; Reijnen, Michel M. P. J.

    2014-01-01

    Background: Radiofrequency ablation (RFA) is associated with an excellent outcome in the treatment of great saphenous vein (GSV) incompetence. The use of thermal energy as a treatment source requires the instillation of tumescence anesthesia. Mechanochemical endovenous ablation (MOCA) combines mecha

  18. Radiofrequency ablation of pulmonary tumors

    Energy Technology Data Exchange (ETDEWEB)

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.i [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy); Lencioni, Riccardo [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy)

    2010-07-15

    The development of image-guided percutaneous techniques for local tumor ablation has been one of the major advances in the treatment of solid tumors. Among these methods, radiofrequency (RF) ablation is currently established as the primary ablative modality at most institutions. RF ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma when liver transplantation or surgical resection are not suitable options and is considered as a viable alternate to surgery for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer. Recently, RF ablation has been demonstrated to be a safe and valuable treatment option for patients with unresectable or medically inoperable lung malignancies. Resection should remain the standard therapy for non-small cell lung cancer (NSCLC) but RF ablation may be better than conventional external-beam radiation for the treatment of the high-risk individual with NSCLC. Initial favourable outcomes encourage combining radiotherapy and RF ablation, especially for treating larger tumors. In the setting of colorectal cancer lung metastases, survival rates provided by RF ablation in selected patients, are substantially higher than those obtained with any chemotherapy regimens and provide indirect evidence that RF ablation therapy improves survival in patients with limited lung metastatic disease.

  19. The radiofrequency magnetic dipole discharge

    Science.gov (United States)

    Martines, E.; Zuin, M.; Marcante, M.; Cavazzana, R.; Fassina, A.; Spolaore, M.

    2016-05-01

    This paper describes a novel and simple concept of plasma source, which is able to produce a radiofrequency magnetized discharge with minimal power requirements. The source is based on the magnetron concept and uses a permanent magnet as an active electrode. The dipolar field produced by the magnet confines the electrons, which cause further ionization, thus producing a toroidally shaped plasma in the equatorial region around the electrode. A plasma can be ignited with such scheme with power levels as low as 5 W. Paschen curves have been built for four different working gases, showing that in Helium or Neon, plasma breakdown is easily obtained also at atmospheric pressure. The plasma properties have been measured using a balanced Langmuir probe, showing that the electron temperature is around 3-4 eV and higher in the cathode proximity. Plasma densities of the order of 1016 m-3 have been obtained, with a good positive scaling with applied power. Overall, the electron pressure appears to be strongly correlated with the magnetic field magnitude in the measurement point.

  20. Percutaneous radiofrequency thermal lumbar sympathectomy and its clinical use

    NARCIS (Netherlands)

    J. Pernak (Jamina)

    1988-01-01

    textabstractPercutaneous radiofrequency thermolesion techniques are commonly used in the treatment of chronic pain in different pain syndromes. There are many reports describing techniques of percutaneous radiofrequency thermolesion for denervation of central & spinal nerves (Mullan 1963), 1965,

  1. Correlations and coherence of monopolar EMG-currents of the medial gastrocnemius muscle in proximal and distal compartments

    Directory of Open Access Journals (Sweden)

    Vinzenz eVon Tscharner

    2014-06-01

    Full Text Available The penniform gastrocnemius muscle contains multiple heads in the proximal regions and the aponeuroses are attached to the Achilles tendon. The multiple head structure lead to the assumption that different regions of the muscle must be activated compartment wise. The purpose of this study was to compare the correlation and coherence of EMG-currents within and between proximal and distal compartments of the medial gastrocnemius muscle, which reflect underling synchronization of motor units. It was hypothesized and shown that phase-inverted signals represent a property that discriminates compartments. However, the phase-inverted and non-inverted signals showed values of correlations that were indicative for highly synchronized signals. The correlation increased with the complexity of the task and was higher for the calf-rising movement than while balancing in a tiptoe position. Because the muscle fibers do not span the whole length of the muscles one has to conclude that the MUs were synchronized by synchronizing the various motor nerves. This study shows that it is essential to measure monopolar signals and use non-isometric contractions to observe synchronization of the EMG-signals. One could speculate that compartmental differences can only be observed if more complex movements that generate rotational forces at the knee or ankle are used.

  2. 21 CFR 882.4400 - Radiofrequency lesion generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiofrequency lesion generator. 882.4400 Section... lesion generator. (a) Identification. A radiofrequency lesion generator is a device used to produce lesions in the nervous system or other tissue by the direct application of radiofrequency currents to...

  3. Radiofrequency Ablation for Treatment of Symptomatic Uterine Fibroids

    Directory of Open Access Journals (Sweden)

    Siân Jones

    2012-01-01

    Full Text Available The use of thermal energy-based systems to treat uterine fibroids has resulted in a plethora of devices that are less invasive and potentially as effective in reducing symptoms as traditional options such as myomectomy. Most thermal ablation devices involve hyperthermia (heating of tissue, which entails the conversion of an external electromagnetic or ultrasound waves into intracellular mechanical energy, generating heat. What has emerged from two decades of peer-reviewed research is the concept that hyperthermic fibroid ablation, regardless of the thermal energy source, can create large areas of necrosis within fibroids resulting in reductions in fibroid volume, associated symptoms and the need for reintervention. When a greater percentage of a fibroid's volume is ablated, symptomatic relief is more pronounced, quality of life increases, and it is more likely that such improvements will be durable. We review radiofrequency ablation (RFA, one modality of hyperthermic fibroid ablation.

  4. Radio-frequency integrated-circuit engineering

    CERN Document Server

    Nguyen, Cam

    2015-01-01

    Radio-Frequency Integrated-Circuit Engineering addresses the theory, analysis and design of passive and active RFIC's using Si-based CMOS and Bi-CMOS technologies, and other non-silicon based technologies. The materials covered are self-contained and presented in such detail that allows readers with only undergraduate electrical engineering knowledge in EM, RF, and circuits to understand and design RFICs. Organized into sixteen chapters, blending analog and microwave engineering, Radio-Frequency Integrated-Circuit Engineering emphasizes the microwave engineering approach for RFICs. Provide

  5. Bipolar transurethral resection versus monopolar transurethral resection for benign prostatic hypertrophy: a systematic review and meta-analysis.

    Science.gov (United States)

    Tang, Yin; Li, Jinhong; Pu, Chuanxiao; Bai, YunJin; Yuan, HaiChao; Wei, Qiang; Han, Ping

    2014-09-01

    To evaluate the efficacy and safety of monopolar (M-TURP) and bipolar (B-TURP) transurethral resection of the prostate in benign prostatic hypertrophy (BPH) patients. Eligible randomized controlled trials (RCTs) were identified from electronic databases without language restrictions. Database search, quality assessment, and data extraction were independently performed. The primary postoperative outcomes of topical M-TURP and B-TURP were maximum flow rate (Qmax) and/or International Prostate Symptom Score (IPSS). Safety was estimated by TUR syndrome; need for transfusion; clot retention; bladder neck contracture (BNC); urethral stricture (US); and catheter removal time. Efficacy and safety were investigated using the Review Manager. Thirty-one trials met the inclusion criteria. Pooled analysis revealed significant difference in efficacy between the M-TURP and B-TURP groups. Safety analysis revealed significant improvement in the TUR syndrome with B-TURP than with M-TURP. Pooled analysis revealed that clot retention was significantly higher in M-TURP than in B-TURP. Moreover, pooled analysis revealed no significant difference between both groups in the blood transfusion frequency or late complications (urethral strictures) and bladder neck constriction. This systematic review indicates that B-TURP was significantly better in the result of Qmax and for decreasing the incidence of TUR syndrome and clot retention. No significant differences were observed in the nature of adverse events such as transfusions, retention after catheter removal, and urethral complications between both groups. Thus, B-TURP is the next generation "gold standard" for benign prostatic obstruction (BPO) because it is associated with a lower rate of clinically relevant complications such as TUR syndrome and clot retention.

  6. Monopolin subunit Csm1 associates with MIND complex to establish monopolar attachment of sister kinetochores at meiosis I.

    Science.gov (United States)

    Sarkar, Sourav; Shenoy, Rajesh T; Dalgaard, Jacob Z; Newnham, Louise; Hoffmann, Eva; Millar, Jonathan B A; Arumugam, Prakash

    2013-01-01

    Sexually reproducing organisms halve their cellular ploidy during gametogenesis by undergoing a specialized form of cell division known as meiosis. During meiosis, a single round of DNA replication is followed by two rounds of nuclear divisions (referred to as meiosis I and II). While sister kinetochores bind to microtubules emanating from opposite spindle poles during mitosis, they bind to microtubules originating from the same spindle pole during meiosis I. This phenomenon is referred to as mono-orientation and is essential for setting up the reductional mode of chromosome segregation during meiosis I. In budding yeast, mono-orientation depends on a four component protein complex referred to as monopolin which consists of two nucleolar proteins Csm1 and Lrs4, meiosis-specific protein Mam1 of unknown function and casein kinase Hrr25. Monopolin complex binds to kinetochores during meiosis I and prevents bipolar attachments. Although monopolin associates with kinetochores during meiosis I, its binding site(s) on the kinetochore is not known and its mechanism of action has not been established. By carrying out an imaging-based screen we have found that the MIND complex, a component of the central kinetochore, is required for monopolin association with kinetochores during meiosis. Furthermore, we demonstrate that interaction of monopolin subunit Csm1 with the N-terminal domain of MIND complex subunit Dsn1, is essential for both the association of monopolin with kinetochores and for monopolar attachment of sister kinetochores during meiosis I. As such this provides the first functional evidence for a monopolin-binding site at the kinetochore.

  7. Monopolar photoelectromagnetic effect in Pb1-xSnxTe(In) under terahertz laser radiation

    Science.gov (United States)

    Chernichkin, V. I.; Ryabova, L. I.; Nicorici, A. V.; Khokhlov, D. R.

    2012-03-01

    We report on the observation of a new effect—the appearance of a galvanic signal in the narrow-gap semiconductor Pb1-xSnxTe(In) in the magnetic field under the action of strong 100 ns-long terahertz laser pulses. The signal changes its sign and kinetics as the temperature increases from 4.2 K to 25 K. This semiconductor possesses inversion symmetry of the crystalline lattice making impossible the observation of the magnetophotogalvanic effect which looks similar in its experimental manifestation. On the other hand, the laser quantum energy is much less than the bandgap of the semiconductor making the effect considerably different from the conventional Kikoin-Noskov photoelectromagnetic effect. Possible mechanisms responsible for the appearance of the effect are discussed.

  8. Permeabilization of plant tissues by monopolar pulsed electric fields: effect of frequency.

    Science.gov (United States)

    Asavasanti, Suvaluk; Ristenpart, William; Stroeve, Pieter; Barrett, Diane M

    2011-01-01

    Pulsed electric fields (PEF) nonthermally induce cell membrane permeabilization and thereby improve dehydration and extraction efficiencies in food plant materials. Effects of electrical field strength and number of pulses on plant tissue integrity have been studied extensively. Two previous studies on the effect of pulse frequency, however, did not provide a clear view: one study suggested no effect of frequency, while the other found a greater impact on tissue integrity at lower frequency. This study establishes the effect of pulse frequency on integrity of onion tissues. Changes in electrical characteristics, ion leakage, texture parameters, and percent weight loss were quantified for a wide range of pulse frequencies under conditions of fixed field strength and pulse number. Optical microscopy and viable-cell staining provided direct visualization of effects on individual cells. The key finding is that lower frequencies (f plant tissue. We hypothesize that cytoplasmic streaming plays a significant role in moving conductive ionic species from permeabilized cells to the intercellular space between plant cells, making subsequent pulses more efficacious at sufficiently low frequencies. The results suggest that decreasing the pulse frequency in PEF may minimize the number of pulses needed to achieve a desired amount of permeabilization, thus lowering the total energy consumption. Practical Application: PEF cause pores to be formed in plant cell membranes, thereby improve moisture removal and potential extraction of desirable components. This study used in situ microscopic evaluation of onion cells, as they were pulsed with electric fields at different frequencies, to determine whether frequency was an important parameter. We illustrate that membranes were more effectively broken at lower frequencies as compared to higher frequencies. Application of this information will allow for improved design of PEF systems for more energy efficient dehydration or extraction of

  9. Managing turbinate hypertrophy: coblation vs. radiofrequency treatment.

    Science.gov (United States)

    Passali, D; Loglisci, M; Politi, L; Passali, G C; Kern, E

    2016-06-01

    The role of inferior turbinate hypertrophy in the reduction of nasal airflow is well established. Although chronic nasal obstruction is not life- threatening, it significantly impairs patients' quality of life, affecting many aspects of daily activities; therefore, patients seek medical intervention. 40 patients were selected (27 males and 13 females) between 27 and 64 years of age with a symptom of nasal obstruction. The patients were divided in two groups: Group 1: coblation, 25 patients (18 males and 7 females); Group 2: radiofrequency, 15 patients (7 males and 6 females). These 40 patients were followed for 3 years. Patients were analyzed using both subjective and objective methods. The visual analog scale (VAS) subjective data and objective data including both active anterior rhinomanometry and acoustic rhinometry were recorded and analyzed. Data were collected pre-operatively and at 1 and 3 years post-operatively. According to our data, both coblation and radiofrequency turbinate reduction benefit patients with good results. The complications, found during the follow-up, are limited to minimal bleeding and crusting. Coblation and radiofrequency were significantly less painful than others procedures during the early post-operative period. In our study, both coblation and radiofrequency provide an improvement in nasal airflow with a reduction in nasal obstructive symptoms in the short term, but their efficacy tended to decrease within 3 years.

  10. Radiofrequency for the treatment of liver tumours.

    NARCIS (Netherlands)

    Ruers, T.J.M.; Jong, K.P. de; Ijzermans, J.N.M.

    2005-01-01

    Resection should still be considered the gold standard for many liver tumours. There is, however, growing interest in the use of radiofrequency (RFA) for the treatment of liver tumours. By RFA, tumour tissue can be destructed selectively without significant damage to vascular structures in the

  11. Radiofrequency for the treatment of liver tumours

    NARCIS (Netherlands)

    Ruers, TJM; de Jong, KP; Ijzermans, JNM

    2005-01-01

    Resection should still be considered the gold standard for many liver tumours. There is, however, growing interest in the use of radiofrequency (RFA) for the treatment of liver tumours. By RFA, tumour tissue can be destructed selectively without significant damage to vascular structures in the

  12. Superconducting Radiofrequency (SRF) Acceleration Technology

    Data.gov (United States)

    Federal Laboratory Consortium — SRF cavities enable accelerators to increase particle beam energy levels while minimizing the use of electrical power by all but eliminating electrical resistance....

  13. Modelado y Simulación del Procedimiento de Electrocirugía Monopolar Laparoscópica para Estimación de Riesgos en Pacientes

    OpenAIRE

    Valenzuela Bautista, Omar J.

    2004-01-01

    Esta tesis presenta un modelo de los riesgos a los que el paciente está expuesto durante una electrocirugía monopolar. Avances tecnológicos en el diseño de ESU´s (unidades de electrocirugía) proporcionan una alta confiabilidad en intervenciones quirÚrgicas mediante esta tecnología. El modelo implementado para representar los órganos internos involucrados en el procedimiento, así como el modelo para representar las extremidades del cuerpo humano están determinados por un circuito eléctrico RC....

  14. Artículo Original: Lesión tisular debida a dispersión térmica por el uso de electrodos monopolare

    OpenAIRE

    Azúa Córdova, Gonzalo; Zúñiga Montero, Marco; Chaves Chaves, Dennis; Quirós Alpízar, José Luis

    2016-01-01

    El uso de unidades de electrocirugía permite di-sección, corte y hemostasia debido al calor gene-rado por el flujo de la corriente eléctrica a través del tejido, efecto denominado diatermia. Este ca-lor, se difunde en un fenómeno conocido como dispersión térmica al tejido vecino, pudiendo le-sionarlo. Comparadas con otras modalidades, las unidades monopolares son las que producen ma-yor lesión tisular por dispersión térmica y dentro de las diferentes modalidades de uso que permiten estas unid...

  15. Comparación de las curvas de reclutamiento de unidades motoras extraídas con M-waves monopolares y bipolares

    OpenAIRE

    Erro Vicente, Leire

    2015-01-01

    El objetivo de este proyecto fin de máster es el estudio y caracterización de curvas de reclutamiento de unidades motoras a partir de M-waves monopolares y bipolares. En este proyecto, se registraron las M-waves de 20 sujetos masculinos de dos músculos del cuádriceps femoral (vasto lateral y vasto medial). A los sujetos se les aplicaron pulsos eléctricos de intensidad creciente desde los 10 mA hasta la intensidad que produce el reclutamiento completo de todas las unidades motoras....

  16. The optimal radiofrequency temperature in radiofrequency thermocoagulation for idiopathic trigeminal neuralgia

    Science.gov (United States)

    Tang, Yuan-Zhang; Yang, Li-Qiang; Yue, Jian-Ning; Wang, Xiao-Ping; HE, Liang-Liang; NI, Jia-Xiang

    2016-01-01

    Abstract Objective: Our previous study evaluated the effectiveness and safety of radiofrequency thermocoagulation (RFT) of trigeminal gasserian ganglion for idiopathic trigeminal neuralgia (ITN). The aim of this study was to evaluate the optimal radiofrequency temperature of computed tomography (CT)-guided RFT for treatment of ITN. Methods: A retrospective study of patients with ITN treated with a single CT-guided RFT procedure between January 2002 and December 2013. Patients were divided into ≤75 °C, 75 °C, and ≥80 °C groups according to the highest radiofrequency temperature used. Pain relief was graded from poor to excellent, and facial numbness/dysesthesia from I (absent) to IV (most severe). Results: A total of 1161 RFT procedures were undertaken in the 1137 patients. The mean follow-up time was 46 ± 31 months. There were no significant differences in the rate of excellent pain relief according to the radiofrequency temperature used. However, more patients experienced with no facial numbness or facial numbness gradually resolved and those patients treated at 75 °C had a lower rate of grade IV facial numbness/dysesthesia than other groups. Conclusions: The optimal radiofrequency temperature to maximize pain relief and minimize facial numbness or dysesthesia may be 75 °C, but this requires confirmation. PMID:27428194

  17. Radio-frequency ion deflector for mass separation

    Energy Technology Data Exchange (ETDEWEB)

    Schlösser, Magnus, E-mail: magnus.schloesser@googlemail.com; Rudnev, Vitaly; Ureña, Ángel González, E-mail: laseres@pluri.ucm.es [Unidad de Láseres y Haces Moleculares, Instituto Plurisdisciplinar, Universidad Complutense de Madrid, Madrid 28040 (Spain)

    2015-10-15

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

  18. Global model of a radiofrequency H2 plasma in DENISE

    Science.gov (United States)

    Zorat, Roberto; Goss, Jonathan; Boilson, Deirdre; Vender, David

    2000-05-01

    A global model of a radiofrequency (rf) inductively coupled H2 plasma discharge in the Deuterium Negative Ion Source Experiment (DENISE) has been developed using the numerical code `Global Model Solver' (GMS). The volume-averaged energy and particle balance equations, along with the quasi-neutrality condition, are numerically solved to determine the averaged densities of all the species included in the model and the electron temperature. The effects of the multicusp magnetic field and of the asymmetry of the source chamber are considered in the model. The values of the volume-averaged electron density and the average electron temperature obtained are compared to experimental measurements in the pressure and input power ranges of interest and a reasonably good agreement is found.

  19. 75 FR 80827 - Compliance Policy Guide; Radiofrequency Identification Feasibility Studies and Pilot Programs for...

    Science.gov (United States)

    2010-12-23

    ...; Radiofrequency Identification Feasibility Studies and Pilot Programs for Drugs; Notice To Extend Expiration Date...) Sec. 400.210 entitled ``Radiofrequency Identification (RFID) Feasibility Studies and Pilot Programs... ``Radiofrequency Identification (RFID) Feasibility Studies and Pilot Programs for Drugs.'' Previous extensions...

  20. Fraxelated radiofrequency device for acne scars

    Science.gov (United States)

    Rao, Babar K.; Khokher, Sairah

    2012-09-01

    Acne scars can be improved with various treatments such as topical creams, chemical peels, dermal fillers, microdermabrasion, laser, and radiofrequency devices. Some of these treatments especially lasers and deep chemical peels can have significant side effects such as post inflammatory hyperpigmentation in darker skin types. Fraxelated RF Laser devices have been reported to have lower incidence of side effects in all skin phototypes. Nine patients between ages 18 and 35 of various skin phototypes were selected from a private practice and treated with a RF fraxelated device (E-matrix) for acne scars. Outcomes were measured by physician observation, subjective feedback received by patients, and comparison of before and after photographs. In this small group of patients with various skin phototypes, fraxelated radiofrequency device improved acne scars with minimal side effects and downtime.

  1. Radiofrequency and microwave radiation in the microelectronics industry.

    Science.gov (United States)

    Cohen, R

    1986-01-01

    The microscopic precision required to produce minute integrated circuits is dependent on several processes utilizing radiofrequency and microwave radiation. This article provides a review of radiofrequency and microwave exposures in microelectronics and of the physical and biologic properties of these types of radiation; summarizes the existing, relevant medical literature; and provides the clinician with guidelines for diagnosis and treatment of excessive exposures to microwave and radiofrequency radiation.

  2. ROLE OF RADIOFREQUENCY ABLATION IN ADENOMA SEBACEUM

    Directory of Open Access Journals (Sweden)

    Ch. Madh

    2016-03-01

    Full Text Available Adenoma sebaceum, pathognomonic of tuberous sclerosis, are tiny angiofibromas which commonly occur over central part of face. Recurrence after treatment is common and hence a need for inexpensive, safe and efficient treatment is required. Radiofrequency ablation is a safe and an economical procedure and has been known to cause less scarring with good aesthetic results compared to other ablative methods such as electrocautery.

  3. Radiofrequency tonsillotomy in Sweden 2009-2012.

    Science.gov (United States)

    Sunnergren, Ola; Hemlin, Claes; Ericsson, Elisabeth; Hessén-Söderman, Anne-Charlotte; Hultcrantz, Elisabeth; Odhagen, Erik; Stalfors, Joacim

    2014-06-01

    The Swedish National Registry for Tonsil Surgery has been operational since 1997. All ENT clinics in Sweden are encouraged to submit data for all patients scheduled for tonsil surgery. Preoperatively, age, gender and indication are recorded. Postoperatively, method (tonsillectomy or tonsillotomy), technique, and perioperative complications are recorded. Postoperative bleedings, pain, infections, and symptom relief are assessed through questionnaires. An earlier report from this registry showed that tonsillotomy had become more common than tonsillectomy in children with tonsil-related upper airway obstruction. The aim of this study was to categorize which instruments were used for tonsillotomy in Sweden and to compare their outcome and complication rate. All children 2-18 years, reported to the registry from March 2009 until September 2012, who underwent tonsillotomy on the indication upper airway obstruction, were included in the study. 1,676 patients were identified. In 1,602 cases (96%), a radiofrequency instrument was used. The postoperative bleeding rate was low (1.2%) and the degree of symptom relief was high (95.1%). Three different radiofrequency instruments (ArthroCare Coblation(®), Ellman Surgitron(®), and Sutter CURIS(®)) were used in 96% of the patients. There were no significant differences in the number of postoperative bleedings, postoperative infections or symptom relief between the instruments. The only difference found was in the number of days on analgesics, where more days were registered after use of Coblation(®). In Sweden, radiofrequency tonsillotomy is the dominant surgical technique used for tonsil hypertrophy causing upper airway obstruction in children. There are no significant differences in outcome between the different radiofrequency instruments except for number of days on analgesics after surgery.

  4. Radiofrequency Microtenotomy for Elbow Epicondylitis: Midterm Results.

    Science.gov (United States)

    Tasto, James P; Richmond, John M; Cummings, Jeffrey R; Hardesty, Renee; Amiel, David

    2016-01-01

    We conducted a prospective, nonrandomized, single-center clinical study to evaluate the safety and midterm effectiveness of microtenotomy using a radiofrequency probe to treat chronic tendinosis of the elbow. All patients had failed conservative treatment for 6 months. The radiofrequency-based microtenotomy was performed using the Topaz Microdebrider (ArthroCare). Patients were followed annually for up to 9 years postoperatively. Pain status was documented using a visual analog scale self-reported measure. Eighty consecutive patients with tendinosis of the elbow were enrolled; 69 patients were treated for lateral epicondylitis and 11 for medial epicondylitis. The duration of follow-up ranged from 6 months to 9 years (mean, 2.5 years). Ninety-one percent of the patients reported a successful outcome. Within the lateral epicondylitis group, the preoperative visual analog scale improved from 6.9 to 1.3 postoperatively and demonstrated an 81% improvement (P ≤ .01). For the medial epicondylitis patients, the preoperative visual analog scale improved from 6.1 to 1.3 after surgery, a 79% improvement (P ≤ .01). No complications were reported. Radiofrequency-based microtenotomy is a safe and effective procedure for elbow epicondylitis. The results are durable with successful outcomes observed at 9 years after surgery.

  5. Large-signal model of the bilayer graphene field-effect transistor targeting radio-frequency applications: Theory versus experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pasadas, Francisco, E-mail: Francisco.Pasadas@uab.cat; Jiménez, David [Departament d' Enginyeria Electrònica, Escola d' Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain)

    2015-12-28

    Bilayer graphene is a promising material for radio-frequency transistors because its energy gap might result in a better current saturation than the monolayer graphene. Because the great deal of interest in this technology, especially for flexible radio-frequency applications, gaining control of it requires the formulation of appropriate models for the drain current, charge, and capacitance. In this work, we have developed them for a dual-gated bilayer graphene field-effect transistor. A drift-diffusion mechanism for the carrier transport has been considered coupled with an appropriate field-effect model taking into account the electronic properties of the bilayer graphene. Extrinsic resistances have been included considering the formation of a Schottky barrier at the metal-bilayer graphene interface. The proposed model has been benchmarked against experimental prototype transistors, discussing the main figures of merit targeting radio-frequency applications.

  6. Endovascular Radiofrequency Ablation for Varicose Veins

    Science.gov (United States)

    2011-01-01

    or worse as other chronic diseases such as back pain and arthritis. Lower limb VV is a very common disease affecting adults – estimated to be the 7th most common reason for physician referral in the US. There is a very strong familial predisposition to VV. The risk in offspring is 90% if both parents affected, 20% when neither affected and 45% (25% boys, 62% girls) if one parent affected. The prevalence of VV worldwide ranges from 5% to 15% among men and 3% to 29% among women varying by the age, gender and ethnicity of the study population, survey methods and disease definition and measurement. The annual incidence of VV estimated from the Framingham Study was reported to be 2.6% among women and 1.9% among men and did not vary within the age range (40-89 years) studied. Approximately 1% of the adult population has a stasis ulcer of venous origin at any one time with 4% at risk. The majority of leg ulcer patients are elderly with simple superficial vein reflux. Stasis ulcers are often lengthy medical problems and can last for several years and, despite effective compression therapy and multilayer bandaging are associated with high recurrence rates. Recent trials involving surgical treatment of superficial vein reflux have resulted in healing and significantly reduced recurrence rates. Endovascular Radiofrequency Ablation for Varicose Veins RFA is an image-guided minimally invasive treatment alternative to surgical stripping of superficial venous reflux. RFA does not require an operating room or general anaesthesia and has been performed in an outpatient setting by a variety of medical specialties including surgeons and interventional radiologists. Rather than surgically removing the vein, RFA works by destroying or ablating the refluxing vein segment using thermal energy delivered through a radiofrequency catheter. Prior to performing RFA, color-flow Doppler ultrasonography is used to confirm and map all areas of venous reflux to devise a safe and effective

  7. Radiofrequency ablation of the liver: effect of variation of portal venous blood flow on lesion size in an in-vitro perfused bovine liver.

    Science.gov (United States)

    Huang, Liping; Dodd, Gerald D; Lanctot, Anthony C

    2012-08-01

    An in vitro perfused bovine liver model was used to evaluate the relationship between the sizes of radiofrequency ablation lesions and variation in portal venous blood flow. Fourteen bovine livers were perfused with autologous heparinized blood at 37°C and 40% to 50% oxygenation via the portal vein. Flow rates were adjusted from 10 to 50 mL/min/100 g tissue. A 480-kHz generator and a 3.0-cm monopolar internally cooled electrode were used to create 57 ablations. The long-axis diameter, short-axis diameter (SAD), and volume of each ablation zone were measured and calculated from the dissected livers. Correlations between SAD, long-axis diameter, and volume versus blood flow were assessed using linear regression analysis. SAD and lesion volume demonstrated inverse linear correlations with blood flow (for SAD, y = -0.044x + 3.925, r = 0.836, P portal venous blood flow, with an average 4.4-mm change in SAD and an average 5.6-cm(3) change in volume for each 10 mL/min/100 g change in flow rate. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

  8. A cooled intraesophageal balloon to prevent thermal injury during endocardial surgical radiofrequency ablation of the left atrium: a finite element study

    Energy Technology Data Exchange (ETDEWEB)

    Berjano, Enrique J [Center for Research and Innovation on Bioengineering, Valencia Polytechnic University, Camino de Vera s/n, 46022 Valencia (Spain); Hornero, Fernando [Cardiac Surgery Department, Valencia University General Hospital, Avd Tres Cruces s/n, 46014, Valencia (Spain)

    2005-10-21

    Recent clinical studies on intraoperative monopolar radiofrequency ablation of atrial fibrillation have reported some cases of injury to the esophagus. The aim of this study was to perform computer simulations using three-dimensional finite element models in order to investigate the feasibility of a cooled intraesophageal balloon appropriately placed to prevent injury. The models included atrial tissue and a fragment of esophagus and lung linked by connective tissue. The lesion depth in the esophagus was assessed using a 50 deg. C isotherm and expressed as a percentage of thickness of the esophageal wall. The results are as follows: (1) chilling the esophagus by means of a cooled balloon placed in the lumen minimizes the lesion in the esophageal wall compared to the cases in which no balloon is used (a collapsed esophagus) and with a non-cooled balloon; (2) the temperature of the cooling fluid has a more significant effect on the minimization of the lesion than the rate of cooling (the thermal transfer coefficient for forced convection); and (3) pre-cooling periods previous to RF ablation do not represent a significant improvement. Finally, the results also suggest that the use of a cooled balloon could affect the transmurality of the atrial lesion, especially in the cases where the atrium is of considerable thickness. (note)

  9. The efficacy of capacitive radio-frequency diathermy in reducing buttock and posterior thigh cellulite measured through the cellulite severity scale.

    Science.gov (United States)

    De La Casa Almeida, Maria; Suarez Serrano, Carmen; Medrano Sánchez, Ester Maria; Diaz Mohedo, Esther; Chamorro Moriana, Gema; Rebollo Salas, Manuel

    2014-10-01

    Cellulite, despite its high prevalence in women, has been subjected to very little research, while the majority has been carried out using unvalidated evaluation tools. To determine the efficacy of capacitive radio-frequency diathermy (CRFD) in reducing buttock and posterior thigh cellulite and to verify its relationship with the reduction of body weight. Design: Experimental clinical study consists of two parallel groups. Totally 54 lower limbs of 27 women (26.41 ± 6.16 years) were considered with each patient's two limbs being assigned one to each group via simple random distribution. First group received local application of CRFD (30 min) and the second received the same treatment followed by a supplementary whole-segment application of CRFD (20 min). Each limb received 20 sessions, twice a week. Cellulite Severity Scale dimensions score, weight and Body Mass Index (BMI) were taken for the evaluation of the study. A significance of p less than 0.01 was observed for all the variables in both groups, thereby demonstrating the effectiveness of both the treatments; no significant differences were observed between groups (p > 0.05). Monopolar static application of CRFD is effective in reducing buttock and posterior thigh cellulite. It appears that there is not necessarily any relationship between weight loss, decreased BMI and reduction in cellulite.

  10. Real-time monitoring of radiofrequency ablation of liver tumors using thermal-dose calculation by MR temperature imaging: initial results in nine patients, including follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit-Coiffe, Matthieu; Quesson, Bruno; Moonen, Chrit T.W. [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Laumonier, Herve; Trillaud, Herve [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service de Radiologie, Hopital Saint-Andre, CHU Bordeaux, Bordeaux (France); Seror, Olivier [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service de Radiologie, Hopital Jean Verdier, Bondy (France); Sesay, Musa-Bahazid [Service d' Anesthesie Reanimation III, Hopital Pellegrin, CHU Bordeaux, Bordeaux (France); Grenier, Nicolas [Universite Victor Segalen Bordeaux 2, Laboratoire Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231, Bordeaux Cedex (France); Service d' Imagerie Diagnostique et Therapeutique de l' Adulte, Hopital Pellegrin, CHU Bordeaux, Bordeaux (France)

    2010-01-15

    To assess the practical feasibility and effectiveness of real-time magnetic resonance (MR) temperature monitoring for the radiofrequency (RF) ablation of liver tumours in a clinical setting, nine patients (aged 49-87 years, five men and four women) with one malignant tumour (14-50 mm, eight hepatocellular carcinomas and one colorectal metastasis), were treated by 12-min RF ablation using a 1.5-T closed magnet for real-time temperature monitoring. The clinical monopolar RF device was filtered at 64 MHz to avoid electromagnetic interference. Real-time computation of thermal-dose (TD) maps, based on Sapareto and Dewey's equation, was studied to determine its ability to provide a clear end-point of the RF procedure. Absence of local recurrence on follow-up MR images obtained 45 days after the RF ablation was used to assess the apoptotic and necrotic prediction obtained by real-time TD maps. Seven out of nine tumours were completely ablated according to the real-time TD maps. Compared with 45-day follow-up MR images, TD maps accurately predicted two primary treatment failures, but were not relevant in the later progression of one case of secondary local tumour. The real-time TD concept is a feasible and promising monitoring method for the RF ablation of liver tumours. (orig.)

  11. Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Cosedis Nielsen, Jens; Johannessen, Arne; Raatikainen, Pekka;

    2012-01-01

    There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation.......There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation....

  12. CT-guided radiofrequency tumor ablation in children

    Energy Technology Data Exchange (ETDEWEB)

    Botsa, Evanthia [National and Kapodistrian University of Athens, First Pediatric Clinic, Agia Sofia Children' s Hospital, Athens (Greece); Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas [Sotiria General Hospital for Chest Diseases, Department of Medical Imaging and Interventional Radiology, Athens (Greece); Koutsogiannis, Ioannis [General Military Hospital NIMTS, Department of Medical Imaging, Athens (Greece); Ziakas, Panayiotis D. [Warren Alpert Medical School of Brown University Rhode Island Hospital, Division of Infectious Diseases, Providence, RI (United States); Alexopoulou, Efthimia [Attikon University Hospital, Second Department of Radiology, Athens University School of Medicine, Athens (Greece)

    2014-11-15

    Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

  13. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    CERN Document Server

    Avva, J; Miki, C; Saltzberg, D; Vieregg, A G

    2014-01-01

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. The measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as the most promising northern site for UHE neutrino detection.

  14. Achieving low-emissivity materials with high transmission for broadband radio-frequency signals.

    Science.gov (United States)

    Liu, Liu; Chang, Huiting; Xu, Tao; Song, Yanan; Zhang, Chi; Hang, Zhi Hong; Hu, Xinhua

    2017-07-07

    The use of low-emissivity (low-e) materials in modern buildings is an extremely efficient way to save energy. However, such materials are coated by metallic films, which can strongly block radio-frequency signals and prevent indoor-outdoor wireless communication. Here, we demonstrate that, when specially-designed metallic metasurfaces are covered on them, the low-e materials can remain low emissivity for thermal radiation and allow very high transmission for a broad band of radio-frequency signals. It is found that the application of air-connected metasurfaces with subwavelength periods is critical to the observed high transmission. Such effects disappear if periods are comparable to wavelengths or metal-connected structures are utilized. The conclusion is supported by both simulations and experiments. Advantages such as easy to process, low cost, large-area fabrication and design versatility of the metasurface make it a promising candidate to solve the indoor outdoor communication problem.

  15. Intraoperative radiofrequency ablation with or without tumorectomy for hepatocellular carcinoma in locations dif ifcult for a percutaneous approach

    Institute of Scientific and Technical Information of China (English)

    Hyung Ook Kim; Seung Kwon Kim; Byung Ho Son; Chang Hak Yoo; Hyun Pyo Hong; Yong Kyun Cho; Byung Ik Kim

    2009-01-01

    BACKGROUND: Although hepatic resection is widely accepted as a proper modality for treating hepatocellular carcinoma (HCC), a majority of patients are unable to undergo surgical resection due to various tumor and patient factors. Radiofrequency ablation (RFA) has mostly been used as a therapeutic alternative to resection for treating HCC. The objective of this study was to evaluate the results of intraoperative RFA for HCCs in locations dififcult for a percutaneous approach. METHODS: Eight patients (male, seven;age, 49-67 years) with 8 HCCs in dififcult locations were treated by intraoperative RFA. Six of the patients had local tumor progression after initial transarterial chemoembolization or ultrasound (US) guided percutaneous RFA. The locations of the tumors were hepatic dome in six patients, posterior subcapsule in one, and caudate lobe in one. The tumor size was 2.0 to 6.4 cm (mean, 3.9 cm). Intraoperative RFA was performed at the tumor itself and an anticipated resection line under US guidance with 3 cm monopolar single or clustered internally cooled electrodes. Tumor resection was performed in six patients. One month later, treatment response was assessed by contrast material-enhanced computed tomography (CT). CT studies were performed every 2 or 3 months after RFA. RESULTS: RFA was technically successful in all tumors, and the contrast-enhanced CT images acquired one month later showed complete disappearance of tumor enhancement. One pneumothorax occurred. After a median follow-up of 18 months (range, 6-30 months), no tumors showed local progression. During the follow-up period, four new recurrent tumors were observed in three patients. Four patients were alive at the time of this report and the other four died of hepatorenal syndrome, liver failure, and progression of new recurrent tumors. CONCLUSION: Intraoperative RFA with tumor resection can be an alterative treatment option for HCC in locations dififcult for a percutaneous approach.

  16. Local recurrence following hepatic radiofrequency ablation: diagnosis and treatment; Diagnostik und Therapie von Lokalrezidiven nach Radiofrequenzablation an der Leber

    Energy Technology Data Exchange (ETDEWEB)

    Eisele, R.M.; Schumacher, G.; Neuhaus, P. [Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie, Charite Campus Virchow-Klinikum, Berlin (Germany)

    2008-11-15

    Background: radiofrequency ablation (RFA) is an established treatment in irresectable malignant liver disease. The most severe constraint is re-occurrence at site of ablation. Whereas factors influencing local recurrence rates have been determined, little is known about the timespan within local recurrence (LR) is to be expected, and further treatment options. Patients and methods: in the presented trial, RFA was performed using two different types of monopolar devices. All procedures were conducted under general anesthesia. Follow-up examinations took part after 3, 6, 12 months and annually. Results: 149 RFAs in 125 patients were enrolled. Percutaneous access was chosen in 74 cases (50%), laparoscopic in 15 (10%) and open surgical in 60 cases (40%). Indications were primary liver tumors in 99 (67%) and metastases in 50 cases (33%). Overall LR rate was 29.5% on a per-patient- and 19.7% on a per-tumor-basis. The majority of LRs (71%) occurred within 9 months after the RFA despite observations beyond 2 years following the treatment (Figure 1). 75% of LR could be treated by targeted interventions (RFA, n = 18, 53%, laser-induced thermo therapy (LITT), n = 2.6%, brachytherapy, n = 2.6% or transarterial chemoembolisation (TACE), n = 2.6%) or resection (n = 6.18%); 4 patients underwent liver transplantation (12%) (Figure 2). Conclusion: local recurrence can be considered rather common after RFA. It is observed during the first 3 years of the follow-up period, and schedules have to be designed according to this finding. Follow-on treatment is feasible in approximately 75% of LR. Factors influencing the secondary success of repeated procedures have yet to be determined. (orig.)

  17. Radio-frequency measurement in semiconductor quantum computation

    Science.gov (United States)

    Han, TianYi; Chen, MingBo; Cao, Gang; Li, HaiOu; Xiao, Ming; Guo, GuoPing

    2017-05-01

    Semiconductor quantum dots have attracted wide interest for the potential realization of quantum computation. To realize efficient quantum computation, fast manipulation and the corresponding readout are necessary. In the past few decades, considerable progress of quantum manipulation has been achieved experimentally. To meet the requirements of high-speed readout, radio-frequency (RF) measurement has been developed in recent years, such as RF-QPC (radio-frequency quantum point contact) and RF-DGS (radio-frequency dispersive gate sensor). Here we specifically demonstrate the principle of the radio-frequency reflectometry, then review the development and applications of RF measurement, which provides a feasible way to achieve high-bandwidth readout in quantum coherent control and also enriches the methods to study these artificial mesoscopic quantum systems. Finally, we prospect the future usage of radio-frequency reflectometry in scaling-up of the quantum computing models.

  18. Radiofrequency ablation for benign thyroid nodules.

    Science.gov (United States)

    Bernardi, S; Stacul, F; Zecchin, M; Dobrinja, C; Zanconati, F; Fabris, B

    2016-09-01

    Benign thyroid nodules are an extremely common occurrence. Radiofrequency ablation (RFA) is gaining ground as an effective technique for their treatment, in case they become symptomatic. Here we review what are the current indications to RFA, its outcomes in terms of efficacy, tolerability, and cost, and also how it compares to the other conventional and experimental treatment modalities for benign thyroid nodules. Moreover, we will also address the issue of treating with this technique patients with cardiac pacemakers (PM) or implantable cardioverter-defibrillators (ICD), as it is a rather frequent occurrence that has never been addressed in detail in the literature.

  19. Monopolar versus bipolar transurethral resection of prostate for benign prostatic hyperplasia: Operative outcomes and surgeon preferences, a real-world scenario

    Science.gov (United States)

    Madduri, Vijay Kumar Sarma; Bera, Malay Kumar; Pal, Dilip Kumar

    2016-01-01

    Context: Monopolar transurethral resection of prostate (M-TURP) is considered the gold standard for the management of bladder outlet obstruction due to benign prostatic hyperplasia. Its newly introduced modification, bipolar TURP (B-TURP), promises to overcome its most prominent shortcomings, namely bleeding and dilutional hyponatremia. Literature is conflicting regarding merits of B-TURP over M-TURP. Aims: To find a difference, if any, in perioperative outcomes between M-TURP and B-TURP in a real-wold setting. Settings and Design: Prospective nonrandomized study. Subjects and Methods: Operative outcomes of patients undergoing M-TURP and B-TURP from February 2014 to October 2015 were compared. Statistical Analysis Used: Categorical data were compared by Fischer exact test and numerical data were compared by independent samples Mann–Whitney U-test. P <0.05 was considered statistically significant. Results: The mean size of prostate operated by bipolar technology was significantly greater than those operated by monopolar technology (38.12 ± 9.59 cc vs. 66.49 ± 22.95 cc; P < 0.001). The mean fall in postoperative serum sodium concentration was 0.99 ± 0.76 mEq/L for the B-TURP group as compared to 3.60 ± 2.89 mEq/L for the M-TURP group (P < 0.001). The mean drop in postoperative hemoglobin concentration (P = 0.28) was statistically insignificant, even though larger glands were operated by B-TURP. There were three instances of the transurethral resection (TUR) syndrome in the M-TURP group whereas no TUR syndrome occurred in the B-TURP group. Conclusions: In spite of various contrary viewpoints in literature, surgeons prefer to operate on larger prostates using bipolar technology. B-TURP definitely reduces the incidence of bleeding and dilutional hyponatremia, making it a contender to replace M-TURP as the new gold standard. PMID:27453650

  20. Bipolar plasma vaporization versus monopolar TUR and "cold-knife" TUI in secondary bladder neck sclerosis - an evidence based, retrospective critical comparison in a single center clinical setting.

    Science.gov (United States)

    Moldoveanu, C; Geavlete, B; Jecu, M; Stanescu, F; Adou, L; Bulai, C; Ene, C; Geavlete, P

    2014-03-15

    A long term, retrospective study was performed aiming to outline a critical comparison concerning the efficacy, safety and durability of the bipolar plasma vaporization (BPV), standard monopolar transurethral resection (TUR) and "cold-knife" "star" transurethral incision (TUI) in secondary bladder neck sclerosis (BNS) cases. Of the 126 patients included in the trial based on maximum flow rate (Qmax) below 10 mL/s and International Prostate Symptom Score (IPSS) over 19, classical resection was performed in 46 cases, "cold-knife" TUI in 37 cases and bipolar vaporization in 43 patients. The evaluation protocol comprised IPSS, QoL (quality of life) score, Qmax and PVR (post-voiding residual urinary volume) assessment performed at 1, 3, 6, 12, 18 and 24 months after the initial intervention. Significant intraoperative complications (capsular perforation - 8.7%; bleeding - 4.3%) occurred secondary to monopolar resection. "Star" TUI was the fastest technique, followed by plasma-button vaporization (7.2 and 11.4 versus 16.5 minutes). BPV and TUI patients benefitted from the shortest catheterization periods (0.75 and 1 versus 2.0 days) and hospital stays (1.0 and 1.25 versus 2.0 days). Immediate postoperative adverse events consisted of hematuria (6.5% of the TUR cases) and acute urinary retention (8.1% of the TUI group). Significantly higher long term BNS recurrence rates requiring re-treatment were established in the TUI (18.7%) and TUR (12.8%) series by comparison to BPV (5.4%). Among patients that completed the follow-up protocol, equivalent IPSS, QoL, Qmax and PVR features were determined in the 3 study arms. The plasma vaporization approach was confirmed as a successful match to conventional TUR and "cold-knife" TUI in terms of surgical safety profile, postoperative recovery, therapeutic durability and urodynamic and symptom score parameters.

  1. Láser, luz pulsada, radiofrecuencia y otras fuentes de energía: ¿complemento ocasional a la Cirugía Plástica? Laser, IPL (Intense Pulsed light, radiofrequency and other energy sources: Occasional complement for Plastic Surgery?

    Directory of Open Access Journals (Sweden)

    R. García Pumarino Santofimia

    2008-03-01

    Full Text Available Las consultas de Cirugía Plástica se están llenando de pacientes con expectativas crecientes acerca de los resultados de los tratamientos con distintas fuentes de energía. El objetivo es conseguir un elevado índice de beneficio cosmético en el mínimo número de sesiones y con un tiempo breve de recuperación. Los tres elementos sobre los que podemos trabajar son el soporte, la textura y las alteraciones pigmentarias de la piel. Los sistemas de luz y de radiofrecuencia permiten combinar distintos niveles de tratamiento, como son la dermis profunda, la dermis papilar y la epidermis y constituyen un complemento a los procedimientos quirúrgicos, aportando un concepto "biológico" al estimular la regeneración y la neocolagenogénesis. En este artículo se describen los fundamentos de estos tratamientos complementarios que son de obligado conocimiento para los cirujanos plásticos.Plastic Surgery offices are currently full of patients who have growing expectations about the outcome of the treatments made with different energy sources. The aim is to get a high cosmetic benefit index with the lowest number of sessions and recovery time. The three elements we can work with are tone, texture and pigmentary skin disorders. The light and radiofrequency systems allow the combination of different treatment levels, such as deep dermis, papillary dermis and epidermis. These systems represent a complement for the surgical procedures, providing a "biological" concept as they stimulate the tissue regeneration and the neocollagenosis. In this article we describe the fundamentals of these complementary treatments for plastic surgeons.

  2. Radio-frequency scanning tunnelling microscopy.

    Science.gov (United States)

    Kemiktarak, U; Ndukum, T; Schwab, K C; Ekinci, K L

    2007-11-01

    The scanning tunnelling microscope (STM) relies on localized electron tunnelling between a sharp probe tip and a conducting sample to attain atomic-scale spatial resolution. In the 25-year period since its invention, the STM has helped uncover a wealth of phenomena in diverse physical systems--ranging from semiconductors to superconductors to atomic and molecular nanosystems. A severe limitation in scanning tunnelling microscopy is the low temporal resolution, originating from the diminished high-frequency response of the tunnel current readout circuitry. Here we overcome this limitation by measuring the reflection from a resonant inductor-capacitor circuit in which the tunnel junction is embedded, and demonstrate electronic bandwidths as high as 10 MHz. This approximately 100-fold bandwidth improvement on the state of the art translates into fast surface topography as well as delicate measurements in mesoscopic electronics and mechanics. Broadband noise measurements across the tunnel junction using this radio-frequency STM have allowed us to perform thermometry at the nanometre scale. Furthermore, we have detected high-frequency mechanical motion with a sensitivity approaching approximately 15 fm Hz(-1/2). This sensitivity is on par with the highest available from nanoscale optical and electrical displacement detection techniques, and the radio-frequency STM is expected to be capable of quantum-limited position measurements.

  3. Pulmonary radiofrequency ablation (Part 1): current state.

    Science.gov (United States)

    Plasencia Martínez, J M

    2015-01-01

    The risks involved in surgical treatment and conventional radiotherapy in patients with early lung cancer or lung metastases often make these treatments difficult to justify. However, on the other hand, it is also unacceptable to allow these lesions to evolve freely because, left untreated, these neoplasms will usually lead to the death of the patient. In recent years, alternative local therapies have been developed, such as pulmonary radiofrequency ablation, which has proven to increase survival with a minimal risk of complications. There are common recommendations for these treatments, and although the specific indications for using one technique or another have yet to be established, there are clearly defined situations that will determine the outcome of the treatment. It is important to know these situations, because appropriate patient selection is essential for therapeutic success. This article aims to describe the characteristics and constraints of pulmonary radiofrequency ablation and to outline its role in thoracic oncology in light of the current evidence. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  4. Neurohumoral indicators of efficacy radiofrequency cardiac denervation

    Science.gov (United States)

    Evtushenko, A. V.; Evtushenko, V. V.; Saushkina, Yu. V.; Lishmanov, Yu. B.; Pokushalov, E. A.; Sergeevichev, D. S.; Gusakova, A. M.; Suslova, T. E.; Dymbrylova, O. N.; Bykov, A. N.; Syryamkin, V. I.; Kistenev, Yu. V.; Anfinogenova, Ya. D.; Smyshlyaev, K. A.; Lotkov, A. I.; Kurlov, I. O.

    2015-11-01

    In this study, we compared pre- and postoperative parameters of the cardiac sympathetic innervation. The aim of the study was to examine the approaches to evaluating the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive and laboratory methods. The study included 32 people with long-lasting persistent atrial fibrillation (AF). The patients were divided into 2 groups according to the objectives of the study: group 1 (main) - 21 patients with mitral valve diseases, which simultaneously with radiofrequency ablation (RFA) AF carried out on the effects of the paraganglionic nervous plexuses by C. Pappone (2004) and N. Doll (2008) schemes. The second group (control) contained 11 patients with heart diseases in sinus rhythm (the RF denervation not been performed). All patients, who underwent surgical treatment, were received examination of cardiac sympathetic tone by using 123I-MIBG. All of them made blood analysis from ascending aorta and coronary sinus to determine the level of norepinephrine and its metabolites before and after cardiac denervation. Data of radionuclide examination are correlating with laboratory data.

  5. Neurohumoral indicators of efficacy radiofrequency cardiac denervation

    Energy Technology Data Exchange (ETDEWEB)

    Evtushenko, A. V., E-mail: ave@cardio-tomsk.ru; Evtushenko, V. V. [National Research Tomsk State University, Tomsk (Russian Federation); Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Saushkina, Yu. V.; Gusakova, A. M.; Suslova, T. E.; Dymbrylova, O. N.; Smyshlyaev, K. A.; Kurlov, I. O. [Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Lishmanov, Yu. B.; Anfinogenova, Ya. D. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Sergeevichev, D. S. [Academician E.N. Meshalkin State Research Institute of Circulation Pathology, Novosibirsk (Russian Federation); Bykov, A. N.; Syryamkin, V. I.; Kistenev, Yu. V. [National Research Tomsk State University, Tomsk (Russian Federation); Lotkov, A. I. [Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, Tomsk (Russian Federation); Pokushalov, E. A.

    2015-11-17

    In this study, we compared pre- and postoperative parameters of the cardiac sympathetic innervation. The aim of the study was to examine the approaches to evaluating the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive and laboratory methods. The study included 32 people with long-lasting persistent atrial fibrillation (AF). The patients were divided into 2 groups according to the objectives of the study: group 1 (main) - 21 patients with mitral valve diseases, which simultaneously with radiofrequency ablation (RFA) AF carried out on the effects of the paraganglionic nervous plexuses by C. Pappone (2004) and N. Doll (2008) schemes. The second group (control) contained 11 patients with heart diseases in sinus rhythm (the RF denervation not been performed). All patients, who underwent surgical treatment, were received examination of cardiac sympathetic tone by using {sup 123}I-MIBG. All of them made blood analysis from ascending aorta and coronary sinus to determine the level of norepinephrine and its metabolites before and after cardiac denervation. Data of radionuclide examination are correlating with laboratory data.

  6. Gamma-Ray Bursts Subset and Supernova Remnants Low Radio-Frequency Turnover

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang

    2000-01-01

    Durations of gamma-ray bursts (GRB's) are featured by >2s subset and <2s one, with initial corresponding energy ratio being 20:1. It is found that supernova remants(SNR 's) turnover frequencies peak at 100 and 500 MHz. After assuming that GRB's originate from hypernova and making an analysis on the evolution of GRB's, we find that the initial energy of two GRB subsets leads to a different radio-frequency turnover of their remnant spectra, which accords positively with the turnover-frequency ratio of SNR's.

  7. Radiofrequency coblation of congenital nasopharyngeal teratoma: a novel technique.

    Science.gov (United States)

    Hwang, Sang Yun; Jefferson, Niall; Mohorikar, Alok; Jacobson, Ian

    2015-01-01

    Introduction. Congenital nasopharyngeal teratomas are rare tumours that pose difficulties in diagnosis and surgical management. We report the first use of radiofrequency coblation in the management of such tumours. Case Report. A premature baby with a perinatal diagnosis of a large, obstructing nasooropharyngeal mass was referred to the ENT service for further investigations and management. The initial biopsy was suggestive of a neuroblastoma, but the tumour demonstrated rapid growth despite appropriate chemotherapy. In a novel use of radiofrequency coblation, the nasooropharyngeal mass was completely excised, with the final histopathology revealing a congenital nasopharyngeal teratoma. Conclusion. We report the first use of radiofrequency coblation to excise a congenital nasopharyngeal teratoma and discuss its advantages.

  8. Radiofrequency interference with medical devices. A technical information statement.

    Science.gov (United States)

    1998-01-01

    The past few years have seen increased reports that medical devices, such as pacemakers, apnea monitors, electrically powered wheelchairs, etc., have failed to operate correctly because of interference from various emitters of radiofrequency energy. This condition is called radiofrequency interference (RFI). The consequences of these failures range from inconvenience to serious injuries and death. Reasons for this problem are twofold: 1) increasing numbers of electronically controlled medical devices with inadequate electronic protection against RFI, and 2) a significant increase in the number of RF sources in the environment. Medical devices are widely used outside the hospital and may be attached to, or implanted in, patients. Portable wireless communications equipment, including cellular phones, handheld transceivers, and vehicle-mounted transceivers, comprise one of the largest sources of RFI. Some medical devices are especially sensitive to the type of digital modulation that some of the wireless communications devices utilize. The prevailing international standard for the RF immunity of medical devices is the 1993 revision of the International Electro-technical Commission (IEC) Standard IEC 60601-1-2. This standard sets a minimum immunity level of 3 volts per meter (V/m) in the 26-1000 MHz frequency range. For non-life supporting devices, testing is required only at the specific frequencies of 27.12, 40.68, and 915 MHz. Technology exists to protect, or "harden," most medical devices from RF fields that are much more intense than the 3 V/m level specified in present RFI standards. Most of these techniques, including shielding, grounding, and filtering, are not costly if they are incorporated into the initial design of the electronics system. COMAR recommends that the various parties involved in the manufacture and use of RFI-prone medical devices take steps to avoid serious RFI problems that may lead to safety hazards. Medical device manufacturers should

  9. Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

    Energy Technology Data Exchange (ETDEWEB)

    Manaa, C., E-mail: chadlia.el.manaa@gmail.com [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Kouki, F. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Durand-Drouhin, O. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Bouchriha, H. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); and others

    2014-06-02

    We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method.

  10. Multiparametric imaging with heterogeneous radiofrequency fields

    Science.gov (United States)

    Cloos, Martijn A.; Knoll, Florian; Zhao, Tiejun; Block, Kai T.; Bruno, Mary; Wiggins, Graham C.; Sodickson, Daniel K.

    2016-08-01

    Magnetic resonance imaging (MRI) has become an unrivalled medical diagnostic technique able to map tissue anatomy and physiology non-invasively. MRI measurements are meticulously engineered to control experimental conditions across the sample. However, residual radiofrequency (RF) field inhomogeneities are often unavoidable, leading to artefacts that degrade the diagnostic and scientific value of the images. Here we show that, paradoxically, these artefacts can be eliminated by deliberately interweaving freely varying heterogeneous RF fields into a magnetic resonance fingerprinting data-acquisition process. Observations made based on simulations are experimentally confirmed at 7 Tesla (T), and the clinical implications of this new paradigm are illustrated with in vivo measurements near an orthopaedic implant at 3T. These results show that it is possible to perform quantitative multiparametric imaging with heterogeneous RF fields, and to liberate MRI from the traditional struggle for control over the RF field uniformity.

  11. Radiofrequency encoded angular-resolved light scattering

    DEFF Research Database (Denmark)

    Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.

    2015-01-01

    The sensitive, specific, and label-free classification of microscopic cells and organisms is one of the outstanding problems in biology. Today, instruments such as the flow cytometer use a combination of light scatter measurements at two distinct angles to infer the size and internal complexity...... of cells at rates of more than 10,000 per second. However, by examining the entire angular light scattering spectrum it is possible to classify cells with higher resolution and specificity. Current approaches to performing these angular spectrum measurements all have significant throughput limitations...... Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...

  12. Emerging indications of endoscopic radiofrequency ablation

    Science.gov (United States)

    Becq, Aymeric; Camus, Marine; Rahmi, Gabriel; de Parades, Vincent; Marteau, Philippe

    2015-01-01

    Introduction Radiofrequency ablation (RFA) is a well-validated treatment of dysplastic Barrett's esophagus. Other indications of endoscopic RFA are under evaluation. Results Four prospective studies (total 69 patients) have shown that RFA achieved complete remission of early esophageal squamous intra-epithelial neoplasia at a rate of 80%, but with a substantial risk of stricture. In the setting of gastric antral vascular ectasia, two prospective monocenter studies, and a retrospective multicenter study, (total 51 patients), suggest that RFA is efficacious in terms of reducing transfusion dependency. In the setting of chronic hemorrhagic radiation proctopathy, a prospective monocenter study and a retrospective multicenter study (total 56 patients) suggest that RFA is an efficient treatment. A retrospective comparative study (64 patients) suggests that RFA improves stents patency in malignant biliary strictures. Conclusions Endoscopic RFA is an upcoming treatment modality in early esophageal squamous intra-epithelial neoplasia, as well as in gastric, rectal, and biliary diseases. PMID:26279839

  13. LAPAROSCOPIC NEPHRECTOMY USING RADIOFREQUENCY THERMAL ABLATION

    Directory of Open Access Journals (Sweden)

    B. Ya. Alekseev

    2012-01-01

    Full Text Available The wide use of current diagnostic techniques, such as ultrasound study, computed tomography, and magnetic resonance imaging, has led to significantly increased detection rates for disease in its early stages. This gave rise to a change in the standards for the treatment of locally advanced renal cell carcinoma (RCC. Laparoscopic nephrectomy (LN has recently become the standard treatment of locally advanced RCC in the clinics having much experience with laparoscopic surgery. The chief drawback of LN is difficulties in maintaining intraoperative hemostasis and a need for creating renal tissue ischemia. The paper gives the intermediate results of application of the new procedure of LN using radiofrequency thermal ablation in patients with non-ischemic early-stage RCC.

  14. Modes of oscillation in radiofrequency Paul traps

    DEFF Research Database (Denmark)

    Landa, H.; Reznik, B.; Drewsen, M.;

    2012-01-01

    We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem of stable trapping of general threedimensional crystals is considered and the validity of the pseudopotential approximation is discussed. We analytically derive the micromotion amplitude of the ions......, rigorously proving well-known experimental observations. We use a recently proposed method to find the modes that diagonalize the linearized time-dependent dynamical problem. This allows one to obtain explicitly the ('Floquet-Lyapunov') transformation to coordinates of decoupled linear oscillators. We...... demonstrate the utility of the method by analyzing the modes of a small 'peculiar' crystal in a linear Paul trap. The calculations can be readily generalized to multispecies ion crystals in general multipole traps, and time-dependent quantum wavefunctions of ion oscillations in such traps can be obtained....

  15. Radiofrequency ablation of a misdiagnosed Brodie's abscess.

    Science.gov (United States)

    Chan, Rs; Abdullah, Bjj; Aik, S; Tok, Ch

    2011-04-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie's abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie's abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment.

  16. Process for selected gas oxide removal by radiofrequency catalysts

    Science.gov (United States)

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  17. Percutaneous radiofrequency thermocoagulation of osteoid osteomas: factors affecting therapeutic outcome

    Energy Technology Data Exchange (ETDEWEB)

    Cribb, G.L.; Goude, W.H.; Cool, P.; Tins, B.; Cassar-Pullicino, V.N.; Mangham, D.C. [Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry (United Kingdom)

    2005-11-01

    To examine factors which affect local recurrence of osteoid osteomas treated with percutaneous CT-guided radiofrequency thermocoagulation. A prospective study was carried out on 45 patients with osteoid osteoma who underwent percutaneous radiofrequency thermocoagulation with a minimum follow-up of 12 months There were seven local recurrences (16%); all occurred within the first year. Local recurrence was significantly related to a non-diaphyseal location (P<0.01). There was no significant relationship (P=0.05) between local recurrence and age of the patient, duration of symptoms, previous treatment, size of the lesion, positive biopsy, radiofrequency generator used or the number of needle positions. There were no complications. Osteoid osteomas in a non-diaphyseal location are statistically more likely to recur than those in a diaphyseal location when treated with CT-guided percutaneous radiofrequency thermocoagulation. This relationship between local recurrence and location has not been previously reported. (orig.)

  18. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation.

    OpenAIRE

    Chun, KR; Bestehorn, K; Pocock, SJ; FIRE AND ICE Investigators; , COLLABORATORS; Kuck, KH; Metzner, A; Ouyang, F; Chun, J; Fürnkranz, A; Elvan, A.; Arentz, T.; Kühne, M.; Sticherling, C; Gellér, L

    2016-01-01

    BACKGROUND: Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation. Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology. METHODS: We conducted a multicenter, randomized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillatio...

  19. A case of splenic abscess after radiofrequency ablation

    Institute of Scientific and Technical Information of China (English)

    Dimitris Zacharoulis; Emmanuel Katsogridakis; Constantinos Hatzitheofilou

    2006-01-01

    Radiofrequency ablation (RFA) is an innovative technique used primarily for the palliative treatment of unresectable liver tumors. Its therapeutic indications however, have been expanded and now include various other organs and diseases. There is a paucity of data regarding technical details and complications of the use of RFA in the spleen. We report a case of partial splenectomy using radiofrequency ablation for splenic hydatid disease,complicated by an abscess formation.

  20. Radio-frequency plasma transducer for use in harsh environments.

    Science.gov (United States)

    May, Andrew; Andarawis, Emad

    2007-10-01

    We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

  1. Laser ablation loading of a radiofrequency ion trap

    CERN Document Server

    Zimmermann, K; Herrera-Sancho, O A; Peik, E

    2012-01-01

    The production of ions via laser ablation for the loading of radiofrequency (RF) ion traps is investigated using a nitrogen laser with a maximum pulse energy of 0.17 mJ and a peak intensity of about 250 MW/cm^2. A time-of-flight mass spectrometer is used to measure the ion yield and the distribution of the charge states. Singly charged ions of elements that are presently considered for the use in optical clocks or quantum logic applications could be produced from metallic samples at a rate of the order of magnitude 10^5 ions per pulse. A linear Paul trap was loaded with Th+ ions produced by laser ablation. An overall ion production and trapping efficiency of 10^-7 to 10^-6 was attained. For ions injected individually, a dependence of the capture probability on the phase of the RF field has been predicted. In the experiment this was not observed, presumably because of collective effects within the ablation plume.

  2. Analysis and analytical characterization of bioheat transfer during radiofrequency ablation.

    Science.gov (United States)

    Wang, Keyong; Tavakkoli, Fatemeh; Wang, Shujuan; Vafai, Kambiz

    2015-04-13

    Understanding thermal transport and temperature distribution within biological organs is important for therapeutic aspects related to hyperthermia treatments such as radiofrequency ablation (RFA). Unlike surface heating, the RFA treatment volumetrically heats up the biological media using a heating probe which provides the input energy. In this situation, the shape of the affected region is annular, which is described by an axisymmetric geometry. To better understand the temperature responses of the living tissues subject to RFA, comprehensive characteristics of bioheat transport through the annular biological medium is presented under local thermal non-equilibrium (LTNE) condition. Following the operational features of the RFA treatment, based on the porous media theory, analytical solutions have been derived for the blood and tissue temperature distributions as well as an overall heat exchange correlation in cylindrical coordinates. Our analytical results have been validated against three limiting cases which exist in the literature. The effects of various physiological parameters, such as metabolic heat generation, volume fraction of the vascular space, ratio of the effective blood to tissue conductivities, different biological media and the rate of heat exchange between the lumen and the tissue are investigated. Solutions developed in this study are valuable for thermal therapy planning of RFA. A criterion is also established to link deep heating protocol to surface heating.

  3. Compact Superconducting Radio-frequency Accelerators and Innovative RF Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kephart, Robert [Fermilab; Chattopadhyay, Swaapan [Northern Illinois U.; Milton, Stephen [Colorado State U.

    2015-04-10

    We will present several new technical and design breakthroughs that enable the creation of a new class of compact linear electron accelerators for industrial purposes. Use of Superconducting Radio-Frequency (SRF) cavities allow accelerators less than 1.5 M in length to create electron beams beyond 10 MeV and with average beam powers measured in 10’s of KW. These machines can have the capability to vary the output energy dynamically to produce brehmstrahlung x-rays of varying spectral coverage for applications such as rapid scanning of moving cargo for security purposes. Such compact accelerators will also be cost effective for many existing and new industrial applications. Examples include radiation crosslinking of plastics and rubbers, creation of pure materials with surface properties radically altered from the bulk, modification of bulk or surface optical properties of materials, sterilization of medical instruments animal solid or liquid waste, and destruction of organic compounds in industrial waste water effluents. Small enough to be located on a mobile platform, such accelerators will enable new remediation methods for chemical and biological spills and/or in-situ crosslinking of materials. We will describe one current design under development at Fermilab including plans for prototype and value-engineering to reduce costs. We will also describe development of new nano-structured field-emitter arrays as sources of electrons, new methods for fabricating and cooling superconducting RF cavities, and a new novel RF power source based on magnetrons with full phase and amplitude control.

  4. Thermal Response of In Vivo Human Skin to Fractional Radiofrequency Microneedle Device

    Directory of Open Access Journals (Sweden)

    Woraphong Manuskiatti

    2016-01-01

    Full Text Available Background. Fractional radiofrequency microneedle system (FRMS is a novel fractional skin resurfacing system. Data on thermal response to this fractional resurfacing technique is limited. Objectives. To investigate histologic response of in vivo human skin to varying energy settings and pulse stacking of a FRMS in dark-skinned subjects. Methods. Two female volunteers who were scheduled for abdominoplasty received treatment with a FRMS with varying energy settings at 6 time periods including 3 months, 1 month, 1 week, 3 days, 1 day, and the time immediately before abdominoplasty. Biopsy specimens were analyzed using hematoxylin and eosin (H&E, Verhoeff-Van Gieson (VVG, colloidal iron, and Fontana-Masson stain. Immunohistochemical study was performed by using Heat Shock Protein 70 (HSP70 antibody and collagen III monoclonal antibody. Results. The average depth of radiofrequency thermal zone (RFTZ ranged from 100 to 300 μm, correlating with energy levels. Columns of cell necrosis and collagen denaturation followed by inflammatory response were initially demonstrated, with subsequent increasing of mucin at 1 and 3 months after treatment. Immunohistochemical study showed positive stain with HSP70. Conclusion. A single treatment with a FRMS using appropriate energy setting induces neocollagenesis. This wound healing response may serve as a mean to improve the appearance of photodamaged skin and atrophic scars.

  5. Right phrenic injury after radiofrequency catheter ablation of atrial tachycardia at crista terminalis

    Institute of Scientific and Technical Information of China (English)

    JIA Yu-he; WANG Fang-zheng; GAO Dong-sheng; CHU Jian-min; PU Jie-ling; REN Xiao-qing; HUA Wei; ZHANG Shu

    2011-01-01

    A 62-year-old woman with frequent occurrence of symptomatic atrial tachycardia with a foci located at the root of the upper crista terminalis was found to have right diaphragm paresis after receiving a total of 8 radiofrequency energy deliveries (40-60 W, 50-60℃) and a total duration of 540 seconds of ablation therapy (7Fr 8 mm deflectable ablation catheter). The right diaphragm paresis remained resolved up to 14 months after the procedure as confirmed by repeated chest X-rays.

  6. Design studies of a high-current radiofrequency quadrupole for accelerator-driven systems programme

    Indian Academy of Sciences (India)

    S V L S Rao; P Singh

    2010-02-01

    A 3 MeV, 30 mA radiofrequency quadrupole (RFQ) accelerator has been designed for the low-energy high-intensity proton accelerator (LEHIPA) project at BARC, India. The beam and cavity dynamics studies were performed using the computer codes LIDOS, TOUTATIS, SUPERFISH and CST microwave studio. We have followed the conventional design technique with slight modifications and compared that with the equipartitioned (EP) type of design. The sensitivity of the RFQ to the variation of input beam Twiss–Courant parameters and emittance has also been studied. In this article we discuss both design strategies and the details of the 3D cavity simulation studies.

  7. Experimental observation and computational analysis of striations in electronegative capacitively coupled radio-frequency plasmas

    CERN Document Server

    Liu, Yong-Xin; Korolov, Ihor; Donko, Zoltan; Wang, You-Nian; Schulze, Julian

    2016-01-01

    Self-organized spatial structures in the light emission from the ion-ion capacitive RF plasma of a strongly electronegative gas (CF4) are observed experimentally for the first time. Their formation is analyzed and understood based on particle-based kinetic simulations. These "striations" are found to be generated by the resonance between the driving radio-frequency and the eigenfrequency of the ion-ion plasma (derived from an analytical model) that establishes a modulation of the electric field, the ion densities, as well as the energy gain and loss processes of electrons in the plasma. The growth of the instability is followed by the numerical simulations.

  8. Moessbauer absorption by thick ferromagnets in radio-frequency magnetic field

    CERN Document Server

    Dzyublik, A Y

    2002-01-01

    The dynamical scattering theory is developed for transmission of the Moessbauer radiation through a ferromagnetic absorber of arbitrary thickness whose magnetization periodically reverses under the influence of an external radio-frequency (RF) magnetic field. The thickness dependence of the Moessbauer absorption spectrum as well as the time dependence and energy distribution of the transmitted beam are analyzed. The transmitted spectrum as a function of the frequency of transmitted gamma-quanta, reveals a sideband structure separated by twice the frequency of the RF field, which collapses to a single line at high frequencies.

  9. Three-phase shots and monopolar reclose in the core network of 400 kV of the Area de Control Occidental of CFE and Its normal probability of occurrence; Disparos trifasicos y de recierre monopolar en la red troncal de 400 kV del area de control occidental, CFE, y su probabilidad normal de ocurrencia

    Energy Technology Data Exchange (ETDEWEB)

    Narvaez Perez, Camilo; Garcia Conejo, Dante Aristoteles [Comision Federal de Electricidad, Centro Nacional de Control de Energia, Area de Control Occidental, Zapopan, Jalisco (Mexico)]. E-mail: camilo.narvaez@cfe.gob.mx; camilo.narvaez@univa.mx; Ramirez Peredo, Patricia [Universidad de Guadalajara, Guadalajara, Jalisco (Mexico)]. E-mail: patyrape@hotmail.com; Blanco Gomez, Cesar Eduardo [Comision Federal de Electricidad, Centro Nacional de Control de Energia, Area de Control Occidental, Zapopan, Jalisco (Mexico)

    2013-03-15

    The growing power demand of users, who make loads of power systems, causes the components of such systems operating near its operating limits. And the transmission line, being the most common component in these, requires a thorough analysis in regard to the probability of three-phase shots and monopolars reclosing, considering thunderstorms, the demand system time, the flows circulating in lines, maintenance on other lines and other imponderantes. This research analyzes the normal probability of occurrence of shots in the 400 kV core network of the Area de Control Occidental, CFE and its impact on studies conducted prior to the maintenance. We intend to use the methodology in the Comision Federal de Electricidad and results can be validated with data from previous years, based on a pseudo shots forecast in a given period. [Spanish] La creciente demanda de energia electrica de los usuarios que componen las cargas de los sistemas electricos de potencia, provoca que los componentes de dichos sistemas funcionen cerca de sus limites operativos. Y la linea de transmision, al ser el componente mas comun en estos, requiere de un analisis minucioso en lo que respecta a la probabilidad de disparos trifasicos y recierres monopolares, considerando tormentas electricas, la demanda horaria del sistema, los flujos que circulan en las lineas, los mantenimientos en las demas lineas y demas imponderantes. En esta investigacion se analiza la probabilidad normal de ocurrencia de disparos en la red troncal de 400 kV del Area de Control Occidental y su impacto en los estudios que se realizan previos a los mantenimientos. Se pretende utilizar la metodologia en la Comision Federal de Electricidad, y los resultados pueden ser validados con datos de los anos anteriores, ya que se hace un pseudo pronostico de disparos en un periodo dado.

  10. Correction of phase errors in quantitative water-fat imaging using a monopolar time-interleaved multi-echo gradient echo sequence.

    Science.gov (United States)

    Ruschke, Stefan; Eggers, Holger; Kooijman, Hendrik; Diefenbach, Maximilian N; Baum, Thomas; Haase, Axel; Rummeny, Ernst J; Hu, Houchun H; Karampinos, Dimitrios C

    2017-09-01

    To propose a phase error correction scheme for monopolar time-interleaved multi-echo gradient echo water-fat imaging that allows accurate and robust complex-based quantification of the proton density fat fraction (PDFF). A three-step phase correction scheme is proposed to address a) a phase term induced by echo misalignments that can be measured with a reference scan using reversed readout polarity, b) a phase term induced by the concomitant gradient field that can be predicted from the gradient waveforms, and c) a phase offset between time-interleaved echo trains. Simulations were carried out to characterize the concomitant gradient field-induced PDFF bias and the performance estimating the phase offset between time-interleaved echo trains. Phantom experiments and in vivo liver and thigh imaging were performed to study the relevance of each of the three phase correction steps on PDFF accuracy and robustness. The simulation, phantom, and in vivo results showed in agreement with the theory an echo time-dependent PDFF bias introduced by the three phase error sources. The proposed phase correction scheme was found to provide accurate PDFF estimation independent of the employed echo time combination. Complex-based time-interleaved water-fat imaging was found to give accurate and robust PDFF measurements after applying the proposed phase error correction scheme. Magn Reson Med 78:984-996, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  11. Radiofrequency balloon angioplasty. Rationale and proof of principle

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G.J.; Lee, B.I.; Waller, B.F.; Barry, K.J.; Kaplan, J.; Connolly, R.; Dreesen, R.G.; Nardella, P.

    1988-11-01

    Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).

  12. Effects of monopolar electrocoagulation and bipolar electrocoagulation in laparoscopy for infertility on ovarian function%腹腔镜不孕症手术使用单、双极电凝对卵巢功能的影响

    Institute of Scientific and Technical Information of China (English)

    李建华

    2011-01-01

    目的:探讨腹腔镜不孕症手术中使用单、双极电凝对卵巢功能的影响.方法:选择100例因输卵管因素导致的不孕症患者,均行腹腔镜下输卵管的修复整形手术,使用不同的止血方法随机分为单极电凝组50例、双极电凝组50例.分别于术前、术后1、3个月抽血检测促卵泡激素(FSH)、黄体生成素(LH)、雌二醇(E2),月经第11天开始B超监测排卵情况,术后随访1年.结果:两组病例术后1、3个月较术前均出现不同程度的FSH、LH增高和E2下降,单极电凝组与术前比较差异有统计学意义(P<0.05),双极电凝组与术前比较差异无统计学意义(P>0.05).结论:腹腔镜下不孕症手术中使用单、双极电凝止血会引起对卵巢功能的损害,而使用单极电凝止血对卵巢功能的损害较使用双极电凝止血大.单极电凝组术后发生月经改变明显多于双极电凝组(P<0.05).双极电凝组术后妊娠率较单极电凝组高.%Objective: To explore the effects of monopolar electrocoagulation and bipolar electrocoagulation in laparoscopy for infertility on ovarian function. Methods: 100 infertile patients because of tubal factor were selected, and all the patients received fallopian tube surgery under laparoscope, then they were divided into monopolar electrocoagulation group ( 50 women) and bipolar electrocoagulation group (50 women) according to different hemostatic methods. Their blood samples were obtained to detect the levels of follicle - stimulating hormone ( FSH) , luteinizing hormone ( LH ) and estradiol before surgery, at one and three months after surgery, B ultrasound was used to monitor the ovulation situation from the eleventh day of menstrual cycle, all the patients were followed up for one year after surgery. Results: Compared with before surgery, the levels of FSH and LH at one and three months after surgery increased, the level of estradiol decreased, there was significant difference in monopolar

  13. Radiofrequency treatment alters cancer cell phenotype

    Science.gov (United States)

    Ware, Matthew J.; Tinger, Sophia; Colbert, Kevin L.; Corr, Stuart J.; Rees, Paul; Koshkina, Nadezhda; Curley, Steven; Summers, H. D.; Godin, Biana

    2015-07-01

    The importance of evaluating physical cues in cancer research is gradually being realized. Assessment of cancer cell physical appearance, or phenotype, may provide information on changes in cellular behavior, including migratory or communicative changes. These characteristics are intrinsically different between malignant and non-malignant cells and change in response to therapy or in the progression of the disease. Here, we report that pancreatic cancer cell phenotype was altered in response to a physical method for cancer therapy, a non-invasive radiofrequency (RF) treatment, which is currently being developed for human trials. We provide a battery of tests to explore these phenotype characteristics. Our data show that cell topography, morphology, motility, adhesion and division change as a result of the treatment. These may have consequences for tissue architecture, for diffusion of anti-cancer therapeutics and cancer cell susceptibility within the tumor. Clear phenotypical differences were observed between cancerous and normal cells in both their untreated states and in their response to RF therapy. We also report, for the first time, a transfer of microsized particles through tunneling nanotubes, which were produced by cancer cells in response to RF therapy. Additionally, we provide evidence that various sub-populations of cancer cells heterogeneously respond to RF treatment.

  14. Radiofrequency ablation of idiopathic ventricular tachycardia

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, J.; Shah, A.; Hua, W.; Gerloff, J.; Riters, A. [Royal Melbourne Hospital, Melbourne, VIC (Australia)

    1996-04-01

    Radiofrequency ablation (RFA) has been shown to be very effective in the treatment of supraventricular tachycardias and has replaced surgical ablation. Only a few reports of RFA for idiopathic ventricular tachycardia (VT) have appeared in the literature during the last two years. This paper presents our experience with RFA for idiopathic VT in 19 patients. In all patients the diagnostic study and therapeutic RFA were combined in a single procedure. Pacemapping were used to guide the site of RFA in patients with VT arising from the RV. Local activation time (LAT), Purkinje potentials (PP) and pacemapping were used to guide RFA in those patients with LV septal tachycardias. Idiopathic VT frequently arises from the RVOT and inferobasal portion of the LV septum. These tachycardias can be diagnosed on clinical and ECG grounds. RFA for idiopathic VT arising from these areas has a high success rate and this mode of treatment should be considered as a nonpharmacological curative treatment for symptomatic patients. 13 refs., 3 tabs., 4 figs.

  15. Epidemiology of health effects of radiofrequency exposure.

    Science.gov (United States)

    Ahlbom, Anders; Green, Adele; Kheifets, Leeka; Savitz, David; Swerdlow, Anthony

    2004-12-01

    We have undertaken a comprehensive review of epidemiologic studies about the effects of radiofrequency fields (RFs) on human health in order to summarize the current state of knowledge, explain the methodologic issues that are involved, and aid in the planning of future studies. There have been a large number of occupational studies over several decades, particularly on cancer, cardiovascular disease, adverse reproductive outcome, and cataract, in relation to RF exposure. More recently, there have been studies of residential exposure, mainly from radio and television transmitters, and especially focusing on leukemia. There have also been studies of mobile telephone users, particularly on brain tumors and less often on other cancers and on symptoms. Results of these studies to date give no consistent or convincing evidence of a causal relation between RF exposure and any adverse health effect. On the other hand, the studies have too many deficiencies to rule out an association. A key concern across all studies is the quality of assessment of RF exposure. Despite the ubiquity of new technologies using RFs, little is known about population exposure from RF sources and even less about the relative importance of different sources. Other cautions are that mobile phone studies to date have been able to address only relatively short lag periods, that almost no data are available on the consequences of childhood exposure, and that published data largely concentrate on a small number of outcomes, especially brain tumor and leukemia.

  16. Radiofrequency radiation leakage from microwave ovens.

    Science.gov (United States)

    Lahham, Adnan; Sharabati, Afifeh

    2013-12-01

    This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm(-2) with an average value equalling 3.64 μW cm(-2). Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm(-2). The highest radiation leakage from any tested oven was ∼16.4 μW cm(-2), and found in two cases only. In no case did the leakage exceed the limit of 1 mW cm(-2) recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age.

  17. Evaluation of radiofrequency dielectric heaters workers exposure.

    Science.gov (United States)

    Benes, M; Del Frate, S; Villalta, R

    2008-01-01

    Radiofrequency dielectric heaters (RFDH) are widely used in the woodworking industry for gluing laminates by applying pressure and RF heating. The workers operating such equipment remain in the vicinity of the machinery all day and can therefore be exposed to considerable levels of electric and magnetic field at RFs. This work describes the method used to measure the strength of fields generated by this particular machinery. This procedure is based on current methods cited in the literature and introduces the necessary modifications to meet this specific case. In particular, as there is often a scarcity of technical data available relating to such heaters, it is suggested that a spectrum analyser be used for measurements in the frequencies domain. On the basis of the data obtained the norms of reference are established, the instrumentation to be used in successive stages determined as well as the identification of possible sources of interference from spurious signals. Furthermore, a mapping of the field strengths is presented and the means of determining the decay curve as a function of distance. This last type of measurement is done to estimate the effectiveness of grounding the machinery. The report ends with an estimate of the exposure of workers to electromagnetic fields and also some recommendations for reducing risk.

  18. Radiofrequency catheter ablation maintains its efficacy better than antiarrhythmic medication in patients with paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Raatikainen, M J Pekka; Hakalahti, Antti; Uusimaa, Paavo;

    2015-01-01

    BACKGROUND: The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) is a randomized trial comparing radiofrequency catheter ablation (RFA) to antiarrhythmic drugs (AADs) as first-line treatment of paroxysmal atrial fibrillation (PAF). In order...

  19. Study on the Radiofrequency Specific Energy Absorption Rates of Various Tissues in Female Pelvic Model Under MR Scan%MR射频能量特定吸收率在女性盆腔不同组织中分布规律的研究

    Institute of Scientific and Technical Information of China (English)

    曾雁冰; 周宇佳; 黄绮华; 辛学刚

    2012-01-01

    Objective: The radiofrequency specific energy absorption rates are the key to evaluate the safety of patients under MR scan, In order to protect patients against excessive radio frequency energy absorption, the understanding of SAR distribution in different tissues is essential. Methods: Based on the CT scanning images of a volunteer, the numerical model of female pelvic cavity was established from the original CT scanning data. Numerical 3D models of skin (a), fat (b), muscle(c), bone(d), pelvic(e),uterine cavity(f) were obtained based on different gray values after the optimized segmentations. Combining with the different electromagnetic dielectric parameters of different tissues, the electromagnetic model of female pelvis was finally established by comprising of six different tissues. The FDTD simulation was used to calculate the SAR distribution in the different tissues at 64 MHz using the local SAR calculation formula from standard NEMA MS-10. Results: Among the six tissues, the values of SARavg are highest in skin and lowest in uterus at 64 MHz; the values of SAR1g are highest in skin and lowest in bone at the same conditions. Conclusions: Local SARs distribution in different tissues is different. The values of SARs are determined by the different dielectric parameters, the different sizes of various tissues, and the source-object distances.%目的:磁共振(MR)扫描中,特定吸收率(specific absorption rate,SAR)是衡量被检者安全的最重要指标.为了确保被检者的安全,需了解不同人体组织在MR射频作用下SAR分布规律.方法:采集女性志愿者原始X射线断层成像数据,重建女性盆腔数值断层图像;根据断层图像灰度值分割出皮肤、脂肪、肌肉、骨骼、子宫、子宫腔等不同人体组织原始蒙罩,对分割的断层图像进行网格优化和三角面片优化后,结合不同组织电磁参数,建立女性盆腔电磁数值模型.依据NEMA MS- 10标准中的局部SAR计算原则,运用

  20. A Rare Complication of Radiofrequency Tonsil Ablation: Horner Syndrome

    Directory of Open Access Journals (Sweden)

    Cuneyt Kucur

    2015-01-01

    Full Text Available Chronic tonsillitis is a common disease, and several different surgical techniques are used to treat this condition. In recent years, techniques such as radiofrequency ablation and coblation have been commonly used for tonsil surgery. In this report, we present the cases of two pediatric patients who developed ptosis, miosis, and enophthalmos (Horner syndrome after radiofrequency ablation for tonsil reduction and discuss the technique of radiofrequency ablation of the tonsils. In the early postoperative period, miosis and ptosis were observed on the right side in one patient and on the left side in the other patient. Both patients were treated with 1 mg/kg/day methylprednisolone, which were tapered by halving the dose every 3 days. Miosis and ptosis improved after treatment in both patients. Along with the case presentation, we discuss the effectiveness and complications of radiofrequency ablation of the tonsils. These unusual complications of tonsil ablation may help ENT physicians who do not yet have a preferred surgical technique for tonsillectomy to make an informed decision. Limited data are available about the possible complications of radiofrequency ablation of the tonsils. The present report contributes to the literature on this topic.

  1. A Rare Complication of Radiofrequency Tonsil Ablation: Horner Syndrome.

    Science.gov (United States)

    Kucur, Cuneyt; Ozbay, Isa; Oghan, Fatih; Yildirim, Nadir; Zeybek Sivas, Zuhal; Canbaz Kabay, Sibel

    2015-01-01

    Chronic tonsillitis is a common disease, and several different surgical techniques are used to treat this condition. In recent years, techniques such as radiofrequency ablation and coblation have been commonly used for tonsil surgery. In this report, we present the cases of two pediatric patients who developed ptosis, miosis, and enophthalmos (Horner syndrome) after radiofrequency ablation for tonsil reduction and discuss the technique of radiofrequency ablation of the tonsils. In the early postoperative period, miosis and ptosis were observed on the right side in one patient and on the left side in the other patient. Both patients were treated with 1 mg/kg/day methylprednisolone, which were tapered by halving the dose every 3 days. Miosis and ptosis improved after treatment in both patients. Along with the case presentation, we discuss the effectiveness and complications of radiofrequency ablation of the tonsils. These unusual complications of tonsil ablation may help ENT physicians who do not yet have a preferred surgical technique for tonsillectomy to make an informed decision. Limited data are available about the possible complications of radiofrequency ablation of the tonsils. The present report contributes to the literature on this topic.

  2. A Rare Complication of Radiofrequency Tonsil Ablation: Horner Syndrome

    Science.gov (United States)

    Ozbay, Isa; Yildirim, Nadir; Zeybek Sivas, Zuhal; Canbaz Kabay, Sibel

    2015-01-01

    Chronic tonsillitis is a common disease, and several different surgical techniques are used to treat this condition. In recent years, techniques such as radiofrequency ablation and coblation have been commonly used for tonsil surgery. In this report, we present the cases of two pediatric patients who developed ptosis, miosis, and enophthalmos (Horner syndrome) after radiofrequency ablation for tonsil reduction and discuss the technique of radiofrequency ablation of the tonsils. In the early postoperative period, miosis and ptosis were observed on the right side in one patient and on the left side in the other patient. Both patients were treated with 1 mg/kg/day methylprednisolone, which were tapered by halving the dose every 3 days. Miosis and ptosis improved after treatment in both patients. Along with the case presentation, we discuss the effectiveness and complications of radiofrequency ablation of the tonsils. These unusual complications of tonsil ablation may help ENT physicians who do not yet have a preferred surgical technique for tonsillectomy to make an informed decision. Limited data are available about the possible complications of radiofrequency ablation of the tonsils. The present report contributes to the literature on this topic. PMID:26064747

  3. Magnetoreception in birds: the effect of radio-frequency fields.

    Science.gov (United States)

    Wiltschko, Roswitha; Thalau, Peter; Gehring, Dennis; Nießner, Christine; Ritz, Thorsten; Wiltschko, Wolfgang

    2015-02-01

    The avian magnetic compass, probably based on radical pair processes, works only in a narrow functional window around the local field strength, with cryptochrome 1a as most likely receptor molecule. Radio-frequency fields in the MHz range have been shown to disrupt the birds' orientation, yet the nature of this interference is still unclear. In an immuno-histological study, we tested whether the radio-frequency fields interfere with the photoreduction of cryptochrome, but this does not seem to be the case. In behavioural studies, birds were not able to adjust to radio-frequency fields like they are able to adjust to static fields outside the normal functional range: neither a 2-h pre-exposure in a 7.0 MHz field, 480 nT, nor a 7-h pre-exposure in a 1.315 MHz field, 15 nT, allowed the birds to regain their orientation ability. This inability to adjust to radio-frequency fields suggests that these fields interfere directly with the primary processes of magnetoreception and therefore disable the avian compass as long as they are present. They do not have lasting adverse after-effects, however, as birds immediately after exposure to a radio-frequency field were able to orient in the local geomagnetic field.

  4. MATHEMATICAL MODELS FOR SOME RADIO-FREQUENCY TRANSMISSION-LINE TRANSFORMERS

    Science.gov (United States)

    MATRICES(MATHEMATICS), *PHASE SHIFT CIRCUITS, *RADIOFREQUENCY, *TRANSFORMERS, *TRANSMISSION LINES, BROADBAND, DIELECTRIC PROPERTIES, ELECTRICAL IMPEDANCE, FERRITES, IMPEDANCE MATCHING , MATHEMATICAL ANALYSIS.

  5. 47 CFR 2.1091 - Radiofrequency radiation exposure evaluation: mobile devices.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radiofrequency radiation exposure evaluation... Procedures Radiofrequency Radiation Exposure § 2.1091 Radiofrequency radiation exposure evaluation: mobile... stations devices only) and part 90 of this chapter are subject to routine environmental evaluation for...

  6. 47 CFR 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radiofrequency radiation exposure evaluation... Procedures Radiofrequency Radiation Exposure § 2.1093 Radiofrequency radiation exposure evaluation: portable.... These criteria for SAR evaluation are similar to those recommended by the National Council on...

  7. [Somnoplasty: treatment of chronic snoring using radiofrequency irradiation of the palate].

    Science.gov (United States)

    Galindo Campillo, A N; García Simal, M; Navarro Cunchillos, M; Toledano Muñoz, A

    2003-12-01

    The goal of this study is to evaluate the efficacy and the safety of tissue reduction of the palate by means of radiofrequency for the treatment of snoring. Fifty-three patients were evaluated. Eight of them (15%) met criteria for mild OSAS. All of them underwent RF energy treatment with several ablation sites and the mean total energy administered was about 2500 J per treatment session. 40 patients (75%) underwent an additional RF treatment and the energy administered in the second session was the same as in the first one. We evaluated postoperative pain, snoring and the satisfaction of the patient and his enviroment. After a mean follow-up of 20 months no adverse effect was reported. The success diminishes with time as happens other surgical procedures (UPPP or LAUP) but the absence of serious adverse side-effects and the minimal postoperative pain support the use of RF as an effective procedure for reducing snoring.

  8. Carbon dioxide dissociation in non-thermal radiofrequency and microwave plasma

    Science.gov (United States)

    Huang, Qiang; Zhang, Diyu; Wang, Dongping; Liu, Kezhao; Kleyn, Aart W.

    2017-07-01

    We have studied carbon dioxide dissociation in inductively coupled radiofrequency plasma and microwave plasma at low gas pressure. Both systems exhibit features of non-thermal plasma. The highest energy efficiency observed is 59.3% (2.13 mmol kJ-1), exceeding the maximum value of about 45% in case of thermodynamic equilibrium, and a maximum conversion of 80.6% is achieved. Different discharge conditions, such as the source frequency, discharge gas pressure and the addition of argon, will affect the plasma parameters, especially the electron energy distribution. This plays a great role in the energy transfer from non-thermal plasma to the molecular dissociation reaction channel by enabling the ladder climbing of the carbon dioxide molecular vibration. The results indicate the importance of ladder climbing.

  9. Low power radiofrequency electromagnetic radiation for the treatment of pain due to osteoarthritis of the knee

    Directory of Open Access Journals (Sweden)

    U. Santosuosso

    2011-09-01

    Full Text Available Different techniques have been used in some rheumatic diseases to induce a therapeutic effect by heating deep tissues. These techniques are commonly known as ‘thermotherapy’ (1-4. It should be observed that adequate heating of deep tissues cannot be obtained by conduction or convection of heat because the skin and subcutaneous fat are good thermal insulators and because heating is reduced by blood flow in superficial vessels. Heating of deep tissues can instead be obtained by conversion of other forms of energy into heat. Conversion heat is generated by different types of radiations absorbed by deep tissues: when radiation interacts with tissues, some energy is converted into heat. High power radiofrequency electromagnetic radiation (RF, which produces strong thermal energy, has been widely applied in medicine for ablative procedures (5-7.

  10. Influence of radiofrequency surgery on architecture of the palatine tonsils.

    Science.gov (United States)

    Plzak, Jan; Macokova, Pavla; Zabrodsky, Michal; Kastner, Jan; Lastuvka, Petr; Astl, Jaromir

    2014-01-01

    Radiofrequency surgery is a widely used modern technique for submucosal volume reduction of the tonsils. So far there is very limited information on morphologic changes in the human tonsils after radiofrequency surgery. We performed histopathological study of tonsillectomy specimens after previous bipolar radiofrequency induced thermotherapy (RFITT). A total of 83 patients underwent bipolar RFITT for hypertrophy of palatine tonsils. Tonsil volume reduction was measured by 3D ultrasonography. Five patients subsequently underwent tonsillectomy. Profound histopathological examination was performed to determine the effect of RFITT on tonsillar architecture. All tonsillectomy specimens showed the intact epithelium, intact germinal centers, normal vascularization, and no evidence of increased fibrosis. No microscopic morphological changes in tonsillectomy specimens after bipolar RFITT were observed. RFITT is an effective submucosal volume reduction procedure for treatment of hypertrophic palatine tonsils with no destructive effect on microscopic tonsillar architecture and hence most probably no functional adverse effect.

  11. Radiofrequency Coblation of Congenital Nasopharyngeal Teratoma: A Novel Technique

    Directory of Open Access Journals (Sweden)

    Sang Yun Hwang

    2015-01-01

    Full Text Available Introduction. Congenital nasopharyngeal teratomas are rare tumours that pose difficulties in diagnosis and surgical management. We report the first use of radiofrequency coblation in the management of such tumours. Case Report. A premature baby with a perinatal diagnosis of a large, obstructing nasooropharyngeal mass was referred to the ENT service for further investigations and management. The initial biopsy was suggestive of a neuroblastoma, but the tumour demonstrated rapid growth despite appropriate chemotherapy. In a novel use of radiofrequency coblation, the nasooropharyngeal mass was completely excised, with the final histopathology revealing a congenital nasopharyngeal teratoma. Conclusion. We report the first use of radiofrequency coblation to excise a congenital nasopharyngeal teratoma and discuss its advantages.

  12. Influence of Radiofrequency Surgery on Architecture of the Palatine Tonsils

    Directory of Open Access Journals (Sweden)

    Jan Plzak

    2014-01-01

    Full Text Available Radiofrequency surgery is a widely used modern technique for submucosal volume reduction of the tonsils. So far there is very limited information on morphologic changes in the human tonsils after radiofrequency surgery. We performed histopathological study of tonsillectomy specimens after previous bipolar radiofrequency induced thermotherapy (RFITT. A total of 83 patients underwent bipolar RFITT for hypertrophy of palatine tonsils. Tonsil volume reduction was measured by 3D ultrasonography. Five patients subsequently underwent tonsillectomy. Profound histopathological examination was performed to determine the effect of RFITT on tonsillar architecture. All tonsillectomy specimens showed the intact epithelium, intact germinal centers, normal vascularization, and no evidence of increased fibrosis. No microscopic morphological changes in tonsillectomy specimens after bipolar RFITT were observed. RFITT is an effective submucosal volume reduction procedure for treatment of hypertrophic palatine tonsils with no destructive effect on microscopic tonsillar architecture and hence most probably no functional adverse effect.

  13. Photoacoustic characterization of radiofrequency ablation lesions

    Science.gov (United States)

    Bouchard, Richard; Dana, Nicholas; Di Biase, Luigi; Natale, Andrea; Emelianov, Stanislav

    2012-02-01

    Radiofrequency ablation (RFA) procedures are used to destroy abnormal electrical pathways in the heart that can cause cardiac arrhythmias. Current methods relying on fluoroscopy, echocardiography and electrical conduction mapping are unable to accurately assess ablation lesion size. In an effort to better visualize RFA lesions, photoacoustic (PA) and ultrasonic (US) imaging were utilized to obtain co-registered images of ablated porcine cardiac tissue. The left ventricular free wall of fresh (i.e., never frozen) porcine hearts was harvested within 24 hours of the animals' sacrifice. A THERMOCOOLR Ablation System (Biosense Webster, Inc.) operating at 40 W for 30-60 s was used to induce lesions through the endocardial and epicardial walls of the cardiac samples. Following lesion creation, the ablated tissue samples were placed in 25 °C saline to allow for multi-wavelength PA imaging. Samples were imaged with a VevoR 2100 ultrasound system (VisualSonics, Inc.) using a modified 20-MHz array that could provide laser irradiation to the sample from a pulsed tunable laser (Newport Corp.) to allow for co-registered photoacoustic-ultrasound (PAUS) imaging. PA imaging was conducted from 750-1064 nm, with a surface fluence of approximately 15 mJ/cm2 maintained during imaging. In this preliminary study with PA imaging, the ablated region could be well visualized on the surface of the sample, with contrasts of 6-10 dB achieved at 750 nm. Although imaging penetration depth is a concern, PA imaging shows promise in being able to reliably visualize RF ablation lesions.

  14. Percutaneous radiofrequency ablation in painful bone metastases

    Directory of Open Access Journals (Sweden)

    German Garabano

    2015-09-01

    Full Text Available Backgraund There are different treatment for painful bone metastases (mtts, with different results. CT-guided Percutaneous Radiofrequency Ablation (CT-PRA is one of them. The pupose of this retrospective study was to assess the initial results using this methods, focusing on pain relief, showing details of the surgical technique. Methods 18 patients with an average age of 59.2 years and 15 months follow-up were treated. Nine mtts were located in the femur, 4 dorsal / lumbar spine, 3 in scapula and 2 in Iliac. The Mtts origin were Breast Ca 7 cases, lung in 4, Kidney in 4 and 3 in Thyroid. The rachis mtts were found at more than 10mm of the medullary cavity and mtts of long bones showed low risk of fracture. Lesions >3cm were treated whit CT-PRA  using Valleylab Rita needle and these <3cm with CoolTip needle. Pain was assessed by Visual Analog Scale (VAS preoperatively, at 2, 7 and 30 days, and then at 3 and 6 months. Results Preoperative pain score was 8.33 on average. At 7 days of ablatión de VAS score was 5 on average and at 30 days was 2 points. After at 3 and 6 months de VAS average was 1. This method had excellent patients tolerance and no complications. There were two recurrences which underwent endoprosthesis unconventional proximal femur and knee respectively, evolving favorably. Conclusion CT-guided APRF impresses a promising, simple and effective tool in the treatment of painfull bone mtts, achieving excellent pain control with good tolerance by the patient.

  15. Laparoscopic radiofrequency ablation of neuroendocrine liver metastases.

    Science.gov (United States)

    Berber, Eren; Flesher, Nora; Siperstein, Allan E

    2002-08-01

    We previously reported on the safety and efficacy of laparoscopic radiofrequency thermal ablation (RFA) for treating hepatic neuroendocrine metastases. The aim of this study is to report our 5-year RFA experience in the treatment of these challenging group of patients. Of the 222 patients with 803 liver primary and secondary tumors undergoing laparoscopic RFA between January 1996 and August 2001, a total of 34 patients with 234 tumors had neuroendocrine liver metastases. There were 25 men and 9 women with a mean +/- SEM age of 52 +/- 2 years who underwent 42 ablations. Primary tumor types included carcinoid tumor in 18 patients, medullary thyroid cancer in 7, secreting islet cell tumor in 5, and nonsecreting islet cell tumor in 4. There was no mortality, and the morbidity was 5%. The mean hospital stay was 1.1 days. Symptoms were ameliorated in 95%, with significant or complete symptom control in 80% of the patients for a mean of 10+ months (range 6-24 months). All patients were followed for a mean +/- SEM of 1.6 +/- 0.2 years (range 1.0-5.4 years). During this period new liver lesions developed in 28% of patients, new extrahepatic disease in 25%, and local liver recurrence in 13%; existing liver lesions progressed in 13%. Overall 41% of patients showed no progression of their cancer. Nine patients (27%) died. Mean +/- SEM survivals after diagnosis of primary disease, detection of liver metastases, and performance of RFA were 5.5 +/- 0.8 years, 3.0 +/- 0.3 years, and 1.6 +/- 0.2 years, respectively. Sixty-five percent of the patients demonstrated a partial or significant decrease in their tumor markers during follow-up. In conclusion, RFA provides excellent local tumor control with overnight hospitalization and low morbidity in the treatment of liver metastases from neuroendocrine tumors. It is a useful modality in the management of these challenging group of patients.

  16. Radiofrequency ablation for treatment of atrial fibrillation.

    Science.gov (United States)

    Safaei, Nasser; Montazerghaem, Hossein; Azarfarin, Rasoul; Alizadehasl, Azin; Alikhah, Hossein

    2011-01-01

    Atrial Fibrillation (AF) is the most common cardiac arrhythmia which represents a major public health problem. The main purpose of this research is to evaluate the Radiofrequency (RF) ablation effects in the patients with chronic AF scheduled for cardiac surgery because of different heart diseases. The descriptive and prospective study was conducted on 60 patients with AF scheduled for surgery along with RF ablation. The data were collected by questionnaire and included: patients' age, sex, NYHA class, operation type, past medical history, type and cause of valvular heart disease, preoperative ECG (electrocardiogram), duration of surgery, clamping time, cardiopulmonary bypass, and RF ablation time. RF ablation was followed by the main operation. The follow up examination, ECG, and echocardiography were performed 3 and 6 months after operation. The mean age of patients was 48±10 years (18-71 years). Forty one patients had permanent AF and 19 had the persistent AF. The left ventricular ejection fraction was 48.27±9.75 percent before operation, and reached to 56.27±7.87 percent after the surgery (P<0.001). The mean NYHA class before the surgery was 2.83±0.68 which decreased to 1.34±0.46 6 months after the surgery with RF ablation (P<0.001). One patient (1.6%) died after surgery. Complete relief and freedom from AF recurrence was observed in 70% of patients in the mean follow up in 7 months after the surgery. The sinus rhythm with efficient atrial contraction was established in 100% of discharged patients. RF ablation is an effective procedure to cure atrial fibrillation in patients undergoing cardiac surgeries.

  17. Investigations on bipolar radio-frequency current application for interstitial thermotherapy (RF-ITT)

    Science.gov (United States)

    Desinger, Kai; Mueller, Gerhard J.; Stein, Thomas; Tschepe, Johannes

    1996-01-01

    This paper discusses the feasibility of radio-frequency current in bipolar technique for interstitial thermotherapy (rf-ITT). A short survey of established methods for interstitial tissue coagulation, e.g. the interstitial laser photocoagulation (ILP) and microwave exposure are given. In addition, a new concept for interstitial application of bipolar or quasi-bipolar radio- frequency alternating current is presented. Theoretical investigations of the electrical field distribution generated by a dipole model come together in the different mechanisms of heat generation by using radio-frequency alternating current. New concepts of bipolar or quasi- bipolar coaxial layered applicators are presented. This bipolar needle electrode enables the surgeon to use a partial and homogeneous exposure of radio-frequency current for interstitial thermotherapy, e.g. for the treatment of BPH or for concha coagulation in ENT. Less power is needed due to the limited current exposition at the immediate operation site and a highly safe procedure is possible. Therefore, to determine the thermal damage of tissue, depending on the rf parameters, a computer model for a real-time simulation of the spatial electrical field distribution especially for a multiple probe application is currently being developed. This is an appropriate tool for dosimetry. A similar program for LITT, called LITCIT, developed at the Laser-Medizin-Zentrum Berlin has already shown its efficiency in clinical use. Furthermore the feasibility of a 'cross-over' applicator is discussed which combines ILP and rf-application by using metallized optical fibers for a simultaneous application of electrical energy and laser radiation.

  18. Radiofrequency exposure from wireless LANs utilizing Wi-Fi technology.

    Science.gov (United States)

    Foster, Kenneth R

    2007-03-01

    This survey measured radiofrequency (RF) fields from wireless local area networks (WLANs) using Wi-Fi technology against a background of RF fields in the environment over the frequency range 75 MHz-3 GHz. A total of 356 measurements were conducted at 55 sites (including private residences, commercial spaces, health care and educational institutions, and other public spaces) in four countries (U.S., France, Germany, Sweden). Measurements were conducted under conditions that would result in the higher end of exposures from such systems. Where possible, measurements were conducted in public spaces as close as practical to the Wi-Fi access points. Additional measurements were conducted at a distance of approximately 1 m from a laptop while it was uploading and downloading large files to the WLAN. This distance was chosen to allow a useful comparison of fields in the far-field of the antenna in the laptop, and give a representative measure of the exposure that a bystander might receive from the laptop. The exposure to the user, particularly if the antenna of the client card were placed against his or her body, would require different measurement techniques beyond the scope of this study. In all cases, the measured Wi-Fi signal levels were very far below international exposure limits (IEEE C95.1-2005 and ICNIRP) and in nearly all cases far below other RF signals in the same environments. An discusses technical aspects of the IEEE 802.11 standard on which WLANs operate that are relevant to determining the levels of RF energy exposure from WLANs. Important limiting factors are the low operating power of client cards and access points, and the low duty cycle of transmission that normally characterizes their operation.

  19. Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Walfridsson, H; Walfridsson, U; Nielsen, J Cosedis

    2015-01-01

    AIMS: The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) trial assessed the long-term efficacy of an initial strategy of radiofrequency ablation (RFA) vs. antiarrhythmic drug therapy (AAD) as first-line treatment for patients with PAF. I......L and symptom burden in patients with PAF. Patients randomized to RFA showed greater improvement in physical scales (SF-36) and the EQ-visual analogue scale. CLINICAL TRIAL REGISTRATION: URL http://www.clinicaltrials.gov. Unique identifier: NCT00133211....

  20. Differentially-Enhanced Sideband Imaging via Radio-frequency Encoding

    CERN Document Server

    Fard, A M; Jalali, B

    2015-01-01

    We present a microscope paradigm that performs differential interference imaging with high sensitivity via optical amplification and radio-frequency (RF) heterodyne detection. This method, termed differentially-enhanced sideband imaging via radio-frequency encoding (DESIRE), uniquely exploits frequency-to-space mapping technique to encode the image of an object onto the RF sidebands of an illumination beam. As a proof-of-concept, we show validation experiment by implementing radio frequency (f = 15 GHz) phase modulation in conjunction with spectrally-encoded laser scanning technique to acquire one-dimensional image of a barcode-like object using a commercial RF spectrum analyzer.

  1. Endoscopic ultrasound-guided radiofrequency ablation of the pancreas

    DEFF Research Database (Denmark)

    Silviu, Ungureanu Bogdan; Daniel, Pirici; Claudiu, Mărgăritescu;

    2015-01-01

    ultrasound (EUS)-guided radiofrequency ablation (RFA) probe through a 19G needle in order to achieve a desirable necrosis area in the pancreas. Radiofrequency ablation of the head of the pancreas was performed on 10 Yorkshire pigs with a weight between 25 kg and 35 kg and a length of 40-70 cm. Using an EUS...... a coagulative necrosis area with minimal invasion and inflammatory tissue at about 2 cm surrounding the lesion. CONCLUSION: EUS-RFA is a feasible technique and might represent a promising therapy for the future treatment of pancreatic cancer. However, further studies are necessary to investigate EUS-guided RFA...

  2. Endovenous radiofrequency ablation for the treatment of varicose veins.

    Science.gov (United States)

    Kayssi, Ahmed; Pope, Marc; Vucemilo, Ivica; Werneck, Christiane

    2015-04-01

    Varicose veins are a common condition that can be treated surgically. Available operative modalities include saphenous venous ligation and stripping, phlebectomy, endovenous laser therapy and radiofrequency ablation. Radiofrequency ablation is the newest of these technologies, and to our knowledge our group was the first to use it in Canada. Our experience suggests that it is a safe and effective treatment for varicose veins, with high levels of patient satisfaction reported at short-term follow-up. More studies are needed to assess long-term effectiveness and compare the various available treatment options for varicose veins.

  3. Bacterial meningitis after radiofrequency diathermy for adenoid hypertrophy.

    Science.gov (United States)

    Nagasaki, Azusa; Sato, Atsuo; Shiro, Hiroyuki

    2014-06-01

    A 6-year-old otherwise healthy girl who underwent radiofrequency diathermy for adenoid hypertrophy presented with fever on the same day and was diagnosed as having bacterial meningitis 2 days later. Culture of cerebrospinal fluid indicated that the pathogens were penicillin-sensitive Streptococcus pneumoniae and methicillin-sensitive Staphylococcus aureus. The serotype of the causative pneumococcus, 11A, was not covered by the 7-valent pneumococcal conjugate vaccine the patient had been inoculated with. Although not previously reported, radiofrequency diathermy for adenoid hypertrophy can be considered a risk factor for bacteremia and meningitis.

  4. 免钛夹单极梯度电凝法腹腔镜阑尾切除术120例临床体会%Clinical analysis of 120 cases of laparoscopic appendectomy using monopolar gradient electrocoagulation without clips

    Institute of Scientific and Technical Information of China (English)

    徐玉刚; 崔刚; 梁建伟; 杨光; 刘君

    2011-01-01

    Objective:To explore the security and surgical techniques of monopolar gradient electrocoagulation in laparoscopic appendectomy (LA) without clips. Methods:Clinical data of 120 patients who underwent LA with monopolar gradient electrocoagulation from 2009 to 2011 were retrospectively analyzed. Results:All of the 120 cases were treated successfully under laparoscopy without conversion to open surgery. Mean operation time was 45min ( range ,30-90min). Mean length of hospital stay was 4d (range,2-7d). No severe complications were found. Conclusions:The monopolar gradient electrocoagulation is a feasible and safe method with shorter operation time,less blood loss, and less hosptial cost. This procedure is worth popularization without titanium clips left.%目的:探讨腹腔镜阑尾切除术(laparoscopic appendectomy,LA)应用免钛夹单极梯度电凝法处理阑尾系膜的安全性和手术技巧.方法:回顾分析为120例患者应用免钛夹单极梯度电凝法行LA的临床资料.结果:120例手术均获成功,手术时间30~90min,平均45min.术后住院2~7d,平均4d,术后无出血、肠梗阻等并发症发生.结论:应用免钛夹梯度电凝法行LA安全可行,患者出血少,手术时间短,费用低,且无钛夹遗留,值得推广应用.

  5. 鼻内镜下吸引器联合单极电凝治疗鼻顶鼻中后部出血%Endoscopic Treatment of Epistaxis by Monopolar Electrocoagulation and Self-designed Suction Apparatus

    Institute of Scientific and Technical Information of China (English)

    卿箭

    2011-01-01

    [目的]探讨鼻内镜下自制吸引器联合单极电凝治疗鼻顶、中后部鼻出血的疗效.[方法]在鼻内镜引导下,探查63例鼻顶、中后部鼻出血患者的出血点.先自制吸引器,在鼻腔局部麻醉下进行,用单极靠近吸引器末端金属电凝止血.术后常规使用抗生素及止血药.随访并观察治疗效果.[结果] 63例患者均安全顺利完成手术,其中5例术后再出血,行第2次治疗成功.随访半年,均无再次鼻出血.[结论]鼻内镜联合单极电凝治疗鼻顶部、中后部出血方便、实用、有效,并发症少,并能避免盲目性.%[Objective] To explore the effect on treatment of nose bleeding by monopolar electrocoagulation and self-designed suction apparatus underEndoscopy. [Method] Under the guidance of the nasal endoscope, to find 63 cases of patients with bleeding nose bleeding, which locating on thenasal roof or postmedian of nasal cavity. All patients were cured by monopolar electrocoagulation and self-designed suction apparatus under localanesthesia. [Results] 63 cases all got safety and satisfactory results.no nose bleeding recurred with 6 months follow-up. [Conclusion] Under theguidance of endoscope, the monopolar electrocoagulation accompanied by self-designed suction apparatus was simple and effective method on treatmentof nose bleeding, especially at the portion of the nasal roof or postmedian of nasal cavity

  6. Energy

    CERN Document Server

    Foland, Andrew Dean

    2007-01-01

    Energy is the central concept of physics. Unable to be created or destroyed but transformable from one form to another, energy ultimately determines what is and isn''t possible in our universe. This book gives readers an appreciation for the limits of energy and the quantities of energy in the world around them. This fascinating book explores the major forms of energy: kinetic, potential, electrical, chemical, thermal, and nuclear.

  7. Evaluation of the safety and effectiveness of monopolar hook during laparoscopic pelvic lymphadenectomy for gynecological cancer%单极电钩在腹腔镜盆腔淋巴结清扫术中的应用价值

    Institute of Scientific and Technical Information of China (English)

    张潍; 陈必良; 辛晓燕; 杨红; 刘淑娟; 蔡国青

    2013-01-01

    目的:评价单极电钩在腹腔镜盆腔淋巴结清扫术中的有效性、安全性.方法:设计开放、随机、配对、前瞻性实验,比较76例腹腔镜下妇科恶性肿瘤根治术患者单侧淋巴结清扫过程中出血量、淋巴结清扫数量、手术时间、术后髂窝引流量、10周后淋巴囊肿形成率及直径等数据.结果:单极电钩清扫盆腔淋巴结较之目前较流行的超声刀清扫过程,止血效果相当,但单侧淋巴结清扫数量(13.1±4.5个)、单侧手术时间(26.3±6.1min)、单侧淋巴囊肿形成率(11/76)明显优于后者.结论:合理应用单极电钩可完成腹腔镜盆腔淋巴结清扫,治疗效果强于超声刀,可降低腹腔镜手术费用.%Objective: In this prospective randomized pilot study, we evaluated the safety and effectiveness of monopolar hook during laparoscopic pelvic lymphadeneetomy for gynecological cancer,and compared to ultrasound knife. Methods: All 76 patients with gynecological cancer , who were suitable to perform laparoscopic lymphadeneetomy, were randomly assigned for lymphadeneetomy in one side of the pelvis using monopolar hook, whereas, the other side using ultrasound knife. Results: Compared with the ultrasound knife, monopolar hook had the same ability in hemosta-sis and cutting during the pelvic lymphadeneetomy, but, make a superior performance in single - side lymph nodes dis-section(13. 1 ±4.5 Vs 9.4 ±3.7 ,P <0.001) .operation time(26. 3 ±6. 1min Vs 39. 4 ±7.5min ,P = 0.003) and lymphocele formation rate (11/76 Vs 16/76, P < 0. 001). Conclusion: Laparoscopic pelvic lymphadeneetomy with monopolar hook is better than ultrasound knife and with decreased cost.

  8. 单双极电凝法行腹腔镜阑尾切除术的临床应用研究%The clinical practice research of the iaparoscopic appendectomy with the monopolar and bipolar electrocoagulation

    Institute of Scientific and Technical Information of China (English)

    杨富财; 李建忠; 任恒宽

    2011-01-01

    目的:研究应用单双极电凝法行腹腔镜阑尾切除术的可行性和安全性.方法:48例阑尾炎患者均采用单双极电凝法行腹腔镜阑尾切除术,用双极电凝和剪刀处理阑尾动脉和系膜,用单极电钩分离粘连并切开阑尾根部浆膜层,钛夹或缝线处理阑尾根部后切除阑尾.结果:48例手术均获成功,均无残端粪漏发生,亦无残端脓肿及其他并发症发生.术后平均住院3.5d,均痊愈出院.结论:用单双极电凝法行腹腔镜阑尾切除术安全、可行、经济实用,易在基层医院大力推广.%Objective:To study the feasibility and safety of the application of monopolar and bipolar electrocoagulation in the laparoscopic appendectomy (LA). Methods:Forty-eight patients who suffered from appendicitis underwent LA with the monopolar and bipolar electrocoagulation. Appendix artery and mesoappendix were treated with bipolar electrocoagulation and scissors, the adhesion and placenta percreta layer in the root of appendix was isolated and cut with monopolar electrical hook, the root of appendix was dealt with Titanium clip or suture before appendix was cut. Results:All operations were successfully performed,no complications such as stump fecal leakage or stump abscess occurred. The mean postoperative hospital stay was 3.5 d. Conclusions:The monopolar and bipolar electrocoagulation in LA is a workable,secure,economical and practical method,which is worth generalization in primary hospital.

  9. Simulation of Myelinated Nerve Conduction Block Induced by Electrical Stimulus of Monopolar and Bipolar Electrodes%不同电极电刺激对有髓神经传导阻断影响的仿真研究

    Institute of Scientific and Technical Information of China (English)

    孙晨; 张旭; 任朝晖; 董谦; 崔南

    2011-01-01

    目的 比较双电极双向脉冲刺激和单电极双向脉冲刺激在神经纤维传导阻断中的阻断阈值以及对神经纤维的损伤,并通过该研究为电刺激促进脊髓损伤后下尿路功能重建的动物实验选择最优的刺激模式.方法 以有限长单根有髓神经为研究对象,以两栖动物的有髓神经纤维FrankenhaeuserHuxley(F-H)模型为仿真研究基础.结果 比较了单、双电极在双向对称方波以及双向间歇方波作用下的阻断阈值以及单双电极在同样的刺激条件下(包括刺激波形、频率以及电流强度)产生的离子电流强度大小.结论 双电极的阻断阈值大于单电极的阻断阈值.在相同的刺激条件下,双电极双向脉冲刺激对神经的损伤程度小于单电极双向脉冲刺激.%To compare the thresholds and the degrees of axonal injury caused by the impulse stimulations of monopolar and bipolar electrodes in simulation study of nerve conduction block. This study aimed to find an optimal stimulus pattern for the animal experiment of restoring the normal function of lower urinary tract after spinal cord injury through electrical stimulation. We used the myelinated nerve fiber with limited length as the research object, and the Frankenhaeuser-Huxley ( F - H) model for mammal' s marrow nerve fiber as the basic system. We simulated the symmetry biphasic pulses and intermittent biphasic pulses to compare the block threshold and ionic current intensity generated by monopolar and bipolar electrodes. The simulating results indicated that the conduction block threshold induced by bipolar electrode is higher than that of monopolar electrode, and monopolar electrode caused greater damage to the axon when the other situations were same.

  10. Standard guidelines for electrosurgery with radiofrequency current

    Directory of Open Access Journals (Sweden)

    Mutalik Sharad

    2009-08-01

    Full Text Available Definition: Radiofrequency (RF induces thermal destruction of the targeted tissue by an electrical current at a frequency of 0.5 MHz (RF. As the electrode tip is not heated, there is minimal thermal damage to the surrounding tissues, producing good esthetic results. Therefore, RF ablation is also known as cold ablation or "coblation." Modality: It has three modes of operation: (a Cut, (b cut and coagulate and (c coagulate. Therefore, it can be used for various purposes like incision, ablation, fulguration, shave excision and coagulation. Because of the coagulation facility, hemostasis can be achieved and operation becomes easier and faster. Indications: It is effective in treating various skin conditions like dermatosis papulosa nigra, warts, molluscum contagiosum, colloid milia, acquired junctional, compound and dermal melanocytic nevi, seborrheic keratosis, skin tags, granuloma pyogenicum, verrucous epidermal nevi, xanthelesma, rhinophyma, superficial basal cell carcinoma and telangiectasia. It can also be used for cosmetic indications such as resurfacing, earlobe repair and blepharoplasty. Anesthesia: The procedure is accomplished either under topical anesthesia eutactic mixture of local anesthetics or local injectable anesthesia, under all aseptic precautions. Procedure: While operating, only the tip of the electrode should come in contact with the tissue. Actual contact of the electrode with the tissue should be very brief in order to prevent excessive damage to the deeper tissues. This can be accomplished by moving the electrode quickly. Complications: Complications are uncommon and mainly occur due to an improper technique. The treating physician should be aware of the contraindications of the procedure as listed in these guidelines. Physician qualification: RF surgery may be performed by a dermatologist who has acquired adequate training during post-graduation or through recognized fellowships and workshops dedicated to RF surgery. He

  11. Sources of exposure to radiofrequency and microwave radiations in the UK

    CERN Document Server

    Allen, S G

    1983-01-01

    A comprehensive survey is presented of sources of radiofrequency and microwave fields in the United Kingdom that give rise to the exposure of both workers and the general public. The information is presented in the context of the existing guidelines for the restrictions of exposures to such fields and of proposed new guidelines based on restricting the rate of energy absorption averaged over the human body to 0.4 watts per kilogram or, at frequencies below 3 MHz, limiting field strengths to 600 volts per metre. It is concluded that unless account is taken of time averaging relaxations and possible modifying factors relating to energy absorption arising under near field and partial body exposure conditions, there may be difficulties in applying the proposed guidelines to the use of radio frequencies for industrial heating purposes and to some portable and mobile transmitters used for communications.

  12. Phonon-assisted radiofrequency absorption by gold nanoparticles resulting in hyperthermia

    CERN Document Server

    Postnikov, Andrei

    2015-01-01

    It is suggested that in gold nanoparticles (GNPs) of about 5 nm sizes used in the radiofrequency (RF) hyperthermia, an absorption of the RF photon by the Fermi electron occurs with involvement of the longitudinal acoustic vibrational mode (LAVM), the dominating one in the distribution of vibrational density of states (VDOS). This physical mechanism helps to explain two observed phenomena: the size dependence of the heating rate (HR) in GNPs and reduced heat production in aggregated GNPs. The argumentation proceeds within the one-electron approximation, taking into account the discretenesses of energies and momenta of both electrons and LAVMs. The heating of GNPs is thought to consist of two consecutive processes: first, the Fermi electron absorbs simultaneously the RF photon and the LAVM available in the GNP; hereafter the excited electron gets relaxed within the GNP's boundary, exciting a LAVM with the energy higher than that of the previously absorbed LAVM. GNPs containing the Ta and/or Fe impurities are pr...

  13. Extreme diffusion limited electropolishing of niobium radiofrequency cavities

    Science.gov (United States)

    Crawford, Anthony C.

    2017-03-01

    A deeply modulated, regular, continuous, oscillating current waveform is reliably and repeatably achieved during electropolishing of niobium single-cell elliptical radiofrequency cavities. Details of the technique and cavity test results are reported here. The method is applicable for cavity frequencies in the range 500 MHz to 3.9 GHz and can be extended to multicell structures.

  14. Longevity of radiofrequency identification device microchips in citrus trees

    Science.gov (United States)

    Long-term identification of individual plants in the field is an important part of many types of botanical and horticultural research. In a previous report, we described methods for using implanted radiofrequency (RFID) microchips to tag citrus trees for field research. This report provides an upd...

  15. Radiofrequency solutions in clinical high field magnetic resonance

    NARCIS (Netherlands)

    Andreychenko, A.|info:eu-repo/dai/nl/341697672

    2013-01-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) benefit from the sensitivity gain at high field (≥7T). However, high field brings also certain challenges associated with growing frequency and spectral dispersion. Frequency growth results in degraded performance of large volume radiofrequency

  16. Effect of Radiofrequency Radiation on DNA Duplex Stability and Replication.

    Science.gov (United States)

    1983-08-01

    R.W., J.B. Dodgson, I.F. Nes, and R.D. Wells. Duplex regions in single-stranded OX174 DNA are cleaved by a restriction endonuclease from Haemophilus ... aegyptius . J Biol Chem 252:7300-7306 (1977). *i Brown, R.F., S.V. Marshall, and C.W. Hughes. Effect of radiofrequency radi- ation (RFR) on excision

  17. Radiofrequency ablation in the treatment of liver tumors in children

    NARCIS (Netherlands)

    van Laarhoven, Stijn; van Baren, Robertine; Tamminga, Rienk Yde Johan; de Jong, Koert Pieter

    Hepatoblastoma and liver metastasis of Wilms' tumors are rare hepatic tumors in children. Treatment of both tumors consists of a combination of chemotherapy and liver surgery. Radiofrequency ablation (RFA) is frequently used for the treatment of adult liver tumors but is rarely mentioned as a

  18. 47 CFR 1.1310 - Radiofrequency radiation exposure limits.

    Science.gov (United States)

    2010-10-01

    ... Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI... Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Sections 17.4.1, 17.4.1.1, 17.4.2... 1500 MHz, exposure limits for field strength and power density are also generally based on...

  19. [Instrumental radiofrequency electromagnetic radiation dosimetry: general principals and modern methodology].

    Science.gov (United States)

    Perov, S Iu; Kudriashov, Iu B; Rubtsova, N B

    2012-01-01

    The modern experimental radiofrequency electromagnetic field dosimetry approach has been considered. The main principles of specific absorbed rate measurement are analyzed for electromagnetic field biological effect assessment. The general methodology of specific absorbed rate automated dosimetry system applied to establish the compliance of radiation sources with the safety standard requirements (maximum permissible levels and base restrictions) is described.

  20. 77 FR 43535 - Grantee Codes for Certified Radiofrequency Equipment

    Science.gov (United States)

    2012-07-25

    ... radiofrequency (RF) devices under part 2 of its rules. This program is one of the primary means that the Commission uses to ensure that the multitude of RF devices used in the United States operates effectively without causing harmful interference and otherwise complies with the rules. RF devices that are subject to...

  1. Electron Paramagnetic Resonance Imaging: 2. Radiofrequency FT-EPR Imaging

    Indian Academy of Sciences (India)

    2016-08-01

    In this part we shall outline the challenges one faces whiledeveloping time-domain radiofrequency (RF) EPR imagingspectrometer for in vivo studies. Time-domain or FT-EPR isquite a different animal compared to the CW modality. Theevolution of FT-EPR instrumentation at the National CancerInstitute, NIH, USA and representative examples of applicationin cancer research are outlined in this article.

  2. Mitral valve perforation appearing years after radiofrequency ablation

    DEFF Research Database (Denmark)

    Fisch-Thomsen, Marie; Jensen, Jesper K; Egeblad, Henrik

    2011-01-01

    The case is reported of a young adult with Wolff-Parkinson-White (WPW) syndrome who, three years after a complicated radiofrequency (RF) catheter ablation procedure, developed dyspnea on exertion. Echocardiography revealed severe mitral valve regurgitation caused by a perforation of the posterior...

  3. Genetic damage in subjects exposed to radiofrequency radiation.

    Science.gov (United States)

    Verschaeve, Luc

    2009-01-01

    Despite many research efforts and public debate there is still great concern about the possible adverse effects of radiofrequency (RF) radiation on human health. This is especially due to the enormous increase of wireless mobile telephones and other telecommunication devices throughout the world. The possible genetic effects of mobile phone radiation and other sources of radiofrequencies constitute one of the major points of concern. In the past several review papers were published on laboratory investigations that were devoted to in vitro and in vivo animal (cyto)genetic studies. However, it may be assumed that some of the most important observations are those obtained from studies with individuals that were exposed to relatively high levels of radiofrequency radiation, either as a result of their occupational activity or as frequent users of radiofrequency emitting tools. In this paper the cytogenetic biomonitoring studies of RF-exposed humans are reviewed. A majority of these studies do show that RF-exposed individuals have increased frequencies of genetic damage (e.g., chromosomal aberrations) in their lymphocytes or exfoliated buccal cells. However, most of the studies, if not all, have a number of shortcomings that actually prevents any firm conclusion. Radiation dosimetry was lacking in all papers, but some of the investigations were flawed by much more severe imperfections. Large well-coordinated multidisciplinary investigations are needed in order to reach any robust conclusion.

  4. Radiofrequency ablation for the treatment of gastric antral vascular ectasia

    DEFF Research Database (Denmark)

    Dray, X.; Repici, A.; Gonzalez, P.;

    2014-01-01

    Background and study aims: The traditional endoscopic treatment for gastric antral vascular ectasia (GAVE) is argon plasma coagulation, but results are not always positive. Radiofrequency ablation (RFA) is a new endoscopic therapy that may be an attractive option for the treatment of GAVE. The ai...

  5. Radiofrequency Ablation of Hepatic Metastases from Thyroid Carcinoma

    NARCIS (Netherlands)

    Wertenbroek, Marieke W. J. L. A. E.; Links, Thera P.; Prins, Ted R.; Plukker, John T. M.; van der Jagt, Erik J.; de Jong, Koert P.

    2008-01-01

    Background: Radiofrequency ablation (RFA) is performed for various types of liver tumors. It might also have a role in the palliative treatment of liver metastases from thyroid carcinoma. Summary: Three patients with liver metastases of thyroid carcinoma were retrieved from our database of 125 patie

  6. [Treatment of pulmonary vein stenosis secondary to radiofrequency ablation].

    Science.gov (United States)

    Ferrero Guadagnoli, Adolfo; Contreras, Alejandro E; Leonardi, Carlos R; Ballarino, Miguel A; Atea, Leonardo; Peirone, Alejandro R

    2014-01-01

    Isolation of the pulmonary veins by applying radiofrequency is an effective treatment for atrial fibrillation. One of the potential complications with higher clinical compromise utilizing this invasive technique is the occurrence of stenosis of one or more pulmonary veins. This complication can be treated by angioplasty with or without stent implantation, with an adequate clinical improvement, but with a high rate of restenosis.

  7. Extreme diffusion limited electropolishing of niobium radiofrequency cavities

    CERN Document Server

    Crawford, Anthony C

    2016-01-01

    Deeply modulated, continuous, diffusion-limited current waveforms for electropolishing niobium single-cell elliptical radiofrequency cavities are reliably and repeatedly achieved at Fermilab. Details of the technique and cavity test results are reported here. The method is applicable for cavity frequencies in the range 500MHz to 3.9 GHz and can be extended to multicell structures.

  8. CT-guided percutaneous radiofrequency ablation of spinal osteoid osteoma

    Institute of Scientific and Technical Information of China (English)

    LIU Chen; LIU Xiao-guang; ZHU Bin; YUAN Hui-shu; HAN Song-bo; MA Yong-qiang

    2011-01-01

    Background This study evaluated the feasibility,efficacy and safety of CT-guided percutaneous radiofrequency ablation in patients with spinal osteoid osteoma.Methods Two patients suffered spinal osteoid osteoma were treated with CT-guided percutaneous radiofrequency ablation under local anesthesia.Lesions located in sacral vertebrae and cervical vertebrae,which were adjacent to nerve root and spinal canal respectively.Tumors were treated under 90°C radiofrequency temperature lasting 4 minutes by an electrode placement.Visual analog scale was used to evaluate the pain improvement.Results No complications were observed pre- and post-operation.Patients recovered to normal activities immediately and achieved complete pain relief in 24 hours.No symptoms were recurrent in 5 months and 4 months follow up.Mild scoliosis has been recovered in case 2.Conclusions CT-guided percutaneous radiofrequency ablation of spinal osteoid osteoma is safe,effective and has more clinical benefits.The long-term outcome needs further observation.

  9. Expanding the Clinical Application of Fractional Radiofrequency Treatment: Findings on Rhytides, Hyperpigmentation, Rosacea, and Acne Redness.

    Science.gov (United States)

    Hongcharu, Wichai; Gold, Michael

    2015-11-01

    While radiofrequency has been used medically for decades to treat a wide variety of conditions, its use therapeutically to target conditions affecting the skin is relatively new. With the development of fractional radiofrequency, which allows for the heat energy to be delivered in a more targeted manner through the use of needles as electrodes, this technique is now the preferred medical treatment option for many skin conditions given the reduction in recovery time and fewer number of reported side effects. The current study examined the clinical effectiveness of SmartScan(TM) Nano-Fractional RFTM treatment. Participants included 12 healthy female volunteers who reported varying degrees of rhytides, hyperpigmentation, or acne redness. Participants each received one treatment of SmartScan Nano-Fractional RF. The areas receiving treatment were photographed in a standardized way, using high-resolution macrophotography, at baseline (prior to receiving the treatment) and one month after treatment. Baseline and post-treatment photographs were then visually compared for treatment effects and analyzed through software-assisted quantification of variation in pigmentation and skin texture. The results indicated that this SmartScan technique for Nano-Fractional RF is effective in improving skin texture, and pigmentation.

  10. Radiofrequency ablation using BarRx for the endoscopic treatment of radiation proctopathy: a series of three cases

    Directory of Open Access Journals (Sweden)

    Patel A

    2014-12-01

    Full Text Available Anish Patel, Rahul Pathak, Vrushak Deshpande, Sunil H Patel, Prasanna C Wickremesinghe, Deepak Vadada Department of Gastrointestinal Medicine, Richmond University Medical Center, Staten Island, NY, USA Abstract: Radiation proctopathy is a complication of pelvic radiotherapy, which occurs in patients treated for carcinoma of the prostate, rectum, urinary bladder, cervix, uterus, and testes. If it presents within 6 weeks to 9 months after therapy, it is called acute radiation proctitis/proctopathy (ARP, and if it occurs 9 months to a year after treatment, it is classified as chronic radiation proctitis/proctopathy (CRP. CRP occurs in 5%–20% of patients receiving pelvic radiation, depending on the radiation dose and the presence or absence of chemotherapy. In many cases, CRP resolves spontaneously, but in some, it can lead to persistent rectal bleeding. Other symptoms of CRP include diarrhea, mucoid discharge, urgency, tenesmus, rectal pain, and fecal incontinence. Despite the availability of several therapies, many patients fail to respond, and continue to suffer in their quality of life. Radiofrequency ablation (RFA is a newer endoscopic technique that uses radiofrequency energy to ablate tissue. This is an emerging way to treat radiation proctopathy and other mucosal telangiectasia. We present three cases of radiation proctopathy treated with RFA at our institute and review the literature on treatment modalities for CRP. We were also able to find 16 other cases of CRP that used RFA, and review their literature as well as literature on other treatment modalities. Keywords: radiofrequency ablation, radiation proctopathy, BarRx, Halo catheter

  11. Detailed investigation of optoelectronic and microstructural properties of plasma polymerized cyclohexane thin films: Dependence on the radiofrequency power

    Energy Technology Data Exchange (ETDEWEB)

    Manaa, C.; Bouaziz, L. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens Cedex 2 (France); Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M.; Zellama, K., E-mail: kacem.zellama@u-picardie.fr; Benlahsen, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens Cedex 2 (France); Kouki, F.; Mejatty, M.; Bouchriha, H. [Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia)

    2015-06-07

    Optical properties of polymerized cyclohexane films deposited by radiofrequency plasma enhanced chemical vapor deposition technique at different radiofrequency powers onto glass and silicon substrates, are studied and correlated with the microstructure of the films, using a combination of atomic force microscopy, Raman and Fourier Transformer Infrared spectroscopy and optical measurements. The optical constants such as refractive index n, dielectric permittivity ε and extinction k and absorption α coefficients, are extracted from transmission and reflection spectra through the commercial software CODE. These constants lead, by using common theoretical models as Cauchy, Lorentz, Tauc and single effective oscillator, to the determination of the static refractive index n{sub s} and permittivity ε{sub s}, the plasma frequency ω{sub p}, the carrier density to effective mass ratio N/m{sub e}{sup *}, the optical conductivity σ{sub oc}, the optical band gap E{sub g} and the oscillation and dispersion energies E{sub 0} and E{sub d}, respectively. We find that n, ε{sub s}, ω{sub p}, N/m{sub e}{sup *}, E{sub d}, increase with radiofrequency power, while E{sub g} and E{sub 0} decrease in the same range of power. These results are well correlated with those obtained from atomic force microscopy, Raman and infrared measurements. They also indicate that the increase of the radiofrequency power promotes the fragmentation of the precursor and increases the carbon C-sp{sup 2} hybridization proportion, which results in an improvement of the optoelectronic properties of the films.

  12. Optimization of the generator settings for endobiliary radiofrequency ablation

    Institute of Scientific and Technical Information of China (English)

    Maximilien; Barret; Sarah; Leblanc; Ariane; Vienne; Alexandre; Rouquette; Frederic; Beuvon; Stanislas; Chaussade; Frederic; Prat

    2015-01-01

    AIM:To determine the optimal generator settings for endobiliary radiofrequency ablation. METHODS:Endobiliary radiofrequency ablation was performed in live swine on the ampulla of Vater,the common bile duct and in the hepatic parenchyma. Radiofrequency ablation time,"effect",and power were allowed to vary. The animals were sacrificed two hours after the procedure. Histopathological assessment of the depth of the thermal lesions was performed. RESULTS:Twenty-five radiofrequency bursts were applied in three swine. In the ampulla of Vater(n = 3),necrosis of the duodenal wall was observed starting with an effect set at 8,power output set at 10 W,and a 30 s shot duration,whereas superficial mucosal damage of up to 350 μm in depth was recorded for an effect set at 8,power output set at 6 W and a 30 s shot duration. In the common bile duct(n = 4),a 1070 μm,safe and efficient ablation was obtained for an effect set at 8,a power output of 8 W,and an ablation time of 30 s. Within the hepatic parenchyma(n = 18),the depth of tissue damage varied from 1620 μm(effect = 8,power = 10 W,ablation time = 15 s) to 4480 μm(effect = 8,power = 8 W,ablation time = 90 s). CONCLUSION:The duration of the catheter application appeared to be the most important parameter influencing the depth of the thermal injury during endobiliary radiofrequency ablation. In healthy swine,the currently recommended settings of the generator may induce severe,supratherapeutic tissue damage in the biliary tree,especially in the high-risk area of the ampulla of Vater.

  13. Energy

    CERN Document Server

    Robertson, William C

    2002-01-01

    Confounded by kinetic energy? Suspect that teaching about simple machines isn t really so simple? Exasperated by electricity? If you fear the study of energy is beyond you, this entertaining book will do more than introduce you to the topic. It will help you actually understand it. At the book s heart are easy-to-grasp explanations of energy basics work, kinetic energy, potential energy, and the transformation of energy and energy as it relates to simple machines, heat energy, temperature, and heat transfer. Irreverent author Bill Robertson suggests activities that bring the basic concepts of energy to life with common household objects. Each chapter ends with a summary and an applications section that uses practical examples such as roller coasters and home heating systems to explain energy transformations and convection cells. The final chapter brings together key concepts in an easy-to-grasp explanation of how electricity is generated. Energy is the second book in the Stop Faking It! series published by NS...

  14. Unipolar radiofrequency treatment to improve the appearance of cellulite.

    Science.gov (United States)

    Alexiades-Armenakas, Macrene; Dover, Jeffrey S; Arndt, Kenneth A

    2008-09-01

    Previous studies suggest that radiofrequency (RF) energy may be effective as a treatment for cellulite. This bilateral paired blinded comparative study assesses the efficacy and safety of a unipolar RF device for improving the appearance of cellulite using a new quantitative cellulite grading system. In this randomized, blinded, split-design study, 10 individuals (aged 32-57 years) with a clinically observable excess of subcutaneous fat and cellulite (minimum grade 2 out of 4) on the thighs received up to six unilateral treatments (number of treatments at the investigator's discretion) at 2-week intervals with unipolar RF. The untreated side of the thigh served as an internal control. Treated thighs were randomly assigned by alternate allocation. Results were evaluated using study participant questionnaires and by two blinded evaluators (JSD, KAA) using photographs and the author's (MAA) cellulite grading scale at each treatment visit and at 1-month and 3-month follow-up visits after the final treatment. A novel quantitative four-point cellulite grading system is presented and applied, which separately grades dimple density, dimple distribution, dimple depth, diameter and contour. All participants responded to treatment (mean of 4.22 and range of three to six treatments). The blinded evaluations of photographs using the cellulite grading scale demonstrated the following mean grading scores for the treated leg versus the control leg: dimple density of 2.73 vs 3.18 (11.25% mean improvement), dimple distribution 2.89 vs 3.32 (10.75% mean improvement), dimple depth 1.47 vs 1.54 (2.5% mean improvement), and mean score of 2.36 (SEM 0.45) vs 2.68 (SEM 0.57) (8.00+/-2.84% mean improvement). The treatment was painless and side effects included minimal to moderate erythema which resolved within 1 to 3 hours. No crusting, scarring or dyspigmentation was observed. This randomized, blinded, split-design, controlled study employing a quantitative four-point grading scale

  15. Optical characteristics of transparent samarium oxide thin films deposited by the radio-frequency sputtering technique

    Indian Academy of Sciences (India)

    A A ATTA; M M EL-NAHASS; KHALED M ELSABAWY; M M ABD EL-RAHEEM; A M HASSANIEN; A ALHUTHALI; ALI BADAWI; AMAR MERAZGA

    2016-11-01

    Transparent metal oxide thin films of samarium oxide (Sm$_2$O$_3$) were prepared on pre-cleaned fused optically flat quartz substrates by radio-frequency (RF) sputtering technique. The as-deposited thin films were annealed at different temperatures (873, 973 and 1073 K) for 4 h in air under normal atmospheric pressure. The topological morphology of the film surface was characterized by using atomic force microscopy (AFM). The optical properties of the as-prepared and annealed thin films were studied using their reflectance and transmittance spectra at nearly normal incident light. The estimated direct optical band gap energy (E$^{d}_{g}$ ) values were found to increase by increasing the annealing temperatures. The dispersion curves of the refractive index of Sm$_2$O$_3$ thin films were found to obey the single oscillator model.

  16. Radiofrequency electromagnetic fields in the Cookridge area of Leeds

    CERN Document Server

    Fuller, K; Judd, P M; Lowe, A J; Shaw, J

    2002-01-01

    On the 8 and 9 May 2002 representatives of the National Radiological Protection Board (NRPB) performed a radiofrequency electromagnetic field survey in the Cookridge area of Leeds in order to assess exposure to radio signals from transmitters mounted on a water tower/a lattice tower and a radio station tower. Guidelines on limiting exposure to radio signals have been published by NRPB and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines are designed to prevent established adverse effects on human health. During this survey, the total exposures due to all radio signals from 30 MHz to 18000 MHz (18 GHz) were measured. This frequency range was chosen as it includes mobile phone base station transmissions, which are at around 900 and 1800 MHz and super high frequency (SHF) transmissions from most of the large microwave dish antennas mounted on the towers. In addition, other major sources of radiofrequency electromagnetic fields in the environment such as broadcast radio...

  17. Pulmonary radiofrequency ablation (Part 2): Procedure and follow-up.

    Science.gov (United States)

    Plasencia Martínez, J M

    2015-01-01

    Pulmonary radiofrequency ablation requires more than just interventional radiology skills. Patients must be selected carefully, and the acts that need to be done before, during, and after the procedure must be coordinated. To guarantee patient safety, radiologists need to know the variants of the technique, the precautions that must be taken, the complications that can occur, and the risks involved. Early differentiation between tumor tissue and normal changes secondary to treatment on imaging tests will make it possible to repeat the treatment without delays, and this will increase survival. This article describes how to coordinate and carry out pulmonary radiofrequency ablation, the complications of the technique, and the current evidence in follow-up. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  18. Addressed qubit manipulation in radio-frequency dressed lattices

    Science.gov (United States)

    Sinuco-León, G. A.; Garraway, B. M.

    2016-03-01

    Precise control over qubits encoded as internal states of ultracold atoms in arrays of potential wells is a key element for atomtronics applications in quantum information, quantum simulation and atomic microscopy. Here we theoretically study atoms trapped in an array of radio-frequency dressed potential wells and propose a scheme for engineering fast and high-fidelity single-qubit gates with low error due to cross-talk. In this proposal, atom trapping and qubit manipulation relies exclusively on long-wave radiation making it suitable for atom-chip technology. We demonstrate that selective qubit addressing with resonant microwaves can be programmed by controlling static and radio-frequency currents in microfabricated conductors. These results should enable studies of neutral-atom quantum computing architectures, powered by low-frequency electromagnetic fields with the benefit of simple schemes for controlling individual qubits in large ensembles.

  19. Radiofrequency ablation of recurrent cholangiocarcinoma after orthotopic liver transplantation - a case report

    Institute of Scientific and Technical Information of China (English)

    Rakesh Rai; Derek Manas; John Rose

    2005-01-01

    AIM: To report the use of radiofrequency ablation in the treatment of recurrenct cholangiocarcinoma in the transplanted liver.METHODS: A lady who underwent orthotopic liver transplantation (OLT) for intrahepatic cholangiocarcinoma recurrence of tumour 13 mo after tralsplantation inspite of adjuvant chemotherapy. Her recurrent tumour was treated with radiofrequency ablation.RESULTS: She survived for 18 mo following the recurrence of her tumour.CONCLUSION: Radiofrequency ablation can be used safely in the transplanted liver to treat recurrent tumour.

  20. First Demonstration of Electron Beam Generation and Characterization with an All Superconducting Radio-frequency (SRF) Photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Kamps, T; Barday, R; Jankowiak, A; Knobloch, J; Kugeler, O; Matveenko, A N; Neumann, A; Quast, T; Rudolph, J; Schubert, S G; Volker, J; Kneisel, P; Nietubyc, R; Sekutowicz, J K; Smedley, J; Volkov, V; Weinberg, G

    2011-09-01

    In preparation for a high brightness, high average current electron source for the energy-recovery linac BERLinPro an all superconducting radio-frequency photoinjector is now in operation at Helmholtz-Zentrum Berlin. The aim of this experiment is beam demonstration with a high brightness electron source able to generate sub-ps pulse length electron bunches from a superconducting (SC) cathode film made of Pb coated on the backwall of a Nb SRF cavity. This paper describes the setup of the experiment and first results from beam measurements.

  1. Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jung Hwan; Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Valcavi, Roberto [Endocrinology Division and Thyroid Disease Center, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Pacella, Claudio M. [Diagnostic Imaging and Interventional Radiology Department, Ospedale Regina Apostolorum, Albano Laziale-Rome (IT); Rhim, Hyun Chul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Na, Dong Kyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of)

    2011-10-15

    Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

  2. Water-cooled radiofrequency neuroablation for sacroiliac joint dysfunctional pain

    OpenAIRE

    2016-01-01

    Sacroiliac (SI) joint dysfunction is a common source of chronic low-back pain. Recent evidences from different parts of the world suggest that cooled radiofrequency (RF) neuroablation of sacral nerves supplying SI joints has superior pain alleviating properties than available existing treatment options for SI joint dysfunctional pain. A 35-year-old male had intractable bilateral SI joint pain (numeric rating scale [NRS] - 9/10) with poor treatment response to intra-articular steroid therapy. ...

  3. Primary papillary thyroid carcinoma previously treated incompletely with radiofrequency ablation

    OpenAIRE

    Kim Hoon; Ryu Woo; Woo Sang; Son Gil; Lee Eun; Lee Jae; Bae Jeoung

    2010-01-01

    Radiofrequency ablation (RFA) recently has been applied to benign thyroid nodules, mainly for the cosmetic reasons, and limited cases of local recurrences or focal distant metastases of well-differentiated thyroid cancer, in the high-risk reoperative condition or for the palliative purpose. But no report has been made on the RFA for primary thyroid cancer to date. We report on a patient with primary papillary carcinoma of thyroid gland who had undergone RFA before the cytological diagnosis of...

  4. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules

    OpenAIRE

    Chiara Dobrinja; Stella Bernardi; Bruno Fabris; Rita Eramo; Petra Makovac; Gabriele Bazzocchi; Lanfranco Piscopello; Enrica Barro; Nicolò de Manzini; Deborah Bonazza; Maurizio Pinamonti; Fabrizio Zanconati; Fulvio Stacul

    2015-01-01

    Background. Radiofrequency ablation (RFA) has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules) and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms). Two Thy3 nodules regrew after the procedure, and these patients accepted t...

  5. Radiofrequency ablation for postsurgical thyroid removal of differentiated thyroid carcinoma

    OpenAIRE

    Xu, Dong; Wang, Lipin; Long, Bin; Ye, Xuemei; Ge, MingHua; Wang, Kejing; Guo, Liang; Li, Linfa

    2016-01-01

    Differentiated thyroid carcinoma (DTC) is the most common endocrine malignancy. Surgical removal with radioactive iodine therapy is recommended for recurrent thyroid carcinoma, and the postsurgical thyroid removal is critical. This study evaluated the clinical values of radiofrequency ablation (RFA) in the postsurgical thyroid removal for DTC. 35 DTC patients who had been treated by subtotal thyroidectomy received RFA for postsurgical thyroid removal. Before and two weeks after RFA, the thyro...

  6. Sympathetic cooling of $^4$He$^+$ ions in a radiofrequency trap

    CERN Document Server

    Roth, B; Schiller, S

    2004-01-01

    We have generated Coulomb crystals of ultracold $^4$He$^+$ ions in a linear radiofrequency trap, by sympathetic cooling via laser--cooled $^9$Be$^+$. Stable crystals containing up to 150 localized He$^+$ ions at $\\sim$20 mK were obtained. Ensembles or single ultracold He$^+$ ions open up interesting perspectives for performing precision tests of QED and measurements of nuclear radii. The present work also indicates the feasibility of cooling and crystallizing highly charged atomic ions using $^9$Be$^+$ as coolant.

  7. Tinnitus and cell phones: the role of electromagnetic radiofrequency radiation

    OpenAIRE

    Seyed Mohammad Javad Mortazavi; Seyed Ali Reza Mortazavi

    2016-01-01

    ABSTRACT INTRODUCTION: Tinnitus is a multifactorial condition and its prevalence has increased on the past decades. The worldwide progressive increase of the use of cell phones has exposed the peripheral auditory pathways to a higher dose of electromagnetic radiofrequency radiation (EMRFR). Some tinnitus patients report that the abusive use of mobiles, especially when repeated in the same ear, might worsen ipsilateral tinnitus. OBJECTIVE: The aim of this study was to evaluate the availabl...

  8. Energy

    Science.gov (United States)

    2003-01-01

    Canada, Britain, and Spain. We found that the energy industry is not in crisis ; however, U.S. government policies, laws, dollars, and even public...CEIMAT (Centro de Investagaciones Energeticas , Medioambeintales y Tecnologicas) Research and development Page 3 of 28ENERGY 8/10/04http://www.ndu.edu...meet an emerging national crisis (war), emergency (natural disaster), or major impact event (Y2K). Certain resources are generally critical to the

  9. Hepatectomia videolaparoscópica com dispositivo de radiofrequência Laparoscopic hepatectomy with radiofrequency device

    Directory of Open Access Journals (Sweden)

    Vivian Resende

    2013-04-01

    Full Text Available As ressecções hepáticas laparoscópicas vêm ganhando adeptos entre cirurgiões pois evidenciam recuperação rápida, menor permanência hospitalar e melhor resultado estético. A utilização do dispositivo laparoscópico de radiofreqüência foi pela primeira vez utilizada, com sucesso, no Brasil, para a ressecção de carcinoma hepatocelular no segmento VI, em dois pacientes cirróticos. Apesar do sangramento intraoperatório continuar sendo um grande desafio para o cirurgião durante ressecções hepáticas laparoscópicas, em ambos os casos, a exclusão vascular hepática foi dispensável e não houve necessidade de hemotransfusão. Os pacientes receberam alta hospitalar no quarto dia pós-operatório.Laparoscopic liver resections are gaining adherents among surgeons, as they show rapid recovery, shorter hospital stay and better cosmetic results. The use of a laparoscopic radiofrequency device was first carried out successfully in Brazil for resection of hepatocellular carcinoma of the segment VI in two cirrhotic patients. Although intraoperative bleeding remains a major challenge for the surgeon during laparoscopic liver resections, in both cases the hepatic vascular exclusion was expendable and there was no need for blood transfusion. Patients were discharged on the fourth postoperative day.

  10. The radio-frequency design of an iris-type coupler for the CPHS radio-frequency quadrupole

    Science.gov (United States)

    Xiong, Zheng-Feng; Zheng, Shu-Xin; Xing, Qing-Zi; Guan, Xia-Ling

    2012-01-01

    The Compact Pulsed Hadron Source (CPHS) project is a university-based proton accelerator platform (13 MeV, 16 kW, 50 mA peak current, 0.5 ms pulse width at 50 Hz) for multi-disciplinary neutron and proton applications. The CPHS linac consists of a 3 MeV radio-frequency quadrupole (RFQ) linac and a 13 MeV drift tube linac (DTL). Both the RFQ and DTL share a 325 MHz, 2.1 MW klystron source. A single iris-type radio-frequency (RF) coupler is used to feed 537 kW of RF power to the RFQ cavity. Three-dimensional electromagnetic models of the ridge-loaded tapered waveguide (RLWG) and the coupler-cavity system are presented, and the design process and results of the RLWG and iris plate are described in detail.

  11. Characteristics of a 13.56 MHz radiofrequency-driven multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Boonyawan, D; Chiraphatpimol, N; Vilaithong, T [Fast Neutron Research Facility, Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2002-11-01

    The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5x10{sup 18} m{sup -3} was obtained. The rms beam emittance is found to be about 32{+-}4 mm mrad, and the energy spread of the argon beam is around 3.1{+-}0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.

  12. Characteristics of a 13.56 MHz radiofrequency-driven multicusp ion source

    Science.gov (United States)

    Boonyawan, D.; Chiraphatpimol, N.; Vilaithong, T.

    2002-11-01

    The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5×1018 m-3 was obtained. The rms beam emittance is found to be about 32+/-4 mm mrad, and the energy spread of the argon beam is around 3.1+/-0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.

  13. Energy Delivery Systems for Treatment of Benign Prostatic Hyperplasia

    Science.gov (United States)

    2006-01-01

    Executive Summary Objective The Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat (MAS) to conduct a health technology assessment on energy delivery systems for the treatment of benign prostatic hyperplasia (BPH). Clinical Need: Target Population and Condition BPH is a noncancerous enlargement of the prostate gland and the most common benign tumour in aging men. (1) It is the most common cause of lower urinary tract symptoms (LUTS) and bladder outlet obstruction (BOO) and is an important cause of diminished quality of life among aging men. (2) The primary goal in the management of BPH for most patients is a subjective improvement in urinary symptoms and quality of life. Until the 1930s, open prostatectomy, though invasive, was the most effective form of surgical treatment for BPH. Today, the benchmark surgical treatment for BPH is transurethral resection of the prostate (TURP), which produces significant changes of all subjective and objective outcome parameters. Complications after TURP include hemorrhage during or after the procedure, which often necessitates blood transfusion; transurethral resection (TUR) syndrome; urinary incontinence; bladder neck stricture; and sexual dysfunction. A retrospective review of 4,031 TURP procedures performed by one surgeon between 1979 and 2003 showed that the incidence of complications was 2.4% for blood transfusion, 0.3% for TUR syndrome, 1.5% for hemostatic procedures, 2.8% for bladder neck contracture, and 1% for urinary stricture. However, the incidence of blood transfusion and TUR syndrome decreased as the surgeon’s skills improved. During the 1990s, a variety of endoscopic techniques using a range of energy sources have been developed as alternative treatments for BPH. These techniques include the use of light amplification by stimulated emission of radiation (laser), radiofrequency, microwave, and ultrasound, to heat prostate tissue and cause coagulation or vaporization. In addition

  14. Epidemiological studies of radio-frequency radiation: Current status and areas of concern

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, John R. [Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva (Israel)

    1996-02-11

    These comments deal with the possible impact on human populations of intense sources of radio-frequency radiation, and not the much lower level of the usual sources of such radiation associated, for example with household appliances. These intense sources were developed and extensively used first in World War II (1940-45). Much of the health evaluation has been done by, and for, military organizations. There are important differences in the energy generated by low frequency (ELF) and radar; it then follows that there may be differences in their effects on human populations. Problems common to both types are: (1) the uncertainty as to biological mechanisms; (2) weak experimental evidence of effect; (3) epidemiological preoccupation with carcinogenesis, with its latency and low incidence. For both types there is the presumption of greater occupational than community risk, the latter often not well studied, and problems as to exposure quantification and specificity. To these one must add (4) the inherently epidemiological problems of a study at a given source of adequate sample size, case-findings, exposure estimation, confounders, and residential and job instability. Despite these problems, there are findings from sets of studies which suggest four possible health effects from radar (radio-frequency radiation) exposure: (A) disturbances in blood counts, not necessarily of clinical severity; (B) changes in chromosomes of white blood cells; (C) increases in frequency of unfavorable reproductive outcomes, especially spontaneous abortion, and (D) increases in cancers of certain sites. A review article on this topic was published elsewhere, providing evidence from various exposures on such possible effects. A brief critique is provided of evidence on these four possible effects, identifying some areas of uncertainty for which studies at sites like Skrunda could provide useful information

  15. Experimental study on the feasibility and safety of radiofrequency ablation for secondary splenomagely and hypersplenism

    Institute of Scientific and Technical Information of China (English)

    Quan-Da Liu; Kuan-Sheng Ma; Zhen-Ping He; Jun Ding; Xue-Quan Huang; Jia-Hong Dong

    2003-01-01

    AIM: To assess the feasibility and safety of radiofrequency ablation (RFA) in treatment of secondary splenomagely and hypersplenism.METHODS: Sixteen healthy mongrel dogs were randomly divided into two groups, group Ⅰ (n=4) and group Ⅱ (n=12).Congestive splenomegaly was induced by ligation of splenic vein and its collateral branches in both groups. At the end of 3rd week postoperation, RFA in spleen was performed in group Ⅱ via laparotomy, complications of RFA were observed,CT scan was performed and the spleens were obtained.The radiofrequency (RF) thermal lesions and histopathology of spleen were examined regularly.RESULTS: No complication or death was observed in both groups; CT revealed that the splenomegaly lasted over 2months after ligation of splenic vein; the segmental RF lesions included hyperintense zone of coagulative necrosis and more extensive peripheral hypointense infarcted zone, the latter was called "bystander effect". The infarcted zone would be absorbed and subsequently disappeared in 4-6 weeks after RFA accompanied with shrinkage of the remnant spleen.The fundamental histopathological changes of splenic lesions caused by RF thermal energy included local coagulative necrosis, peripheral thrombotic infarction zone, subsequent tissue absorption and fibrosis in the zone of thrombotic infarction, the occlusion of vessels in remnant viable spleen,deposition of extensive fibrous protein, and disappearance of congestive splenic sinusoid - "splenic carnification". Those pathologic changes were underline of shrinkage of spleen.CONCLUSION: It is feasible and safe to perform RFA in spleen to treat experimental splenomegaly and hypersplenism. The RFA could be safely performed clinically via laparotomy or laparoscopic procedure while spleen was strictly separated from surrounding organs.

  16. Radiofrequency for the Treatment of Lumbar Radicular Pain: Impact on Surgical Indications

    Directory of Open Access Journals (Sweden)

    José Manuel Trinidad

    2015-01-01

    Full Text Available Study Design. Quasiexperimental study. Objective. To investigate whether radiofrequency treatment can preclude the need for spinal surgery in both the short term and long term. Background. Radiofrequency is commonly used to treat lumbosacral radicular pain. Only few studies have evaluated its effects on surgical indications. Methods. We conducted a quasiexperimental study of 43 patients who had been scheduled for spinal surgery. Radiofrequency was indicated for 25 patients. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment (pulsed radiofrequency of dorsal root ganglion, 76%; conventional radiofrequency of the medial branch, 12%; combined technique, 12%. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment. In addition, we also evaluated adverse effects, ODI, NRS. Results. We observed after treatment with radiofrequency 80% of patients rejected spinal surgery in the short term and 76% in the long term. We conclude that radiofrequency is a useful treatment strategy that can achieve very similar outcomes to spinal surgery. Patients also reported a very high level of satisfaction (84% satisfied/very satisfied. We also found that optimization of the electrical parameters of the radiofrequency improved the outcome of this technique.

  17. Role of percutaneous ultrasonographic guided radiofrequency ablation in the management of hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Youssef

    2014-06-01

    Conclusion: Radiofrequency thermal ablation is a simple, effective and less expensive technique with a low morbidity compared with surgical treatment. Radiofrequency thermal ablation can produce significant long-term survival rates and excellent local control for cirrhotic patients with early stage, unresectable HCC.

  18. Temporal changes in patient characteristics and prior pharmacotherapy in patients undergoing radiofrequency ablation of atrial fibrillation

    DEFF Research Database (Denmark)

    Karasoy, Deniz; Gislason, Gunnar Hilmar; Hansen, Jim

    2013-01-01

    Trends in patient selection and pharmacotherapy before radiofrequency ablation (RFA) of atrial fibrillation are not well studied. We examined temporal trends in RFA utilization on a nationwide scale in Denmark.......Trends in patient selection and pharmacotherapy before radiofrequency ablation (RFA) of atrial fibrillation are not well studied. We examined temporal trends in RFA utilization on a nationwide scale in Denmark....

  19. Radiofrequency Ablation of Benign Thyroid Nodules and Recurrent Thyroid Cancers: Consensus Statement and Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Na, Dong Gyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of); Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Jung, So Lyung [Seoul St. Marys Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2012-06-15

    Radiofrequency ablation is a new non-surgical treatment modality for patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the treatment of benign thyroid nodules and recurrent thyroid cancers using radiofrequency ablation. These recommendations are based on evidence from the current literature and expert consensus

  20. Quantitative sensory testing may predict response to sphenopalatine ganglion pulsed radiofrequency treatment in cluster headaches: a case series

    NARCIS (Netherlands)

    Chua Hai Liang, N.; Vissers, K.C.P.; Wilder-Smith, O.H.G.

    2011-01-01

    Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency thermocoagulation for the management of certain chronic pain syndromes. We present our first three patients with long-standing cluster headaches who were treated with pulsed radiofrequency to the spheno

  1. Simulating the Radio-Frequency Dielectric Response of Relaxor Ferroelectrics: Combination of Coarse-Grained Hamiltonians and Kinetic Monte Carlo Simulations.

    Science.gov (United States)

    Geneste, Grégory; Bellaiche, L; Kiat, Jean-Michel

    2016-06-17

    The radio-frequency dielectric response of the lead-free Ba(Zr_{0.5}Ti_{0.5})O_{3} relaxor ferroelectric is simulated using a coarse-grained Hamiltonian. This concept, taken from real-space renormalization group theories, allows us to depict the collective behavior of correlated local modes gathered in blocks. Free-energy barriers for their thermally activated collective hopping are deduced from this ab initio-based approach, and used as input data for kinetic Monte Carlo simulations. The resulting numerical scheme allows us to simulate the dielectric response for external field frequencies ranging from kHz up to a few tens of MHz for the first time and to demonstrate, e.g., that local (electric or elastic) random fields lead to the dielectric relaxation in the radio-frequency range that has been observed in relaxors.

  2. Simulating the Radio-Frequency Dielectric Response of Relaxor Ferroelectrics: Combination of Coarse-Grained Hamiltonians and Kinetic Monte Carlo Simulations

    Science.gov (United States)

    Geneste, Grégory; Bellaiche, L.; Kiat, Jean-Michel

    2016-06-01

    The radio-frequency dielectric response of the lead-free Ba (Zr0.5Ti0.5)O3 relaxor ferroelectric is simulated using a coarse-grained Hamiltonian. This concept, taken from real-space renormalization group theories, allows us to depict the collective behavior of correlated local modes gathered in blocks. Free-energy barriers for their thermally activated collective hopping are deduced from this ab initio-based approach, and used as input data for kinetic Monte Carlo simulations. The resulting numerical scheme allows us to simulate the dielectric response for external field frequencies ranging from kHz up to a few tens of MHz for the first time and to demonstrate, e.g., that local (electric or elastic) random fields lead to the dielectric relaxation in the radio-frequency range that has been observed in relaxors.

  3. Prótesis de cúpula monopolar en el tratamiento de fracturas y luxofracturas del radio. [Monopolar ­radial­ head ­arthroplasty­ in ­the ­treatment­ of ­fracture and ­fracture-dislocations ­of ­the ­radius.

    Directory of Open Access Journals (Sweden)

    Gerardo L. Gallucci

    2014-06-01

    Full Text Available Objetivo: Evaluar retrospectivamente los resultados clínicos y radiológicos de una serie consecutiva de pacientes con fracturas y luxofracturas de la cúpula radial a quienes se les realizó el reemplazo por una prótesis monopolar. Materiales­ y ­Métodos: Se incluyeron 20 pacientes. Criterios de inclusión: <18 años, con fracturas o luxofracturas de la cúpula radial, tratados con prótesis monoblock de titanio y seguimiento mínimo de un año. Quince eran mujeres, edad promedio 59 años. Siete eran fracturas aisladas y 13, luxofracturas. Se evaluaron el grado de aflojamiento protésico, la erosión capitelar, el ensanchamiento del espacio articular humeral lateral y las calcificaciones heterotópicas. El seguimiento fue de 26 meses. Resultados: La flexo-extensión fue de 139º-5º y la prono-supinación, de 79-79°. El arco total fue de 134°. Fuerza de puño: 84% del lado contralateral. El dolor según la escala analógica visual fue de 2, DASH: 11 puntos, 13 resultados excelentes y 6 buenos. Se detectó aflojamiento del implante (12 casos, aumento de la radiolucidez capitelar (4 casos y ensanchamiento del espacio ulnohumeral lateral (2 casos. Hubo 2 complicaciones: una neurodocitis cubital que debió ser operada y una extracción de implante por aflojamiento y dolor. Conclusiones: El reemplazo de la cúpula radial en lesiones no reconstruibles es una opción terapéutica viable, con buenos resultados funcionales a corto y mediano plazo. La recuperación de la estabilidad articular fue posible en todos los casos y el índice de aflojamiento protésico asintomático fue elevado.

  4. RADIOFREQUENCY ABLATION USING HYPERTONIC SALINE SOLUTION INSTILLATION: AN EX VIVO STUDY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To determine whether radiofrequency ablation using hypertonic saline solution instillation can increase the extent of thermally mediated coagulation in ex vivo pig liver tissue. Methods Fifty-six radiofrequency ablation lesions were produced in fresh ex vivo pig's liver. According to different saline solutions, the lesions were divided into six groups: 25% acetic acid, 18% NaCl, 10% NaCl, 5% NaCl, 0.9% NaCl, and distilled water. After radiofrequency ablation, the lesions size and morphology were measured and compared.Results Using different instillation, the volume of coagulation necrosis was different: 25% acetic acid >18% NaCl >10% NaCl >5% NaCl >0.9% NaCl>distilled water. Conclusion Radiofrequency ablation using hypertonic saline solution instillation can increase the volume of radiofrequency ablation induced necrosis.

  5. Intraductal radiofrequency ablation for management of malignant biliary obstruction.

    Science.gov (United States)

    Rustagi, Tarun; Jamidar, Priya A

    2014-11-01

    Self-expandable metal stents (SEMS) are the current standard of care for the palliative management of malignant biliary strictures. Recently, endoscopic ablative techniques with direct affect to local tumor have been developed to improve SEMS patency. Several reports have demonstrated the technical feasibility and safety of intraductal radiofrequency ablation (RFA), by both endoscopic and percutaneous approaches, in palliation of malignant strictures of the bile duct. Intraductal RFA has also been used in the treatment of occlusion of both covered and uncovered SEMS occlusion from tumor ingrowth or overgrowth. This article provides a comprehensive review of intraductal RFA in the management of malignant biliary obstruction.

  6. Eddy current imaging with an atomic radio-frequency magnetometer

    CERN Document Server

    Wickenbrock, Arne; Blanchard, John W; Budker, Dmitry

    2016-01-01

    We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

  7. Probing properties of cold radiofrequency plasma with polymer probe

    Science.gov (United States)

    Bormashenko, E.; Chaniel, G.; Multanen, V.

    2015-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows the estimation of Debye length of cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  8. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    CERN Document Server

    Deans, Cameron; Hussain, Sarah; Renzoni, Ferruccio

    2016-01-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  9. Radiofrequency Ablation for Iatrogenic Thyroid Artery Pseudoaneurysm: Initial Experience.

    Science.gov (United States)

    Jun, Ye Kyeong; Jung, So Lyung; Byun, Ho Kyun; Baek, Jung Hwan; Sung, Jin Yong; Sim, Jung Suk

    2016-10-01

    Eight iatrogenic thyroid pseudoaneurysms (ITPAs) after thyroid biopsy are reported. The mean ITPA diameter was 7.2 mm (range 4 to 12 mm). Ultrasound (US)-guided compression was initially performed at the neck of the ITPA in all cases. Among them, 4 ITPAs persisted (50%) in which radiofrequency (RF) ablation was performed. Mean RF ablation time and power were 13.5 seconds (range 5 to 24 seconds) and 20 W (range 10 to 50 W), respectively. All 4 cases were treated with RF ablation without any complications.

  10. Probing Properties of Cold Radiofrequency Plasma with Polymer Probe

    CERN Document Server

    Bormashenko, Edward; Multanen, Victor

    2014-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows estimation of the Debye length of the cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  11. Creating Feshbach resonances for ultracold molecule formation with radiofrequency fields

    CERN Document Server

    Owens, Daniel J; Hutson, Jeremy M

    2016-01-01

    We show that radiofrequency (RF) radiation may be used to create Feshbach resonances in ultracold gases of alkali-metal atoms at desired magnetic fields that are convenient for atomic cooling and degeneracy. For the case of $^{39}$K+$^{133}$Cs, where there are no RF-free resonances in regions where Cs may be cooled to degeneracy, we show that a resonance may be created near 21~G with 67~MHz RF radiation. This resonance is almost lossless with circularly polarized RF, and the molecules created are long-lived even with plane-polarized RF.

  12. Risk assessment and management of radiofrequency radiation exposure

    Science.gov (United States)

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-11-01

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  13. Lesion size in relation to ablation site during radiofrequency ablation

    DEFF Research Database (Denmark)

    Petersen, H H; Chen, X; Pietersen, A;

    1998-01-01

    convective cooling by induction of a flow around the electrode tip increases lesion dimensions and power consumptions. Furthermore we conclude that for the given target temperature the power consumption is positively correlated with lesion volume (p ...This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation...... larger for septal applications than apical applications (p convective cooling by induction of flow yielded larger lesion volume, depth and width (p

  14. Radiofrequency Ablation of Hepatic Paragonimiasis:a Case Report

    Institute of Scientific and Technical Information of China (English)

    Wei-gang Cao; Bao-an Qiu

    2012-01-01

    HEPATIC paragonimiasis is a rare disease with non-specific manifestation,which is often misdiagnosed in clinical practice.Long-time drug therapy treating this disease would be accompanied by the possible development of side effects.Given the fact that this disease has seldom been reported in the literature,we provide in this article a detailed report of one case with hepatic paragonimiases treated by radiofrequency ablation,which brought favorable outcome,aiming to shed some light on the understanding of this rare condition.

  15. Thyroid radiofrequency ablation: Updates on innovative devices and techniques

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye Sun; Baek, Jung Hwan; Chung, Sae Rom; Choi, Young Jun; Lee, Jeong Hyun [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Park, Auh Whan [Dept. of Radiology, Vascular and Interventional Radiology Section, University of Virginia Health System, Charlottesville (United States)

    2017-08-01

    Radiofrequency ablation (RFA) is a well-known, effective, and safe method for treating benign thyroid nodules and recurrent thyroid cancers. Thyroid-dedicated devices and basic techniques for thyroid RFA were introduced by the Korean Society of Thyroid Radiology (KSThR) in 2012. Thyroid RFA has now been adopted worldwide, with subsequent advances in devices and techniques. To optimize the treatment efficacy and patient safety, understanding the basic and advanced RFA techniques and selecting the optimal treatment strategy are critical. The goal of this review is to therefore provide updates and analysis of current devices and advanced techniques for RFA treatment of benign thyroid nodules and recurrent thyroid cancers.

  16. Radiofrequency ablation for incidentally identified primary intrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Witold Zgodzinski; N.Joseph Espat

    2005-01-01

    Cholangiocarcinoma is the second most common primary hepato-biliary malignancy. The majority of patients with primary hepatic tumors are not suitable candidates for resection, due to advanced stage of the disease at presentation, anatomic limitations and medical comorbidities. At present, radiofrequency ablation (RFA) may offer an alternative, feasible and safe therapy for selected patients with hepatic tumors, who are not otherwise candidates for hepatic resection. Herein, we present the case of successful RFA in a patient with a solitary, primary intrahepatic cholangiocarcinoma. The patient remained free of disease 24 mo after the procedure, and is still followed up. This is the first report of RFA application inthe treatment of primary intrahepatic cholangiocarcinoma.

  17. Risk assessment and management of radiofrequency radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Dabala, Dana [Railways Medical Clinic Cluj-Napoca, Occupational Medicine Department, 16-20 Bilascu Gheorghe St., 400015 Cluj-Napoca (Romania); Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath St., 400293 Cluj-Napoca (Romania)

    2013-11-13

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  18. Local recurrence of hepatocellular carcinoma after radiofrequency ablation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A 51-year-old Chinese male with a 20-year history of hepatitis B was diagnosed with hepatocellular carcinoma in the right anterior portion of the liver, sized 3.5 cm × 3.2 cm, and was treated with radiofrequency ablation (RFA) on December 18, 2001. The patient did not receive antiviral therapy for hepatitis B virus after RFA. The treated lesion reduced gradually and reached its minimum size of 1.7 cm × 1.5 cm seven years later on November 18, 2008. However computed tomography findings revealed that a recurr...

  19. Computer controls of the CERN PS radio-frequency system

    Energy Technology Data Exchange (ETDEWEB)

    Benincasa, G.P.; Garoby, R.

    1986-06-01

    The PS computer control project has recently been terminated with the integration of the radio-frequency system. While the general controls frame was used, special software and hardware solutions were also necessary to cope with the peculiarities of the RF system. After a brief description of both the RF process and the PS control system, this paper recalls the various operational requirements and real-time constraints and relates on the criteria and methods followed during the design phase. Some implementation is illustrated with emphasis on diagnostics and measurements.

  20. Computer controls of the CERN PS radio-frequency system

    Science.gov (United States)

    Benincasa, G. P.; Garoby, R.

    1986-06-01

    The PS computer control project has recently been terminated with the integration of the radio-frequency system. While the general controls frame was used, special software and hardware solutions were also necessary to cope with the peculiarities of the rf system. After a brief description of both the rf process and the PS control system, this paper recalls the various operational requirements and real-time constraints and relates on the criteria and methods followed during the design phase. Some implementation is illustrated with emphasis on diagnostics and measurements.

  1. Mission Assessment of the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

    Science.gov (United States)

    Dankanich, John W.; Polzin, Kurt A.

    2008-01-01

    Pulsed inductive thrusters have typically been considered for future, high-power, missions requiring nuclear electric propulsion. These high-power systems, while promising equivalent or improved performance over state-of-the-art propulsion systems, presently have no planned missions for which they are well suited. The ability to efficiently operate an inductive thruster at lower energy and power levels may provide inductive thrusters near term applicability and mission pull. The Faraday Accelerator with Radio-frequency Assisted Discharge concept demonstrated potential for a high-efficiency, low-energy pulsed inductive thruster. The added benefits of energy recapture and/or pulse compression are shown to enhance the performance of the pulsed inductive propulsion system, yielding a system that con compete with and potentially outperform current state-of-the-art electric propulsion technologies. These enhancements lead to mission-level benefits associated with the use of a pulsed inductive thruster. Analyses of low-power near to mid-term missions and higher power far-term missions are undertaken to compare the performance of pulsed inductive thrusters with that delivered by state-of-the-art and development-level electric propulsion systems.

  2. New concept for treating female stress urinary incontinence with radiofrequency.

    Science.gov (United States)

    Lordelo, Patrícia; Vilas Boas, Andrea; Sodré, Danielle; Lemos, Amanda; Tozetto, Sibele; Brasil, Cristina

    2017-06-14

    To evaluate the clinical response and adverse effects of radiofrequency on the urethral meatus in the treatment of stress urinary incontinence in women. This phase one study included ten women with Stress Urinary Incontinence (SUI). The evaluation consisted of 1 hour Pad tests to quantify urine loss and to assess the degree of procedure satisfaction by using the Likert scale. To evaluate safety, we observed the number of referred side effects. Average age was 53.10 years±7.08 years. In assessing the final Pad Test, 70% showed a reduction and 30% a worsening of urinary loss. Using the Pad Test one month later, there was a reduction in all patients (p=0.028). The degree of satisfaction was 90% and no side effects have been observed. One patient reported burning sensation. The treatment of SUI with radiofrequency on the urethral meatus has no adverse effects, being a low risk method that reduces urinary loss in women. However, to increase the validity of the study, larger clinical trials are warranted. Copyright® by the International Brazilian Journal of Urology.

  3. [Effects of radiofrequency electromagnetic fields on mammalian spermatogenesis].

    Science.gov (United States)

    Susa, Martina; Pavicić, Ivan

    2007-12-01

    This article reviews studies about the effects of radiofrequency electromagnetic (RF EM) fields on male reproductive system and reproductive health in mammals. According to current data, there are almost 4 million active mobile phone lines in Croatia while this number has risen to 2 billion in the world. Increased use of mobile technology raises scientific and public concern about possible hazardous effects of RF fields on human health. The effects of radiofrequencies on reproductive health and consequences for the offspring are still mainly unknown. A number of in vivo and in vitro studies indicated that RF fields could interact with charged intracellular macromolecular structures. Results of several laboratory studies on animal models showed how the RF fields could affect the mammalian reproductive system and sperm cells. Inasmuch as, in normal physiological conditions spermatogenesis is a balanced process of division, maturation and storage of cells, it is particularly vulnerable to the chemical and physical environmental stimuli. Especially sensitive could be the cytoskeleton, composed of charged proteins; actin, intermedial filaments and microtubules. Cytoskeleton is a functional and structural part of the cell that has important role in the sperm motility, and is actively involved in the morphologic changes that occur during mammalian spermiogenesis.

  4. Effect of radiofrequency radiation in cultured mammalian cells: A review.

    Science.gov (United States)

    Manna, Debashri; Ghosh, Rita

    2016-01-01

    The use of mobile phone related technologies will continue to increase in the foreseeable future worldwide. This has drawn attention to the probable interaction of radiofrequency electromagnetic radiation with different biological targets. Studies have been conducted on various organisms to evaluate the alleged ill-effect on health. We have therefore attempted to review those work limited to in vitro cultured cells where irradiation conditions were well controlled. Different investigators have studied varied endpoints like DNA damage, cell cycle arrest, reactive oxygen species (ROS) formation, cellular morphology and viability to weigh the genotoxic effect of such radiation by utilizing different frequencies and dose rates under various irradiation conditions that include continuous or pulsed exposures and also amplitude- or frequency-modulated waves. Cells adapt to change in their intra and extracellular environment from different chemical and physical stimuli through organized alterations in gene or protein expression that result in the induction of stress responses. Many studies have focused on such effects for risk estimations. Though the effects of microwave radiation on cells are often not pronounced, some investigators have therefore combined radiofrequency radiation with other physical or chemical agents to observe whether the effects of such agents were augmented or not. Such reports in cultured cellular systems have also included in this review. The findings from different workers have revealed that, effects were dependent on cell type and the endpoint selection. However, contradictory findings were also observed in same cell types with same assay, in such cases the specific absorption rate (SAR) values were significant.

  5. Treatment of trigeminal neuralgia: role of radiofrequency ablation

    Directory of Open Access Journals (Sweden)

    Dessy R Emril

    2010-12-01

    Full Text Available Dessy R Emril1 Kok-Yuen Ho21Neurology Department, Syiah Kuala University/Dr Zainoel Abidin Hospital, Banda Aceh, Indonesia; 2Pain Management Centre, Raffles Hospital, SingaporeAbstract: Trigeminal neuralgia (TN is a neuropathic pain condition affecting the face. It has a significant impact on the quality of life and physical function of patients. Evidence suggests that the likely etiology is vascular compression of the trigeminal nerve leading to focal demyelination and aberrant neural discharge. Secondary causes such as multiple sclerosis or brain tumors can also produce symptomatic TN. Treatment must be individualized to each patient. Carbamazepine remains the drug of choice in the first-line treatment of TN. Minimally invasive interventional pain therapies and surgery are possible options when drug therapy fails. Younger patients may benefit from microvascular decompression. Elderly patients with poor surgical risk may be more suitable for percutaneous trigeminal nerve rhizolysis. The technique of radiofrequency rhizolysis of the trigeminal nerve is described in detail in this review.Keywords: interventional treatment, minimally invasive, pain management, radiofrequency rhizolysis, trigeminal neuralgia 

  6. Radiofrequency fistulotomy: a better alternative for treating low anal fistula

    Directory of Open Access Journals (Sweden)

    Pravin Jaiprakash Gupta

    Full Text Available CONTEXT: Wide varieties of approaches are employed in dealing with low anal fistula. However, the simple method of laying open the fistula tract (fistulotomy is still considered to be the favored one. MATERIALS AND METHODS: A modified approach to the procedure of fistulotomy is discussed. This study describes the procedure, which used a technique of radiofrequency surgery, and its outcome in 232 patients with low anal fistula. The patients were followed for a period of 15 months. RESULTS: The patients were discharged on the same day as the procedure. The mean period off work was four days. The average healing time recorded was 67 days. Four wound complications in the form of premature closure of the external wound were noted, which required trimming of the edges. Two of these wounds remained unhealed. The recurrence rate was 1.7%. CONCLUSION: In this era when the emphasis is on criteria like the minimization of hospital stay, reduction of postoperative pain, early resumption of work and low and comparable recurrence rates, there is a future for the procedure of radiofrequency fistulotomy.

  7. CT-guided percutaneous radiofrequency denervation of the sacroiliac joint

    Energy Technology Data Exchange (ETDEWEB)

    Gevargez, A.; Schirp, S.; Braun, M. [Department of Radiology and Microtherapy, University of Witten/Herdecke, Bochum (Germany); Groenemeyer, D. [Department of Radiology and Microtherapy, University of Witten/Herdecke, Bochum (Germany); EFMT Development and Research Center for Microtherapy, Bochum (Germany)

    2002-06-01

    Defining the origin of low back pain is a challenging task. Among a variety of factors the sacroiliac joint (SIJ) is a possible pain generator, although precise diagnosis is difficult. Joint blocks may reduce pain, but are, in cases, of only temporary effect. This study was conducted to evaluate CT-guided percutaneous radiofrequency denervation of the sacroiliac joint in patients with low back pain. The procedure was performed on 38 patients who only temporarily responded to CT-guided SIJ blocks. The denervation was carried out in the posterior interosseous sacroiliac ligaments and on the dorsal rami of the fifth spinal nerve. All interventions were carried out under CT guidance as out-patient therapies. Three months after the therapy, 13 patients (34.2%) were completely free of pain. Twelve patients (31.6%) reported on a substantial pain reduction, 7 patients (18.4%) had obtained a slight and 3 patients (7.9%) no pain reduction. The data of 3 patients (7.9%) was missing. There were no intra- or postoperative complications. Computed tomography-guided percutaneous radiofrequency denervation of the sacroiliac joint appears safe and effective. The procedure may be a useful therapeutic modality, especially in patients with chronic low back pain, who only temporarily respond to therapeutic blocks. (orig.)

  8. Radiofrequency Ablation of Hepatocellular Carcinoma: A Literature Review

    Directory of Open Access Journals (Sweden)

    Yasunori Minami

    2011-01-01

    Full Text Available Radiofrequency ablation (RFA of liver cancers can be performed safely using percutaneous, laparoscopic, or open surgical techniques, and much of the impetus for the use of RFA has come from cohort series that have provided an evidence base for this technique. Here, we give an overview of the current status of radiofrequency ablation (RFA for hepatocellular carcinoma (HCC, including its physical properties, to assess the characteristics that make this technique applicable in clinical practice. We review the technical development of probe design and summarize current indications and outcomes of reported clinical use. An accurate evaluation of treatment response is very important to secure successful RFA therapy since a sufficient safety margin (at least 0.5 cm can prevent local tumor recurrences. We also provide a profile of side effects and information on the integration of this technique into the general management of patients with HCC. To minimize complications of RFA, physicians should be familiar with each feature of complication. Appropriate management of complications is essential for successful RFA treatment. Moreover, adjuvant therapy, such as molecular targeted therapies following curative therapy, is expected to further improve survival after RFA.

  9. ASACUSA's radio-frequency quadrupole decelerator, open to show the four-rod structure along the centre, which crosses 35 resonator chambers formed by the vertical partitions.

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The Radio-Frequency Quadrupole, RFQD, which further decelerates antiprotons ejected from the Antiproton Decelerator (AD). Starting from a momentum of 100 MeV/c (kinetic energy 5.3 MeV), the RFQD delivers very-low-energy antiprotons, adjustable between 10 and 110 keV, to the experiment ASACUSA. In picture _02, the view from the upstream end shows its 4-rod structure, traversing 35 resonator chambers formed by the vertical partitions. The tank has an inner diameter of 390 mm and is pumped to a vacuum of a few E-8 Torr.

  10. Home-based wrinkle reduction using a novel handheld multisource phase-controlled radiofrequency device.

    Science.gov (United States)

    Shemer, Avner; Levy, Hanna; Sadick, Neil S; Harth, Yoram; Dorizas, Andrew S

    2014-11-01

    In the last decade, energy-based aesthetic treatments, using light, radiofrequency (RF), and ultrasound, have gained scientific acceptance as safe and efficacious for non-invasive treatment for aesthetic skin disorders. The phase-controlled multisource radiofrequency technology (3DEEP™), which is based on the simultaneous use of multiple RF generators, was proven to allow significant pigment-independent dermal heating without pain or the need of epidermal cooling. This study was performed in order to evaluate the efficacy and safety of a new handheld device delivering multisource radiofrequency to the skin for wrinkle reduction and skin tightening in the home setting. A total of 69 participants (age 54.3 years ± 8.09; age range 37-72 years) were enrolled in the study after meeting all inclusion/exclusion criteria (100%) and providing informed consent. Participants were provided with the tested device together with a user manual and treatment diary, to perform independent treatments at home for 4 weeks. The tested device, (Newa™, EndyMed Medical, Cesarea, Israel) emits 12 W of 1Mhz, RF energy through six electrodes arranged in a linear fashion. Independent control of RF polarity through each one of the 6 electrodes allows significant reduction of energy flow through the epidermis with increased dermal penetration. Participants were instructed to perform at least 5 treatments a week, for one month. Four follow-up visits were scheduled (once a week) during the period of independent treatments at home, following 4 weeks of home treatments, 1 month follow-up visit (1 month after treatment end) and at 3 months follow-up (3 months following treatment end). Analysis of pre-and post treatment images was conducted by three uninvolved physicians experienced with the Fitzpatrick Wrinkle and Elastosis Scale. Fitzpatrick Wrinkle and Elastosis score of each time point (4 weeks following home use treatments; 1 month follow-up, 3 months follow-up) was compared to baseline

  11. The Biological Effects of Quadripolar Radiofrequency Sequential Application: A Human Experimental Study

    Science.gov (United States)

    Cornaglia, Antonia Icaro; Faga, Angela; Scevola, Silvia

    2014-01-01

    Abstract Objective: An experimental study was conducted to assess the effectiveness and safety of an innovative quadripolar variable electrode configuration radiofrequency device with objective measurements in an ex vivo and in vivo human experimental model. Background data: Nonablative radiofrequency applications are well-established anti-ageing procedures for cosmetic skin tightening. Methods: The study was performed in two steps: ex vivo and in vivo assessments. In the ex vivo assessments the radiofrequency applications were performed on human full-thickness skin and subcutaneous tissue specimens harvested during surgery for body contouring. In the in vivo assessments the applications were performed on two volunteer patients scheduled for body contouring surgery at the end of the study. The assessment methods were: clinical examination and medical photography, temperature measurement with thermal imaging scan, and light microscopy histological examination. Results: The ex vivo assessments allowed for identification of the effective safety range for human application. The in vivo assessments allowed for demonstration of the biological effects of sequential radiofrequency applications. After a course of radiofrequency applications, the collagen fibers underwent an immediate heat-induced rearrangement and were partially denaturated and progressively metabolized by the macrophages. An overall thickening and spatial rearrangement was appreciated both in the collagen and elastic fibers, the latter displaying a juvenile reticular pattern. A late onset in the macrophage activation after sequential radiofrequency applications was appreciated. Conclusions: Our data confirm the effectiveness of sequential radiofrequency applications in obtaining attenuation of the skin wrinkles by an overall skin tightening. PMID:25244081

  12. Radiofrequency induction on sodium/iodide symporter expression of thyroid cancer

    Institute of Scientific and Technical Information of China (English)

    Youxin Tian; Qinjiang Liu; Yaqiong Ni

    2013-01-01

    Objective:The aim of this study was to investigate the ef ects of radiofrequency treatment on sodium/iodide symporter expression of thyroid cancer cells. Methods:In 29 thyroid cancer patients with low or no expression of soda\\iodide symporter, the radio frequency combined 131I therapy was used, the whole-body scintigraphy and serum Ig were detected before and after the radiofrequency treatment. Results:The whole-body scintigraphy showed that 4 cases (4/29) before radiofrequency treatment had positive iodine uptake, 19 cases (19/29) two weeks after radiofrequency treatment had the positive iodine uptake, 12 cases (12/29) four weeks after radiofrequency treatment had the positive iodine uptake. Four weeks after radiofrequency treatment, 5 cases had increased serum Ig levels, 17 cases had decreased serum Ig levels, 7 cases showed no change. 25 cases (25/29) were ef ective, 15 cases (15/29) were cured. Conclusion:The radiofrequency induced the non-expressed the sodium/iodide symporter of thyroid cancer cells regain the iodine intake ability, it improved the clinical ef icacy of 131I therapy in dedif erentiated thyroid cancer.

  13. Factors that influence the radiofrequency power output of GSM mobile phones.

    Science.gov (United States)

    Erdreich, Linda S; Van Kerkhove, Maria D; Scrafford, Carolyn G; Barraj, Leila; McNeely, Mark; Shum, Mona; Sheppard, Asher R; Kelsh, Michael

    2007-08-01

    Epidemiological studies of mobile phone use and risk of brain cancer have relied on self-reported use, years as a subscriber, and billing records as exposure surrogates without addressing the level of radiofrequency (RF) power output. The objective of this study was to measure environmental, behavioral and engineering factors affecting the RF power output of GSM mobile phones during operation. We estimated the RF-field exposure of volunteer subjects who made mobile phone calls using software-modified phones (SMPs) that recorded output power settings. Subjects recruited from three geographic areas in the U.S. were instructed to log information (place, time, etc.) for each call made and received during a 5-day period. The largest factor affecting energy output was study area, followed by user movement and location (inside or outside), use of a hands-free device, and urbanicity, although the two latter factors accounted for trivial parts of overall variance. Although some highly statistically significant differences were identified, the effects on average energy output rate were usually less than 50% and were generally comparable to the standard deviation. These results provide information applicable to improving the precision of exposure metrics for epidemiological studies of GSM mobile phones and may have broader application for other mobile phone systems and geographic locations.

  14. Patient satisfaction and efficacy of accent radiofrequency for facial skin wrinkle reduction

    Directory of Open Access Journals (Sweden)

    Fariba Jaffary

    2013-01-01

    Full Text Available Background: Radiofrequency (RF is a new technique to treat facial wrinkles. This study was designed to assess the efficacy of Accent RF in wrinkle reduction of different areas of the face. Materials and Methods: Patients with mild to severe facial wrinkles were treated with Accent using RF energies of 35-145 W. The average energy used in this study was 83.11 W. Patients received four subsequent weekly RF sessions. Wrinkle improvement was rated by two physicians comparing 6-month post treatment photographs with pretreatment photos. Moreover, patient satisfaction was assessed at 1 and 6 months after the last session of the treatment. Results: A total of 45 women participated in this study. In terms of patient satisfaction one month after the last treatment, 8.9% of the patients declared their dissatisfaction, 53.3% were somehow satisfied, 33.3% were satisfied, and 4.4% were very satisfied. At 6 months, patient satisfaction was as follows: 4.4% dissatisfied, 31.1% somehow satisfied, 46.7% satisfied, and 17.8% very satisfied. Patient satisfaction 6 months after the last treatment was significantly higher than 1 month post treatment (P = 0.006. At 6 months, patient satisfaction was not more than 75% in any treatment areas of the face. Conclusion: The results of this study suggest that Accent RF may be considered as a possible effective option for facial skin rejuvenation although its efficacy and safety needs to be evaluated further in randomized controlled trials.

  15. Simulation of radio-frequency atmospheric pressure glow discharge in γ mode

    Institute of Scientific and Technical Information of China (English)

    Shang Wan-Li; Wang De-Zhen; Michael G. Kong

    2007-01-01

    The existence of two different discharge modes has been verified in an rf (radio-frequency) atmospheric pressure glow discharge (APGD) by Shi [J. Appl. Phys. 97, 023306 (2005)]. In the first mode, referred to as α mode, the discharge current density is relatively low and the bulk plasma electrons acquire the energy due to the sheath expansion.In the second mode, termed γ mode, the discharge current density is relatively high, the secondary electrons emitted by cathode under ion bombardment in the cathode sheath region play an important role in sustaining the discharge. In this paper, a one-dimensional self-consistent fluid model for rf APGDs is used to simulate the discharge mechanisms in the γmode in helium discharge between two parallel metallic planar electrodes. The results show that as the applied voltage increases, the discharge current becomes greater and the plasma density correspondingly increases, consequentially the discharge transits from the c mode into the γ mode. The high collisionality of the APGD plasma results in significant drop of discharge potential across the sheath region, and the electron Joule heating and the electron collisional energy loss reach their maxima in the region. The validity of the simulation is checked with the available experimental and numerical data.

  16. Radiofrequency and microwave tumor ablation in patients with implanted cardiac devices: Is it safe?

    Energy Technology Data Exchange (ETDEWEB)

    Skonieczki, Brendan D., E-mail: bskonieczki@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Wells, Catherine, E-mail: cwells1@bidmc.harvard.edu [Department of Radiology, Harvard Medical School/Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Wasser, Elliot J., E-mail: ewasser@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Dupuy, Damian E., E-mail: ddupuy@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States)

    2011-09-15

    Purpose: To identify malfunction of implanted cardiac devices during or after thermal ablation of tumors in lung, kidney, liver or bone, using radiofrequency (RF) or microwave (MW) energy. Materials and methods: After providing written consent, 19 patients (15 men and 4 women; mean age 78 years) with pacemakers or pacemaker/defibrillators underwent 22 CT image-guided percutaneous RF or MW ablation of a variety of tumors. Before and after each procedure, cardiac devices were interrogated and reprogrammed by a trained cardiac electrophysiology fellow. Possible pacer malfunctions included abnormalities on electrocardiographic (EKG) monitoring and alterations in device settings. Our institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. Informed consent for participation in this retrospective study was deemed unnecessary by our review board. Results: During 20 of 22 sessions, no abnormalities were identified in continuous, EKG tracings or pacemaker functions. However, in two sessions significant changes, occurred in pacemaker parameters: inhibition of pacing during RF application in one, session and resetting of mode by RF energy in another session. These changes did not, result in hemodynamic instability of either patient. MW ablation was not associated with, any malfunction. In all 22 sessions, pacemakers were undamaged and successfully reset to original parameters. Conclusion: RF or MW ablation of tumors in liver, kidney, bone and lung can be performed safely in patients with permanent intra-cardiac devices, but careful planning between radiology and cardiology is essential to avoid adverse outcomes.

  17. Power supply and impedance matching to drive technological radio-frequency plasmas with customized voltage waveforms.

    Science.gov (United States)

    Franek, James; Brandt, Steven; Berger, Birk; Liese, Martin; Barthel, Matthias; Schüngel, Edmund; Schulze, Julian

    2015-05-01

    We present a novel radio-frequency (RF) power supply and impedance matching to drive technological plasmas with customized voltage waveforms. It is based on a system of phase-locked RF generators that output single frequency voltage waveforms corresponding to multiple consecutive harmonics of a fundamental frequency. These signals are matched individually and combined to drive a RF plasma. Electrical filters are used to prevent parasitic interactions between the matching branches. By adjusting the harmonics' phases and voltage amplitudes individually, any voltage waveform can be approximated as a customized finite Fourier series. This RF supply system is easily adaptable to any technological plasma for industrial applications and allows the commercial utilization of process optimization based on voltage waveform tailoring for the first time. Here, this system is tested on a capacitive discharge based on three consecutive harmonics of 13.56 MHz. According to the Electrical Asymmetry Effect, tuning the phases between the applied harmonics results in an electrical control of the DC self-bias and the mean ion energy at almost constant ion flux. A comparison with the reference case of an electrically asymmetric dual-frequency discharge reveals that the control range of the mean ion energy can be significantly enlarged by using more than two consecutive harmonics.

  18. Installation of a cw radiofrequency quadrupole accelerator at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.D.; Bolme, J.; Brown, V. [and others

    1994-09-01

    Chalk River Laboratories (CRL) has had a long history of cw proton beam development for production of intense neutron sources and fissile fuel breeders. In 1986 CRL and Los Alamos National Laboratory (LANL) entered into a collaborative effort to establish a base technologies program for the development of a cw radiofrequency quadrupole (RFQ). The initial cw RFQ design had 50-keV proton injection energy with 600-keV output energy. The 75-mA design current at 600-keV beam energy was obtained in 1990. Subsequently, the RFQ output energy was increased to 1250 keV by replacing the RFQ vanes, still maintaining the 75-m A design current. A new 250-kW cw klystrode rf power source at 267-MHz was installed at CRL. By April of 1993, 55-mA proton beams had been accelerated to 1250 keV. Concurrent developments were taking place on proton source development and on 50-keV low-energy beam transport (LEBT) systems. Development of a dc, high-proton fraction ({ge} 70%) microwave ion source led to utilization of a single-solenoid RFQ direct injection scheme. It was decided to continue this cw RFQ demonstration project at Los Alamos when the CRL project was terminated in April 1993. The LANL goals are to find the current limit of the 1250-keV RFQ, better understand the beam transport properties through the single-solenoid focusing LEBT, continue the application of the cw klystrode tube technology to accelerators, and develop a two-solenoid LEBT which could be the front end of an Accelerator-Driven Transmutation Technologies (ADTT) linear accelerator.

  19. Self-consistent modeling of radio-frequency plasma generation in stellarators

    Science.gov (United States)

    Moiseenko, V. E.; Stadnik, Yu. S.; Lysoivan, A. I.; Korovin, V. B.

    2013-11-01

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell's equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell's equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell's equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell's equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  20. 超声刀结合单极电凝应用于腹腔镜胃癌根治术的评价%Ultrasonic Scalpel and Monopolar Electrocoagulation in Laparoscopic-assisted Radical Gastrectomy for Gastric Carcinoma

    Institute of Scientific and Technical Information of China (English)

    鱼国盛; 汤黎明; 钱峻; 朱杰

    2011-01-01

    Objective To evaluate the outcome of ultrasonic scalpel combined with monopolar electrocoagulation in laparoscopic-assisted radical gastrectomy for gastric carcinoma. Methods From January 2010 to March 2011, 75 patients with curable gastric carcinoma underwent laparoscopic-assisted radical gastrectomy, of which 39 patients were treated solely by ultrasonic scalpel, the other 36 patients underwent ultrasonic scalpel combined with monopolar electrocoagulation. The operation time, intraoperative blood loss, number of resected lymph nodes, and postoperative drainage volume and complications were analyzed retrospectively and compared between the two groups. Results The mean operation time and blood loss of ultrasonic scalpel group were significantly more than that in the study group [ (347 ±38) min vs. (310 ±23) min, t =5. 049, P = 0. 000, and (274 ± 122) ml vs. (186 ± 90) ml, t = 3. 530, P = 0. 000]. The number of harvested lymph nodes, postoperative drainage volume and the incidence rate of complications were comparable between the two groups ( P > 0.05). Conclusion By combining ultrasonic scalpel with monopolar electrocoagulation in laparoscopic-assisted radical gastrectomy for gastric carcinoma, the advantages of the both methods can be utilized so that to reduce operation time and blood loss,and make lymph nodes resection easier.%目的 评价腹腔镜胃癌根治术中联合应用超声刀及单极电凝的效果.方法 回顾分析2010年1月~2011年3月75例腹腔镜胃癌D2根治术的临床资料,前39例单纯使用超声刀(超声刀组),后36例联合应用超声刀与单极电凝(联合组).比较2组手术时间、术中出血量、平均清扫淋巴结个数、术后引流量及术后并发症方面的差异.结果 与超声刀组相比,联合组术中出血少[(274±122)ml vs.(186±90) ml,t=3.530,P=0.000],手术时间短[(347±38)min vs.(310±23) min,t=5.049,P=0.000],2组清扫淋巴结个数、术后引流量及并发症

  1. Effect of percutaneous radiofrequency thermocoagulation on different neuropathic pains

    Institute of Scientific and Technical Information of China (English)

    Youcai Shi; Xiaoxia Hu

    2006-01-01

    BACKGROUND: The clinical treatment of neuropathic pain is very troublesome ,and the physical method of radiofrequency thermocoagulation is a good choice for its treatment.OBJECTIVE: To observe the curative effact of percutaneous radiofrequency thermocoagulation on neuropathic neuralgia.DESIGN:A case follow-up analysis.SETTING: Minimally Invasive Surgery Room,Department of Neurosurgery,Urumqi General Hospital of Lanzhou Military Area Command of Chinese PLA.PARTICIPANTS: Totally 131 patients were selected from the Department of Neurosurgery,Urumqi General Hospital of Lanzhou Military Area Command of Chinese PLA from December 2000 to June 2006,including 73 males and 58 females,aging 37-72 years old,AND the disease course was 2-15 years.①Drug treatment failed to alleviate the pain or induced obvious side the pain or induced obvious side effects; ②With the same pathological changes as pain and effective in the nerve block test; Had signed the informed consents before treatment.Distribution of the neuropathic pain:①Trigeminal neuralgia,which were lighting attack,located at V2 in 28 cases,V3 in 46 cases,V1+V2 in 3 cases,V2+V3 in 28 cases,and V1+V2+V3 in 1 cases;②Migraine located at(except the frontal branch of trigeminal nerve)greater and lesser occipital nerves in 6 cases,auriculotemporal nerve in 3 cases,temporal and zygomatic nerves in 3 cases;③Unilateral neuralgia of C2 and C3 following herpes zoster in 1 case,and chest intercostals neuralgia in 2 cases;④Lasting burning pain in the operative area after thoracotomy was in 1 case of lung cancer.METHODS: ①All the enrolled patients were treated with percutaneous puncture at trigeminal ganglion or peripheral nerve,then nerve block was performed firstly for anesthesia,and the pain disappeared immediately at this moment,there was hypoesthesia or numbness in the area of innervation,which manifested the puncture apposition was correct.then electrostimulation of 50 Hz with the current of 0.1-0.5 V was given for

  2. Two-year results after convective radiofrequency water vapor thermal therapy of symptomatic benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    Dixon CM

    2016-11-01

    Full Text Available Christopher M Dixon,1 Edwin Rijo Cedano,2 Dalibor Pacik,3 Vítězslav Vit,3 Gabriel Varga,3 Lennart Wagrell,4 Thayne R Larson,5 Lance A Mynderse6 1Department of Urology, Phelps Memorial Hospital, Sleepy Hollow, New York, NY, USA; 2Department of Urology, Clinical Canela, La Romana, Dominican Republic; 3Department of Urology, Brno University Hospital, Brno, Czech Republic; 4Urologcentrum, Stockholm, Sweden; 5Institute of Medical Research, Scottsdale, AZ, 6Department of Urology, Mayo Clinic, Rochester, MN, USA Objective: The objective of this study was to assess the effectiveness and safety of convective radiofrequency (RF water vapor thermal therapy in men with lower urinary tract symptoms (LUTS associated with benign prostatic hyperplasia (BPH; a pilot study design with 2-year follow-up evaluations.Patients and methods: Men aged ≥45 years with an International Prostate Symptom Score ≥13, a maximum urinary flow rate (Qmax ≤15 mL/s, and prostate volume 20–120 cc were enrolled in a prospective, open-label pilot study using convective RF water vapor energy with the Rezūm System. Patients were followed up for 2 years after transurethral thermal treatment at 3 international centers in the Dominican Republic, Czech Republic, and Sweden. The transurethral thermal therapy utilizes radiofrequency to generate wet thermal energy in the form of water vapor injected through a rigid endoscope into the lateral lobes and median lobe as needed. Urinary symptom relief, urinary flow, quality of life (QOL impact, sexual function, and adverse events (AEs were assessed at 1 week, 1, 3, 6, 12, and 24 months. Results: LUTS, flow rate, and QOL showed significant improvements from baseline; prostate volumes were appreciably reduced. Sexual function was maintained and no de novo erectile dysfunction occurred. The responses evident as early as 1 month after treatment remained consistent and durable over the 24 months of study. Early AEs were typically transient and

  3. Radiofrequency radiation injures trees around mobile phone base stations.

    Science.gov (United States)

    Waldmann-Selsam, Cornelia; Balmori-de la Puente, Alfonso; Breunig, Helmut; Balmori, Alfonso

    2016-12-01

    In the last two decades, the deployment of phone masts around the world has taken place and, for many years, there has been a discussion in the scientific community about the possible environmental impact from mobile phone base stations. Trees have several advantages over animals as experimental subjects and the aim of this study was to verify whether there is a connection between unusual (generally unilateral) tree damage and radiofrequency exposure. To achieve this, a detailed long-term (2006-2015) field monitoring study was performed in the cities of Bamberg and Hallstadt (Germany). During monitoring, observations and photographic recordings of unusual or unexplainable tree damage were taken, alongside the measurement of electromagnetic radiation. In 2015 measurements of RF-EMF (Radiofrequency Electromagnetic Fields) were carried out. A polygon spanning both cities was chosen as the study site, where 144 measurements of the radiofrequency of electromagnetic fields were taken at a height of 1.5m in streets and parks at different locations. By interpolation of the 144 measurement points, we were able to compile an electromagnetic map of the power flux density in Bamberg and Hallstadt. We selected 60 damaged trees, in addition to 30 randomly selected trees and 30 trees in low radiation areas (n=120) in this polygon. The measurements of all trees revealed significant differences between the damaged side facing a phone mast and the opposite side, as well as differences between the exposed side of damaged trees and all other groups of trees in both sides. Thus, we found that side differences in measured values of power flux density corresponded to side differences in damage. The 30 selected trees in low radiation areas (no visual contact to any phone mast and power flux density under 50μW/m(2)) showed no damage. Statistical analysis demonstrated that electromagnetic radiation from mobile phone masts is harmful for trees. These results are consistent with the fact

  4. Bipolar plasma vaporization versus monopolar TUR and “cold-knife" TUI in secondary bladder neck sclerosis – An evidence based, retrospective critical comparison in a single center clinical setting

    Science.gov (United States)

    Moldoveanu, C; Geavlete, B; Jecu, M; Stanescu, F; Adou, L; Bulai, C; Ene, C; Geavlete, P

    2014-01-01

    Introduction: A long term, retrospective study was performed aiming to outline a critical comparison concerning the efficacy, safety and durability of the bipolar plasma vaporization (BPV), standard monopolar transurethral resection (TUR) and “cold-knife" “star" transurethral incision (TUI) in secondary bladder neck sclerosis (BNS) cases. Materials & Methods: Of the 126 patients included in the trial based on maximum flow rate (Qmax) below 10 mL/s and International Prostate Symptom Score (IPSS) over 19, classical resection was performed in 46 cases, “cold-knife" TUI in 37 cases and bipolar vaporization in 43 patients. The evaluation protocol comprised IPSS, QoL (quality of life) score, Qmax and PVR (post-voiding residual urinary volume) assessment performed at 1, 3, 6, 12, 18 and 24 months after the initial intervention. Results: Significant intraoperative complications (capsular perforation – 8.7%; bleeding – 4.3%) occurred secondary to monopolar resection. “Star" TUI was the fastest technique, followed by plasma-button vaporization (7.2 and 11.4 versus 16.5 minutes). BPV and TUI patients benefitted from the shortest catheterization periods (0.75 and 1 versus 2.0 days) and hospital stays (1.0 and 1.25 versus 2.0 days). Immediate postoperative adverse events consisted of hematuria (6.5% of the TUR cases) and acute urinary retention (8.1% of the TUI group). Significantly higher long term BNS recurrence rates requiring re-treatment were established in the TUI (18.7%) and TUR (12.8%) series by comparison to BPV (5.4%). Among patients that completed the follow-up protocol, equivalent IPSS, QoL, Qmax and PVR features were determined in the 3 study arms. Conclusions: The plasma vaporization approach was confirmed as a successful match to conventional TUR and “cold-knife" TUI in terms of surgical safety profile, postoperative recovery, therapeutic durability and urodynamic and symptom score parameters. PMID:24653766

  5. Radiofrequency fields associated with the Itron smart meter.

    Science.gov (United States)

    Tell, R A; Sias, G G; Vazquez, A; Sahl, J; Turman, J P; Kavet, R I; Mezei, G

    2012-08-01

    This study examined radiofrequency (RF) emissions from smart electric power meters deployed in two service territories in California for the purpose of evaluating potential human exposure. These meters included transmitters operating in a local area mesh network (RF LAN, ∼250 mW); a cell relay, which uses a wireless wide area network (WWAN, ∼1 W); and a transmitter serving a home area network (HAN, ∼70 mW). In all instances, RF fields were found to comply by a wide margin with the RF exposure limits established by the US Federal Communications Commission. The study included specialised measurement techniques and reported the spatial distribution of the fields near the meters and their duty cycles (typically smart meters as deployed. However, the results are restricted to a single manufacturer's emitters.

  6. Novel radio-frequency ion trap with spherical geometry

    CERN Document Server

    Noshad, Houshyar

    2014-01-01

    Confinement of single ions in a novel radio-frequency (RF) quadrupole ion trap with spherical shape is investigated. An optimization of this spherical ion trap (SIT) is carried out in order to suppress its nonlinearity substantially by eliminating the electric octupole moment. Hence, a trapping potential and consequently an electric field very similar to the ideal quadrupole ion trap (QIT) are obtained. Afterwards, three stability regions for the optimized SIT are numerically computed. The regions coincide well with those reported in the literature for the ideal QIT. The reason is attributed to the zero electric octupole moment of our proposed trap. The SIT simple geometry and relative ease of fabrication along with its increased trapping volume compared to the conventional hyperbolic quadrupole ion trap, make it an appropriate choice for miniaturization.

  7. Radio-frequency dressed state potentials for neutral atoms

    CERN Document Server

    Hofferberth, S; Fischer, B; Verdu, J; Schmiedmayer, J

    2006-01-01

    Potentials for atoms can be created by external fields acting on properties like magnetic moment, charge, polarizability, or by oscillating fields which couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here we present an experimental investigation of the remarkable properties of potentials derived from radio-frequency (RF) coupling between electronic ground states. The coupling is magnetic and the vector character allows to design state dependent potential landscapes. On atom chips this enables robust coherent atom manipulation on much smaller spatial scales than possible with static fields alone. We find no additional heating or collisional loss up to densities approaching $10^{15}$ atoms / cm$^3$ compared to static magnetic traps. We demonstrate the creation of Bose-Einstein condensates in RF potentials and investigate the difference in the interference between two independe...

  8. Eddy current imaging with an atomic radio-frequency magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Wickenbrock, Arne, E-mail: wickenbr@uni-mainz.de [Johannes Gutenberg-Universität Mainz, 55128 Mainz (Germany); Leefer, Nathan; Blanchard, John W. [Helmholtz Institut Mainz, 55099 Mainz (Germany); Budker, Dmitry [Johannes Gutenberg-Universität Mainz, 55128 Mainz (Germany); Helmholtz Institut Mainz, 55099 Mainz (Germany); Department of Physics, University of California, Berkeley, California 94720-7300 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-05-02

    We use a radio-frequency {sup 85}Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

  9. Temperature Mapping of Nitrogen-doped Niobium Superconducting Radiofrequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Makita, Junki [Old Dominion Univ., Norfolk, VA (United States); Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    It was recently shown that diffusing nitrogen on the inner surface of superconducting radiofrequency (SRF) cavities at high temperature can improve the quality factor of the niobium cavity. However, a reduction of the quench field is also typically found. To better understand the location of rf losses and quench, we used a thermometry system to map the temperature of the outer surface of ingot Nb cavities after nitrogen doping and electropolishing. Surface temperature of the cavities was recorded while increasing the rf power and also during the quenching. The results of thermal mapping showed no precursor heating on the cavities and quenching to be ignited near the equator where the surface magnetic field is maximum. Hot-spots at the equator area during multipacting were also detected by thermal mapping.

  10. Plasma-beam traps and radiofrequency quadrupole beam coolers.

    Science.gov (United States)

    Maggiore, M; Cavenago, M; Comunian, M; Chirulotto, F; Galatà, A; De Lazzari, M; Porcellato, A M; Roncolato, C; Stark, S; Caruso, A; Longhitano, A; Cavaliere, F; Maero, G; Paroli, B; Pozzoli, R; Romé, M

    2014-02-01

    Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented.

  11. Drone based measurement system for radiofrequency exposure assessment.

    Science.gov (United States)

    Joseph, Wout; Aerts, Sam; Vandenbossche, Matthias; Thielens, Arno; Martens, Luc

    2016-03-10

    For the first time, a method to assess radiofrequency (RF) electromagnetic field (EMF) exposure of the general public in real environments with a true free-space antenna system is presented. Using lightweight electronics and multiple antennas placed on a drone, it is possible to perform exposure measurements. This technique will enable researchers to measure three-dimensional RF-EMF exposure patterns accurately in the future and at locations currently difficult to access. A measurement procedure and appropriate measurement settings have been developed. As an application, outdoor measurements are performed as a function of height up to 60 m for Global System for Mobile Communications (GSM) 900 MHz base station exposure. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc.

  12. Radiofrequency ablation of a misdiagnosed Brodie’s abscess

    Science.gov (United States)

    Chan, RS; Abdullah, BJJ; Aik, S; Tok, CH

    2011-01-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie’s abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie’s abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment. PMID:22291860

  13. Application of radio-frequency identification in perioperative care.

    Science.gov (United States)

    Ku, Hsueh-Ling; Wang, Pa-Chun; Su, Mu-Chun; Liu, Charles C H; Hwang, Wu-Yuin

    2011-08-01

    Every perioperative department could benefit from having an information system that facilitates managerial function and improves efficiency in the OR. The Patient Advancement Monitoring System-Surgical implemented in a hospital in Taipei, Taiwan, is one such a system that uses radio-frequency identification technology for tracking perioperative care of patients along workflow checkpoints. This web-based medical information system can facilitate care provided throughout perioperative services by providing instant patient information to staff members in cross-functional health care teams. Manpower is not wasted on duplicating data entry because the surgical progression is displayed in real time. Satisfaction with the system has been high for both nurses and administrators. Copyright © 2011 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  14. Primary papillary thyroid carcinoma previously treated incompletely with radiofrequency ablation.

    Science.gov (United States)

    Kim, Hoon Yub; Ryu, Woo Sang; Woo, Sang Uk; Son, Gil Soo; Lee, Eun Sook; Lee, Jae Bok; Bae, Jeoung Won

    2010-01-01

    Radiofrequency ablation (RFA) recently has been applied to benign thyroid nodules, mainly for the cosmetic reasons, and limited cases of local recurrences or focal distant metastases of well-differentiated thyroid cancer, in the high-risk reoperative condition or for the palliative purpose. But no report has been made on the RFA for primary thyroid cancer to date. We report on a patient with primary papillary carcinoma of thyroid gland who had undergone RFA before the cytological diagnosis of malignancy, later referred and treated with robotic surgery successfully. We can learn the following lessons from our case; (1) the RFA for operable primary thyroid malignancy should be avoided, because of the possibility of remnant viable cancer and undetectable nodal metastasis, and (2) robotic or endoscopic thyroid surgery may be a feasible operative method for benign or malignant thyroid nodules previously treated with RFA.

  15. [Radiofrequency ablation of a symptomatic benign thyroid nodule].

    Science.gov (United States)

    van Ginhoven, T M; Massolt, E T; Bijdevaate, D C; Peeters, R P; Burgers, J W A; Moelker, A

    2016-01-01

    Radiofrequency ablation (RFA) enables the ablation of selected tissue by means of heat. For the first time in the Netherlands, RFA is being used to treat patients with benign thyroid nodules. RFA is able to reduce the volume of a nodule that may be causing cosmetic complaints or problems due to mass effect. This avoids the need for surgery or treatment with radioactive iodine in this benign condition. The average reduction in size is 80% in the first year, leading to a considerable decrease in both symptomatic and cosmetic complaints. At Erasmus Medical Centre, Rotterdam, the Netherlands, this technique has been introduced in accordance with current guidelines, and it is expected that other centres of excellence will follow in implementing it. It is important that the initial experiences with this technique in the Netherlands in terms of effectiveness, risks and patient satisfaction should be monitored before RFA becomes routine treatment.

  16. Primary papillary thyroid carcinoma previously treated incompletely with radiofrequency ablation

    Directory of Open Access Journals (Sweden)

    Kim Hoon

    2010-01-01

    Full Text Available Radiofrequency ablation (RFA recently has been applied to benign thyroid nodules, mainly for the cosmetic reasons, and limited cases of local recurrences or focal distant metastases of well-differentiated thyroid cancer, in the high-risk reoperative condition or for the palliative purpose. But no report has been made on the RFA for primary thyroid cancer to date. We report on a patient with primary papillary carcinoma of thyroid gland who had undergone RFA before the cytological diagnosis of malignancy, later referred and treated with robotic surgery successfully. We can learn the following lessons from our case; (1 the RFA for operable primary thyroid malignancy should be avoided, because of the possibility of remnant viable cancer and undetectable nodal metastasis, and (2 robotic or endoscopic thyroid surgery may be a feasible operative method for benign or malignant thyroid nodules previously treated with RFA.

  17. Phase responses of harmonics reflected from radio-frequency electronics

    Science.gov (United States)

    Mazzaro, Gregory J.; McGowan, Sean F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Martone, Anthony F.; Narayanan, Ram M.

    2016-05-01

    The phase responses of nonlinear-radar targets illuminated by stepped frequencies are studied. Data is presented for an experimental radar and two commercial electronic targets at short standoff ranges. The amplitudes and phases of harmonics generated by each target at each frequency are captured over a 100-MHz-wide transmit band. As in the authors' prior work, target detection is demonstrated by receiving at least one harmonic of at least one transmit frequency. In the present work, experiments confirm that the phase of a harmonic reflected from a radio-frequency electronic target at a standoff distance is linear versus frequency. Similar to traditional wideband radar, the change of the reflected phase with respect to frequency indicates the range to the nonlinear target.

  18. Effects of radiofrequency hyperthermia on the healthy canine cornea

    Energy Technology Data Exchange (ETDEWEB)

    Glaze, M.B.; Turk, M.A.

    1986-04-01

    Radiofrequency hyperthermia was used to induce axial corneal lesions in the eyes of 10 dogs. Clinical observations were continued for up to 6 months, using biomicroscopy and indirect ophthalmoscopy. Eyes were harvested at intervals for light and electron microscopic evaluation. Clinical alterations included immediate corneal opacification and epithelial disruption at the site of electrode contact. Ulcerative keratitis persisted for 4 to 6 days, accompanied by anterior uveitis. Additional corneal changes included stromal thinning, edema, and vascularization. Final evaluation revealed negligible alterations in corneal contour or clarity 6 months after treatment. Microscopically, epithelial and superficial stromal necrosis preceded epithelial loss. Stromal alterations included edema (associated with focal endothelial detachments), vascularization, and inflammatory cell infiltration. Recovery was characterized by keratocytic hyperplasia and hypertrophy, epithelial proliferation, and stromal condensation.

  19. Multiplexed infrared photodetection using resonant radio-frequency circuits

    Energy Technology Data Exchange (ETDEWEB)

    Liu, R.; Lu, R.; Gong, S.; Wasserman, D. [Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, Urbana, Illinois 61801 (United States); Roberts, C. [Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Allen, J. W.; Allen, M. S. [Air Force Research Laboratory, Munitions Directorate, Eglin Air Force Base, Florida 32542 (United States); Wenner, B. R. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson Air Force Base, Ohio 45433 (United States)

    2016-02-08

    We demonstrate a room-temperature semiconductor-based photodetector where readout is achieved using a resonant radio-frequency (RF) circuit consisting of a microstrip split-ring resonator coupled to a microstrip busline, fabricated on a semiconductor substrate. The RF resonant circuits are characterized at RF frequencies as function of resonator geometry, as well as for their response to incident IR radiation. The detectors are modeled analytically and using commercial simulation software, with good agreement to our experimental results. Though the detector sensitivity is weak, the detector architecture offers the potential for multiplexing arrays of detectors on a single read-out line, in addition to high speed response for either direct coupling of optical signals to RF circuitry, or alternatively, carrier dynamics characterization of semiconductor, or other, material systems.

  20. Multifunctional radio-frequency generator for cold atom experiments

    Science.gov (United States)

    Wei, Chun-hua; Yan, Shu-hua

    2016-05-01

    We present a low cost radio-frequency (RF) generator suitable for experiments with cold atoms. The RF source achieves a sub-hertz frequency with tunable resolution from 0 MHz to 400 MHz and a maximum output power of 33 dBm. Based on a direct digital synthesizer (DDS) chip, we implement a ramping capability for frequency, amplitude and phase. The system can also operate as an arbitrary waveform generator. By measuring the stability in a duration of 600 s, we find the presented device performs comparably as Agilent33522A in terms of short-term stability. Due to its excellent performance, the RF generator has been already applied to cold atom trapping experiments.

  1. Cardiac Radiofrequency Ablation: A Clinical Update for Nurses.

    Science.gov (United States)

    Shoulders, Bridget; Mauriello, Jillian; Shellman, Tamika; Follett, Corrinne

    2016-01-01

    The field of electrophysiology (EP) has rapidly evolved from a focus on diagnostic procedures to an emphasis on interventions. Many cardiac arrhythmias traditionally treated with antiarrhythmic agents, cardioversion, or cardiac surgery are now routinely cured with cardiac ablation. To optimally manage the care of cardiac ablation patients, it is essential that nurses have an understanding of the EP procedures and related nursing implications. There are extensive evidence-based resources available in the medical literature; however, there are limited publications geared toward nurses caring for cardiac ablation patients.This article provides an overview of EP diagnostic and cardiac radio-frequency ablation procedures for select atrial and ventricular tachyarrhythmias. Evidence-based nursing practices related to postprocedure care will be addressed. The objective of this article is to increase nurses' knowledge of common cardiac ablation procedures and the nursing management of the patient postprocedure.

  2. Use of linear radiofrequency device in liver resection

    Directory of Open Access Journals (Sweden)

    Stojanović Miroslav P.

    2010-01-01

    Full Text Available Background/Aim. Linear radiofrequency device (LRFD is disposable tool designed for liver parenchyma transection using controlled radiofrequency to 'seal' blood vessels and bile ducts, making liver resection easier and safer compared to classical resectional techniques. The aim of this study was to determine real value of the LRFD compared to the standard 'keliclasia' technique. Methods. This prospective study analyzed the significant intraoperative parameters and postoperative results of the 200 patients who underwent surgery at the Surgery Clinic of Clinical Centre in Niš, between January 1, 2001, and January 1, 2009. The patients were divided into two groups: the control Keli group (144 patients with the 'keliclasia' resection technique and the control RF group (with resection performed using LRFD - Tissue Link / Dissection Sealer (DS - 3.0 (56 patients. The following parameters were analyzed: duration of liver ischemia, liver parenchyma transection time, intraoperative blood loss, significant intraoperative and postoperative complication rate, duration of hospitalization and mortality. Results. LRFD was used in 56 liver resections. The average duration of liver ischemia in the RF group was shorter than in the Keli group (7 versus 22 minutes. Parenchymal liver transection was significantly slower in the RF group than in the Keli group (2.05 versus 4.34 cm2/minutes, respectively. There was less intraoperative bleeding using LRFD 'Keliclasia' tehniquethan in the control group (390 mL compared to 420 mL, respectively. After the use of LRFD two cases of biliary leak and 4 pleural effusions were registered. Conclusion. LRFD is simple device for safe liver transection with decreased need for liver ischemia and singificant reducing of the intraoperative blood loss. High price for disposable device and slow parenchyma transection are disadvantages of this device.

  3. [Ferguson hemorrhoidectomy, modified by using the Ligasure radiofrequency coagulator].

    Science.gov (United States)

    Carditello, Antonio; Stilo, Francesco

    2007-01-01

    The aim of the study was the evaluation of results of modified Ferguson hemorrhoidectomy, with use of the Ligasure radiofrequency coagulator, compared to the Milligan-Morgan and Longo techniques. From January 1988 to December 2005, 3011 patients underwent Ferguson hemorrhoidectomy (1849 F, 1162 M; age range: 18 to 84 years). One thousand three hundred patients had previously been treated by medical therapy with poor results and in 225 patients (7.5%) the indication was recurrence after previous surgical treatment. All patients underwent a closed Ferguson hemorrhoidectomy (combined with anoplasty in 28 cases of post-hemorrhoidal stenosis). Eighty percent of patients were operated on with loco-regional assisted anaesthesia, and the remainder with narcosis (cases of recurrence). During the last two years we performed hemorrhoidal excision in 116 patients (4%) with the Ligasure radiofrequency coagulator, followed by continuous suturing with Vicryl 4/0. There was no intraoperative mortality. Mean operation time was 25 minutes. Postoperative complications were hemorrhage in 6 patients (0.2%) and acute urinary retention in 9 patients (0.3%). No important complications were observed in any of the patients treated with Ligasure. The hospital stay was 24 hours for 2852 patients, and 36-86 hours in the other 5%. Seventy-two percent of patients (2160) had moderate postoperative pain, while 14% (420) had severe postoperative pain necessitating repeated administration of analgesics. The 115 patients undergoing Ferguson haemorrhoidectomy plus Ligasure were discharged within 24 hours of surgery. No cases of major domiciliary haemorrhage were observed. There were 13 cases of suture dehiscence (none in the Ferguson plus Ligasure group). Five patients presented suture infection, not requiring surgical drainage, but only medical treatment with local antibiotics. These results, obtained with the modified Ferguson technique, as compared to the classical and even the most innovative

  4. Radiofrequency (thermal) ablation versus no intervention or other interventions for hepatocellular carcinoma

    DEFF Research Database (Denmark)

    Weis, Sebastian; Franke, Annegret; Mössner, Joachim

    2013-01-01

    Hepatocellular carcinoma is the fifth most common cancer worldwide. Percutaneous interventional therapies, such as radiofrequency (thermal) ablation (RFA), have been developed for early hepatocellular carcinoma. RFA competes with other interventional techniques such as percutaneous ethanol...

  5. Percutaneous lumbar sympathectomy: A comparison of radiofrequency denervation versus phenol neurolysis

    Energy Technology Data Exchange (ETDEWEB)

    Haynsworth, R.F. Jr.; Noe, C.E. (Baylor Univ. Medical Center, Dallas, TX (USA))

    1991-03-01

    A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration and less incidence of postsympathetic neuralgia as compared to phenol sympathetic blocks. To compare these techniques, 17 patients underwent either phenol lumbar sympathetic blocks (n = 9) or radiofrequency denervation (n = 8). Duration of sympathetic block was followed by a sweat test and temperature measurements. Results indicate that 89% of patients in the phenol group showed signs of sympathetic blockade after 8 weeks, as compared to 12% in the radiofrequency group (P less than 0.05). Although the incidence of post sympathetic neuralgia appears to be less with radiofrequency denervation, further refinement of needle placement to ensure complete lesioning of the sympathetic chain will be required before the technique can offer advantages over current phenol techniques.

  6. Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

    DEFF Research Database (Denmark)

    Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

    2010-01-01

    A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

  7. Bilateral occipital lobe infarction with altitudinal field loss following radiofrequency cardiac catheter ablation

    OpenAIRE

    Chen Celia S; Lee Andrew W; Luu Susie T

    2010-01-01

    Abstract Background Bilateral stroke following radiofrequency catheter ablation is an unusual complication and may result in bilateral altitudinal visual field defects. Bilateral altitudinal visual field defects usually result from prechiasmal pathology causing damage to both retinas or optic nerves and rarely from bilateral symmetric damage to the post chiasmal visual pathways. Case presentation A 48-year-old man complained of visual disturbance on wakening following radiofrequency catheter ...

  8. Papillary Thyroid Carcinoma Treated with Radiofrequency Ablation in a Patient with Hypertrophic Cardiomyopathy: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jianyi; Liu, Xiaosun; Zhang, Qing; Hong, Yanyun; Song, Bin [Department of Gastrointestinal and Thyroid Surgery, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China); Teng, Xiaodong [Department of Pathology, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China); Yu, Jiren [Department of Gastrointestinal and Thyroid Surgery, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China)

    2016-11-01

    Standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease. Herein, we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy. Radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible, although the long-term outcome needs further observation.

  9. Papillary thyroid carcinoma treated with radiofrequency ablation in a patient with hypertrophic cardiomyopathy: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jian Yi; Liu, Xiao Sun; Zhang, Qing; Hong, Yan Yun; Song, Bin; Teng, Xiao Dong; Yu, Ji Ren [The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou (China)

    2016-07-15

    Standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease. Herein, we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy. Radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible, although the long-term outcome needs further observation.

  10. Use of Radiofrequency Ablation in Benign Thyroid Nodules: A Literature Review and Updates

    OpenAIRE

    Kai-Pun Wong; Brian Hung-Hin Lang

    2013-01-01

    Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid...

  11. Cooled radiofrequency denervation for treatment of sacroiliac joint pain: two-year results from 20 cases

    Directory of Open Access Journals (Sweden)

    Ho KY

    2013-07-01

    Full Text Available Kok-Yuen Ho,1 Mohamed Abdul Hadi,2 Koravee Pasutharnchat,2 Kian-Hian Tan21Pain Management Centre, Raffles Hospital, 2Pain Management Centre, Singapore General Hospital, SingaporeBackground: Sacroiliac joint pain is a common cause of chronic low back pain. Different techniques for radiofrequency denervation of the sacroiliac joint have been used to treat this condition. However, results have been inconsistent because the variable sensory supply to the sacroiliac joint is difficult to disrupt completely using conventional radiofrequency. Cooled radiofrequency is a novel technique that uses internally cooled radiofrequency probes to enlarge lesion size, thereby increasing the chance of completely denervating the sacroiliac joint. The objective of this study was to evaluate the efficacy of cooled radiofrequency denervation using the SInergyTM cooled radiofrequency system for sacroiliac joint pain.Methods: The charts of 20 patients with chronic sacroiliac joint pain who had undergone denervation using the SInergyTM cooled radiofrequency system were reviewed at two years following the procedure. Outcome measures included the Numeric Rating Scale for pain intensity, Patient Global Impression of Change, and Global Perceived Effect for patient satisfaction.Results: Fifteen of 20 patients showed a significant reduction in pain (a decrease of at least three points on the Numeric Rating Scale. Mean Numeric Rating Scale for pain decreased from 7.4 ± 1.4 to 3.1 ± 2.5, mean Patient Global Impression of Change was "improved" (1.4 ± 1.5, and Global Perceived Effect was reported to be positive in 16 patients at two years following the procedure.Conclusion: Cooled radiofrequency denervation showed long-term efficacy for up to two years in the treatment of sacroiliac joint pain.Keywords: ablation, chronic low back pain, intervention, neurotomy, sacroiliitis

  12. Bipolar radiofrequency-induced thermotherapy of great saphenous vein: Our initial experience

    Directory of Open Access Journals (Sweden)

    Venkatesh Kasi

    2012-01-01

    Full Text Available The incidence of varicose veins in lower limbs is increasing in the Indian subcontinent. With the advent of radiofrequency ablation (RFA, an effective minimally invasive technique is now available to treat varicose veins. RFA can be performed with either unipolar or bipolar probes. We present a simple technique for bipolar radiofrequency-induced thermotherapy of the great saphenous vein. This can be a safe and effective alternative to surgical procedures.

  13. The radio-frequency design of an iris-type coupler for the CPHS radio-frequency quadrupole

    Institute of Scientific and Technical Information of China (English)

    XIONG Zheng-Feng; ZHENG Shu-Xin; XING Qing-Zi; GUAN Xia-Ling

    2012-01-01

    The Compact Pulsed Hadron Source (CPHS) project is a university-based proton accelerator platform (13 MeV,16 kW,50 mA peak current,0.5 ms pulse width at 50 Hz) for multi-disciplinary neutron and proton applications.The CPHS linac consists of a 3 MeV radio frequency quadrupole (RFQ) linac and a 13 MeV drift tube linac (DTL).Both the RFQ and DTL share a 325 MHz,2.1 MW klystron source.A single iris-type radio-frequency (RF) coupler is used to feed 537 kW of RF power to the RFQ cavity.Threedimensional electromagnetic models of the ridge-loaded tapered waveguide (RLWG) and the coupler-cavity system are presented,and the design process and results of the RLWG and iris plate are described in detail.

  14. The proposed use of radiofrequency ablation for the treatment of fistula-in-ano.

    Science.gov (United States)

    Keogh, Kenneth M; Smart, Neil J

    2016-01-01

    Fistula in ano is a very common presentation to colorectal clinic. Embarrassment due to the symptoms makes accurate estimations of incidence difficult. It is estimated that up to 40% of peri-anal abscess will be accompanied by or preceded by a fistula. Fistulae can be classified into simple fistulae that involve no or minimal sphincter muscle and complex, which involve significant amounts of the anal sphincter muscle, possibly with multiple tracts. For complex fistulae a seton suture is usually placed through the tract and out through the anus to form a loop allowing pockets of sepsis to drain internally and externally and a mature tract of fibrous tissue to develop. Following this period definitive fistula treatment is considered. This can involve a number of procedures that have tremendously varied success rates in the literature. The first stage of surgical treatment is often a core fistulectomy, which entails surgical removal of the tract. This may be followed by insertion of fibrin glue, a collagen plug or formation of a rotation skin flap from surrounding tissue in order to close the resultant tissue defect. All current treatments have a significant failure rate. If this wound breaks down the surgery can leave a large painful peri-anal wound that can lead to ongoing fistulation. Should this occur resiting of the seton will be required with the patient only getting back to square one after months of healing around the seton. In addition removing cores of fibrous tissue passing through the sphincter can threaten the sphincter function resulting in impaired continence. Having seen radiofrequency ablation used to close varicose veins the authors propose that one could use similar techniques to close a fibrous tract matured with a seton in order to close a fistula. The authors propose that a short length radiofrequency catheter could be used to treat fistula in ano. This would in theory be less painful with less tissue destruction. In addition there would be no

  15. Radiofrequency Ablation of Lung Cancer at Okayama University Hospital: A Review of 10 Years of Experience

    Directory of Open Access Journals (Sweden)

    Hiraki,Takao

    2011-10-01

    Full Text Available The application of radiofrequency ablation for the treatment of lung cancer by our group at Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences began in June 2001, and in the present report, we review our 10-year experience with this treatment modality at Okayama University Hospital. The local efficacy of radiofrequency ablation for the treatment of lung cancer depends on tumor size and the type of electrode used, but not on tumor type. An important factor for the prevention of local failure may be the acquisition of an adequate ablative margin. The combination of embolization and radiation therapy enhances the local efficacy. Local failure may be salvaged by repeating the radiofrequency ablation, particularly in small tumors. Survival rates after radiofrequency ablation are quite promising for patients with clinical stage I non-small cell lung cancer and pulmonary metastasis from colorectal cancer, hepatocellular carcinoma, and renal cell carcinoma. The complications caused by radiofrequency ablation can be treated conservatively in the majority of cases. However, attention should be paid to rare but serious complications. This review shows that radiofrequency ablation is a promising treatment for patients with lung cancer.

  16. Diverse radiofrequency sensitivity and radiofrequency effects of mobile or cordless phone near fields exposure in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Styliani Geronikolou

    Full Text Available INTRODUCTION: The impact of electromagnetic fields on health is of increasing scientific interest. The aim of this study was to examine how the Drosophila melanogaster animal model is affected when exposed to portable or mobile phone fields. METHODS/RESULTS: Two experiments have been designed and performed in the same laboratory conditions. Insect cultures were exposed to the near field of a 2G mobile phone (the GSM 2G networks support and complement in parallel the 3G wide band or in other words the transmission of information via voice signals is served by the 2G technology in both mobile phones generations and a 1880 MHz cordless phone both digitally modulated by human voice. Comparison with advanced statistics of the egg laying of the second generation exposed and non-exposed cultures showed limited statistical significance for the cordless phone exposed culture and statistical significance for the 900 MHz exposed insects. We calculated by physics, simulated and illustrated in three dimensional figures the calculated near fields of radiation inside the experimenting vials and their difference. Comparison of the power of the two fields showed that the difference between them becomes null when the experimental cylinder radius and the height of the antenna increase. CONCLUSIONS/SIGNIFICANCE: Our results suggest a possible radiofrequency sensitivity difference in insects which may be due to the distance from the antenna or to unexplored intimate factors. Comparing the near fields of the two frequencies bands, we see similar not identical geometry in length and height from the antenna and that lower frequencies tend to drive to increased radiofrequency effects.

  17. Histological findings in adipocytes when cellulite is treated with a variable-emission radiofrequency system.

    Science.gov (United States)

    Trelles, Mario A; van der Lugt, Claudia; Mordon, Serge; Ribé, Adriana; Al-Zarouni, Marwan

    2010-03-01

    Cellulite is a disorder of the subcutaneous fat layer and the overlying superficial skin. Recently, radiofrequency (RF) has been proposed as an effective treatment of cellulite; however, the mechanism through which the absorbed electrical energy acts on the tissue is still not fully clear. This study reports on the histological findings from biopsies taken immediately after a single RF treatment session, on cellulite located in the buttocks, with a novel technology called automatic multi-frequency and low impedance (AMFLI) RF. Tissue samples were stained with either haematoxylin and eosin (H&E), so that we could study the morphological findings, or with oil red O, to enable us to identify lipid deposits. The histological findings observed in biopsies taken after a single RF treatment showed changes in shape, size, and lipid content, as well as in cytoplasmic and nuclear morphology. After RF treatment adipocytes were more polyhedric, with irregular, degenerated membranes, with less or no lipid content and apoptotic changes. We postulate that RF treatment on cellulite produces a decrease in lipid content of cells as well as changes in the adipocyte membrane which will lead to cell rupture and the death and extrusion of lipid content out of the cell. Further studies are needed to characterise the nature of the extra-cellular lipid material that we have demonstrated with the oil red O stain in our biopsies.

  18. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  19. Case Study of Hepatic Radiofrequency Ablation Causing a Systemic Inflammatory Response Under Total Intravenous Anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Schalte, Gereon; Waning, Christian; Rossaint, Rolf; Mahnken, Andreas H. [University Hospital, RWTH Aachen, Aachen, (Germany); Henzler, Dietrich [Dalhousie University, Queen Elisabeth II Health Sciences Center, Halifax (Canada); Tacke, Josef [Interventional Radiology, Klinikum Passau, Passau (Germany)

    2010-12-15

    To investigate the effects of hepatic radiofrequency ablation (RFA) in patients with malignant liver disease with respect to inflammation activation and stress response. In an observational trial, we investigated the physiologic parameters of 17 patients (20 interventions) who underwent percutaneous RFA under general anesthesia after applying total intravenous anesthesia. TNF{alpha}, IL-6, IL-8, IL-10, adrenaline and noradrenaline, liver enzymes, lactate and creatine kinase were determined pre-interventionally after induction of anesthesia (T1), 90 minutes after initiation of RFA (T2), immediately after the conclusion of the procedure (T3), and 24 hours after the procedure (T4). A significant increase in body temperature (p < 0.001), and mean arterial pressure (p = 0.001) were measured intraoperatively (T2) and the day after the procedure (T4). Increased levels of IL-6 were measured at T3 and T4 (p = 0.001). IL-10 increased immediately after the procedure (T3; p = 0.007). IL-6 levels correlated well with the total energy applied ({gamma} = 0.837). Significant increases in the levels of adrenaline and noradrenaline were present at T3 and T4 (p < 0.001). The RFA-induced destruction of hepatic tissue was associated with increased levels of AST, ALT, GLDH and LDH. Percutaneous RFA of hepatic malignancies causes an inflammatory and endocrine activation, similar to the systemic inflammatory response syndrome. These effects have to be taken in account when dealing with patients susceptible to sepsis or multi-organ failure

  20. Thermocathode radio-frequency gun for the Budker Institute of Nuclear Physics free-electron laser

    Science.gov (United States)

    Volkov, V.; Getmanov, Ya.; Kenjebulatov, E.; Kolobanov, E.; Krutikhin, S.; Kurkin, G.; Ovchar, V.; Petrov, V. M.; Sedlyarov, I.

    2016-12-01

    A radio-frequency (RF) gun for a race-track microtron-recuperator injector driving the free-electron laser (FEL) (Budker Institute of Nuclear Physics) is being tested at a special stand. Electron bunches of the RF gun have an energy of up to 300 keV and a repetition rate of up to 90 MHz. The average electro-beam current can reach 100 mA in the continuous operation regime. The advantages of the new injector are as follows: long lifetime of the cathode for high average beam current; simple scheme of longitudinal beam bunching, which does not require an additional bunching resonator in the injector; absence of dark-current contamination of the injector beam; and comfortable RF gun operation due to the absence of a high potential of 300 kV at the cathode control circuits. In this study we describe the RF gun design, present the main characteristics of the injector with the RF gun, and give the results of testing.

  1. Surface studies of niobium chemically polished under conditions for superconducting radiofrequency cavity production

    Energy Technology Data Exchange (ETDEWEB)

    Hui Tian; Michael Kelley; Charles Reece

    2005-11-14

    The performance of niobium superconducting radiofrequency accelerator cavities is strongly impacted by the topmost several nanometers of the active (interior) surface, especially by the final surface conditioning treatments. We examined the effect of the most commonly employed treatment, buffered chemical polishing (BCP), on polycrystalline niobium sheet over a range of realistic solution flow rates using electron back scatter diffraction (EBSD), stylus profilometry, atomic force microscopy, laboratory XPS and synchrotron (variable photon energy) XPS, seeking to collect statistically significant data sets. We found that the predominant general surface orientation is (100), but others are also present and at the atomic-level details of surface plane orientation are more complex. The post-etch surface exhibits micron-scale roughness, whose extent does not change with treatment conditions. The outermost surface consists of a few-nm thick layer of niobium pentoxide, whose thickness increases with solution flow rate to a maximum of 1.3 - 1.4 times that resulting from static solution. The standard deviation of the roughness measurements is ?? 30% and that of the surface composition is ?? 5%.

  2. Synthesis and characterization of Nd2O3 nanoparticles in a radiofrequency thermal plasma reactor

    Science.gov (United States)

    Dhamale, G. D.; Mathe, V. L.; Bhoraskar, S. V.; Sahasrabudhe, S. N.; Dhole, S. D.; Ghorui, S.

    2016-02-01

    The synthesis of nanocrystalline Nd2O3 through an inductively coupled radiofrequency thermal plasma route is reported. Unlike in conventional synthesis processes, plasma-synthesized nanoparticles are directly obtained in a stable hexagonal crystal structure with a faceted morphology. The synthesized nanoparticles are highly uniform with an average size around 20 nm. The nanoparticles are characterized in terms of phase formation, crystallinity, morphology, size distribution, nature of chemical bonds and post-synthesis environmental effects using standard characterization techniques. X-ray diffraction, transmission electron microscopy, and scanning electron microscopy are used for structural and morphological studies. The thermo-gravimetric technique, using a differential scanning calorimeter, is used to investigate the purity of phase. Fourier transform infrared spectroscopy is used to investigate the nature of existing bonds. The optical response of the nanoparticles is investigated through the electronic transition of Nd3+ ions in its crystalline structure via UV-visible spectroscopy. The presence of defect states and corresponding activation energies in the nanocrystalline Nd2O3 compared to those of the precursors are studied using thermoluminescence.

  3. Comparison of radiofrequency exposure of a mouse dam and foetuses at 900 MHz

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Robert L; Wood, Andrew W [Australian Centre for Radiofrequency Bioeffects Research, Hawthorn, VIC, 3122 (Australia); Deppeler, Lauren; Oliva, Megan; Parente, John; Tambuwala, Faiyaz; Turner, Stephen; Winship, David [Swinburne University of Technology, Hawthorn, VIC, 3122 (Australia)], E-mail: robert.l.mcintosh@team.telstra.com

    2010-02-21

    In vivo studies involving radiofrequency (RF) exposure of rodents require detailed dosimetric analysis to enable correct interpretation of biological outcomes. Detailed anatomical models of mice--a female, a pregnant female, a male and a foetus--have been developed for analyses using finite difference numerical techniques. The mouse models, consisting of 49 tissues, will be made freely available to the research community. In this note, the pregnant mouse model, which included eight mature foetuses, was utilized specifically to consider (a) the RF dosimetry in a radial cavity exposure system operated at a frequency of 900 MHz and (b) a 900 MHz plane wave exposure. A comparison was made between the exposure of the mouse dam and the foetuses as specified by the specific energy absorption rate (SAR) and the resultant temperature change. In general, the SAR levels in the foetuses were determined to be slightly lower (around 14% lower than the average values of the dam) and the peak temperature increase was significantly lower (45%) than the values in the dam. (note)

  4. Enhancement of hydrophobicity and tensile strength of muga silk fiber by radiofrequency Ar plasma discharge

    Science.gov (United States)

    Gogoi, D.; Choudhury, A. J.; Chutia, J.; Pal, A. R.; Dass, N. N.; Devi, D.; Patil, D. S.

    2011-10-01

    The hydrophobicity and tensile strength of muga silk fiber are investigated using radiofrequency (RF) Ar plasma treatment at various RF powers (10-30 W) and treatment times (5-20 min). The Ar plasma is characterized using self-compensated Langmuir and emissive probe. The ion energy is observed to play an important role in determining the tensile strength and hydrophobicity of the plasma treated fibers. The chemical compositions of the fibers are observed to be affected by the increase in RF power rather than treatment time. XPS study reveals that the ions that are impinging on the substrates are mainly responsible for the cleavage of peptide bond and side chain of amino acid groups at the surface of the fibers. The observed properties (tensile strength and hydrophobicity) of the treated fibers are found to be dependent on their variation in atomic concentration and functional composition at the surfaces. All the treated muga fibers exhibit almost similar thermal behavior as compared to the virgin one. At RF power of 10 W and treatment time range of 5-20 min, the treated fibers exhibit properties similar to that of the virgin one. Higher RF power (30 W) and the increase in treatment time deteriorate the properties of the fibers due to incorporation of more surface roughness caused by sufficiently high energetic ion bombardment. The properties of the plasma treated fibers are attempted to correlate with the XPS analysis and their surface morphologies.

  5. Enhancement of hydrophobicity and tensile strength of muga silk fiber by radiofrequency Ar plasma discharge

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, D.; Choudhury, A.J. [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Chutia, J., E-mail: joyanti_c@sify.com [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Pal, A.R.; Dass, N.N. [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Devi, D. [Life Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Patil, D.S. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India)

    2011-10-15

    The hydrophobicity and tensile strength of muga silk fiber are investigated using radiofrequency (RF) Ar plasma treatment at various RF powers (10-30 W) and treatment times (5-20 min). The Ar plasma is characterized using self-compensated Langmuir and emissive probe. The ion energy is observed to play an important role in determining the tensile strength and hydrophobicity of the plasma treated fibers. The chemical compositions of the fibers are observed to be affected by the increase in RF power rather than treatment time. XPS study reveals that the ions that are impinging on the substrates are mainly responsible for the cleavage of peptide bond and side chain of amino acid groups at the surface of the fibers. The observed properties (tensile strength and hydrophobicity) of the treated fibers are found to be dependent on their variation in atomic concentration and functional composition at the surfaces. All the treated muga fibers exhibit almost similar thermal behavior as compared to the virgin one. At RF power of 10 W and treatment time range of 5-20 min, the treated fibers exhibit properties similar to that of the virgin one. Higher RF power (30 W) and the increase in treatment time deteriorate the properties of the fibers due to incorporation of more surface roughness caused by sufficiently high energetic ion bombardment. The properties of the plasma treated fibers are attempted to correlate with the XPS analysis and their surface morphologies.

  6. Capacitively coupled radio-frequency discharges in nitrogen at low pressures

    KAUST Repository

    Alves, Luís Lemos

    2012-07-06

    This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56MHz frequency, 0.11 mbar pressures and 230W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an actinometer). Simulations use a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles (electrons and positive ions N 2 + and N 4 + ), and a zero-dimensional kinetic module, describing the production and destruction of nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define spacetime-dependent electron parameters for the fluid module and to work out spacetime-averaged rates for the kinetic module. The model gives general good predictions for the self-bias voltage and for the intensities of radiative transitions (both average and spatially resolved), underestimating the electron density by a factor of 34. © 2012 IOP Publishing Ltd.

  7. Precision mass measurements of very short-lived, neutron-rich Na isotopes using a radiofrequency spectrometer

    CERN Document Server

    Lunney, M D; Doubre, H; Henry, S; Monsanglant, C; De Saint-Simon, M; Thibault, C; Toader, C F; Borcea, C; Bollen, G

    2001-01-01

    Mass measurements of high precision have been performed on sodium isotopes out to $^{30}$Na using a new technique of radiofrequency excitation of ion trajectories in a homogeneous magnetic field. This method, especially suited to very short-lived nuclides, has allowed us to significantly reduce the uncertainty in mass of the most exotic Na isotopes: a relative error of 5x10$^{-7}$ was achieved for $^{28}$Na having a half-life of only 30.5 ms and 9x10$^{-7}$ for the weakly produced $^{30}$Na. Verifying and minimizing binding energy uncertainties in this region of the nuclear chart is important for clarification of a long standing problem concerning the strength of the $N$=20 magic shell closure. These results are the fruit of the commissioning of the new experimental program Mistral.

  8. Water dissociation in a radio-frequency electromagnetic field with ex situ electrodes—modelling of discharge initiation

    Science.gov (United States)

    Schneider, Jens; Holzer, Frank; Rabe, Carsten; Häupl, Tilmann; Kopinke, Frank-Dieter; Roland, Ulf

    2013-04-01

    Applying a new experimental design with a capillary glass reactor and plate electrodes outside of the reactor allowed the initiation of discharges in aqueous electrolytes under the influence of a radio-frequency (RF) electromagnetic field. This study focused on the mechanism leading to the initiation of such discharges in the restriction of a glass tube. The light emission correlated with discharges was analysed with optical emission spectroscopy. Electrons with energies between 20 and 45 eV were responsible for the dissociation of water molecules into (excited) OH, H and O radicals. Current-voltage characteristics were measured before and under discharge conditions. Modelling of the experimental setup and simulation of electrical field strength distribution support the hypothesis of the origin of discharges in general and experimental findings such as ring-shaped discharges and a minimum solution conductivity of about 1 S m-1 required for discharge initiation with RF voltages of 2 kV.

  9. One-Dimensional Fluid Model of Pulse Modulated Radio-Frequency SiH4/N2/O2 Discharge

    Institute of Scientific and Technical Information of China (English)

    王燕; 刘相梅; 宋远红; 王友年

    2012-01-01

    Driven by pulse modulated radio-frequency plasma in capacitively coupled discharge are studied by source, the behavior of SiH4/N2/02 using a one-dimensional fluid model. Totally, 48 different species (electrons, ions, neutrals, radicals and excited species) are involved in this simulation. Time evolution of the particle densities and electron temperature with different duty cycles are obtained, as well as the electronegativity nsiH-3 /ne of the main negative ion (Sill3 ). The results show that, by reducing the duty cycle, higher electron temperature and particle density can be achieved for the same average dissipated power, and the ion energy can also be effectively reduced, which will offer evident improvement in plasma deposition processes compared with the case of continuous wave discharge.

  10. Periodic conduction and 2:1 block from the left atrium to the pulmonary vein during radiofrequency ablation.

    Science.gov (United States)

    Landolina, Maurizio; Petracci, Barbara; De Ferrari, Gaetano M; Frattini, Folco; Cantù, Francesco; Rordorf, Roberto; De Filippo, Paolo

    2004-11-01

    Paroxysmal atrial fibrillation is often initiated by foci in the pulmonary veins (PVs); the junction between the PVs and the left atrium (LA) has become the target of radiofrequency (RF) ablation performed to isolate the PVs. Ectopic atrial beats originating from the PVs propagate to the LA with a characteristically long conduction time, often with a conduction delay or block within the PV or at the PV-LA junction. However, details about the conduction properties within the PVs and across the PV-LA junction are still scanty. We report a unique case of LA-PV decremental conduction caused by RF applications. New insights into the electroanatomical characteristics of the PV-LA junction are provided. The present report demonstrates, for the first time in humans, that decremental conduction may be related to the progressive damage of the conducting myocardial bundle due to RF energy applications.

  11. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  12. The study of thermal change by chemoport in radiofrequency hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Hoon; Lee, Sun Young; Gim, Yang Soo; Kwak, Keun Tak; Yang, Myung Sik; Cha, Seok Yong [Dept. of Radiation Oncology, Chonbuk National University Hospital, Jeonju (Korea, Republic of)

    2015-12-15

    This study evaluate the thermal changes caused by use of the chemoport for drug administration and blood sampling during radiofrequency hyperthermia. 20 cm size of the electrode radio frequency hyperthermia (EHY-2000, Oncotherm KFT, Hungary) was used. The materials of the chemoport in our hospital from currently being used therapy are plastics, metal-containing epoxy and titanium that were made of the diameter 20 cm, height 20 cm insertion of the self-made cylindrical Agar phantom to measure the temperature. Thermoscope(TM-100, Oncotherm Kft, Hungary) and Sim4Life (Ver2.0, Zurich, Switzerland) was compared to the actual measured temperature. Each of the electrode measurement position is the central axis and the central axis side 1.5 cm, 0 cm(surface), 0.5 cm, 1.8 cm, 2.8 cm in depth was respectively measured. The measured temperature is 24.5 - 25.5℃, humidity is 30% - 32%. In five-minute intervals to measure the output power of 100 W, 60 min. In the electrode central axis 2.8 cm depth, the maximum temperature of the case with the unused of the chemoport, plastic, epoxy and titanium were respectively 39.51℃, 39.11℃, 38.81℃, 40.64℃, simulated experimental data were 42.20 ℃, 41.50℃, 40.70℃, 42.50℃. And in the central axis electrode side 1.5 cm depth 2.8 cm, measured data were 39.37℃, 39.32℃, 39.20℃, 39.46℃, the simulated experimental data were 42.00℃, 41.80℃, 41.20℃, 42.30℃. The thermal variations were caused by radiofrequency electromagnetic field surrounding the chemoport showed lower than in the case of unused in non-conductive plastic material and epoxy material, the titanum chemoport that made of conductor materials showed a slight differences. This is due to the metal contents in the chemoport and the geometry of the chemoport. And because it uses a low radio frequency bandwidth of the used equipment. That is, although use of the chemoport in this study do not significantly affect the surrounding tissue. That is, because the

  13. Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain

    Directory of Open Access Journals (Sweden)

    Mert Akbas

    2016-02-01

    Full Text Available PURPOSE: There are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. METHODS: Infrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25-0.5 ms pulse width was applied for sensory stimulation at frequencies from 50 Hz to 1 V. Paraesthesias were exposed at the roof of the nose at 0.5-0.7 V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2 Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120 s at a temperature of 42 °C. RESULTS: Pain relief could not be achieved in 23% of the patients (unacceptable, whereas pain was completely relieved in 35% of the patients (excellent and mild to moderate pain relief could be achieved in 42% of the patients (good through sphenopalatine ganglion-pulsed radiofrequency treatment. CONCLUSION: Pulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain.

  14. Discrimination between weaned and unweaned Atlantic cod (Gadus morhua) in capture-based aquaculture (CBA) by X-ray imaging and radio-frequency metal detector.

    Science.gov (United States)

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60-70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups - unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented.

  15. Discrimination between weaned and unweaned Atlantic cod (Gadus morhua in capture-based aquaculture (CBA by X-ray imaging and radio-frequency metal detector.

    Directory of Open Access Journals (Sweden)

    Ekrem Misimi

    Full Text Available The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg in the small scale capture-based aquaculture (CBA. Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60-70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups - unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented.

  16. Discrimination between Weaned and Unweaned Atlantic Cod (Gadus morhua) in Capture-Based Aquaculture (CBA) by X-Ray Imaging and Radio-Frequency Metal Detector

    Science.gov (United States)

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60–70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups – unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented. PMID:24743448

  17. Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system: a prospective randomized comparison with conventional procedure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-xiao; LU Cai-yi; XUE Qiao; LI Ke; YAN Wei; ZHOU Sheng-hua

    2012-01-01

    Background Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias.The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.Methods Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups.In the conventional technique group (CMT),a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used.The following parameters were collected and compared between the two groups: ablation procedure time,patient fluoroscopy time,operator fluoroscopy time,energy delivery numbers,maximal energy per deployment,success rate,complication rate and operative cost.Results Forty patients were enrolled and randomized into CMT and MNS groups.The age,gender,tachycardia history and basic cardiovascular diseases of the two groups were comparable (P >0.05).All procedures were conducted successfully without complications.No tachycardia recurred during the follow-up period of (9.3±2.6) months.In the MNS group,the patient and operator fluoroscopy times ((11.5±4.3) min,(4.2±1.5) min),energy delivery numbers (3.2±0.9),and maximal energy per deployment ((16.9±3.4) W) were shorter or lower than those of the CMT group ((14.3±6.2) min,(13.6±3.5) min,6.3±2.1,(23.7±1.3) W,respectively) (P <0.05).But the operative cost for the MNS group was higher than that of the CMT group (P <0.01 ).Conclusion Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

  18. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Juan J. [Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada al Ser Humano, Universitat Politècnica de València, Valencia 46022 (Spain); Pérez-Cajaraville, Juan J. [Pain Unit and Department of Anesthesia and Critical Care, Clínica Universidad de Navarra, University of Navarra, Pamplona 31008 (Spain); Muñoz, Víctor [Neurotherm Spain, Barcelona 08303 (Spain); Berjano, Enrique, E-mail: eberjano@eln.upv.es [Biomedical Synergy, Electronic Engineering Department, Universitat Politècnica de València 46022 (Spain)

    2014-07-15

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m{sup −1}) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of

  19. Measured radiofrequency exposure during various mobile-phone use scenarios.

    Science.gov (United States)

    Kelsh, Michael A; Shum, Mona; Sheppard, Asher R; McNeely, Mark; Kuster, Niels; Lau, Edmund; Weidling, Ryan; Fordyce, Tiffani; Kühn, Sven; Sulser, Christof

    2011-01-01

    Epidemiologic studies of mobile phone users have relied on self reporting or billing records to assess exposure. Herein, we report quantitative measurements of mobile-phone power output as a function of phone technology, environmental terrain, and handset design. Radiofrequency (RF) output data were collected using software-modified phones that recorded power control settings, coupled with a mobile system that recorded and analyzed RF fields measured in a phantom head placed in a vehicle. Data collected from three distinct routes (urban, suburban, and rural) were summarized as averages of peak levels and overall averages of RF power output, and were analyzed using analysis of variance methods. Technology was the strongest predictor of RF power output. The older analog technology produced the highest RF levels, whereas CDMA had the lowest, with GSM and TDMA showing similar intermediate levels. We observed generally higher RF power output in rural areas. There was good correlation between average power control settings in the software-modified phones and power measurements in the phantoms. Our findings suggest that phone technology, and to a lesser extent, degree of urbanization, are the two stronger influences on RF power output. Software-modified phones should be useful for improving epidemiologic exposure assessment.

  20. Radiofrequency Ablation: A Minimally Invasive Approach in Kidney Tumor Management

    Energy Technology Data Exchange (ETDEWEB)

    Salagierski, Maciej, E-mail: maciej.salagierski@umed.lodz.pl [I Urology Department, Medical University of Lodz (Poland); Salagierski, Marek S. [II Urology Department, Medical University of Lodz (Poland)

    2010-11-17

    The management and diagnosis of renal tumors have changed significantly over the last decade. Due to advances in imaging techniques, more than 50% of kidney tumors are discovered incidentally and many of them represent an early stage lesion. This has stimulated the development of nephron-sparing surgery and of the minimally invasive treatment options including ablative techniques, i.e., radiofrequency ablation (RFA) and cryoablation. The objective of the minimally invasive approach is to preserve the renal function and to lower the perioperative morbidity. RFA involves inducing the coagulative necrosis of tumor tissue. Being probably one of the least invasive procedures in kidney tumor management, RFA may be performed percutaneously under ultrasound (US), computed tomography (CT) or magnetic resonance (MR) guidance. Most of the studies show that the RFA procedure is efficient, safe and has a low complication rate. Due to the still limited data on the oncological outcome of RFA, the indication for this intervention remains limited to selected patients with small organ-confined renal tumors and contraindication to surgery or who have a solitary kidney. The aim of our study is to review the literature on RFA of kidney tumors.

  1. Radiofrequency Ablation Treatment for Renal Cell Carcinoma: Early Clinical Experience

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong Hoon; Yoon, Seong Kuk; Cho, Jin Han; Oh, Jong Young; Nam, Kyung Jin; Kwon, Hee Jin; Kim, Su Yeon; Kang, Myong Jin; Choi, Sun Seob; Sung, Gyung Tak [Dong-A University College of Medicine, Busan (Korea, Republic of)

    2008-08-15

    To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43 73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow- up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1 5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17 33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.

  2. Actual role of radiofrequency ablation of liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Philippe L. [Eberhard-Karls-University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany)

    2007-08-15

    The liver is, second only to lymph nodes, the most common site for metastatic disease irrespective of the primary tumour. More than 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improved survival in patients with colorectal metastases, only approximately 20% of patients are eligible for surgery. Thermal ablation and especially radiofrequency ablation emerge as an important additional therapy modality for the treatment of liver metastases. RF ablation shows a benefit in life expectancy and may lead in a selected patient group to cure. Percutaneous RF ablation appears safer (versus cryotherapy), easier (versus laser), and more effective (versus ethanol instillation and transarterial chemoembolisation) compared with other minimally invasive procedures. RF ablation can be performed by a percutaneous, laparoscopical or laparotomic approach, and may be potentially combined with chemotherapy and surgery. At present ideal candidates have tumours with a maximum diameter less than 3.5 cm. An untreatable primary tumour or a systemic disease represents contraindications for performing local therapies. Permanent technical improvements of thermal ablation devices and a better integration of thermal ablation in the overall patient care may lead to prognosis improvement in patients with liver metastases. (orig.)

  3. Sympathetic radiofrequency neurolysis for unilateral lumbar hyperhidrosis: a case report.

    Science.gov (United States)

    Aşik, Züleyha Soytürk; Orbey, Başak Ceyda; Aşik, Ibrahim

    2008-07-01

    Patients with hyperhidrosis suffer from physical, social and mental discomfort which often cannot be treated sufficiently using conservative measures. A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration of action and less incidence of post sympathetic neuralgia. This article reports the authors' experience with sympathetic RF neurolysis in a 35 year old male with right unilateral lumbar hyperhidrosis. Under scopy guided localization of the lumbar spine sympathetic blockade with local anesthetics to L2-5 vertebral levels were performed as a diagnostic block. Lesion effectiveness is monitored by bilateral feet skin temperature measurement. Clinical effects produced by the first sympathetic ganglion block were sustained for 1 week and then RF neurolysis of lumbar sympathetic ganglion was performed to the same levels for a longer effect. The procedure was accomplished within 30 minutes and the patient was discharged within 2 hours after the procedure. Hyperhidrosis was relieved after the procedure and there were no postsympathectomy neuralgia and sexual dysfunction. The patient obtained improvement of lumbar hyperhidrosis at his first month of follow- up and was satisfied with the outcome. In conclusion, RF neurolysis of lumbar sympathetic ganglions is a safe and effective palliative procedure with minimal invasiveness for relieving excessive sweat secretion in patients with localized hyperhidrosis.

  4. A survey of the urban radiofrequency (RF) environment.

    Science.gov (United States)

    Tell, Richard A; Kavet, Robert

    2014-12-01

    In 1980, Tell and Mantiply published a study of radiofrequency (RF) fields measured across 15 major metropolitan areas in the USA. They required a van fully equipped with instrumentation and computing capability for their measurements. This study aimed to assess whether and how hand-held instrumentation available today would facilitate and enhance the efficiency of large-scale surveys of ambient RF fields. In addition, the data would provide a suggestion as to how the profile of ambient RF fields has changed with respect to frequency content and magnitude. Not unexpectedly, the relative power densities were orders of magnitude lower than the Federal Communications Commission's (FCC) maximum permissible exposure (MPE) for the general public, with a maximum time-averaged value across the VHF-FM-UHF-cellular bands of 0.12 % of the MPE (AM's contribution was negligible). In both the 1980 and the present study, the power density in the FM band was a major contributor to overall power density, but over time, power densities in the VHF and UHF band decreased and increased, respectively. From the perspective of absolute power density, the wideband values in the 1980 study, this study and any number of assessments conducted in European nations are not generally different from one another. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Mechanical properties of niobium radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, G., E-mail: gciovati@jlab.org [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Dhakal, P.; Matalevich, J.; Myneni, G. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Schmidt, A.; Iversen, J.; Matheisen, A.; Singer, W. [Deutsches Elektronen-Synchrotron, Notkestraße 85, 22607 Hamburg (Germany)

    2015-08-26

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 620 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structures have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young’s modulus value of 88.5 GPa and a Poisson’s ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities made from ingot material with large crystals are comparable to those of cavities made of fine-grain niobium.

  6. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules

    Directory of Open Access Journals (Sweden)

    Chiara Dobrinja

    2015-01-01

    Full Text Available Background. Radiofrequency ablation (RFA has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms. Two Thy3 nodules regrew after the procedure, and these patients accepted to undergo a total thyroidectomy. Here we present how RFA has affected the operation and the final pathological features of the surgically removed nodules. Results and Conclusions. RFA is effective for the treatment of Thy2 nodules, but it should not be recommended as first-line therapy for the treatment of Thy3 nodules (irrespective of their mutational status, as it delays surgery in case of malignancy. Moreover, it is unknown whether RFA might promote residual tumor progression or neoplastic progression of Thy3 lesions. Nevertheless, here we show for the first time that one session of RFA does not affect subsequent thyroid surgery and/or histological diagnosis.

  7. EFFECT OF MOBILE PHONE RADIOFREQUENCY ON HIPPOCAMPAL CA3 NEURONS

    Directory of Open Access Journals (Sweden)

    Srinivas Rao Bolla

    2015-09-01

    Full Text Available Objective: The purpose of the study is to investigate the effects of mobile phone [MP] radiofrequency electromagnetic fields (RF-EMF exposure for different durations on dendritic morphology and nerve cell damage in CA3 sub region of Hippocampus in Swiss albino mice. Materials &Methods: Total 70 Swiss albino mice of both sexes were used in the study. Animals were divided into 10 groups randomly. Five groups (n=6 were used for assessment of neuronal damage by cresyl violet staining. Another five groups (n=8 were used for assessment of dendritic morphology by Golgi- Cox staining. Groups were divided by exposure duration (15, 30, 45 and 60 minutes/ per day for 30 days; age matched unexposed groups served as controls. Results: Results of the study have shown that there was decrease in the number of viable neurons and dendritic arborization in CA3 sub region of hippocampus in 30, 45 and 60 min exposed groups. Conclusions: Increased neuronal damage and decreased dendritic arborization of hippocampal CA3 neurons was found with increase in exposure duration of MPRF-EMF.

  8. Epicardial radiofrequency ablation on a beating heart: an experimental study.

    Science.gov (United States)

    Ishikawa, Susumu; Oki, Shigeru; Muraoka, Masato; Oshima, Kiyohiro; Kashiwabara, Kenji; Morishita, Yasuo

    2005-02-01

    The effect of epicardial radiofrequency ablation (RFA) during normal heart beating was experimentally studied in order to establish safe and effective procedures for RFA. Seven pigs weighing approximately 30 to 50 kg were used in this study. Fifty-one epicardial RFA lesions were created on both atria using a Cobra Cooled probe with continuous internal irrigation of a saline solution. The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30, 60 and 120 seconds. There was significant positive correlation between the right and left atria in wall thickness. Transmural coagulation was obtained in 69% of the total specimens, which decreased according to the increase of wall thickness especially over 3 mm. Transmural coagulation was seen in 64% of the specimens after RFA of less than 30 seconds, and 86% after ablation of >or=60 seconds. Occurence of 90% or deeper coagulation was higher in the right atrium than in the left one (97% vs. 78%). Right atrial rupture occurred in a region of 1 mm in thickness after ablation of 60 seconds. Further technical improvements associated with new instruments are indispensable to complete epicardial RFA procedures on a beating heart.

  9. Development of A Pulse Radio-Frequency Plasma Jet

    Science.gov (United States)

    Wang, Shou-Guo; Zhao, Ling-Li; Yang, Jing-Hua

    2013-09-01

    A small pulse plasma jet was driven by new developed radio-frequency (RF) power supply of 6.78 MHz. In contrast to the conventional RF 13.56 MHz atmospheric pressure plasma jet (APPJ), the power supply was highly simplified by eliminating the matching unit of the RF power supply and using a new circuit, moreover, a pulse controller was added to the circuit to produce the pulse discharge. The plasma jet was operated in a capacitively coupled manner and exhibited low power requirement of 5 W at atmospheric pressure using argon as a carrier gas. The pulse plasma plume temperature remained at less than 45 °C for an extended period of operation without using water to cool the electrodes. Optical emission spectrum measured at a wide range of 200-1000 nm indicated various excited species which were helpful in applying the plasma jet for surface sterilization to human skin or other sensitive materials. Institude of Plasma Physics, Chinese Academy of Science, Hefei, China.

  10. Importância da radiofrequência na oftalmologia

    Directory of Open Access Journals (Sweden)

    José Ricardo Carvalho Lima Rehder

    2013-04-01

    Full Text Available Este trabalho revisa e faz uma análise crítica da radiofrequência em oftalmologia. O aquecimento da córnea tem sido realizado desde 1889 com diferentes finalidades terapêuticas e cirúrgicas. O princípio do aquecimento da córnea causa um enrugamento do colágeno que muda a curvatura da córnea. Após a aprovação da FDA em 2004, iniciou-se um estudo multicêntrico no Brasil coordenado pela Faculdade de Medicina do ABC que resultou na análise de 258 pacientes. Como conclusão o estudo mostrou que o procedimento tem um resultado temporário e que os melhores resultados foram obtidos em pacientes entre 45 e 55 anos de idade sem correção óptica para longe. Acreditamos que o problema ainda não foi resolvido e que novas pesquisas devem ser realizadas.

  11. Polarization image segmentation of radiofrequency ablated porcine myocardial tissue

    Science.gov (United States)

    Ahmad, Iftikhar; Gribble, Adam; Murtza, Iqbal; Ikram, Masroor; Pop, Mihaela; Vitkin, Alex

    2017-01-01

    Optical polarimetry has previously imaged the spatial extent of a typical radiofrequency ablated (RFA) lesion in myocardial tissue, exhibiting significantly lower total depolarization at the necrotic core compared to healthy tissue, and intermediate values at the RFA rim region. Here, total depolarization in ablated myocardium was used to segment the total depolarization image into three (core, rim and healthy) zones. A local fuzzy thresholding algorithm was used for this multi-region segmentation, and then compared with a ground truth segmentation obtained from manual demarcation of RFA core and rim regions on the histopathology image. Quantitative comparison of the algorithm segmentation results was performed with evaluation metrics such as dice similarity coefficient (DSC = 0.78 ± 0.02 and 0.80 ± 0.02), sensitivity (Sn = 0.83 ± 0.10 and 0.91 ± 0.08), specificity (Sp = 0.76 ± 0.17 and 0.72 ± 0.17) and accuracy (Acc = 0.81 ± 0.09 and 0.71 ± 0.10) for RFA core and rim regions, respectively. This automatic segmentation of parametric depolarization images suggests a novel application of optical polarimetry, namely its use in objective RFA image quantification. PMID:28380013

  12. A mathematical model of bipolar radiofrequency-induced thermofusion.

    Science.gov (United States)

    Wagenpfeil, J; Nold, B; Fischer, K; Neugebauer, A; Rothmund, R; Krämer, B; Brucker, S; Mischinger, J; Schwentner, C; Schenk, M; Wallwiener, D; Stenzl, A; Enderle, M; Sawodny, O; Ederer, M

    2014-01-01

    Bipolar radiofrequency-induced thermofusion has become a widely accepted method successfully used in open and particularly in minimally-invasive surgery for the sealing of blood vessels and tissue of up to several millimeters diameter. Despite its wide-spread application, the thermofusion process itself is not well understood on a quantitative and dynamic level, and manufacturers largely rely on trial-and-error methods to improve existing instruments. To predict the effect of alternative generator control strategies and to allow for a more systematic approach to improve thermofusion instruments, a mathematical model of the thermofusion process is developed. The system equations describe the spatial and temporal evolution of the tissue temperature due to Joule heating and heat transfer, and the loss of tissue water due to vaporization. The resulting effects on the tissue properties, most importantly the electrical resistivity, heat capacity and thermal conductivity, are considered as well. Experimental results indicate that the extent of the lateral thermal damage is directly affected by Joule heating of the lateral tissue. The experimental findings are supported by simulation results using the proposed mathematical model of thermofusion.

  13. Bilateral Intra-Articular Radiofrequency Ablation for Cervicogenic Headache

    Science.gov (United States)

    Tang, Teresa; Taftian, David; Chhatre, Akhil

    2017-01-01

    Introduction. Cervicogenic headache is characterized by unilateral neck or face pain referred from various structures such as the cervical joints and intervertebral disks. A recent study of patients with cervical pain showed significant pain relief after cervical medial branch neurotomy but excluded patients with C1-2 joint pain. It remains unclear whether targeting this joint has potential for symptomatic relief. To address this issue, we present a case report of C1-2 joint ablation with positive outcomes. Case Presentation. A 27-year-old female presented with worsening cervicogenic headache. Her pain was 9/10 by visual analog scale (VAS) and described as cramping and aching. Pain was localized suboccipitally with radiation to her jaw and posterior neck, worse on the right. Associated symptoms included clicking of her temporomandibular joint, neck stiffness, bilateral headaches with periorbital pain, numbness, and tingling. History, physical exam, and diagnostic studies indicated localization to the C1-2 joint with 80% decrease in pain after C1-2 diagnostic blocks. She underwent bilateral intra-articular radiofrequency ablation of the C1-C2 joint. Follow-up at 2, 4, 8, and 12 weeks showed improved function and pain relief with peak results at 12 weeks. Conclusion. Clinicians may consider C1-C2 joint ablation as a viable long-term treatment option for cervicogenic headaches. PMID:28149652

  14. Thermal modeling of lesion growth with radiofrequency ablation devices

    Directory of Open Access Journals (Sweden)

    Nguyen Uyen D

    2004-08-01

    Full Text Available Abstract Background Temperature is a frequently used parameter to describe the predicted size of lesions computed by computational models. In many cases, however, temperature correlates poorly with lesion size. Although many studies have been conducted to characterize the relationship between time-temperature exposure of tissue heating to cell damage, to date these relationships have not been employed in a finite element model. Methods We present an axisymmetric two-dimensional finite element model that calculates cell damage in tissues and compare lesion sizes using common tissue damage and iso-temperature contour definitions. The model accounts for both temperature-dependent changes in the electrical conductivity of tissue as well as tissue damage-dependent changes in local tissue perfusion. The data is validated using excised porcine liver tissues. Results The data demonstrate the size of thermal lesions is grossly overestimated when calculated using traditional temperature isocontours of 42°C and 47°C. The computational model results predicted lesion dimensions that were within 5% of the experimental measurements. Conclusion When modeling radiofrequency ablation problems, temperature isotherms may not be representative of actual tissue damage patterns.

  15. RADIOFREQUENCY AND MICROWAVE RADIATION HEALTH EFFECTS AND OCCUPATIONAL EXPOSURE

    Directory of Open Access Journals (Sweden)

    Ivana Damnjanović

    2011-12-01

    Full Text Available In the recent years, there have been considerable discussion and concern about the possible hazards of RF/MW radiation. More recently, the growth and development in personal mobile communications have focused attention on the frequencies associated with this technology. A number of studies have examined the health effects of RF/MW electromagnetic fields (EMFs, originating from occupational exposure, hobbies, or residence near the radio or television transmitters. Particularly controversial are the biophysical mechanisms by which these RF fields may affect biological systems. General health effects reviews explore possible carcinogenic, reproductive and neurological effects. Health effects by exposure source have been observed in radar traffic devices, wireless communications with cellular phones, radio transmission, and magnetic resonance imaging (MRI. Several epidemiological surveys have suggested associations with non-specific complaints such as headache, tiredness, sleep disturbance, loss of memory, and dizziness. These findings, which echo reports of illness associated with other types of radiofrequency (RF radiation, relate not only to the use of mobile phones, but also to residence near the mobile phone base stations and other settings involving occupational exposure. The biological effects suggest that some precautions are necessary, and preventive approaches are highly recommended. Further researches are required to give more information about the effects of microwave radiation on our health, especially in occupational setting and professionally exposed workers.

  16. An anatomically realistic temperature phantom for radiofrequency heating measurements.

    Science.gov (United States)

    Graedel, Nadine N; Polimeni, Jonathan R; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L

    2015-01-01

    An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the unperfused case. We describe an anatomically realistic human head phantom that allows rapid three-dimensional (3D) temperature mapping at 7T. The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature-sensitive contrast agent (TmDOTMA(-)) validated by direct fiber optic temperature measurements. Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2-4 minutes. Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. © 2014 Wiley Periodicals, Inc.

  17. Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp; Takaki, Haruyuki [Mie University School of Medicine, Department of Interventional Radiology (Japan); Yamada, Tomomi [Mie University School of Medicine, Department of Translational Medicine (Japan); Yamanaka, Takashi; Uraki, Junji; Kashima, Masataka; Nakatsuka, Atsuhiro; Takeda, Kan [Mie University School of Medicine, Department of Interventional Radiology (Japan)

    2012-12-15

    Purpose: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). Methods: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.ResultsNine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P < 0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R{sup 2} = 0.68, P < 0.0001) and norepinephrine (R{sup 2} = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. Conclusion: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

  18. Radiofrequency Exposure Amongst Employees of Mobile Network Operators and Broadcasters.

    Science.gov (United States)

    Litchfield, Ian; van Tongeren, Martie; Sorahan, Tom

    2016-10-13

    Little is known about personal exposure to radiofrequency (RF) fields amongst employees in the telecommunications industry responsible for installing and maintaining transmitters. IARC classified RF exposure as a possible carcinogen, although evidence from occupational studies was judged to be inadequate. Hence, there is a need for improved evidence of any potentially adverse health effects amongst the workforce occupationally exposed to RF radiation. In this study, results are presented from an exposure survey using data from personal monitors used by employees in the broadcasting and telecommunication industries of the UK. These data were supplemented by spot measurements using broadband survey metres and information on daily work activities provided by employee questionnaires. The sets of real-time personal data were categorised by four types of site determined by the highest powered antenna present (high, medium or low power and ground-level sites). For measurements gathered at each type of site, the root mean square and a series of box plots were produced. Results from the daily activities diaries suggested that riggers working for radio and television broadcasters were exposed to much longer periods as compared to colleagues working for mobile operators. Combining the results from the measurements and daily activity diaries clearly demonstrate that exposures were highest for riggers working for broadcasting sites. This study demonstrates that it is feasible to carry out exposure surveys within these populations that will provide reliable estimates of exposure that can be used for epidemiological studies of occupational groups exposed to RF fields.

  19. Radiofrequency ablation for hepatocellular carcinoma: surgeon’s views

    Directory of Open Access Journals (Sweden)

    Zhi-qiang HUANG

    2013-05-01

    Full Text Available The clinical efficacy of hepatectomy and radiofrequency ablation (RFA in treatment of hepatocellular carcinoma (HCC was reviewed in present article. Currently, although hepatectomy remains the prior option for the treatment of liver cancer, an equivalent treatment result for the extirpation of small HCC (less than 3cm in diameter can be achieved by RFA. Because of limitation in term of size, location of tumor and technique of physician, there were still drawbacks to RFA application. To make a breakthrough in RFA application and to achieve equivalent result as resection, it is essential to abide by the principle of hepatic surgery and to destroy the liver tumor totally in only single ablation. Nowadays, with assistance of laparoscope, the technique has been developed to achieve complete ablation in one operation in treatment of HCC in particular location or of certain size (larger than 3cm in diameter, and the process was safe, painless and less invasive. Therefore, the treatment to HCC could be further improved in the future by combining minimally invasive surgery and RFA based on surgical principle.

  20. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules.

    Science.gov (United States)

    Dobrinja, Chiara; Bernardi, Stella; Fabris, Bruno; Eramo, Rita; Makovac, Petra; Bazzocchi, Gabriele; Piscopello, Lanfranco; Barro, Enrica; de Manzini, Nicolò; Bonazza, Deborah; Pinamonti, Maurizio; Zanconati, Fabrizio; Stacul, Fulvio

    2015-01-01

    Background. Radiofrequency ablation (RFA) has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules) and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms). Two Thy3 nodules regrew after the procedure, and these patients accepted to undergo a total thyroidectomy. Here we present how RFA has affected the operation and the final pathological features of the surgically removed nodules. Results and Conclusions. RFA is effective for the treatment of Thy2 nodules, but it should not be recommended as first-line therapy for the treatment of Thy3 nodules (irrespective of their mutational status), as it delays surgery in case of malignancy. Moreover, it is unknown whether RFA might promote residual tumor progression or neoplastic progression of Thy3 lesions. Nevertheless, here we show for the first time that one session of RFA does not affect subsequent thyroid surgery and/or histological diagnosis.

  1. Radiofrequency ablation for postsurgical thyroid removal of differentiated thyroid carcinoma.

    Science.gov (United States)

    Xu, Dong; Wang, Lipin; Long, Bin; Ye, Xuemei; Ge, Minghua; Wang, Kejing; Guo, Liang; Li, Linfa

    2016-01-01

    Differentiated thyroid carcinoma (DTC) is the most common endocrine malignancy. Surgical removal with radioactive iodine therapy is recommended for recurrent thyroid carcinoma, and the postsurgical thyroid removal is critical. This study evaluated the clinical values of radiofrequency ablation (RFA) in the postsurgical thyroid removal for DTC. 35 DTC patients who had been treated by subtotal thyroidectomy received RFA for postsurgical thyroid removal. Before and two weeks after RFA, the thyroid was examined by ultrasonography and (99m)TcO4 (-) thyroid imaging, and the serum levels of free triiodothyronine (FT3), free thyroxin (FT4), thyroid stimulating hormone (TSH) and thyroglobulin (Tg) were detected. The efficacy and complications of RFA were evaluated. Results showed that, the postsurgical thyroid removal by RFA was successfully performed in 35 patients, with no significant complication. After RFA, the average largest diameter and volume were significantly decreased in 35 patients (P > 0.05), and no obvious contrast media was observed in ablation area in the majority of patients. After RFA, the serum FT3, FT4 and Tg levels were markedly decreased (P RFA, radioiodine concentration in the ablation area was significantly reduced in the majority of patients. The reduction rate of thyroid update was 0.69±0.20%. DTC staging and interval between surgery and RFA had negative correlation (Pearson coefficient = -0.543; P = 0.001), with no obvious correlation among others influential factors. RFA is an effective and safe method for postsurgical thyroid removal of DTC.

  2. Radio-frequency interference mitigating hyperspectral L-band radiometer

    Science.gov (United States)

    Toose, Peter; Roy, Alexandre; Solheim, Frederick; Derksen, Chris; Watts, Tom; Royer, Alain; Walker, Anne

    2017-02-01

    Radio-frequency interference (RFI) can significantly contaminate the measured radiometric signal of current spaceborne L-band passive microwave radiometers. These spaceborne radiometers operate within the protected passive remote sensing and radio-astronomy frequency allocation of 1400-1427 MHz but nonetheless are still subjected to frequent RFI intrusions. We present a unique surface-based and airborne hyperspectral 385 channel, dual polarization, L-band Fourier transform, RFI-detecting radiometer designed with a frequency range from 1400 through ≈ 1550 MHz. The extended frequency range was intended to increase the likelihood of detecting adjacent RFI-free channels to increase the signal, and therefore the thermal resolution, of the radiometer instrument. The external instrument calibration uses three targets (sky, ambient, and warm), and validation from independent stability measurements shows a mean absolute error (MAE) of 1.0 K for ambient and warm targets and 1.5 K for sky. A simple but effective RFI removal method which exploits the large number of frequency channels is also described. This method separates the desired thermal emission from RFI intrusions and was evaluated with synthetic microwave spectra generated using a Monte Carlo approach and validated with surface-based and airborne experimental measurements.

  3. Percutaneous treatment of bone tumors by radiofrequency thermal ablation

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Santiago, Fernando, E-mail: ferusan@ono.com [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Mar Castellano Garcia, Maria del; Guzman Alvarez, Luis [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Martinez Montes, Jose Luis [Department of Traumatology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Ruiz Garcia, Manuel; Tristan Fernandez, Juan MIguel [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain)

    2011-01-15

    We present our experience of the treatment of bone tumors with radiofrequency thermal ablation (RFTA). Over the past 4 years, we have treated 26 cases (22 benign and 4 malignant) using CT-guided RFTA. RFTA was the sole treatment in 19 cases and was combined with percutaneous cementation during the same session in the remaining seven cases. Our approach to the tumors was simplified, using a single point of entrance for both RFTA and percutaneous osteoplasty. In the benign cases, clinical success was defined as resolution of pain within 1 month of the procedure and no recurrence during the follow-up period. It was achieved in 19 out of the 21 patients in which curative treatment was attempted. The two non-resolved cases were a patient with osteoid osteoma who developed a symptomatic bone infarct after a symptom-free period of 2 months and another with femoral diaphysis osteoblastoma who suffered a pathological fracture after 8 months without symptoms. The procedure was considered clinically successful in the five cases (4 malign and 1 benign) in which palliative treatment was attempted, because there was a mean ({+-}SD) reduction in visual analogue scale (VAS) pain score from 9.0 {+-} 0.4 before the procedure to <4 during the follow-up period.

  4. Atrio-oesophageal fistula after transcatheter radiofrequency ablation.

    Science.gov (United States)

    Moss, Caroline E; Fernandez-Caballero, Sandra; Walker, David

    2015-01-05

    A 68-year-old woman presented 3 weeks following unsuccessful transcatheter radiofrequency ablation (TcRFA) for treatment of her chronic atrial fibrillation. Neurological signs manifested on day 2 of admission with generalised tonic-clonic seizures and reduced Glasgow Coma Score. She was treated for presumed central nervous system (CNS) infection, intubated and transferred to the intensive care unit. CT of the head showed bilateral oedema secondary to acute embolic stroke. Blood cultures grew Streptococcus viridans, and lumbar puncture findings were consistent with CNS infection. Echocardiography showed only a septostomy puncture from the atrial fibrillation ablation procedure. Thoracic CT demonstrated air in the left atrium, consistent with the diagnosis of atrio-oesophageal fistula, a rarely reported iatrogenic complication of TcRFA. MRI of the head showed significant neurological injury with innumerable embolic infarcts. After discussion with her family regarding the significant neurological insult, and with no signs of any clinical improvement, the patient died on day 8 of admission.

  5. Radiofrequency-dressed-state potentials for neutral atoms

    DEFF Research Database (Denmark)

    Hofferberth, S.; Lesanovsky, Igor; Fischer, B.

    2006-01-01

    Potentials for atoms can be created by external fields acting on properties such as magnetic moment, charge, polarizability, or by oscillating fields that couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronica......Potentials for atoms can be created by external fields acting on properties such as magnetic moment, charge, polarizability, or by oscillating fields that couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground...... and electronically excited states of an atom with light. Here, we present an extensive experimental analysis of potentials derived from radiofrequency (RF) coupling of electronic ground states. The coupling is magnetic and the vector character allows the design of versatile microscopic state-dependent potential...... landscapes. Compared with standard magnetic trapping, we find no additional heating or (collisional) loss up to densities of 1015 atoms cm-3. We demonstrate robust evaporative cooling in RF potentials, which allows easy production of Bose-Einstein condensates in complex potentials. Altogether, this makes RF...

  6. Water-cooled radiofrequency neuroablation for sacroiliac joint dysfunctional pain.

    Science.gov (United States)

    Biswas, Binay Kumar; Dey, Samarjit; Biswas, Saumya; Mohan, Varinder Kumar

    2016-01-01

    Sacroiliac (SI) joint dysfunction is a common source of chronic low-back pain. Recent evidences from different parts of the world suggest that cooled radiofrequency (RF) neuroablation of sacral nerves supplying SI joints has superior pain alleviating properties than available existing treatment options for SI joint dysfunctional pain. A 35-year-old male had intractable bilateral SI joint pain (numeric rating scale [NRS] - 9/10) with poor treatment response to intra-articular steroid therapy. Bilateral water cooled = RF was applied for neuroablation of nerves supplying both SI joints. Postprocedure pain intensity was 5/10 and after 7 days it was 2/10. On 18(th)-month follow-up, he is pain free except for mild pain (NRS 2/10) on occasional extreme twisting of the back. This case attempts to highlight that sacral neuroablation based on cooled RF technique can be a long lasting remedial option for chronic SI joint pain unresponsive to conventional treatment.

  7. Water-cooled radiofrequency neuroablation for sacroiliac joint dysfunctional pain

    Directory of Open Access Journals (Sweden)

    Binay Kumar Biswas

    2016-01-01

    Full Text Available Sacroiliac (SI joint dysfunction is a common source of chronic low-back pain. Recent evidences from different parts of the world suggest that cooled radiofrequency (RF neuroablation of sacral nerves supplying SI joints has superior pain alleviating properties than available existing treatment options for SI joint dysfunctional pain. A 35-year-old male had intractable bilateral SI joint pain (numeric rating scale [NRS] - 9/10 with poor treatment response to intra-articular steroid therapy. Bilateral water cooled = RF was applied for neuroablation of nerves supplying both SI joints. Postprocedure pain intensity was 5/10 and after 7 days it was 2/10. On 18th-month follow-up, he is pain free except for mild pain (NRS 2/10 on occasional extreme twisting of the back. This case attempts to highlight that sacral neuroablation based on cooled RF technique can be a long lasting remedial option for chronic SI joint pain unresponsive to conventional treatment.

  8. Radiofrequency ablation of hepatocellular carcinoma: pros and cons.

    Science.gov (United States)

    Rhim, Hyunchul; Lim, Hyo K

    2010-09-01

    Among locoregional treatments for hepatocellular carcinoma (HCC), radiofrequency ablation (RFA) has been accepted as the most popular alternative to curative transplantation or resection, and it shows an excellent local tumor control rate and acceptable morbidity. The benefits of RFA have been universally validated by the practice guidelines of international societies of hepatology. The main advantages of RFA include 1) it is minimally invasive with acceptable morbidity, 2) it enables excellent local tumor control, 3) it has promising long-term survival, and 4) it is a multimodal approach. Based on these pros, RFA will play an important role in managing the patient with early HCC (smaller than 3 cm with fewer than four tumors). The main limitations of current RFA technology in hepatic ablation include 1) limitation of ablation volume, 2) technically infeasible in some tumors due to conspicuity and dangerous location, and 3) the heat-sink effect. Many technical approaches have been introduced to overcome those limitations, including a novel guiding modality, use of artificial fluid or air, and combined treatment strategies. RFA will continue to play a role as a representative ablative modality in the management of HCC, even in the era of targeted agents.

  9. Tinnitus and cell phones: the role of electromagnetic radiofrequency radiation

    Directory of Open Access Journals (Sweden)

    Luisa Nascimento Medeiros

    2016-02-01

    Full Text Available ABSTRACT INTRODUCTION: Tinnitus is a multifactorial condition and its prevalence has increased on the past decades. The worldwide progressive increase of the use of cell phones has exposed the peripheral auditory pathways to a higher dose of electromagnetic radiofrequency radiation (EMRFR. Some tinnitus patients report that the abusive use of mobiles, especially when repeated in the same ear, might worsen ipsilateral tinnitus. OBJECTIVE: The aim of this study was to evaluate the available evidence about the possible causal association between tinnitus and exposure to electromagnetic waves. METHODS: A literature review was performed searching for the following keywords: tinnitus, electromagnetic field, mobile phones, radio frequency, and electromagnetic hypersensitivity. We selected 165 articles that were considered clinically relevant in at least one of the subjects. RESULTS: EMRFR can penetrate exposed tissues and safety exposure levels have been established. These waves provoke proved thermogenic effects and potential biological and genotoxic effects. Some individuals are more sensitive to electromagnetic exposure (electrosensitivity, and thus, present earlier symptoms. There may be a common pathophysiology between this electrosensitivity and tinnitus. CONCLUSION: There are already reasonable evidences to suggest caution for using mobile phones to prevent auditory damage and the onset or worsening of tinnitus.

  10. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules

    Science.gov (United States)

    Dobrinja, Chiara; Bernardi, Stella; Fabris, Bruno; Eramo, Rita; Makovac, Petra; Bazzocchi, Gabriele; Piscopello, Lanfranco; Barro, Enrica; de Manzini, Nicolò; Bonazza, Deborah; Pinamonti, Maurizio; Zanconati, Fabrizio; Stacul, Fulvio

    2015-01-01

    Background. Radiofrequency ablation (RFA) has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules) and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms). Two Thy3 nodules regrew after the procedure, and these patients accepted to undergo a total thyroidectomy. Here we present how RFA has affected the operation and the final pathological features of the surgically removed nodules. Results and Conclusions. RFA is effective for the treatment of Thy2 nodules, but it should not be recommended as first-line therapy for the treatment of Thy3 nodules (irrespective of their mutational status), as it delays surgery in case of malignancy. Moreover, it is unknown whether RFA might promote residual tumor progression or neoplastic progression of Thy3 lesions. Nevertheless, here we show for the first time that one session of RFA does not affect subsequent thyroid surgery and/or histological diagnosis. PMID:26265914

  11. Water-cooled radiofrequency neuroablation for sacroiliac joint dysfunctional pain

    Science.gov (United States)

    Biswas, Binay Kumar; Dey, Samarjit; Biswas, Saumya; Mohan, Varinder Kumar

    2016-01-01

    Sacroiliac (SI) joint dysfunction is a common source of chronic low-back pain. Recent evidences from different parts of the world suggest that cooled radiofrequency (RF) neuroablation of sacral nerves supplying SI joints has superior pain alleviating properties than available existing treatment options for SI joint dysfunctional pain. A 35-year-old male had intractable bilateral SI joint pain (numeric rating scale [NRS] – 9/10) with poor treatment response to intra-articular steroid therapy. Bilateral water cooled = RF was applied for neuroablation of nerves supplying both SI joints. Postprocedure pain intensity was 5/10 and after 7 days it was 2/10. On 18th-month follow-up, he is pain free except for mild pain (NRS 2/10) on occasional extreme twisting of the back. This case attempts to highlight that sacral neuroablation based on cooled RF technique can be a long lasting remedial option for chronic SI joint pain unresponsive to conventional treatment. PMID:28096589

  12. [RADIOFREQUENCY ABLATION FOR THE TREATMENT OF VARICOSE VEINS].

    Science.gov (United States)

    Sugiyama, Satoru; Miyade, Yoshio; Inaki, Yasuhiko

    2015-05-01

    Significant advances in the endovenous technique for treating incompetent saphenous veins could change the surgical strategy in patients with varicose veins. Radiofrequency ablation (RFA) was approved as a new technique for the treatment of varicose veins in Japan in June 2014. In RFA, the ablation temperature is controlled by a sensor at the upper end of the catheter. The vein wall is heated with stable conductive power of 120 degrees C, resulting in endothelial denudation. The RFA method was approved in 1998 in Europe and in 1999 in the USA. The ClosurePLUS catheter was developed in 2003 and ClosureFAST in 2006. High occlusion rates and lower postoperative complication rates were reported with ClosureFAST than with ClosurePLUS. It is expected that this new ablation technique will control saphenous vein reflux with less pain and less ecchymosis after surgery. The treatment of varicose veins is less invasive with RFA devices and will become widely accepted as an alternative to conventional surgery for varicose veins in Japan.

  13. Does the addition of alcohol increase the efficacy of radiofrequency ablation of T2 and T3 sympathetic ganglia in hyperhidrosis?

    Directory of Open Access Journals (Sweden)

    Osama Yehia A. Khalifa

    2017-04-01

    Conclusion: Efficacy of T2 and T3 sympathetic ablation with radiofrequency and alcohol is significantly higher than their ablation with radiofrequency alone with possible higher incidence of axillary pain.

  14. Energies; Energies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    In the framework of the National Debate on the energies in a context of a sustainable development some associations for the environment organized a debate on the nuclear interest facing the renewable energies. The first part presents the nuclear energy as a possible solution to fight against the greenhouse effect and the associated problem of the wastes management. The second part gives information on the solar energy and the possibilities of heat and electric power production. A presentation of the FEE (French wind power association) on the situation and the development of the wind power in France, is also provided. (A.L.B.)

  15. Image-guided radiofrequency ablation of Bosniak category III or IV cystic renal tumors: initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea); Lee, Hyun Moo [Sungkyunkwan University School of Medicine, Department of Urology, Samsung Medical Center, Seoul (Korea)

    2008-07-15

    The purpose of this study was to assess the efficacy of image-guided radiofrequency (RF) ablation of cystic renal tumors. Between November 2005 and August 2007, computed tomography (CT) or ultrasound-guided RF ablation was performed in nine patients with 14 Bosniak category III (n = 5) or IV (n = 9) cystic renal tumors using an internally cooled RF ablation system. We evaluated the number of sessions, cycles and duration of energy application, treatment results, lesion size change, and complications. Together the cystic renal tumors required 15 sessions and 23 cycles of energy application. The duration of energy application per one tumor ablation ranged from 1 to 12 min (mean 6 min). The last follow-up CT indicated complete coagulation of 14/14 (100%) lesions. None of these tumors had recurred within 1-19 months (mean 8 months). The maximum diameter of the cystic renal tumors was significantly reduced from 2.5 {+-} 0.6 cm before ablation to 1.7 {+-} 0.7 cm at the last follow-up CT (P < 0.01). Complications were pneumothorax (n = 2), inguinal paresthesia (n = 1), and arteriovenous fistula (n = 1). Image-guided RF ablation is an effective treatment for Bosniak category III or IV cystic renal tumors, which might need relatively shorter duration of energy application than purely solid renal tumors of the same size. (orig.)

  16. A combination therapy of ethanol injection and radiofrequency ablation under general anesthesia for the treatment of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Kazutaka Kurokohchi; Tomohiko Taminato; Shigeki Kuriyama; Seishiro Watanabe; Hirohito Yoneyama; Akihiro Deguchi; Tsutomu Masaki; Takashi Himoto; Hisaaki Miyoshi; Hamdy Saad Mohammad; Akira Kitanaka

    2008-01-01

    AIM: To summarize the effects of laparoscopic ethanol injection and radiofrequency ablation (L-EI-RFA), thora-coscopic (T-EI-RFA) and open-surgery assisted EI-RFA (O-EI-RFA) under general anesthesia for the treatment of hepatocellular carcinoma (HCC).METHODS: Time-lag performance of RFA after ethanol injection (Time-lag PEI-RFA) was performed in all cases. The volume of coagulated necrosis and the applied energy for total and per unit volume coagulated necrosis were examined in the groups treated under general (group G) or local anesthesia (group L).RESULTS: The results showed that the total applied energy and the applied energy per unit volume of whole and marginal, coagulated necrosis were significantly larger in group G than those in the group L, resulting in a larger volume of coagulated necrosis in the group G. The rate of local tumor recurrence within one year was extremely low in group G.CONCLUSION: These results suggest that EI-RFA, under general anesthesia, may be effective for the treatment of HCC because a larger quantity of ethanol and energy could be applied during treatment under pain-free condition for the patients.

  17. Radiofrequência na dor crônica Radiofrecuencia en el dolor crónico Radiofrequency in chronic pain

    Directory of Open Access Journals (Sweden)

    José Luciano Braun Filho

    2009-06-01

    Full Text Available Radiofrequência (RF é uma técnica minimamente invasiva alvo-seletiva e tem sido usada durante muitos anos para o tratamento de diferentes doenças, como dor lombar crônica, neuralgia trigeminal e outros. Trata-se de uma corrente elétrica alternada com frequência oscilatória de 500.000 hz, que flui através de um eletrodo introduzido percutaneamente. O calor é formado ao redor do eletrodo porque o tecido age como um resistor. Essa técnica pode, portanto, ser usada para causar lesões em tecidos nervosos no tratamento de dor crônica. O objetivo desta revisão é abordar alguns aspectos importantes do mecanismo e evolução da radiofrequência na dor crônica. Serão abordados os aspectos básicos da Física e o mecanismo de ação da radiofrequência, método que tem sido usado para tratar dores crônicas de diferentes etiologias, além da evolução com o advento da radiofrequência pulsátil. O uso da radiofrequência no manejo da dor crônica é uma ferramenta útil em diferentes condições dolorosas e tem sido usada com sucesso por mais de 25 anos. Seu mecanismo de ação ainda não foi totalmente elucidado. A radiofrequência pulsátil é, em particular, uma técnica minimamente destrutiva e poderá ser uma alternativa à forma convencional de tratamento para a dor por radiofrequência.Radiofrecuencia (RF es una técnica mínimamente invasiva con blanco selectivo, y ha sido usada durante muchos años para el tratamiento de diferentes patologías como dolor lumbar crónico, neuralgia trigeminal entre otros. Radiofrecuencia es una corriente eléctrica alternada con frecuencia oscilatoria de 500.000 hz. La corriente fluye por medio de un electrodo introducido percutáneamente y el calor es formado alrededor del electrodo, porque el tejido actúa como una resistencia. Por lo tanto, la radiofrecuencia puede ser usada para causar lesiones en tejidos nerviosos para tratamiento de dolor crónico. El objetivo de esta revisión es abordar

  18. Pulsed radiofrequency on radial nerve under ultrasound guidance for treatment of intractable lateral epicondylitis.

    Science.gov (United States)

    Oh, Dae Seok; Kang, Tae Hyung; Kim, Hyae Jin

    2016-06-01

    Lateral epicondylitis is a painful and functionally limiting disorder. Although lateral elbow pain is generally self-limiting, in a minority of people symptoms persist for a long time. When various conservative treatments fail, surgical approach is recommended. Surgical denervation of several nerves that innervate the lateral humeral epicondyle could be considered in patients with refractory pain because it denervates the region of pain. Pulsed radiofrequency is a minimally invasive procedure that improves chronic pain when applied to various neural tissues without causing any significant destruction and painful complication. This procedure is safe, minimally invasive, and has less risk of complications relatively compared to the surgical approach. The radial nerve can be identified as a target for pulsed radiofrequency lesioning in lateral epicondylitis. This innovative method of pulsed radiofrequency applied to the radial nerve has not been reported before. We reported on two patients with intractable lateral epicondylitis suffering from elbow pain who did not respond to nonoperative treatments, but in whom the ultrasound-guided pulsed radiofrequency neuromodulation of the radial nerve induced symptom improvement. After a successful diagnostic nerve block, radiofrequency probe adjustment around the radial nerve was performed on the lateral aspect of the distal upper arm under ultrasound guidance and multiple pulsed treatments were applied. A significant reduction in pain was reported over the follow-up period of 12 weeks.

  19. Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Martel, Jose [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain)]. E-mail: jmartel@fhalcorcon.es; Bueno, Angel [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain); Ortiz, Eduardo [Departamento de Cirugia ortopedica, Fundacion Hospital Alcorcon, Madrid (Spain)

    2005-12-15

    Objectives: To report our experience with percutaneous cool-tip radiofrequency ablation of osteoid osteomas and to evaluate clinical outcome. Methods and material: Forty-one patients with clinically and radiologically suspected osteoid osteoma were seen over a 48-month period (27 males and 14 females with a mean age of 18.7 years; range 5-43 years). Thirty-eight patients were treated by computed tomography (CT)-guided percutaneous radiofrequency ablation. The procedure was performed under regional or general anaesthesia. After location of the nidus, a 14G-bone biopsy needle is introduced into the nidus. Sampling is performed with a 17G-bone biopsy needle using a coaxial technique. The radiofrequency needle with a 10 mm active tip (cool-tip) is inserted through the biopsy needle and is connected to the radiofrequency generator for 6-8 min. Results: Primary success was obtained in 37 patients (97%) with a 100% secondary success rate. All patients are currently pain-free. No major complications occurred. Patients could resume unrestricted normal activity within 24 h. Conclusions: Percutaneous radiofrequency ablation of osteoid osteomas is an efficient and safe method that can be considered the procedure of choice for most cases.

  20. Ablation effects of noninvasive radiofrequency field-induced hyperthermia on liver cancer cells

    Directory of Open Access Journals (Sweden)

    Kaiyun Chen

    2016-05-01

    Full Text Available To have in-depth analysis of clinical ablation effect of noninvasive radiofrequency field-induced hyperthermia on liver cancer cells, this paper collected liver cancer patients’ treatment information from 10 hospitals during January 2010 and December 2011, from which 1050 cases of patients were randomly selected as study object of observation group who underwent noninvasive radiofrequency field-induced hyperthermia treatment; in addition, 500 cases of liver cancer patients were randomly selected as study object of control group who underwent clinical surgical treatment. After treatment was completed, three years of return visit were done, survival rates of the two groups of patients after 1 year, 2 years, and 3 years were compared, and clinical effects of radiofrequency ablation of liver cancer were evaluated. Zoom results show that the two groups are similar in terms of survival rate, and the difference is without statistical significance. 125 patients in observation group had varying degrees of adverse reactions, while 253 patients in control group had adverse reactions. There was difference between groups P < 0.05, with significant statistical significance. It can be concluded that radiofrequency ablation of liver cancer is more secure. Therefore, the results of this study fully demonstrate that liver cancer treatment with noninvasive radiofrequency field-induced hyperthermia is with safety effect and satisfactory survival rate, thus with relatively high clinical value in clinical practice.

  1. Radiofrequency upper thoracic sympathectomy in the treatment of critical upper limb ischemia--a case series.

    Science.gov (United States)

    Gabrhelik, Tomas; Stehlik, Daniel; Adamus, Milan; Zalesak, Bohumil; Michalek, Pavel

    2013-06-01

    Patients with significant medical and social problems resulting from impaired perfusion of the upper limbs caused by micro- or macro-angiopathy are now frequent in clinical practice. Vasospastic disease of the upper limbs of combined origin is a difficult condition to treat by conservative methods and therapeutic strategies are usually multidisciplinary. In addition to standard pharmacotherapy, treatment may involve regional anaesthesia, thoracoscopic or radiofrequency sympathectomy and surgical treatment of defects, including plastic surgery. This paper describes our successful work in the treatment of upper limb critical ischemia using radiofrequency upper thoracic sympathectomy. In three case reports we present the results of radiofrequency thermolysis applied to treat patients with chronic defects of the hand and fingers. These patients were diagnosed with upper limb critical ischemia of combined origin, standard conservative treatment methods failed and surgical intervention was originally not indicated, however, radiofrequency thermolysis proved to be beneficial. Radiofrequency thoracic sympathectomy could improve peripheral perfusion of the upper limbs and thereby contribute to healing of chronic defects, reduction of pain and improvement in the quality of life of the patients.

  2. Surgical Radiofrequency MAZE III Ablation for Treatment of Atrial Fibrillation During Open Heart Surgery

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    Fariborz Akbarzadeh

    2006-05-01

    Full Text Available Background: Atrial fibrillation is a common arrhythmia in patients with rheumatic mitral and other valve diseases who are candidates for valve repair surgeries. Conversion of rhythm to sinus has positive effects on quality of life and lower use of medications. The aim of this clinical study was to evaluate the effectiveness of the radiofrequency ablation Maze III procedure in the treatment of atrial fibrillation associated with rheumatic heart valve disease. Methods: We applied a modified Cox III Maze procedure using radiofrequency ablation in the treatment of atrial fibrillation associated with rheumatic heart valve disease and evaluated the outcome of 20 patients of atrial fibrillation associated rheumatic valve disease who underwent radiofrequency ablation Maze III procedure plus heart valve surgery. Demographic, echocardiographic, Electrocardiographic and Doppler study data were calculated before surgery, six month and one year after surgery.. Results: No perioperative deaths occurred in the study group. Duration of additional time for doing radiofrequency ablation was about 22 minutes. Freedom from atrial fibrillation was 85% and 75% at six months and one year follow-up respectively... Conclusions: The addition of the radiofrequency ablation Maze procedure to heart valve surgery is safe and effective in the treatment of atrial fibrillation associated with rheumatic heart valve disease.

  3. Target radiofrequency combined with collagenase chemonucleolysis in the treatment of lumbar intervertebral disc herniation.

    Science.gov (United States)

    Zhang, Daying; Zhang, Yong; Wang, Zhijian; Zhang, Xuexue; Sheng, Mulan

    2015-01-01

    Both target radiofrequency thermocoagulation and collagenase chemonucleolysis are effective micro-invasive therapy means for lumbar intervertebral disc herniation. In order to analyze the clinical effects of target radiofrequency thermocoagulation combined with collagenase chemonucleolysis on lumbar intervertebral disc herniation, the contents of hydroxyproline and glycosaminoglycan were measured and the histological changes of nucleus pulposus was detected in the vitro experiments. Radiofrequency thermocoagulation reduced the hydrolyzation of herniated nucleus pulposus caused by collagenase, as well as the content of hydroxyproline and glycosaminoglycan. Furthermore, 236 patients with lumbar intervertebral disc herniation were treated by target radiofrequency thermocoagulation combined with collagenase chemonucleolysis. The efficiency was evaluated according to Macnab criteria, and the index of lumbar disc herniation (IDH) was compared pre-operation with 3 months post-operation. The post-operative good rate was 66.5% (157/236) at 2 weeks post-operation, and 88.1% (208/236) at 3 months post-operation. In the post-operative follow-up exam, 86.8% of the re-examined cases demonstrated smaller or ablated protrusion, with reduced IDH values from pre-operation, which was statistically significant. No serious complications were detected intra-operatively and post-operatively. In conclusion, target radiofrequency combined with collagenase chemonucleolysis was an effective and safe method for treatment of lumbar intervertebral disc herniation.

  4. Utility of intercostal nerve conventional thermal radiofrequency ablations in the injured worker after blunt trauma.

    Science.gov (United States)

    Engel, Andrew J

    2012-01-01

    Intercostal nerve blocks offer short-term therapeutic relief and serve as a diagnostic test for intercostal neuralgia. This original case report demonstrates the efficacy of radiofrequency ablations for long-term pain relief of intercostal neuralgia. To date, there have been no studies that demonstrate the efficacy of thermal conventional intercostal nerve radiofrequency ablations for intercostal neuralgia. Describe the use of conventional thermal radiofrequency ablations of the intercostal nerves to treat blunt chest wall trauma. Case report. Clinical practice. Six patients suffering from work-related injuries to the chest wall whose treatment focused on conventional thermal radiofrequency ablations of the intercostal nerves. Four of the 6 patients were pain free by their final visit. The remaining 2 patients experienced pain relief until one began wearing a brace after an L5-S1 fusion; the other required repeat treatment after 5.5 months. Case series. There was limited follow-up as patients were either discharged after receiving potentially curative care or were lost to follow-up. Following conventional thermal radiofrequency ablations of the intercostal nerves, 5 of the 6 patients experienced either long-term pain relief or required no additional care. The treatment has potential efficacy for injuries, including rib fractures or intercostal neuralgia, stemming from blunt trauma to the chest wall. In addition, there may be a potential for this treatment to help patients suffering from postthoracotomy pain.

  5. Radiofrequency ablation of hepatic metastasis: Results of treatment in forty patients

    Directory of Open Access Journals (Sweden)

    Rath G

    2008-01-01

    Full Text Available Aim: To evaluate the local control of hepatic metastasis with radiofrequency ablation treatment. Materials and Methods: We did a retrospective analysis in 40 patients treated with radiofrequency ablation for hepatic metastasis. The tumors ablated included up to two metastatic liver lesions, with primaries in breast, gastrointestinal tract, cervix, etc. Radiofrequency ablation was performed under general anesthesia in all cases, using ultrasound guidance. Radionics Cool-Tip RF System was used to deliver the treatment. Results: The median age of patients treated was 49 years. There were 13 female and 27 male patients. The median tumor size ablated was 1.5 cm (0.75-4.0 cm. A total of 52 radiofrequency ablation cycles were delivered. Successful ablation was achieved in all patients with hepatic metastasis less than 3 cm in size. Pain was the most common complication seen (75%. One patients developed skin burns. At 2-year follow-up 7.5% of patients had locally recurrent disease. Conclusions: Radiofrequency ablation is a minimally invasive treatment modality. It can be useful in a select group of patients with solitary liver metastasis of less than 3 cm size.

  6. Adaptive Response in Animals Exposed to Non-Ionizing Radiofrequency Fields: Some Underlying Mechanisms

    Directory of Open Access Journals (Sweden)

    Yi Cao

    2014-04-01

    Full Text Available During the last few years, our research group has been investigating the phenomenon of adaptive response in animals exposed to non-ionizing radiofrequency fields. The results from several separate studies indicated a significant increase in survival, decreases in genetic damage as well as oxidative damage and, alterations in several cellular processes in mice pre-exposed to radiofrequency fields and subsequently subjected to sub-lethal or lethal doses of γ-radiation or injected with bleomycin, a radiomimetic chemical mutagen. These observations indicated the induction of adaptive response providing the animals the ability to resist subsequent damage. Similar studies conducted by independent researchers in mice and rats have supported our observation on increased survival. In this paper, we have presented a brief review of all of our own and other independent investigations on radiofrequency fields-induced adaptive response and some underlying mechanisms discussed.

  7. Bilateral occipital lobe infarction with altitudinal field loss following radiofrequency cardiac catheter ablation

    Directory of Open Access Journals (Sweden)

    Chen Celia S

    2010-03-01

    Full Text Available Abstract Background Bilateral stroke following radiofrequency catheter ablation is an unusual complication and may result in bilateral altitudinal visual field defects. Bilateral altitudinal visual field defects usually result from prechiasmal pathology causing damage to both retinas or optic nerves and rarely from bilateral symmetric damage to the post chiasmal visual pathways. Case presentation A 48-year-old man complained of visual disturbance on wakening following radiofrequency catheter ablation. The patient had a CHADS score of 1 pre-operatively and no complications were noted intra-operatively. Examination revealed a bilateral superior altitudinal defect and MRI of the brain showed multifocal areas of infarction predominantly involving the occipital lobes which correlated to with the visual deficits. Conclusion While the risk of thromboembolism and perioperative stroke during radiofrequency catheter ablation is small, it is not insignificant.

  8. [The assessment of modulated radiofrequence electromagnetic radiation on cognitive function in rats of different ages].

    Science.gov (United States)

    Priakhin, E A; Triapitsyna, G A; Andreev, S S; Kolomiets, I A; Polevik, N D; Akleev, A V

    2007-01-01

    The modulated radiofrequence electromagnetic radiation influence on cognitive function of male uninbred Wister rat exposed at the age of sexual maturation (2 months) and at the age of morphofunctional maturity (3.5 months) was examined. Animals were subjected to pulse electromagnetic radiation (925 MHz) modulated as a GSM standard with the power density 1.2 mW/cm2 for 10 minutes every day for 12 days. At day 8 of exposure the cognitive function were examined with the Morris water maze. In the result of investigation it was determines that modulated radiofrequence electromagnetic radiation at the sexual maturation age did not affect the spatial learning and improve the visual orientation performance. Modulated radiofrequence electromagnetic exposure of animals at the sex maturity age did not affect the visual performance and improve the spatial performance of male rats.

  9. Radiofrequency Coblation Versus Intramural Bipolar Cautery for the Treatment of Inferior Turbinate Hypertrophy.

    Science.gov (United States)

    Shah, Anil N; Brewster, Douglas; Mitzen, Kelly; Mullin, David

    2015-09-01

    Compare intramural bipolar electrocautery and radiofrequency coblation in the treatment of inferior turbinate hypertrophy with regards to objective and subjective improvement in nasal obstruction, rate and type of complications, experience during the procedure, and rate of recovery. Prospective, single-blinded study. Single tertiary medical center from 2008 to 2010. Forty-one adult patients with inferior turbinate hypertrophy refractory to medical management were treated with radiofrequency coblation in one nostril and intramural bipolar cautery in the other. Subjective and objective data, including use of a Visual Analog Scale (VAS) for subjective outcomes, acoustic rhinometry, and nasal endoscopy, were then obtained from each patient comparing the 2 techniques. Radiofrequency coblation was significantly less painful than intramural bipolar cautery during the procedure (P = .03) and during the early postoperative period (P hypertrophy with less discomfort during the procedure and early post-operative period. © The Author(s) 2015.

  10. Pulsed radiofrequency neuromodulation treatment on the lateral femoral cutaneous nerve for the treatment of meralgia paresthetica.

    Science.gov (United States)

    Choi, Hyuk Jai; Choi, Seok Keun; Kim, Tae Sung; Lim, Young Jin

    2011-08-01

    We describe a rare case of pulsed radiofrequency treatment for pain relief associated with meralgia paresthetica. A 58-year-old female presented with pain in the left anterior lateral thigh. An imaging study revealed no acute lesions compared with a previous imaging study, and diagnosis of meralgia paresthetica was made. She received temporary pain relief with lateral femoral cutaneous nerve blocks twice. We performed pulsed radiofrequency treatment, and the pain declined to 25% of the maximal pain intensity. At 4 months after the procedure, the pain intensity did not aggravate without medication. Pulsed radiofrequency neuromodulation treatment on the lateral femoral cutaneous nerve may offer an effective, low risk treatment in patients with meralgia paresthetica who are refractory to conservative medical treatment.

  11. Endoscopic management of an esophagopericardial fistula after radiofrequency ablation for atrial fibrillation.

    Science.gov (United States)

    Quénéhervé, Lucille; Musquer, Nicolas; Léauté, Franck; Coron, Emmanuel

    2013-06-07

    A case is reported of a 76-year-old man with a past history of atrial fibrillation. A radiofrequency ablation procedure was suggested following several failed cardioversion attempts. However, an esophagopericardial fistula complicated the procedure. This life-threatening complication was successfully managed using both the placement of a covered esophageal stent and surgical pericardial and mediastinal drainage. In fact, no persisting fistula could be detected when the esophageal stent was removed seven weeks later. Atrioesophageal and esophagopericardial fistulas are two of the most severe complications associated with cardiological radiofrequency ablation procedures. They are responsible for majority of the deaths associated with this procedure. Despite the extremely high morbimortality associated with cardiothoracic surgery in such conditions, this treatment is the gold-standard for the management of such complications. This case report emphasizes the importance and efficacy of the endoscopic approach as part of a multidisciplinary management approach to this serious adverse event following radiofrequency ablation for atrial fibrillation.

  12. Statistical analysis of personal radiofrequency electromagnetic field measurements with nondetects.

    Science.gov (United States)

    Röösli, Martin; Frei, Patrizia; Mohler, Evelyn; Braun-Fahrländer, Charlotte; Bürgi, Alfred; Fröhlich, Jürg; Neubauer, Georg; Theis, Gaston; Egger, Matthias

    2008-09-01

    Exposimeters are increasingly applied in bioelectromagnetic research to determine personal radiofrequency electromagnetic field (RF-EMF) exposure. The main advantages of exposimeter measurements are their convenient handling for study participants and the large amount of personal exposure data, which can be obtained for several RF-EMF sources. However, the large proportion of measurements below the detection limit is a challenge for data analysis. With the robust ROS (regression on order statistics) method, summary statistics can be calculated by fitting an assumed distribution to the observed data. We used a preliminary sample of 109 weekly exposimeter measurements from the QUALIFEX study to compare summary statistics computed by robust ROS with a naïve approach, where values below the detection limit were replaced by the value of the detection limit. For the total RF-EMF exposure, differences between the naïve approach and the robust ROS were moderate for the 90th percentile and the arithmetic mean. However, exposure contributions from minor RF-EMF sources were considerably overestimated with the naïve approach. This results in an underestimation of the exposure range in the population, which may bias the evaluation of potential exposure-response associations. We conclude from our analyses that summary statistics of exposimeter data calculated by robust ROS are more reliable and more informative than estimates based on a naïve approach. Nevertheless, estimates of source-specific medians or even lower percentiles depend on the assumed data distribution and should be considered with caution. Copyright 2008 Wiley-Liss, Inc.

  13. Rapid progression of hepatocellular carcinoma after Radiofrequency Ablation

    Institute of Scientific and Technical Information of China (English)

    Andrea Ruzzenente; Giovanni de Manzoni; Matteo Molfetta; Silvia Pachera; Bruno Genco; Matteo Donataccio; Alfredo Guglielmi

    2004-01-01

    AIM: To report the results of radiofrequency ablation (RFA)of hepatocellular carcinoma (HCC) in cirrhotic patients and to describe the treatment related complications (mainly the rapid intrahepatic neoplastic progression).METHODS: Eighty-seven consecutive cirrhotic patients with 104 HCC (mean diameter 3.9 cm, 1.3 SD) were submitted to RFA between January 1998 and June 2003. In all cases RFA was performed with percutaneous approach under ultrasound guidance using expandable electrode needles.Treatment efficacy (necrosis and recurrence) was estimated with dual phase computed tomography (CT) and alphafetoprotein (AFP) level.RESULTS: Complete necrosis rate after single or multiple treatment was 100%, 87.7% and 57.1% in HCC smaller than 3 cm, between 3 and 5 cm and larger than 5 cm respectively (P=0.02). Seventeen lesions of 88(19.3%)developed local recurrence after complete necrosis during a mean follow up of 19.2 mo. There were no treatment-related deaths in 130 procedures and major complications occurred in 8 patients (6.1%). In 4 patients, although complete local necrosis was achieved, we observed rapid intrahepatic neoplastic progression after treatment. Risk factors for rapid neoplastic progression were high preoperative AFP values and location of the tumor near segmental portal branches.CONCLUSION: RFA is an effective treatment for hepatocellular carcinoma smaller than 5 cm with complete necrosis in more than 80% of lesions. Patients with elevated AFP levels and tumors located near the main portal branch are at risk for rapid neoplastic progression after RFA. Further studies are necessary to evaluate the incidence and pathogenesis of this underestimated complication.

  14. Noninvasive radiofrequency treatment effect on mitochondria in pancreatic cancer cells.

    Science.gov (United States)

    Curley, Steven A; Palalon, Flavio; Lu, Xiaolin; Koshkina, Nadezhda V

    2014-11-01

    The development of novel therapeutic approaches for cancer therapy is important, especially for tumors that have poor response or develop resistance to standard chemotherapy and radiation. We discovered that noninvasive radiofrequency (RF) fields can affect cancer cells but not normal cells, inhibit progression of tumors in mice, and enhance the anticancer effects of chemotherapy. However, it remains unclear what physiological and molecular mechanisms this treatment induces inside cells. Here, we studied the effect of RF treatment on mitochondria in human pancreatic cancer cells. The morphology of mitochondria in cells was studied via electron microscopy. The alteration of mitochondrial membrane potential (Δψ) was accessed using a Mitotracker probe. The respiratory activity of mitochondria was evaluated by analyzing changes in oxygen consumption rates determined with a Mito Stress Test Kit. The production of intracellular reactive oxygen species was performed using flow cytometry. The colocalization of mitochondria and autophagosome markers in cells was performed using fluorescence immunostaining and confocal microscopy analysis. RF fields treatment changed the morphology of mitochondria in cancer cells, altered polarization of the mitochondrial membrane, substantially impaired mitochondrial respiration, and increased reactive oxygen species production, indicating RF-induced stress on the mitochondria. We also observed frequent colocalization of the autophagosome marker LC3B with the mitochondrial marker Tom20 inside cancer cells after RF exposure, indicating the presence of mitochondria in the autophagosomes. This suggests that RF-induced stress can damage mitochondria and induce elimination of damaged organelles via autophagy. RF treatment impaired the function of mitochondria in cancer cells. Therefore, mitochondria can represent one of the targets of the RF treatment. © 2014 American Cancer Society.

  15. Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Mylona, Sophia, E-mail: mylonasophia@yahoo.com; Karagiannis, Georgios, E-mail: gekaragiannis@yahoo.gr; Patsoura, Sofia, E-mail: sofia.patsoura@yahoo.gr [Hellenic Red Cross Hospital ' Korgialenio-Benakio' (Greece); Galani, Panagiota, E-mail: gioulagalani@yahoo.com [Amalia Fleming Hospital (Greece); Pomoni, Maria, E-mail: marypomoni@gmail.com [Evgenidion Hospital (Greece); Thanos, Loukas, E-mail: loutharad@yahoo.com [Sotiria Hospital (Greece)

    2012-08-15

    Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8-10 min at 80-110 Degree-Sign C and a power of 90-110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n - 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

  16. Nanoionics-Based Switches for Radio-Frequency Applications

    Science.gov (United States)

    Nessel, James; Lee, Richard

    2010-01-01

    Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

  17. Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure

    Directory of Open Access Journals (Sweden)

    Raymond Patrick Hom

    2016-01-01

    Full Text Available Purpose: Atrial fibrillation (AF is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary bypass. The goal of this retrospective cohort study was to identify clinical factors associated with metabolic acidosis following the Mini-Maze procedure. Materials and Methods: After Institutional Review Board approval, we studied patients undergoing the Mini-Maze procedure, off-pump coronary artery bypass grafting or patients conventional Cox-Maze on cardiopulmonary bypass. The first base deficit value obtained in the Intensive Care Unit was used as a measure of metabolic acidosis. Using logistic regression with Akaike information criteria, we analyzed preoperative, intraoperative, and postoperative data to determine the factors associated with changes in base deficit. Results: A multivariable model using stepwise selection demonstrated that diabetes mellitus and weight were associated with a decrease in the base deficit by 2.87 mEq/L (95% CI: −5.55-−0.19 and 0.04 mEq/L (95%CI: −0.08, 0.004, respectively. Furthermore, creatinine was associated with a 1.57 mEq/L (95% CI: 0.14, 2.99 increase in the base deficit. Conclusion: The Mini-Maze procedure was not associated with postoperative metabolic acidosis. Instead, nondiabetic patients and patients with higher creatinine were associated with greater base deficits after undergoing cardiac surgery.

  18. Atrial fibrillation ablation using a closed irrigation radiofrequency ablation catheter.

    Science.gov (United States)

    Golden, Keith; Mounsey, John Paul; Chung, Eugene; Roomiani, Pahresah; Morse, Michael Andew; Patel, Ankit; Gehi, Anil

    2012-05-01

    Catheter ablation is an effective therapy for symptomatic, medically refractory atrial fibrillation (AF). Open-irrigated radiofrequency (RF) ablation catheters produce transmural lesions at the cost of increased fluid delivery. In vivo models suggest closed-irrigated RF catheters create equivalent lesions, but clinical outcomes are limited. A cohort of 195 sequential patients with symptomatic AF underwent stepwise AF ablation (AFA) using a closed-irrigation ablation catheter. Recurrence of AF was monitored and outcomes were evaluated using Kaplan-Meier survival analysis and Cox proportional hazards models. Mean age was 59.0 years, 74.9% were male, 56.4% of patients were paroxysmal and mean duration of AF was 5.4 years. Patients had multiple comorbidities including hypertension (76.4%), tobacco abuse (42.1%), diabetes (17.4%), and obesity (mean body mass index 30.8). The median follow-up was 55.8 weeks. Overall event-free survival was 73.6% with one ablation and 77.4% after reablation (reablation rate was 8.7%). Median time to recurrence was 26.9 weeks. AF was more likely to recur in patients being treated with antiarrhythmic therapy at the time of last follow-up (recurrence rate 30.3% with antiarrhythmic drugs, 13.2% without antiarrhythmic drugs; hazard ratio [HR] 2.2, 95% confidence interval [CI] 1.1-4.4, P = 0.024) and in those with a history of AF greater than 2 years duration (HR 2.7, 95% CI 1.1-6.9, P = 0.038). Our study represents the largest cohort of patients receiving AFA with closed-irrigation ablation catheters. We demonstrate comparable outcomes to those previously reported in studies of open-irrigation ablation catheters. Given the theoretical benefits of a closed-irrigation system, a large head-to-head comparison using this catheter is warranted. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

  19. Outcome after Radiofrequency Ablation of Sarcoma Lung Metastases

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    Koelblinger, Claus, E-mail: claus.koelblinger@bhs.at [KH Barmherzige Schwestern Ried, Department of Radiology (Austria); Strauss, Sandra, E-mail: s.strauss@ucl.ac.uk [UCL and UCLH, Department of Medical Oncology (United Kingdom); Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Department of Radiology (United Kingdom)

    2013-05-14

    PurposeResection is the mainstay of management in patients with sarcoma lung metastases, but there is a limit to how many resections can be performed. Some patients with inoperable disease have small-volume lung metastases that are amenable to thermal ablation. We report our results after radiofrequency ablation (RFA).MethodsThis is a retrospective study of patients treated from 2007 to 2012 in whom the intention was to treat all sites of disease and who had a minimum CT follow-up of 4 months. Treatment was performed under general anesthesia/conscious sedation using cool-tip RFA. Follow-up CT scans were analyzed for local control. Primary tumor type, location, grade, disease-free interval, prior resection/chemotherapy, number and size of lung tumors, uni- or bilateral disease, complications, and overall and progression-free survival were recorded.ResultsTwenty-two patients [15 women; median age 48 (range 10–78) years] with 55 lung metastases were treated in 30 sessions. Mean and median tumor size and initial number were 0.9 cm and 0.7 (range 0.5–2) cm, and 2.5 and 1 (1–7) respectively. Median CT and clinical follow-up were 12 (4–54) and 20 (8–63) months, respectively. Primary local control rate was 52 of 55 (95 %). There were 2 of 30 (6.6 %) Common Terminology Criteria grade 3 complications with no long-term sequelae. Mean (median not reached) and 2- and 3-year overall survival were 51 months, and 94 and 85 %. Median and 1- and 2-year progression-free survival were 12 months, and 53 and 23 %. Prior disease-free interval was the only significant factor to affect overall survival.ConclusionRFA is a safe and effective treatment for patients with small-volume sarcoma metastases.

  20. Screen printed flexible radiofrequency identification tag for oxygen monitoring.

    Science.gov (United States)

    Martínez-Olmos, A; Fernández-Salmerón, J; Lopez-Ruiz, N; Rivadeneyra Torres, A; Capitan-Vallvey, L F; Palma, A J

    2013-11-19

    In this work, a radiofrequency identification (RFID) tag with an optical indicator for the measurement of gaseous oxygen is described. It consists of an O2 sensing membrane of PtOEP together with a full electronic system for RFID communication, all printed on a flexible substrate. The membrane is excited by an LED at 385 nm wavelength and the intensity of the luminescence generated is registered by means of a digital color detector. The output data corresponding to the red coordinate of the RGB color space is directly related to the concentration of O2, and it is sent to a microcontroller. The RFID tag is designed and implemented by screen printing on a flexible substrate for the wireless transmission of the measurement to a remote reader. It can operate in both active and passive mode, obtaining the power supply from the electromagnetic waves of the RFID reader or from a small battery, respectively. This system has been fully characterized and calibrated including temperature drifts, showing a high-resolution performance that allows measurement of very low values of oxygen content. Therefore this system is perfectly suitable for its use in modified atmosphere packaging where the oxygen concentration is reduced below 2%. As the reading of the O2 concentration inside the envelope is carried out with an external RFID reader using wireless communication, there is no need for perforations for probes or wires, so the packaging remains completely closed. With the presented device, a limit of detection of 40 ppm and a resolution as low as 0.1 ppm of O2 can be reached with a low power consumption of 3.55 mA.

  1. Personal radiofrequency electromagnetic field exposure measurements in Swiss adolescents.

    Science.gov (United States)

    Roser, Katharina; Schoeni, Anna; Struchen, Benjamin; Zahner, Marco; Eeftens, Marloes; Fröhlich, Jürg; Röösli, Martin

    2017-02-01

    Adolescents belong to the heaviest users of wireless communication devices, but little is known about their personal exposure to radiofrequency electromagnetic fields (RF-EMF). The aim of this paper is to describe personal RF-EMF exposure of Swiss adolescents and evaluate exposure relevant factors. Furthermore, personal measurements were used to estimate average contributions of various sources to the total absorbed RF-EMF dose of the brain and the whole body. Personal exposure was measured using a portable RF-EMF measurement device (ExpoM-RF) measuring 13 frequency bands ranging from 470 to 3600MHz. The participants carried the device for three consecutive days and kept a time-activity diary. In total, 90 adolescents aged 13 to 17years participated in the study conducted between May 2013 and April 2014. In addition, personal measurement values were combined with dose calculations for the use of wireless communication devices to quantify the contribution of various RF-EMF sources to the daily RF-EMF dose of adolescents. Main contributors to the total personal RF-EMF measurements of 63.2μW/m(2) (0.15V/m) were exposures from mobile phones (67.2%) and from mobile phone base stations (19.8%). WLAN at school and at home had little impact on the personal measurements (WLAN accounted for 3.5% of total personal measurements). According to the dose calculations, exposure from environmental sources (broadcast transmitters, mobile phone base stations, cordless phone base stations, WLAN access points, and mobile phones in the surroundings) contributed on average 6.0% to the brain dose and 9.0% to the whole-body dose. RF-EMF exposure of adolescents is dominated by their own mobile phone use. Environmental sources such as mobile phone base stations play a minor role. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Electrophysiological characteristics and radiofrequency ablation of right atrial flutter

    Directory of Open Access Journals (Sweden)

    Yoga Yuniadi

    2007-09-01

    Full Text Available This study aimed to elaborate the electrophysiology characteristics and radiofrequency ablation (RFA results of atrial flutter (AFL which has not been established in Indonesia. Three multipolar catheters were inserted percutaneously and positioned into coronary sinus (CS, His bundle area and around tricuspid annulus. Eight mm ablation catheter was used to make linear ablation at CTI of typical and reverse typical AFL. Bidirectional block was confirmed by conduction time prolongation of more than 90 msec from low lateral to CS ostium and vice versa, and/or by means of differential pacing. Thirty AFL from 27 patients comprised of 19 typical AFL, 5 reverse typical AFL and 6 atypical AFL enrolled the study. Mean tachycardia cycle length (TCL were 261.8 ± 42.84, 226.5 ± 41.23, and 195.4 ± 9.19 msec, respectively (p = 0.016. CTI conduction time occupied up to 60% of TCL with mean conduction time of 153.0 ± 67.37 msec. CS activation distributed to three categories which comprised of proximal to distal, distal to proximal and fusion activation. Only nine of 27 patients had no structural heart disease. RFA of symptomatic typical and reverse typical AFL demonstrated 96% success and 4.5 % recurrence rate during 13 ± 8 months follow up. Typical AFL is the predominant type of AFL in our population. The majority of AFL cases suffered from structural heart disease. RFA was highly effective to cure typical and reverse typical AFL. (Med J Indones 2007; 16:151-8 Keywords: atrial flutter, electrophysiology, ablation

  3. Efficacy of percutaneous radiofrequency ablation of osteoid osteoma in children

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    Donkol, Ragab H. [Cairo University, Department of Radiology, Faculty of Medicine, Cairo (Egypt); Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Al-Nammi, Ahmed [Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Moghazi, Khaled [Alexandria University, Faculty of Medicine, Alexandria (Egypt)

    2008-02-15

    Percutaneous radiofrequency (RF) ablation of osteoid osteoma has high technical and clinical success rates. However, there are limited data on its use in the treatment of osteoid osteoma in children. To assess the safety and efficacy of CT-guided percutaneous RF ablation of osteoid osteoma in children and compare the outcomes with published data on its use in patients unselected for age. From January 2003 to July 2006, 23 children with osteoid osteoma were treated with CT-guided RF ablation using a straight rigid electrode. Their mean age was 11 years (range 3.5-16 years) and there were 15 boys and 8 girls. The procedures were carried out under general anaesthesia. Follow-up was performed to assess technical and clinical outcome. The mean follow-up period was 2.5 years (range 13-49 months). Technical success was achieved in 21 children (91.3%). Failure occurred in two children, in one due to failure to adequately localize the nidus within the dense sclerosis and in the other because of a short ablation time (2 min) because he developed hyperthermia. Clinical success was achieved in 18 patients within 2-5 days (primary clinical success rate 78.2%).These patients were allowed to fully weight-bear and function without limitation 1 week after the procedure. Pain recurrence was observed in two patients; one was treated successfully with a second ablation after 6 months (secondary clinical success rate 82.6%). Hyperthermia was observed in two patients during the procedure. Three other minor complications were observed: wound infection in one child and skin burn in two children. No major immediate or delayed complications were observed. Percutaneous CT-guided RF ablation is an effective and safe minimally invasive procedure for the treatment of osteoid osteoma in children. It has high technical and clinical success rates that are slightly lower than those of patients with a wider range of ages. (orig.)

  4. High-resolution MRI encoding using radiofrequency phase gradients.

    Science.gov (United States)

    Sharp, Jonathan C; King, Scott B; Deng, Qunli; Volotovskyy, Vyacheslav; Tomanek, Boguslaw

    2013-11-01

    Although MRI offers highly diagnostic medical imagery, patient access to this modality worldwide is very limited when compared with X-ray or ultrasound. One reason for this is the expense and complexity of the equipment used to generate the switched magnetic fields necessary for MRI encoding. These field gradients are also responsible for intense acoustic noise and have the potential to induce nerve stimulation. We present results with a new MRI encoding principle which operates entirely without the use of conventional B0 field gradients. This new approach--'Transmit Array Spatial Encoding' (TRASE)--uses only the resonant radiofrequency (RF) field to produce Fourier spatial encoding equivalent to conventional MRI. k-space traversal (image encoding) is achieved by spin refocusing with phase gradient transmit fields in spin echo trains. A transmit coil array, driven by just a single transmitter channel, was constructed to produce four phase gradient fields, which allows the encoding of two orthogonal spatial axes. High-resolution two-dimensional-encoded in vivo MR images of hand and wrist were obtained at 0.2 T. TRASE exploits RF field phase gradients, and offers the possibility of very low-cost diagnostics and novel experiments exploiting unique capabilities, such as imaging without disturbance of the main B0 magnetic field. Lower field imaging (imaging are favorable application domains as, in both cases, it is technically easier to achieve the short RF pulses desirable for long echo trains, and also to limit RF power deposition. As TRASE is simply an alternative mechanism (and technology) of moving through k space, there are many close analogies between it and conventional B0 -encoded techniques. TRASE is compatible with both B0 gradient encoding and parallel imaging, and so hybrid sequences containing all three spatial encoding approaches are possible.

  5. The effects of radiofrequency electromagnetic radiation on sperm function.

    Science.gov (United States)

    Houston, B J; Nixon, B; King, B V; De Iuliis, G N; Aitken, R J

    2016-12-01

    Mobile phone usage has become an integral part of our lives. However, the effects of the radiofrequency electromagnetic radiation (RF-EMR) emitted by these devices on biological systems and specifically the reproductive systems are currently under active debate. A fundamental hindrance to the current debate is that there is no clear mechanism of how such non-ionising radiation influences biological systems. Therefore, we explored the documented impacts of RF-EMR on the male reproductive system and considered any common observations that could provide insights on a potential mechanism. Among a total of 27 studies investigating the effects of RF-EMR on the male reproductive system, negative consequences of exposure were reported in 21. Within these 21 studies, 11 of the 15 that investigated sperm motility reported significant declines, 7 of 7 that measured the production of reactive oxygen species (ROS) documented elevated levels and 4 of 5 studies that probed for DNA damage highlighted increased damage due to RF-EMR exposure. Associated with this, RF-EMR treatment reduced the antioxidant levels in 6 of 6 studies that discussed this phenomenon, whereas consequences of RF-EMR were successfully ameliorated with the supplementation of antioxidants in all 3 studies that carried out these experiments. In light of this, we envisage a two-step mechanism whereby RF-EMR is able to induce mitochondrial dysfunction leading to elevated ROS production. A continued focus on research, which aims to shed light on the biological effects of RF-EMR will allow us to test and assess this proposed mechanism in a variety of cell types.

  6. Radiofrequency treatment on respiratory symptoms due to gastroesophageal reflux disease

    Institute of Scientific and Technical Information of China (English)

    GAO Xiang; TIAN Shu-rui; WANG Zhong-gao; WU Ji-min; JI Feng; ZHANG Cheng-chao; NING Ya-chan; LI Zhi-tong; HU Zhi-wei; CHEN Xiu

    2011-01-01

    Background Diagnosis and treatment for respiratory symptoms (RSs) of gastroesophageal reflux disease (GERD) is more difficult than that for common esophageal symptoms. The goal of this study was to evaluate the efficacy and safety of radiofrequency (RF) treatment on RSs of GERD in a preliminary 12-month follow-up observation.Methods From April 2006 to October 2008,505 GERD patients with mainly respiratory presentations such as wheezing,chronic cough or hoarseness,were treated by endoscopic RF. A questionnaire was completed before and after treatment,using a six-point scale ranging from 0 to 5 to assess symptom severity and frequency. The symptom score was the sum of frequency and severity.Results Symptom scores were significantly improved at the end of the follow-up period. The mean heartburn score decreased from 5.31 to 1.79. The mean regurgitation score decreased from 5.02 to 1.64;mean cough score decreased from 6.77 to 2.85;mean wheezing score decreased from 7.83 to 3.07;and mean hoarseness score decreased from 5.13 to 1.81 (P <0.01). No major complications or deaths occurred. Minor complications included temporary post-procedural retrosternal unease or pain (n=106;21.0%),mild fever (n=86;17.0%),transient nausea/vomiting (n=97;19.2%),and transient dysphagia (n=42;9.3%). Thirty-five (6.9%) patients had recurrence of symptoms. Endoscopic RF treatment was repeated in six patients,and laparoscopic fundoplication was performed in seven.Conclusion Endoscopic RF is an effective and safe means to treat RSs in patients with GERD.

  7. Value or waste: Perfusion imaging following radiofrequency ablation - early experience.

    Science.gov (United States)

    Thieme, Stefan F; Vahldiek, Janis L; Tummler, Katja; Poch, Franz; Gemeinhardt, Ole; Hiebl, Bernhard; Lehmann, Kai S; Hamm, B; Niehues, Stefan M

    2015-01-01

    Radiofrequency ablation (RFA) is an evolving technique in treatment of hepatic malignant tumors. By heating local tissue it leads to coagulative necrotic areas around the ablation probe. Temperature falls with increasing distance to the probe, risking incomplete necrosis at the margins of the RFA-induced lesion. Therefore, immediate non-invasive and precise detection of incomplete ablation is necessary for early enlargement of the ablation if needed. This in vivo pig study compares early experiences of immediate post-interventional computed tomography (CT) perfusion volume analysis to macroscopic and CT image evaluation in healthy pig liver. RFA was performed in vivo in healthy pig livers. Different CT perfusion algorithms (Maximum slope analysis and Patlak plot) were used to quantify three different perfusion parameters. Data points were acquired from rectangular grids. These grids were semiautomatically overlayed to macroscopic images documented after liver explantation. Each data point was visually assigned to zones defined as "inner" and "outer necrotic zone", "margin" or "vital tissue". Significant differences between necrotic zones and vital tissue are shown for equivalent blood volume (p <  0.0001), arterial flow (p <  0.01) and flow extraction product (p <  0.001). Looking at equivalent blood volume and flow extraction product, there were also significant differences (EquivBV: p <  0.0001, FE: p <  0.001) between margins, necrotic and vital areas. In a porcine model these early results could show that all of the used CT perfusion parameters allowed discrimination of necrosis from vital tissue after RFA at high levels of significance. In addition, the parameters EquivBV and FE that give an estimate of the tissue blood volume and the permeability, were able to precisely discern different zones also seen macroscopically. From this data CT perfusion analysis could be precise tool for measurement and visualization of ablated liver lesions and

  8. Curative effect and mechanism of radiofrequency ablation nucleoplasty in the treatment of cervical vertigo.

    Science.gov (United States)

    Yin, Hai-Dong; Zhang, Xin-Mei; Huang, Ming-Guang; Chen, Wei; Song, Yang; Du, Qing-Jun; Wu, Yu-Ning; Yang, Ruo-Bin

    2017-04-01

    This study aims to investigate the curative effects and mechanism of radiofrequency ablation nucleoplasty in the treatment of cervical vertigo. A total of 27 patients diagnosed with cervical vertigo from January 2012 to October 2014 received treatment of radiofrequency ablation nucleoplasty. The narrow-side vertebral artery diameters were examined by using Philips 1.5-T body dual-gradient MRI system. The haemodynamic parameters were detected by using transcranial Doppler sonography. Both of the vertebral artery diameters and haemodynamic parameters were recorded and compared before and after treatment. The curative effects in early post-operative application were evaluated according to the Nagashima standards. Radiofrequency ablation nucleoplasty was performed in a total of 59 cervical discs in 27 patients. The average operation time was 42.7 min, and the symptoms of 92.6% patients were alleviated after radiofrequency ablation nucleoplasty post-operation application. There was no significant difference in the narrow-side vertebral artery diameters before and after treatment in both Group A (p = 0.12) and Group B (p = 0.48); however, the blood flow velocity was significantly higher than that before treatment in both Group A (p = 0.01) and Group B (p = 0.03), respectively. Radiofrequency ablation nucleoplasty improves the blood flow in the narrow-side vertebral artery and illustrates the therapeutic effect on cervical vertigo in patients who have no direct compression of the vertebral artery. Advances in knowledge: Radiofrequency intradiscal nucleoplasty can be used as a minimally invasive procedure for treating cervical vertigo.

  9. INTRAOPERATIVE RADIOFREQUENCY AND CRYOABLATION FOR ATRIAL FIBRILLATION IN PATIENTS WITH VALVULAR HEART DISEASE

    Directory of Open Access Journals (Sweden)

    N. Maghamipour N. Safaie

    2007-05-01

    Full Text Available Patients with valvular heart disease and suffering atrial fibrillation of more than 12 months duration have a low probability of remaining in sinus rhythm after valve surgery alone. We performed intra-operative radiofrequency ablation or cryoablation as an alternative to surgical maze ІІІ procedure to create linear lesion lines for conversion of this arrhythmia to sinus rhythm. A total of 30 patients with valvular heart disease and chronic persistent atrial fibrillation underwent different combinations of valve surgery and concomitant maze procedure with radiofrequency or cryo probes. These patients aged 48.10 ± 9.84 years in radiofrequency ablation group and 51.10 ± 13.93 years in cryoablation group. Both atrial ablation with radiofrequency probes, needed 26.15 ± 3.67 min extra ischemic time and ablation by mean of cryo-probes needed an extra ischemic time of 29.62 ± 4.27 min. There was one in hospital death postoperatively because of respiratory failure but no other complication. 6 months after the operation, among 30 patients with both atrial ablations, 25 patients were in sinus rhythm, no patient had junctional rhythm and 5 patients had persistent atrial fibrillation. At 12 months follow up, freedom from atrial fibrillation was 85% in radiofrequency group and 80% in cryo group. Doppler echocardiography in these patients demonstrated atrial contractility in 70% of the patients. Intraoperative radiofrequency or cryo-ablation of both atriums are effective and less invasive alternatives for the original maze procedure to eliminate the atrial fibrillation, and can be done in patients with valvular heart disease without increasing the risk of operation.

  10. Comparison of QuadrapolarTM radiofrequency lesions produced by standard versus modified technique: an experimental model

    Directory of Open Access Journals (Sweden)

    Safakish R

    2017-06-01

    Full Text Available Ramin Safakish Allevio Pain Management Clinic, Toronto, ON, Canada Abstract: Lower back pain (LBP is a global public health issue and is associated with substantial financial costs and loss of quality of life. Over the years, different literature has provided different statistics regarding the causes of the back pain. The following statistic is the closest estimation regarding our patient population. The sacroiliac (SI joint pain is responsible for LBP in 18%–30% of individuals with LBP. Quadrapolar™ radiofrequency ablation, which involves ablation of the nerves of the SI joint using heat, is a commonly used treatment for SI joint pain. However, the standard Quadrapolar radiofrequency procedure is not always effective at ablating all the sensory nerves that cause the pain in the SI joint. One of the major limitations of the standard Quadrapolar radiofrequency procedure is that it produces small lesions of ~4 mm in diameter. Smaller lesions increase the likelihood of failure to ablate all nociceptive input. In this study, we compare the standard Quadrapolar radiofrequency ablation technique to a modified Quadrapolar ablation technique that has produced improved patient outcomes in our clinic. The methodology of the two techniques are compared. In addition, we compare results from an experimental model comparing the lesion sizes produced by the two techniques. Taken together, the findings from this study suggest that the modified Quadrapolar technique provides longer lasting relief for the back pain that is caused by SI joint dysfunction. A randomized controlled clinical trial is the next step required to quantify the difference in symptom relief and quality of life produced by the two techniques. Keywords: lower back pain, radiofrequency ablation, sacroiliac joint, Quadrapolar radiofrequency ablation

  11. A Technical Approach to the Evaluation of Radiofrequency Radiation Emissions from Mobile Telephony Base Stations.

    Science.gov (United States)

    Buckus, Raimondas; Strukčinskienė, Birute; Raistenskis, Juozas; Stukas, Rimantas; Šidlauskienė, Aurelija; Čerkauskienė, Rimantė; Isopescu, Dorina Nicolina; Stabryla, Jan; Cretescu, Igor

    2017-03-01

    During the last two decades, the number of macrocell mobile telephony base station antennas emitting radiofrequency (RF) electromagnetic radiation (EMR) in residential areas has increased significantly, and therefore much more attention is being paid to RF EMR and its effects on human health. Scientific field measurements of public exposure to RF EMR (specifically to radio frequency radiation) from macrocell mobile telephony base station antennas and RF electromagnetic field (EMF) intensity parameters in the environment are discussed in this article. The research methodology is applied according to the requirements of safety norms and Lithuanian Standards in English (LST EN). The article presents and analyses RF EMFs generated by mobile telephony base station antennas in areas accessible to the general public. Measurements of the RF electric field strength and RF EMF power density were conducted in the near- and far-fields of the mobile telephony base station antenna. Broadband and frequency-selective measurements were performed outside (on the roof and on the ground) and in a residential area. The tests performed on the roof in front of the mobile telephony base station antennas in the near-field revealed the presence of a dynamic energy interaction within the antenna electric field, which changes rapidly with distance. The RF EMF power density values on the ground at distances of 50, 100, 200, 300, 400, and 500 m from the base station are very low and are scattered within intervals of 0.002 to 0.05 μW/cm². The results were compared with international exposure guidelines (ICNIRP).

  12. Mitochondrial DNA damage and oxidative damage in HL-60 cells exposed to 900MHz radiofrequency fields.

    Science.gov (United States)

    Sun, Yulong; Zong, Lin; Gao, Zhen; Zhu, Shunxing; Tong, Jian; Cao, Yi

    2017-03-01

    HL-60 cells, derived from human promyelocytic leukemia, were exposed to continuous wave 900MHz radiofrequency fields (RF) at 120μW/cm(2) power intensity for 4h/day for 5 consecutive days to examine whether such exposure is capable damaging the mitochondrial DNA (mtDNA) mediated through the production of reactive oxygen species (ROS). In addition, the effect of RF exposure was examined on 8-hydroxy-2'-dexoyguanosine (8-OHdG) which is a biomarker for oxidative damage and on the mitochondrial synthesis of adenosine triphosphate (ATP) which is the energy required for cellular functions. The results indicated a significant increase in ROS and significant decreases in mitochondrial transcription factor A, mtDNA polymerase gamma, mtDNA transcripts and mtDNA copy number in RF-exposed cells compared with those in sham-exposed control cells. In addition, there was a significant increase in 8-OHdG and a significant decrease in ATP in RF-exposed cells. The response in positive control cells exposed to gamma radiation (GR, which is also known to induce ROS) was similar to those in RF-exposed cells. Thus, the overall data indicated that RF exposure was capable of inducing mtDNA damage mediated through ROS pathway which also induced oxidative damage. Prior-treatment of RF- and GR-exposed the cells with melatonin, a well-known free radical scavenger, reversed the effects observed in RF-exposed cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Anthropometric differentiation of effects of radiofrequency electromagnetic fields of frequency 100 MHz on workers

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    Patryk Zradziński

    2014-06-01

    Full Text Available Background: Thermal effects of radiofrequency electromagnetic fields (REMF exposure of humans may be assessed by calculations of the parameter recognized as SAR (specific energy absorption rate in virtual human body models, which actually do not represent anthropometric properties of the entire population. Therefore, it is important to determine the relations between SAR values and anthropometric parameters that enable individualization of SAR estimation independently of body properties of a given person. Material and Methods: The analysis concerned 48 exposure scenarios of 4 virtual body models (male and female to vertically or horizontally polarized REMF of 27 MHz or 100 MHz frequency of various directions of propagation. Results: In the subgroup of results 100 MHz / vertical polarization statistically significant (strong; p < 0.05 correlations were identified between SAR averaged in the whole body and height, mass, BMI, circumference of chest, waist, neck and frontal cross-section area, and between local SAR in head and neck and the height, mass, circumference of chest waist or neck and frontal cross-section area. Identified relations and SAR in the Gustav model were used to estimate the variety of SAR in Polish population of adults (5-95. percentile of female and male: ±30% for SAR averaged in the whole body, ±50% for localized SAR. Conclusions: It was demonstrated that in the preliminary classified type of assessed REMF exposure (e.g., in terms of field polarization and frequency it is possible to identify statistical relations between various SAR parameters and anthropometric properties of the exposed body. Related quantities can be used for individualized assessment of worker's electromagnetic hazards. Med Pr 2014;65(3:351–360

  14. Monitoring radio-frequency heating of contaminated soils using electrical resistance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A.L.; Daily, W.D.

    1993-09-01

    Electrical resistance tomography (ERT) was used to monitor a radio-frequency heating process for the insitu remediation of volatile organic compounds from subsurface water and soil at the Savannah River Site, near Aiken, South Carolina. A dipole antenna located in a horizontal well in the unsaturated zone was used to heat a contaminated clay layer. The heat-induced changes were tomographically imaged by their effects on the formation electrical resistivity. The resistivity changes observed appear to be related to heating and vaporization of the pore water, formation of steam condensate, and infiltration of rainwater through the heated zones and adjacent areas. There is a clear asymmetry downward in the resistivity decreases associated with the heating process. The resistivity decreases observed in the vicinity of the heating well are believed to be caused by the heating and downward migration of warm water originally located within a radius of a few feet around the heating well; the magnitude of the change is between 10--20%. The decreasing resistivity implies an increasing rate of radio wave attenuation as heating progressed; therefore, the rate of energy deposition around the heating well increased while the penetration distance of the radio waves decreased. Saturation changes in the clay near the antenna during heating were estimated to be 50--55% based on the observed resistivity decreases. Resistivity changes observed at distances greater than 3 meters to one side of the antenna appear to be related to rainwater infiltration. We propose that gaps in near surface clay layers allow rainwater to migrate downward and reach the top of clay rich zone penetrated by the antenna borehole. The water may then accumulate along the top of the clay.

  15. Radiofrequency-assisted Liposuction for Neck and Lower Face Adipodermal Remodeling and Contouring

    Science.gov (United States)

    Keramidas, Evangelos

    2016-01-01

    Background: The purpose of this study is to report our experience using radiofrequency-assisted liposuction (RFAL) for neck and face contouring. This article details the operative technique, selection, complications, third-party surgeon appraisal, and patient satisfaction survey. Methods: From November 2009 to November 2013, 55 patients who underwent RFAL treatment were enrolled in the study. Postoperative patient satisfaction surveys were conducted, and 2 independent plastic surgeons evaluated contour and skin quality with randomized preoperative and postoperative photographs at 6 months postoperatively. The different parameters recorded involved age, sex, weight, body mass index, operative time, amount of fat aspirated and energy delivered, complications, and aesthetic outcome in 1 and 4 weeks and 3 and 6 months. Our longest follow-up was 4 years. Patients were asked 6 months postoperatively to grade their satisfaction as poor, no change, moderate, good, and excellent. Results: The mean age was 51 years (range, 35–61 years), and the mean amount of fat aspirated was 30 mL (range, 10–200 mL). Five out of 55 patients (9.1%) developed tissue hardness that resolved with massage. All patients were followed up for a minimum of 6 months. Eighty-five percent of patients were satisfied with their contouring result and degree of skin tightening (48/55 patients). Two independent plastic surgeons considered the improvement in contouring and degree of skin tightening good to excellent in 52 of 55 cases. Conclusions: In appropriately selected patients, RFAL neck and face contouring represent a safe procedure to achieve significant improvement of the skin laxity and fat deposits of the cervicomental zone and jowls. PMID:27622118

  16. The effect of radiofrequency thermal capsulorrhaphy on glenohumeral translation, rotation, and volume.

    Science.gov (United States)

    Victoroff, Brian N; Deutsch, Allen; Protomastro, Paul; Barber, J Edward; Davy, Dwight T

    2004-01-01

    The purpose of this study is to evaluate the effects of radiofrequency (RF) thermal capsulorrhaphy on the kinematic properties of the glenohumeral joint as determined by changes in resistance to multidirectional translational forces, alteration in the range of internal and external rotation, and changes in glenohumeral joint volume. Nonablative RF thermal energy was used to contract the glenohumeral joint capsule in 6 cadaveric shoulders. Measurements of translation were made after application of a 30-N load in anterior, posterior, and inferior directions. The maximum arc of internal and external rotation after application of a 1-N-m moment was also determined for vented specimens before and after thermal capsulorrhaphy. The percent reduction in glenohumeral capsular volume was measured by use of a saline solution injection-aspiration technique. Capsular shrinkage resulted in reductions in anterior, posterior, and inferior translation. The largest percent reductions in anterior translation were seen in external rotation at 45 degrees (48%, P translation, the largest percent reductions were seen in internal rotation at 45 degrees (40%, P translation were noted in internal rotation at 45 degrees (27%, P translation were observed but were not statistically significant. The maximum arc of humeral rotation was reduced by a mean of 14 degrees at 45 degrees abduction and 9 degrees at 90 degrees abduction. The mean percent reduction in capsular volume for all shoulders was 37% (range, 8%-50%). This could not be correlated with percent reductions in translation and rotation. This study demonstrated the significant effect of RF thermal capsulorrhaphy in reducing glenohumeral multidirectional translation and volume with only a small loss of rotation in cadaveric shoulders.

  17. Percutaneous radiofrequency rhizotomy of lumbar spinal facets: the results of 46 cases.

    Science.gov (United States)

    Göçer, A I; Cetinalp, E; Tuna, M; Ildan, F; Bağdatoğlu, H; Haciyakupoğlu, S

    1997-01-01

    The results of percutaneous radiofrequency rhizotomy of lumbar spinal facets in 46 patients followed at least three months (mean 15 months) are reported and compared with those reported previously. Satisfactory pain relief three months after the procedure was achieved in 36.4 percent of patients without operations and in 41.7 percent of patients, with operations other than fusion. No patient had previously undergone fusion. Treatment of low-back pain by using radio-frequency thermocoagulation of spinal facets is a simple, safe, and well-tolerated procedure. It can be used to relief of pain in spite of decreasing rates of success within the follow-up period.

  18. Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ji Won; Yoo, Seung Min [College of Medicine, Chungang University, Seoul, (Korea, Republic of); Kwak, Seo Hyun [Seoul Veterans Hospital, Seoul (Korea, Republic of)

    2005-07-15

    The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 {rho} 0.5 mm in group I and 11.4 {rho} 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal

  19. Indication of the radiofrequency induced lesion size by pre-ablation measurements

    DEFF Research Database (Denmark)

    Stagegaard, Niels; Petersen, Helen Høgh; Chen, Xu;

    2005-01-01

    for assessing these factors prior to ablation may indicate the lesion size which will be obtained for any given catheter position. METHODS AND RESULTS: Radiofrequency ablation was performed in vitro on strips of left ventricular porcine myocardium during two different levels of convective cooling (0 or 0.1 m......, during unchanged conditions, radiofrequency ablation was performed as either temperature-controlled, power-controlled or irrigated tip ablation and lesion size was determined. DeltaIMP increased significantly (P convective cooling. Delta......T was significantly increased by increasing contact pressure (P correlation between the obtained lesion size and power output...

  20. Alteração topográfica da curvatura corneana após aplicação de radiofreqüência em modelo animal Corneal topographic alteration after radiofrequency application to an animal model

    Directory of Open Access Journals (Sweden)

    Leonardo Verri Paulino

    2005-08-01

    Full Text Available OBJETIVOS: Verificar as alterações topográficas em córneas de olhos suínos enucleados após aplicações de radiofreqüência. MÉTODOS: Foi utilizado um protótipo produtor de radiofreqüência, com 10 diferentes possibilidades de potência. Para cada potência foram utilizados 10 olhos de porco enucleados que foram topografados pré e pós-aplicação de radiofreqüência seguindo nomograma com 8 pontos na primeira fase, 16 pontos na segunda fase, e 24 pontos na terceira fase, somando 3 fases para cada olho, num total de 300 aplicações e 400 topografias. RESULTADOS:Ocorreram variações da curvatura corneana após as aplicações de radiofreqüência para todas as potências utilizadas, demonstradas pela variação das médias de KM (dioptria mínima inicial e KM final (35,78 e 37,37, respectivamente com uma variação de 1,59 dioptrias (pPURPOSE: To verify the topographical alterations in enucleated pig eye cornea after radiofrequency application. METHODS: A prototype radiofrequency modulator with 10 different energy possibilities was used. For each energy we used 10 enucleated pig eyes that were topographed before and after applyng radiofrequency, following a nomogram with 8 spots in step one, 16 spots in step 2, and 24 spots in step 3, in a total of 3 steps for each eye, 300 applications and 400 topographies. RESULTS: Corneal curvature variation occurred after radiofrequency applications for all utilized selections, demonstrated by the mean variation of initial KM (minimum dioptry and final KM (35.78 and 37.37 respectively with 1.59 dioptries of variation (p<0.001. The energy that demonstrated more stability was 0.625W/s (65ºC. CONCLUSION: The obtained topographic values demonstrated that the central corneal curvature increased after radiofrequency application, and the higher the energy and the more spots used, more curved became the cornea, despite homogeneity.

  1. In vivo histological evaluation of non-insulated microneedle radiofrequency applicator with novel fractionated pulse mode.

    Science.gov (United States)

    Harth, Yoram; Frank, Ido

    2013-12-01

    Microneedle radiofrequency is a novel method that allows non-thermal penetration of the epidermis followed by RF coagulation in selected depth of the dermis surrounded by zone of non-coagulative volumetric heating. The first generation of Microneedle RF applicators used insulated needles. These treatments were limited by a few factors, including low volume of dermal heating, lack of effect in the papillary dermis and pinpoint bleeding during the treatment. The system tested in this study (EndyMed PRO, Intensif applicator, EndyMed Medical, Cesarea, Israel) utilizes special extra sharp tapered non-insulated microneedles and a special pulse mode, allowing full coagulation during treatment and higher effective volume of dermal heat. After Ethics Committee approval, one female pig (Type Large white X Landrace, 34 Kg) was chosen for the study. The animal was anesthetized using Ketamine, Xylazin and Isofluran. The EndyMed PRO, Intensif applicator (was used for treatment with different needle depth penetration (1 mm-3.5 mm) and in multiple energy settings. Six mm punch biopsies were harvested for histological analysis at the following time points: immediately after the treatment, 4 days after the treatment and 14 days after the treatment. H&E and Masson-Trichrome stains were processed. Visual inspection of the treated skin, immediately after the treatment, revealed arrays of pinpoint erythematous papules surrounded by undamaged epidermal tissue. Treatment field showed no sign of bleeding. Mild to moderate Erythema and Edema developed a few minutes after the treatment, varying according to the total energy delivered. The histologies taken 4-day after therapy showed in all energy settings, dry micro crusts over the treatment zones, with full healing of epidermis. In the 14-day specimens there was a replacement of the crusts/debris by a normal looking stratum corneum with complete healing of epidermis and dermis. The current in vivo study confirms that the EndyMed PRO

  2. A Measurement Method of Time Jitter of a Laser Pulse with Respect to the Radio-Frequency Wave Phase in a Photocathode Radio-Frequency Gun

    Institute of Scientific and Technical Information of China (English)

    刘圣广; 李永贵; 王鸣凯

    2002-01-01

    In a photo-cathode radio-frequency (rf) gun, the micro-bunched charge output from the gun is dependent linearly on the laser injection phase, due to the Scottay effect in the process of photoemission and the procedure of the electron longitudinal acceleration. Based on this principle, a new method is proposed, which should be utilized to measure the time jitter between the driving laser pulse and the rf phase with a very high resolution of a few tens of femtoseconds.

  3. Ohm's Law for a Bipolar Semiconductor: The Role of Carrier Concentration and Energy Nonequilibria

    Science.gov (United States)

    Lashkevych, Igor; Titov, Oleg Yu.; Gurevich, Yuri G.

    2016-09-01

    The effective linear electrical conductivity of a nondegenerate bipolar semiconductor, sandwiched between two metals, is investigated taking into account both its nonequilibrium charge carriers (both electrons and holes) and nonequilibrium temperature. We stress that even in the linear perturbative approximation both carrier concentration and energy nonequilbria arise automatically when an electrical current flows. The expression for the effective electrical conductivity is obtained and shown to depend on the electron and hole electrical conductivity, the thermal conductivity, the bandgap, charge carriers lifetimes, and both bulk and surface recombination rates. The effective electrical conductivity is equal to the classical result, i.e., the sum of the electron and hole electrical conductivities, only if the surface recombination rate at the interface is sufficiently strong or the charge carrier lifetime is sufficiently small. In this article, partial cases are considered, specifically, semiconductors with small and large thermal conductivities, semiconductors with monopolar electron and monopolar holes, strong and weak surface recombination rates, and small and large charge carrier lifetimes. Expressions for the effective electrical conductivity are obtained in all partial cases.

  4. Ohm's Law for a Bipolar Semiconductor: The Role of Carrier Concentration and Energy Nonequilibria

    Science.gov (United States)

    Lashkevych, Igor; Titov, Oleg Yu.; Gurevich, Yuri G.

    2017-01-01

    The effective linear electrical conductivity of a nondegenerate bipolar semiconductor, sandwiched between two metals, is investigated taking into account both its nonequilibrium charge carriers (both electrons and holes) and nonequilibrium temperature. We stress that even in the linear perturbative approximation both carrier concentration and energy nonequilbria arise automatically when an electrical current flows. The expression for the effective electrical conductivity is obtained and shown to depend on the electron and hole electrical conductivity, the thermal conductivity, the bandgap, charge carriers lifetimes, and both bulk and surface recombination rates. The effective electrical conductivity is equal to the classical result, i.e., the sum of the electron and hole electrical conductivities, only if the surface recombination rate at the interface is sufficiently strong or the charge carrier lifetime is sufficiently small. In this article, partial cases are considered, specifically, semiconductors with small and large thermal conductivities, semiconductors with monopolar electron and monopolar holes, strong and weak surface recombination rates, and small and large charge carrier lifetimes. Expressions for the effective electrical conductivity are obtained in all partial cases.

  5. Radiofrequency ablation of liver metastases; Radiofrequenzablation von Lebermetastasen

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, P.L.; Clasen, S.; Schmidt, D.; Wiskirchen, J.; Tepe, G.; Claussen, C.D. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Boss, A. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Sektion fuer Experimentelle Radiologie der Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Gouttefangeas, C. [Abt. Immunologie des Inst. fuer Zellbiologie, Eberhard-Karls-Univ. Tuebingen (Germany); Burkart, C. [Zentrum fuer gastroenterologische Onkologie der Medizinischen Klinik, Eberhard-Karls-Univ. Tuebingen (Germany)

    2004-04-01

    The liver is the second only to lymph nodes as the most common site of metastatic disease irrespective of the primary tumor. Up to 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improvement of the survival time, only approximately 20% of the patients are eligible for surgical intervention. Radiofrequency (RF) ablation represents one of the most important alternatives as well as complementary methods for the therapy of liver metastases. RF ablation can lead in a selected patient group to a palliation or to an increased life expectancy. RF ablation appears either safer (vs. cryotherapy) or easier (vs. laser) or more effective (percutaneous ethanol instillation [PEI]), transarterial chemoembolisation [TACE] in comparison with other minimal invasive procedures. RF ablation can be performed percutaneously, laparoscopically or intraoperatively and may be combined with chemotherapy as well as with surgical resection. Permanent technical improvements of RF systems, a better understanding of the underlying electrophysiological principles and an interdisciplinary approach will lead to a prognosis improvement in patients with liver metastases. (orig.) [German] Die Leber ist unabhaengig vom Primaertumor nach den Lymphknoten die zweithaeufigste Lokalisation von Metastasen. Bis zu 50% aller Patienten mit malignen Erkrankungen werden im Verlauf ihrer Erkrankung Lebermetastasen entwickeln, die mit einer signifikanten Morbiditaet und Mortalitaet verbunden sind. Obwohl die chirurgische Resektion zu einer verlaengerten Ueberlebenszeit fuehrt, sind nur ca. 20% der Patienten fuer einen chirurgischen Eingriff geeignet. Die Radiofrequenz-(RF-)Ablation stellt derzeit eine der effektivsten Alternativen und komplementaeren Methoden bei der Therapie von Lebermetastasen dar. In einem selektierten Patientengut fuehrt die RF-Ablation ueber den palliativen Einsatz hinaus zu einer

  6. Oncogenesis: An "Off-Target" Effect of Radiofrequency Ablation.

    Science.gov (United States)

    Rozenblum, Nir; Zeira, Evelyne; Scaiewicz, Viviana; Bulvik, Baruch; Gourevitch, Svetlana; Yotvat, Hagit; Galun, Eithan; Goldberg, S Nahum

    2015-08-01

    To compare hepatocellular carcinoma (HCC) development after radiofrequency (RF) ablation, partial surgical hepatectomy, and a sham operation and to inhibit HCC recurrence after RF ablation in a mouse model of spontaneously forming HCC in the setting of chronic inflammation (ie, the MDR2 knockout model). Animal experiments were performed according to an approved animal care committee protocol. The authors compared the survival of MDR2 knockout mice (an inflammation-induced HCC model) that underwent RF ablation, 35% partial hepatectomy (ie, left lobectomy), or a sham operation (controls) by using Kaplan-Meier survival curve analysis. Tumor load and tumor frequency in mice that underwent sham operation were further compared with those of mice treated with RF ablation at 1 month after therapy by using a two-tailed Student t test. Liver slices from mice treated with RF ablation were stained for α-smooth muscle actin and Ki-67 to establish the role of liver regeneration in the tumorigenic effect of RF ablation. Finally, tumor load and tumor incidence were evaluated in mice treated with a c-met inhibitor after RF ablation by using the Mann-Whitney U test. Ablation of 3.5% ± 0.02 of the MDR2 knockout mice liver induced increased tumor load (P = .007) and reduced survival (P = .03) in comparison to that of controls, with no significant difference to the 10-fold volume removal of partial hepatectomy. Seven days after RF treatment, the border zone of the coagulation zone was surrounded by α-smooth muscle actin-positive activated myofibroblasts. A significant elevation of hepatocyte proliferation was also seen 7 days after RF ablation in the distant liver (ablated lobe: P = .003; untreated lobe: P = .02). A c-met inhibitor significantly attenuated HCC development in MDR2 knockout mice treated with RF ablation (P = .001). Liver regeneration induced by RF ablation facilitates c-met/hepatocyte growth factor axis-dependent HCC tumor formation after treatment in the MDR2

  7. Clinical Efficacy of Pulsed Radiofrequency Neuromodulation for Intractable Meralgia Paresthetica.

    Science.gov (United States)

    Lee, Jae Jun; Sohn, Jong Hee; Choi, Hyuk Jai; Yang, Jin Seo; Lee, Kwang Ho; Do, Hye Jin; Lee, Sung Ho; Cho, Yong Jun

    2016-03-01

    Meralgia paresthetica (MP) is a neurologic disorder of the lateral femoral cutaneous nerve (LFCN), which is characterized by a localized area of paresthesia and numbness on the anterolateral aspect of the thigh. In most patients with MP, symptoms can be successfully managed with conservative treatment. However, in a small group of MP patients who are refractory to medical treatment, more aggressive low-risk treatment should be considered. The objective of this study was to evaluate clinical outcomes of pulsed radiofrequency (PRF) neuromodulation of the LFCN in MP patients refractory to conservative treatment. Retrospective evaluation. We retrospectively reviewed the clinical data of 11 patients with medically intractable MP who underwent PRF neuromodulation of the LFCN. These patients with MP underwent a diagnostic LFCN block using 2.0% lidocaine. Temporary pain relief > 50% was considered to be a positive response to the diagnostic nerve block. Following a positive response to the diagnostic nerve block, patients underwent PRF neuromodulation at 42 degrees for 2 minutes. Patient pain was evaluated using a 10-cm visual analog scale (VAS). In MP patients who received PRF, we statistically evaluated VAS scores and the presence of any complications for 6 or more months after the procedure. The mean initial patient VAS score was 6.4 ± 0.97 cm. This score was decreased to 0.91 ± 0.70 cm, 0.82 ± 0.75 cm, and 0.63 ± 0.90 cm at the one-, 3-, and 6- month follow-ups, respectively (P < 0.001). Sixty-three point six percent of patients achieved complete pain relief (pain-free) in the last follow-up, whereas 27.3% of patients achieved successful pain relief (= 50% reduction in pain as determined by the VAS score). Furthermore, we did not observe any complications after the procedure. PRF neuromodulation of the LFCN provides immediate and long-lasting pain relief without complications. Therefore, PRF of the LCFN can be used as an alternative treatment in patients with MP

  8. Radiofrequency thermocoagulation rhizotomy for recurrent trigeminal neuralgia after microvascular decompression

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liang-wen; LIU Yu-guang; WU Cheng-yuan; XU Shu-jun; ZHU Shu-gan

    2011-01-01

    Background Microvascular decompression (MVD) is a well accepted surgical treatment strategy for trigeminal neuralgia (TN) with satisfying long-term outcome.However,considerable recurrent patients need more effective management.The purpose of this study was to evaluate the effectiveness of radiofrequency thermocoagulation rhizotomy (RTR) on patients with recurrent TN after MVD.Methods Totally 62 cases of recurrent TN after MVD undergoing RTR from January 2000 to January 2010 were retrospectively evaluated.Based on surgical procedures undertaken,these 62 cases were classified into two subgroups:group A consisted of 23 cases that underwent traditional RTR by free-hand; group B consisted of 39 cases that underwent RTR under the guidance of virtual reality imaging technique or neuronavigation system.The patients in group Awere followed up for 14 to 70 months (mean,40±4),and those in group B were followed up for 13 to 65 months (mean,46±7).Kaplan-Meier analyses of the pain-free survival curves were used for the censored survival data,and the log-rank test was used to compare survival curves of the two groups.Results All patients in both groups A and B attained immediate pain relief after RTR.Both groups attained good pain relief rate within the first two years of follow-up:92.3%,84.6% and 82.6%,69.6% respectively (P >0.05).After 2 years,the virtual reality or neuronavigation assisted RTR group (group B) demonstrated higher pain relief rates of 82.5%,76.2% and 68.8% at 3,4 and 5 years after operation respectively,while those in group A was 57.2%,49.6%,and 36.4% (P <0.05).Low levels of minor complications were recorded,while neither mortalities nor significant morbidity was documented.Conclusions RTR was effective in alleviating the pain of TN cases suffering from unsuccessful MVD management.With the help of virtual reality imaging technique or neuronavigation system,the patients could attain better long-term pain relief.

  9. Design, Construction and Operation of a Low-Power, Autonomous Radio-Frequency Data-Acquisition Station for the TARA Experiment

    CERN Document Server

    Kunwar, S; Allen, C; Belz, J; Besson, D; Byrne, M; Farhang-Boroujeny, B; Gillman, W H; Hanlon, W; Hanson, J; Myers, I; Novikov, A; Prohira, S; Ratzlaff, K; Rezazadeh, A; Sanivarapu, V; Schurig, D; Shustov, A; Smirnova, M; Takai, H; Thomson, G B; Young, R

    2015-01-01

    Employing a 40-kW radio-frequency transmitter just west of Delta, UT, and operating at 54.1 MHz, the TARA (Telescope Array RAdar) experiment seeks radar detection of extensive air showers (EAS) initiated by ultra-high energy cosmic rays (UHECR). For UHECR with energies in excess of $10^{19}$ eV, the Doppler-shifted "chirps" resulting from EAS shower core radar reflections should be observable above background (dominantly galactic) at distances of tens of km from the TARA transmitter. In order to stereoscopically reconstruct cosmic ray chirps, two remote, autonomous self-powered receiver stations have been deployed. Each remote station (RS) combines both low power consumption as well as low cost. Triggering logic, the powering and communication systems, and some specific details of hardware components are discussed.

  10. Effects of Multipolar Radiofrequency and Pulsed Electromagnetic Field Treatment for Face and Neck Rejuvenation

    Science.gov (United States)

    de Oliveira, Thais Cristina Ferraz; Rocha, Sheyla de Fatima Soares; Ramos, Daniel Gontijo; Ramos, Camila Gontijo; Carvalho, Michelle Vanessa dos Anjos

    2017-01-01

    Skin aging is a gradual process that leads to wrinkle formation, laxity, and overall changes in skin appearance. In recent years, the demands to noninvasive treatments for facial rejuvenation increased, along with a variety of technologies and devices, such as radiofrequency. The present study aimed to evaluate the clinical effects of a multipolar radiofrequency and pulsed electromagnetic field treatment for face and neck rejuvenation. Eleven patients with mild to moderate grades of photoaging underwent eight radiofrequency and pulsed electromagnetic field treatment sessions, once a week. Clinical photographs were taken before and a week after the end of the treatment, and improvement of facial skin parameters was evaluated by two different investigators. Significant improvement in skin laxity was observed in all eleven patients (100%). Improvement in facial contour was noted in 73% and 100% of patients when analyzed by investigators A and B, respectively. The score for overall improvement in skin condition was 3 ± 0.78 for investigator A and 3.6 ± 0.67 for investigator B. All patients were satisfied with the procedure and noted significant improvement in the skin. The combined multipolar radiofrequency and pulsed electromagnetic field device is effective and safe for treatment of aged skin in Brazilian patients. PMID:28373880

  11. Adiabatic radio-frequency potentials for the coherent manipulation of matter waves

    DEFF Research Database (Denmark)

    Lesanovsky, Igor; Schumm, Thorsten; Hofferberth, S.

    2006-01-01

    Adiabatic dressed state potentials are created when magnetic substates of trapped atoms are coupled by a radio-frequency field. We discuss their theoretical foundations and point out fundamental advantages over potentials purely based on static fields. The enhanced flexibility enables one...

  12. Predictive value of HATCH score on atrial fibrillation recurrence post radiofrequency catheter ablation

    Institute of Scientific and Technical Information of China (English)

    缪丹丹

    2012-01-01

    Objective To determine the predictive value of HATCH score on recurrence of atrial fibrillation(AF) after radiofrequency catheter ablation (RFCA). Methods The data of 123 consecutive AF patients(74 paroxysmal and 49 persistent AF) who underwent RFCA between April 2009 and December 2010 in our department were retrospectively

  13. 77 FR 74668 - Compliance Policy Guide; Radiofrequency Identification Feasibility Studies and Pilot Programs for...

    Science.gov (United States)

    2012-12-17

    ... Feasibility Studies and Pilot Programs for Drugs; Notice To Extend Expiration Date AGENCY: Food and Drug... ``Radiofrequency Identification (RFID) Feasibility Studies and Pilot Programs for Drugs'' to December 31, 2014. FOR... (RFID) Feasibility Studies and Pilot Programs for Drugs.'' Previous extensions of the expiration date...

  14. Pulsed radiofrequency treatment in interventional pain management: mechanisms and potential indications-a review

    NARCIS (Netherlands)

    Chua Hai Liang, N.; Vissers, K.C.P.; Sluijter, M.E.

    2011-01-01

    BACKGROUND: The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide th

  15. Electromagnetic and Thermal Aspects of Radiofrequency Field Propagation in Ultra-High Field MRI

    NARCIS (Netherlands)

    van Lier, A.L.H.M.W.

    2012-01-01

    In MRI, a radiofrequency (RF) pulse is used to generate a signal from the spins that are polarized by a strong magnetic field. For higher magnetic field strengths, a higher frequency of the RF pulse is required in order to match the Larmor frequency. A higher frequency, in turn, leads to a shorter w

  16. Treatment of osteoid osteoma with CT-guided percutaneous radiofrequency thermoablation.

    Science.gov (United States)

    de Palma, Luigi; Candelari, Roberto; Antico, Ettore; Politano, Rocco; Luniew, Eugenio; Giordanengo, Maurizio; Di Giansante, Silvio; Marinelli, Mario; Paci, Enrico

    2013-05-01

    Osteoid osteoma is a benign bone tumor with a male predominance occurring mainly in children and young adults. The most common symptom is intermittent pain that worsens at night and is at least partially relieved by nonsteroidal anti-inflammatory drugs. The purpose of this study was to assess the long-term effectiveness of computed tomography-guided percutaneous radiofrequency thermoablation in patients with a minimum follow-up of 2 years. Twenty patients with osteoid osteoma (15 men and 5 women) with a mean age of 20.7 years (range, 4-61 years; 12 patients aged 20 years or younger) underwent computed tomography-guided percutaneous radiofrequency thermoablation. Lesion sites were the femur (n=9), tibia (n=7), pelvis (n=1), talus (n=1), cuneiform bone (n=1), and humerus (n=1). Mean follow-up was 44 months (range, 3-106 months). Pain relief was significant in 95% of patients; it disappeared within 24 hours in 14 patients, within 3 days in 4, and within 7 days in 1. The patient with persistent symptoms underwent another percutaneous radiofrequency thermoablation procedure that was successful. The difference between pre- and postoperative pain was significant (P ≤ .01). No recurrences occurred. Computed tomography-guided percutaneous radiofrequency thermoablation is a safe, minimally invasive, and economical procedure with high technical and clinical success rates, and it effectively and durably enhances quality of life.

  17. Combination technique of radiofrequency ablation with sclerotherapy in acquired lymphangiectasis of the vulva

    Directory of Open Access Journals (Sweden)

    Khunger Niti

    2009-01-01

    Full Text Available Aquired lymphangiectasis of the vulva is an uncommon condition and only few cases have been reported following tuberculous lymphadenitis. A case is reported that was successfully treated with a unique combination therapy of radiofrequency ablation and sclerotherapy with polidocanol. There was no recurrence at two years of follow-up.

  18. Radiofrequency ablation therapy of intractable ventricular tachycardia present with a left ventricular assist device

    DEFF Research Database (Denmark)

    Nielsen, Jan Møller; Kristiansen, Steen Buus; Gerdes, Christian;

    2015-01-01

    Ventricular tachycardia (VT) occurs in up to 59% of patients with left ventricular assist devices (LVAD). In some of these patients, the VT cannot be managed medically or by implantable cardioverter-defibrillator. In this case, a 66-year-old male was successfully treated with radiofrequency...

  19. Reversal of premature ventricular complex-induced cardiomyopathy following successful radiofrequency catheter ablation.

    Science.gov (United States)

    Efremidis, Michalis; Letsas, Konstantinos P; Sideris, Antonios; Kardaras, Fotios

    2008-06-01

    Premature ventricular complex (PVC)-induced cardiomyopathy is an underappreciated cause of left-ventricular (LV) dysfunction. The present report describes the case of an elderly man with a very high burden of monomorphic PVCs and LV dysfunction. Elimination of the left ventricular focus following radiofrequency catheter ablation resulted in reversal of cardiomyopathy.

  20. Effects of Multipolar Radiofrequency and Pulsed Electromagnetic Field Treatment for Face and Neck Rejuvenation

    Directory of Open Access Journals (Sweden)

    Thais Cristina Ferraz de Oliveira

    2017-01-01

    Full Text Available Skin aging is a gradual process that leads to wrinkle formation, laxity, and overall changes in skin appearance. In recent years, the demands to noninvasive treatments for facial rejuvenation increased, along with a variety of technologies and devices, such as radiofrequency. The present study aimed to evaluate the clinical effects of a multipolar radiofrequency and pulsed electromagnetic field treatment for face and neck rejuvenation. Eleven patients with mild to moderate grades of photoaging underwent eight radiofrequency and pulsed electromagnetic field treatment sessions, once a week. Clinical photographs were taken before and a week after the end of the treatment, and improvement of facial skin parameters was evaluated by two different investigators. Significant improvement in skin laxity was observed in all eleven patients (100%. Improvement in facial contour was noted in 73% and 100% of patients when analyzed by investigators A and B, respectively. The score for overall improvement in skin condition was 3 ± 0.78 for investigator A and 3.6 ± 0.67 for investigator B. All patients were satisfied with the procedure and noted significant improvement in the skin. The combined multipolar radiofrequency and pulsed electromagnetic field device is effective and safe for treatment of aged skin in Brazilian patients.

  1. Pulsed radiofrequency treatment in interventional pain management: mechanisms and potential indications-a review

    NARCIS (Netherlands)

    Chua Hai Liang, N.; Vissers, K.C.P.; Sluijter, M.E.

    2011-01-01

    BACKGROUND: The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide

  2. Long-term survival following radiofrequency ablation of colorectal liver metastases

    DEFF Research Database (Denmark)

    Babawale, Simeon Niyi; Jensen, Thomas Mandøe; Frøkjær, Jens Brøndum

    2015-01-01

    AIM: To retrospectively evaluate the long-term survival of patients that received radiofrequency ablation (RFA) therapies of colorectal liver metastases. METHODS: In 2005 to 2008, RFA of 105 colorectal liver metastases (CRLM) were performed on 49 patients in our institution. The liver metastases ...

  3. Hip fracture after radiofrequency ablation therapy for bone tumors : two case reports

    NARCIS (Netherlands)

    Dierselhuis, Edwin F.; Jutte, Paul C.; van der Eerden, Pepijn J. M.; Suurmeijer, Albert J. H.; Bulstra, Sjoerd K.

    2010-01-01

    Radiofrequency ablation (RFA) has become a valuable therapeutic modality in cancer treatment over the last decade. In orthopedic surgery, RFA is used for the treatment of benign bone tumors and bone metastases. Complications are rare and, to our knowledge, bone fracture as a complication due solely

  4. Effect of percutaneous renal sympathetic nerve radiofrequency ablation in patients with severe heart failure.

    Science.gov (United States)

    Dai, Qiming; Lu, Jing; Wang, Benwen; Ma, Genshan

    2015-01-01

    This study aimed to investigate the clinical feasibility and effects of percutaneous renal sympathetic nerve radiofrequency ablation in patients with heart failure. A total of 20 patients with heart failure were enrolled, aged from 47 to 75 years (63±10 years). They were divided into the standard therapy (n = 10), and renal nerve radiofrequency ablation groups (n = 10). There were 15 males and 5 female patients, including 8 ischemic cardiomyopathy, 8 dilated cardiomyopathy, and 8 hypertensive cardiopathy. All of the patients met the criteria of New York Heart Association classes III-IV cardiac function. Patients with diabetes and renal failure were excluded. Percutaneous renal sympathetic nerve radiofrequency ablation was performed on the renal artery wall under X-ray guidance. Serum electrolytes, neurohormones, and 24 h urine volume were recorded 24 h before and after the operation. Echocardiograms were performed to obtain left ventricular ejection fraction at baseline and 6 months. Heart rate, blood pressure, symptoms of dyspnea and edema were also monitored. After renal nerve ablation, 24 h urine volume was increased, while neurohormone levels were decreased compared with those of pre-operation and standard therapy. No obvious change in heart rate or blood pressure was recorded. Symptoms of heart failure were improved in patients after the operation. No complications were recorded in the study. Percutaneous renal sympathetic nerve radiofrequency ablation may be a feasible, safe, and effective treatment for the patients with severe congestive heart failure.

  5. Long-lasting analgesic effect of radiofrequency treatment of the lumbosacral dorsal root ganglion

    NARCIS (Netherlands)

    Geurts, JWM; Wynne, HJ; van Wijk, R.

    2001-01-01

    Object. The authors conducted a study to establish the benefit of radiofrequency (RF) treatment of the lumbosacral dorsal root ganglion (DRG) as a therapy to reduce symptomatic pain in patients with chronic spinal pain radiating to the leg. Methods. Two hundred seventy-nine patients were evaluated a

  6. Radiofrequency ablation-assisted liver resection:a step toward bloodless liver resection

    Institute of Scientific and Technical Information of China (English)

    Athanasios Petrou; Kyriakos Neofytou; Constantinos Mihas; Jessamy Bagenal; Michael Kontos; John Griniatsos; Evangelos Felekouras

    2015-01-01

    BACKGROUND: Liver resection is currently the most efficient curative approach for a wide variety of liver tumors. The ap-plication of modern techniques and new surgical devices has improved operative outcomes. Radiofrequency ablation is used more often for liver parenchymal transection. This study aimed to assess the efficacy and safety of radiofrequency abla-tion-assisted liver resection. METHODS: A retrospective study of 145 consecutive patients who underwent radiofrequency ablation-assisted liver resec-tion was performed. Intraoperative blood loss, need for trans-fusion or intraoperative Pringle maneuver, the duration of liver parenchymal transection, perioperative complications, and postoperative morbidity and mortality were all evaluated. RESULTS: Fifty minor and ninety-five major liver resections were performed. The mean intraoperative blood loss was 251 mL, with a transfusion rate of 11.7%. The Pringle maneuver was necessary in 12 patients (8.3%). The mean duration for parenchymal transection was 51.75 minutes. There were 47 patients (32.4%) with postoperative complications. There is no mortality within 30 days after surgery. CONCLUSIONS: Radiofrequency ablation-assisted liver re-section permits both major and minor liver resections with minimal blood loss and without occlusion of hepatic inflow. Furthermore it decreases the need for blood transfusion and reduces morbidity and mortality.

  7. Coronary plaque composition as assessed by greyscale intravascular ultrasound and radiofrequency spectral data analysis

    NARCIS (Netherlands)

    N. Gonzalo (Nieves); H.M. Garcia-Garcia (Hector); J.M.R. Ligthart (Jürgen); G.A. Rodriguez-Granillo (Gaston); E. Meliga (Emanuele); Y. Onuma (Yoshinobu); J.C.H. Schuurbiers (Johan); N. Bruining (Nico); P.W.J.C. Serruys (Patrick)

    2008-01-01

    textabstractObjectives: (i) To explore the relation between greyscale intravascular ultrasound (IVUS) plaque qualitative classification and IVUS radiofrequency data (RFD) analysis tissue types; (ii) to evaluate if plaque composition as assessed by RFD analysis can be predicted by visual assessment o

  8. 54. Radiofrequency perforation of pulmonary valve and PDA stenting in a preterm neonate

    Directory of Open Access Journals (Sweden)

    D. Khaymaf

    2016-07-01

    Full Text Available Transcatheter radiofrequency perforation of the pulmonary valve and PDA stenting is considered as a modality for pulmonary atresia and intact ventricular septum with mildly hypoplastic tripartate right ventricle. We present a preterm neonate who has undergone this procedure. we assume that transcatheter radiofrequency perforation of pulmonary valve and PDA stenting is a safer approach for pulmonary atresia with intact ventricular septum in preterm newborns, than surgical approach.We present 5 days old, preterm (36 weeks gestation baby girl, with 2.2 kg. She was reffered to our centre with the diagnosis of pulmonary atresia with intact ventricular septum, mildly hypoplastic tripartate right ventricle. Right ventricle angiography showed tripartate right ventricle with no sinusoids. She underwent successful radiofrequency perforation of pulmonary valve followed by balloon dilatation. At the same time prograde PDA stenting was done. Repeat right ventricle angiography showed good right ventricular outflow tract forward flow, and descending aorta angiography showed good PDA flow supplying both pulmonary arteries. The baby was extubated on same day, and prosoglandin E1 was discontinued immediately after the procedure.The baby mainatined saturation more than 80% on room air. The baby was discharged after 2 days. Our case is pecular because to our knowledge this is the lowest weight for wich radiofrequency perforation and PDA stenting is done as well as being preterm.

  9. Residential characteristics and radiofrequency electromagnetic field exposures from bedroom measurements in Germany

    DEFF Research Database (Denmark)

    Breckenkamp, J; Blettner, M; Schüz, J

    2012-01-01

    The objectives of this study were to assess total exposure to radiofrequency electromagnetic fields (RF-EMF) in bedrooms and the contribution of different radioservices (FM radio, analogue TV and DVB-T, TETRA, GSM900 downlink, GSM1800 downlink, UMTS downlink, DECT, and wireless LAN and blue tooth...

  10. Wide-bandwidth charge sensitivity with a radio-frequency field-effect transistor

    NARCIS (Netherlands)

    Nishiguchi, K.; Yamaguchi, H.; Fujiwara, A.; Van der Zant, H.S.J.; Steele, G.A.

    2013-01-01

    We demonstrate high-speed charge detection at room temperature with single-electron resolution by using a radio-frequency field-effect transistor (RF-FET). The RF-FET combines a nanometer-scale silicon FET with an impedance-matching circuit composed of an inductor and capacitor. Driving the RF-FET w

  11. Evaluation of microneedling fractional radiofrequency device for treatment of acne scars

    Directory of Open Access Journals (Sweden)

    Byalekere Shivanna Chandrashekar

    2014-01-01

    Full Text Available Background: Various treatment modalities including non-invasive methods such as chemical peels, topical retinoids, microdermabrasion, minimally invasive techniques such as microneedling, fractional lasers, microneedling radiofrequency devices and invasive procedures such as acne scar surgeries and ablative lasers are used for acne scars, each with its own unique advantages and disadvantages. This study is a retrospective assessment of efficacy and safety of microneedling fractional radiofrequency in the treatment of acne scars. Methods: Thirty one patients of skin types III-V with moderate and severe facial acne scarring received four sequential fractional radiofrequency treatments over a period of 6 months with an interval of 6 weeks between each session. Goodman & Baron′s acne scar grading system was used for assessment by a side by side comparison of preoperative and post- operative photographs taken at their first visit and at the end of 3 months after the last session. Results: Estimation of improvement with Goodman and Baron′s Global Acne Scarring System showed that by qualitative assessment of 31 patients with grade 3 and grade 4 acne scars, 80.64% showed improvement by 2 grades and 19.35% showed improvement by 1 grade. Quantitative assessment showed that 58% of the patients had moderate, 29% had minimal, 9% had good and 3% showed very good improvement. Adverse effects were limited to transient pain, erythema, edema and hyperpigmentation. Conclusion: Microneedling fractional radiofrequency is efficacious for the treatment of moderate and severe acne scars.

  12. Feature Profile Evolution During Etching of SiO2 in Radio-Frequency or Direct-Current Plasmas

    Science.gov (United States)

    Zhao, Zhanqiang; Dai, Zhongling; Wang, Younian

    2012-01-01

    We have developed a plasma etching simulator to investigate the evolution of pattern profiles in SiO2 material under different plasma conditions. This model focuses on energy and angular dependent etching yield (physical sputtering in this paper), neutral and ion angular distributions, and reflection of ions or neutrals on the surface of a photoresist or SiO2. The effect of positive charge accumulation on the surface of insulated mask or SiO2 is studied and the charge accumulation contributes to a deflection of ion trajectory. The wafer profile evolution has been simulated using a cellular-automata-like method under radio-frequency (RF) bias and direct-current (DC) bias, respectively. On the basis of the critical role of angular distribution of ions or neutrals, the wafer profile evolution has been simulated for different variances of angles. Observed microtrenching has been well reproduced in the simulator. The ratio of neutrals to ions has been considered and the result shows that because the neutrals are not accelerated by an electric field, their energy is much lower compared with ions, so they are easily reflected on the surface of SiO2, which makes the trench shallower.

  13. Ophthalmic branch radiofrequency thermocoagulation for atypical trigeminal neuralgia:a case report.

    Science.gov (United States)

    Du, Shibin; Ma, Xiaoliang; Li, Xiaoqin; Yuan, Hongjie

    2015-01-01

    Trigeminal neuralgia is an intense neuralgia involving facial areas supplied by trigeminal nerve. The pain is characterized by sudden onset, short persistence, sharp or lancinating. Trigeminal neuralgia commonly affects frontal areas, infraorbital or paranasal areas, mandibular areas and teeth. While Trigeminal neuralgia affecting merely the upper eyelid is rare. Here we report a case of atypical Trigeminal neuralgia confined to the upper eyelid. The patient was pain free during the follow-up period of 6 months after unusual ophthalmic branch radiofrequency thermocoagulation. A 55-year-old female patient was diagnosed as primary trigeminal neuralgia involving the right upper eyelid. As the pain could not be controlled by drug therapy, peripheral nerve branch radiofrequency thermocoagulation was recommended. A combination of infratrochlear, supratrochlear and lacrimal radiofrequency thermocoagulation was implemented in this case. The point where the bridge of the nose abuts the supraorbital ridge and the point slightly above the lateral canthus along outer border of the orbit were selected respectively as the puncture sites. After positive diagnostic test, radiofrequency thermocoagulation of the above-mentioned nerve branches was performed respectively. The patient was pain free immediately after the treatment and during the follow-up period of 6 months. Trigeminal neuralgia is a common severe and chronic facial neuralgia which requires accurate diagnosis and effective therapy. With typical clinical symptoms, normal neurological signs, normal CT and MRI findings, the patient was diagnosed as classic trigeminal neuralgia. As the patient was drug resistant, some invasive treatments were considered. Peripheral branch neurolysis was chosen for its minimal invasiveness, convenience, low risk and not affecting further invasive treatments. According to the anatomic data and the diagnostic test results, infratrochlear, supratrochlear and lacrimal nerve were responsible

  14. Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.-X.; Xie, X.-Y.; Lu, M.-D. E-mail: lumd@21cn.com; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J

    2004-01-01

    AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.

  15. Temperature responsive porous silicon nanoparticles for cancer therapy - spatiotemporal triggering through infrared and radiofrequency electromagnetic heating.

    Science.gov (United States)

    Tamarov, Konstantin; Xu, Wujun; Osminkina, Liubov; Zinovyev, Sergey; Soininen, Pasi; Kudryavtsev, Andrey; Gongalsky, Maxim; Gaydarova, Azha; Närvänen, Ale; Timoshenko, Victor; Lehto, Vesa-Pekka

    2016-11-10

    One critical functionality of the carrier system utilized in targeted drug delivery is its ability to trigger the release of the therapeutic cargo once the carrier has reached its target. External triggering is an alluring approach as it can be applied in a precise spatiotemporal manner. In the present study, we achieved external triggering through the porous silicon (PSi) nanoparticles (NPs) by providing a pulse of infrared or radiofrequency radiation. The NPs were grafted with a temperature responsive polymer whose critical temperature was tailored to be slightly above 37°C. The polymer coating improved the biocompatibility of the NPs significantly in comparison with their uncoated counterparts. Radiation induced a rapid temperature rise, which resulted in the collapse of the polymer chains facilitating the cargo release. Both infrared and radiofrequency radiation were able to efficiently trigger the release of the encapsulated drug in vitro and induce significant cell death in comparison to the control groups. Radiofrequency radiation was found to be more efficient in vitro, and the treatment efficacy was verified in vivo in a lung carcinoma (3LL) mice model. After a single intratumoral administration of the carrier system combined with radiofrequency radiation, there was clear suppression of the growth of the carcinoma and a prolongation of the survival time of the animals. The temperature responsive (TR) polymer grafted on the surface of porous silicon nanoparticles (PSi NPs) changes its conformation in response to the heating induced by infrared or radiofrequency radiation. The conformation change allows the loaded doxorubicin to escape from the pores, achieving controlled drug release from TR PSi NPs, which displayed efficacy against malignant cells both in vitro and in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Successful treatment of meralgia paresthetica with pulsed radiofrequency of the lateral femoral cutaneous nerve.

    Science.gov (United States)

    Philip, Cyril N; Candido, Kenneth D; Joseph, Ninos J; Crystal, George J

    2009-01-01

    Meralgia paresthetica is a rarely encountered sensory mononeuropathy characterized by paresthesia, pain or sensory impairment along the distribution of the lateral femoral cutaneous nerve caused by entrapment or compression of the nerve as it crosses the anterior superior iliac spine and runs beneath the inguinal ligament. We describe the first reported use of pulsed radiofrequency neuromodulation to relieve the intractable pain associated with meralgia paresthetica. A 33-year-old morbidly obese female with a history of lower back pain and previous spinal fusion presented with sensory dysesthesias and paresthesias in the right anterolateral thigh, consistent with meralgia paresthetica. Temporary relief occurred with multiple lateral femoral cutaneous nerve and fascia lata blocks at 2 different institutions. The patient expressed dissatisfaction with her previous treatments and requested "any" therapeutic intervention that might lead to long-lasting pain relief. At this time, we located the anterior superior iliac spine and reproduced concordant dysesthesia. Pulsed radiofrequency was then undertaken at 42 degrees C for 120 seconds followed by dexamethasone and bupivicaine. The patient reported exceptional and prolonged pain relief at 6-month follow-up. Since this case report is not a prospective, randomized, controlled or blinded study, no conclusions may be drawn from the results attained on behalf of this single individual. Additional, larger group analyses studying this technique while eliminating bias from patient variables would be essential prior to assuming any validity to using pulsed radiofrequency techniques of neuromodulation for managing peripheral neuropathic pain processes. The patient had experienced long-standing pain that was recalcitrant to conservative/pharmacologic therapy and multiple nerve blocks with local steroid instillations. A single treatment with pulsed radiofrequency resulted in complete and sustained cessation of pain. No side effects

  17. Radiofrequency ablation of the supra-orbital nerve in the treatment algorithm of hemicrania continua.

    Science.gov (United States)

    Weyker, Paul; Webb, Christopher; Mathew, Leena

    2012-01-01

    Hemicrania continua (HC) is an uncommon primary headache disorder in which the diagnosis centers on unilaterality and its absolute responsiveness to indomethacin. We describe 3 patients with a long standing history of headache diagnosed as hemicrania continua. There was profound response to indomethacin which was limited by side effects. In one patient the therapy with indomethacin was limited secondary to co-morbidities. Initial diagnostic blockade provided significant relief of symptoms based on which radio-frequency ablation of the supraorbital nerve was performed with substantial improvement in symptoms. Traditionally, hemicrania continua has been managed exclusively with oral analgesics and is defined by its singular response to indomethacin. Radio-frequency ablation (RFA) has been reported in the literature for multiple indications. This case series is unique in that it describes 3 patients diagnosed with hemicrania continua with pain referred in the supraorbital nerve distribution, who underwent radiofrequency ablation of the supraorbital nerve with resultant resolution of headaches. Traditionally, hemicrania continua has been managed exclusively with oral analgesics and is defined by its singular response to indomethacin. This report is unique in that it describes three patients diagnosed with hemicrania continua with pain referred in the supraorbital nerve distribution who underwent radiofrequency ablation of the supraorbital nerve with resultant resolution of headaches. After the RFA medical management was minimal to none in both patients. Though the utility and cost efficacy of RFA of peripheral nerves needs to be confirmed in well-designed trials we present these cases as an example of how this minimally invasive technique can safely provide analgesia in a difficult to treat cephalgia. Moreover if precise anatomical localization of the headache is possible then diagnostic blockade of the appropriate peripheral nerve may be performed followed by

  18. Non-Lethal Weapons The Use Radiofrequency/Microwave Energy for Stunning/Immobilization

    Science.gov (United States)

    2008-11-26

    chromaffin cells are immobilized on a glass fiber filter ( GFF ) of diameter 10 mm. The cells are continuously superfused at a rate of 1.0 ml/min with a...inlet and outlet tubing with non-perturbing fluoroptic temperature probes placed as close as physically possible to the GFF where the cells are...3.5 and 6 GHz, where % refers to the area of the GFF homogeneous to within 30%. Figure 3

  19. Is radiofrequency energy a necessary and safe complement to cryotherapy for successful pulmonary vein isolation?

    Directory of Open Access Journals (Sweden)

    Ahmed Abdelaal

    2011-06-01

    Conclusions: Our study suggests that hybrid ablation therapy is necessary in most patients to achieve PV disconnection after a maximum of four blinded applications of balloon-cryotherapy (especially in inferior PVs, with a significant short-term success rate.

  20. Improvement of clinical parameters in patients with gastroesophageal reflux disease after radiofrequency energy delivery

    Institute of Scientific and Technical Information of China (English)

    Hai-Feng Liu; Jian-Guo Zhang; Jun Li; Xiao-Guang Chen; Wei-An Wang

    2011-01-01

    AIM: To evaluate the efficacy of Stretta procedure with gastroesophageal reflux disease (GERD) based on symptom control, medication changes and oesophagitis grade.METHODS: Ninety patients with a history of GERD underwent Stretta procedure from June 2007 to March 2010. All patients with GERD diagnosed by the presence of endoscopically evidenced oesophagitis or abnormal esophageal pH testing. We evaluated GERD-health-related quality of life, satisfaction, medication use and endoscopy at baseline, 6, 12 mo after treatment. Complications of the procedure were analyzed. RESULTS: We found that patients experienced significant changes in symptoms of GERD after Stretta procedure. The onset of GERD symptom relief was less than 2 mo (70.0%) or 2 to 6 mo (16.7%). The mean GERD-HRQL score was 25.6 (baseline), 7.3 (6 mo, P< 0.01), and 8.1 (12 mo, P< 0.01).The mean heartburn score was 3.3 (baseline), and 1.2 (12 mo, P< 0.05). The percentage of patients with satisfactory GERD control improved from 31.1% at baseline to 86.7% after treatment, and patient satisfaction improved from 1.4 at baseline to 4.0 at 12 mo (P< 0.01). Medication usage decreased significantly from 100% of patients on proton pump inhibitors therapy at baseline to 76.7% of patients showing elimination of medications or only as needed use of antacids/H2-RA at 12 mo. An improvement in endoscopic grade of oesophagitis was seen in 33 of the 41 patients. All patients had either no erosions or only mild erosive disease (grade A) at 6 mo. CONCLUSION: The experience with Stretta procedure confirms that it is well tolerated, safe, effective and durable in the treatment of GERD. The Stretta procedure provides the drug-refractory patients with a new minimally invasive method.