scholarly journals Optimization of the Clinical Setting Using Numerical Simulations of the Electromagnetic Field in an Obese Patient Model for Deep Regional Hyperthermia of an 8 MHz Radiofrequency Capacitively Coupled Device in the Pelvis

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 979
Author(s):  
Takayuki Ohguri ◽  
Kagayaki Kuroda ◽  
Katsuya Yahara ◽  
Sota Nakahara ◽  
Sho Kakinouchi ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Numerical Simulations ◽  
Obese Patient ◽  
Salt Solution ◽  
Clinical Setting ◽  
Regional Hyperthermia ◽  
Capacitively Coupled ◽  
Patient Model ◽  
Deep Target ◽  
Deep Regional Hyperthermia

Background: The purpose of this study was to evaluate the effectiveness of the clinical setting for deep regional hyperthermia of an 8 MHz radiofrequency (RF) capacitively coupled device in the pelvis by using numerical simulations of the electromagnetic field. Methods: A three-dimensional patient model of cervical cancer of the uterus in an obese patient was reconstructed with computed tomography data. The specific absorption rate (SAR) and temperature distributions among the various heating settings were evaluated using numerical simulations. Results: The averaged SAR value of the deep target tumor was similar between with or without overlay boluses (OBs), and that of the subcutaneous fat (SF) at the edges of cooling boluses with OBs was lower than that of the SF without OBs. The use of OBs reduced the overheating of the SF. The 0.5% salt solution in the OB produced the least overheated areas outside the deep target tumor compared with the other concentrations. The insertion of the intergluteal cleft (IGC) bolus could improve the temperature concentration of the deep target tumor. Conclusions: The use of OBs and the salt solution concentration in the OB were important to optimize the temperature distribution. IGC bolus might contribute to temperature optimization. Further studies with individualized numerical simulations in each patient are expected.

scholarly journals Theoretical Analysis and Design of an Innovative Coil Structure for Transcranial Magnetic Stimulation

2021 ◽  
Vol 11 (4) ◽  
pp. 1960
Author(s):  
Naming Zhang ◽  
Ziang Wang ◽  
Jinhua Shi ◽  
Shuya Ning ◽  
Yukuo Zhang ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Transcranial Magnetic Stimulation ◽  
Theoretical Analysis ◽  
Numerical Simulations ◽  
Magnetic Stimulation ◽  
Influential Factors ◽  
Intersection Angle ◽  
Electromagnetic Field Distribution ◽  
Analysis And Design ◽  
Coil Structure

Previous research showed that pulsed functional magnetic stimulation can activate brain tissue with optimum intensity and frequency. Conventional stimulation coils are always set as a figure-8 type or Helmholtz. However, the magnetic fields generated by these coils are uniform around the target, and their magnetic stimulation performance still needs improvement. In this paper, a novel type of stimulation coil is proposed to shrink the irritative zone and strengthen the stimulation intensity. Furthermore, the electromagnetic field distribution is calculated and measured. Based on numerical simulations, the proposed coil is compared to traditional coil types. Moreover, the influential factors, such as the diameter and the intersection angle, are also analyzed. It was demonstrated that the proposed coil has a better performance in comparison with the figure-8 coil. Thus, this work suggests a new way to design stimulation coils for transcranial magnetic stimulation.

scholarly journals The Effects of Red Clover Seed Treatment with Cold Plasma and Electromagnetic Field on Germination and Seedling Growth Are Dependent on Seed Color

2021 ◽  
Vol 11 (10) ◽  
pp. 4676
Author(s):  
Anatolii Ivankov ◽  
Rasa Zukiene ◽  
Zita Nauciene ◽  
Laima Degutyte-Fomins ◽  
Irina Filatova ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Cold Plasma ◽  
Trifolium Pratense ◽  
Root Nodules ◽  
Germination Rate ◽  
Red Clover ◽  
Seed Color ◽  
Seed Treatments ◽  
Capacitively Coupled ◽  
Clover Seed

This study aimed to estimate the effects of cold plasma (CP) and electromagnetic field (EMF) treatment of red clover (Trifolium pratense) seeds with different coat colors on germination kinetics, the content of seed phytohormones, and the growth of seedlings. Seeds of red clover cultivar ‘Arimaiciai’ were treated with radio-frequency EMF or capacitively coupled low-pressure CP for different durations. There were no differences in germination kinetics between yellow, brown, and dark purple seeds in control, but the germination rate of seeds treated with CP and EMF depended on seed color: The germination of yellow seeds was stimulated stronger compared to dark purple and brown seeds, and EMF did not stimulate germination in brown seeds. The content of phytohormones in control seeds and the shift in their amount induced by seed treatments were also strongly dependent on seed color. No relationship was found between the effect on germination kinetics and changes in phytohormone levels. In the control, seedlings growing from the yellow seeds were heavier, and the number of root nodules was 12.5 times larger compared to seedlings of dark purple seeds. Seed treatments with CP and EMF significantly increased the number of root nodules, and this effect was stronger in seedlings from dark purple seeds compared to those from yellow seeds.

scholarly journals The Evaluation of Oncological Hyperthermia Centers and Turkey Modeling Oncological Hyperthermia Centers and Turkey Modeling

2020 ◽  
Keyword(s):  
Cancer Patients ◽  
Cancer Diagnosis ◽  
Treatment Options ◽  
Hyperthermia Treatment ◽  
Regional Hyperthermia ◽  
Oncological Treatment ◽  
Number Of Patients ◽  
Effective Role ◽  
Deep Regional Hyperthermia ◽  
Modern Radiotherapy

Introduction and Objectives: The latest technology and current treatments are used in the treatment of cancer in Turkey; however, oncological hyperthermia devices are currently not available. This study aimed to demonstrate the necessity of oncological hyperthermia devices in Turkey where cancer treatment is performed effectively. In this direction, some important oncological hyperthermia centers have been examined to what kind of planning can be developed in this country. Materials and Methods: The data were collected regarding the number of patients who had undergone hyperthermia during the treatment of cancer and the distribution of oncological diagnoses, devices per population, and rate of hyperthermia use. Subsequently, a model was prepared for Turkey, and an evaluation was performed on the number of cancer patients that can be applied to this treatment and the need for the number of oncological hyperthermia devices. Results: According to the data obtained, an average of 375 patients are treated annually per hyperthermia device in relevant centers. When a similar projection is applied for Turkey, hyperthermia treatment can be applied to an average of 400 patients annually with 0.18 hyperthermia devices per one million population. According to this result, considering the population and the annual cancer diagnosis rates, it is predicted that 13 deep regional hyperthermia devices are required across the country. Conclusion: The presence of deep regional hyperthermia devices in comprehensive oncology centers plays an effective role in oncological treatment with modern radiotherapy devices. This condition along with the sufficient number of radiation oncologists will significantly benefit the capacity to provide oncological treatment options holistically.

scholarly journals Leapfrogging of electrical solitons in coupled nonlinear transmission lines: effect of an imperfect varactor

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Nkongho Achere Akem ◽  
Alain M. Dikandé ◽  
B. Z. Essimbi
Keyword(s):  
Harmonic Oscillator ◽  
Transmission Line ◽  
Numerical Simulations ◽  
Transmission Lines ◽  
Nonlinear Transmission Lines ◽  
Capacitively Coupled ◽  
Nonlinear Transmission ◽  
Damped Harmonic Oscillator ◽  
Initial Values ◽  
Soliton Pair

AbstractThe leapfrogging dynamics of a pair of electrical solitons is investigated, by considering two capacitively coupled nonlinear transmission lines with and without intraline resistances. We discuss two distinct transmission line set-ups: in the first, we assume two RLC ladder lines with intraline varactors and a coupling linear capacitor, and in the second, we consider two capacitively coupled lossless lines with a varactor carrying impurity (imperfect diode) in one of the two interacting transmission lines. In the first context, we find that the soliton-pair leapfrogging mimics the motion of a damped harmonic oscillator, the frequency and damping coefficient of which are obtained analytically. Numerical simulations predict leapfrogging of the soliton pair when the differences in the initial values of the amplitude and phase are reasonably small, and the resistance is not too large. In the second context, leapfrogging occurs when the impurity rate is small enough and the differences in the initial values of the amplitude as well as phase are also small. As the impurity rate increases, the soliton signal in the imperfect line gets accelerated upon approaching the defective diode, causing only this specific soliton signal to move faster than its counterpart, leading to the suppression of leapfrogging.

Evaluation of Oncological Hyperthermia Centers and Turkey Modeling Oncological Hyperthermia Centers and Turkey Modeling

2020 ◽  
Author(s):  
Fatih Goksel ◽  
Fatih Demircioglu
Keyword(s):  
Cancer Diagnosis ◽  
Treatment Options ◽  
Hyperthermia Treatment ◽  
Regional Hyperthermia ◽  
Oncological Treatment ◽  
Radiation Oncologists ◽  
The World ◽  
Effective Role ◽  
Deep Regional Hyperthermia ◽  
Modern Radiotherapy

Abstract Background Hyperthermia is a radio/chemo sensitizing method effectively used in oncological treatments. These devices, which have been used effectively in many centers around the world in the treatment of cancer, are currently unavailable in our country. In this study, hyperthermia treatments that could be applied, the number of hyperthermia devices required and the potential effects in our country have been investigated in line with the applications of hyperthermia worldwide.Methods Based on the data obtained from certain reference centers the number and ratios of hyperthermia applications were determined and the data obtained was modeled according to the number of cancer cases in our country.Results According to the data obtained, an average of 375 patients are treated annually per hyperthermia device in relevant centers. When a similar projection is applied for our country, hyperthermia treatment can be applied to an average of 400 patients annually with 0,18 hyperthermia devices per one million population. According to this, considering the population and the annual cancer diagnosis rates, it is predicted that 13 deep regional hyperthermia devices are required across the country.Conclusion The presence of deep regional hyperthermia devices in comprehensive oncology centers that play an effective role in oncological treatment with modern radiotherapy devices and have enough radiation oncologists will significantly benefit the capacity to provide oncological treatment options holistically.

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