Tissue-mimicking phantom is a biological tissue replacement which has been used as a replacement to understand the relationship between the electromagnetic and the human body. However, many of the developed phantoms are produced for several MHz to several GHz region, and less in the kHz region. This research introduces a new phantom to understand the electromagnetic effect at kHz region. The phantom is a 500 kHz phantom which mimics human muscle dielectric properties. The dielectric properties of the phantom are adjusted by aluminum powder content, which is 40% of the total phantoms content. In this research, we use different phantom dielectric properties measurement method compared to the one at higher frequencies. Furthermore, the phantom thermal properties and density are measured to be used in numerical calculations.
Transcatheter renal denervation (RDN) is a novel treatment to reduce blood pressure in patients with resistant hypertension using an energy-based catheter, mostly radio frequency (RF) current, by eliminating renal sympathetic nerve. However, several inconsistent RDN treatments were reported, mainly due to RF current narrow heating area, and the inability to confirm a successful nerve ablation in a deep area. We proposed microwave energy as an alternative for creating a wider ablation area. However, confirming a successful ablation is still a problem. In this paper, we designed a prediction method for deep renal nerve ablation sites using hybrid numerical calculation-driven machine learning (ML) in combination with a microwave catheter. This work is a first-step investigation to check the hybrid ML prediction capability in a real-world situation. A catheter with a single-slot coaxial antenna at 2.45 GHz with a balloon catheter, combined with a thin thermometer probe on the balloon surface, is proposed. Lumen temperature measured by the probe is used as an ML input to predict the temperature rise at the ablation site. Heating experiments using 6 and 8 mm hole phantom with a 41.3 W excited power, and 8 mm with 36.4 W excited power, were done eight times each to check the feasibility and accuracy of the ML algorithm. In addition, the temperature on the ablation site is measured for reference. Prediction by ML algorithm agrees well with the reference, with a maximum difference of 6 • C and 3 • C in 6 and 8 mm (both power), respectively. Overall, the proposed ML algorithm is capable of predicting the ablation site temperature rise with high accuracy.
Cancer is the third leading cause of mortality in the world and is one of the most difficult diseases to detect and cure. This fact motivates us to investigate a treatment method by using radiofrequency (RF) ablation. RF ablation therapy kills cancer cells by electromagnetically heating them up. The treatment uses an applicator that is inserted into the body to heat the cells. The cancer cells are exposed to a temperature of more than 60 °C in short duration (a few seconds to a few minutes), thereby causing cell destruction locally. To ensure effective treatment, a minimally invasive method is selected so that good local temperature distribution inside the cancer cells can be achieved. In this paper, a coax-fed dipole-type applicator is proposed for interstitial irradiation technique in hepatic cell treatment. The applicator design is conducted by simulation in CST Microwave Studio to obtain an appropriate size at operating frequency of 2.45 GHz. We also consider localizing the ablation area by designing the tip of the applicator such that the main electromagnetic radiation locally exists around it. The proposed applicator is inserted into a simple phantom model of an adult human body with normal and cancerous liver cells. Both simulation and measured results show that the proposed applicator is able to operate at center frequency of 2.45 GHz in a blood droplet-type ablation zone. A temperature of 60 °C around the cancer cell can be achieved by simulation. Moreover, a square four-array applicator is analyzed to increase the ablation zone for a larger tumor cell. The simulation results show that a reasonably wider local ablation area can be achieved. Abstrak Aplikator Dipole Catu Koaksial untuk RF Ablation pada Kanker Hati. Sekarang ini, kanker merupakan penyebab kematian utama nomor tiga di dunia. Kanker menjadi masalah kesehatan yang serius dimana sangat sulit untuk dideteksi dan diobati. Oleh karena itu kami melakukan studi metode pengobatan sel kanker menggunakan metode RF ablation. Terapi RF ablation merupakan metode membunuh kanker dengan cara pemanasan sel kanker secara elektromagnetik. Pengobatan ini menggunakan aplikator yang dimasukkan ke dalam tubuh agar dapat memanaskan sel kanker. Sel kanker dikenai suhu lebih dari 60 derajat Celsius dalam waktu yang singkat sehingga terjadi kerusakan sel kanker secara lokal. Untuk mendapatkan teknik pengobatan yang baik, kami memilih metode invasif secara minimal sehingga tercapai distribusi yang optimal di dalam sel kanker. Pada makalah ini, sebuah aplikator dipole catu koaksial diusulkan dengan teknik radiasi secara interstisial (injeksi) untuk pengobatan kanker hati. Aplikator dirancang secara simulasi dengan CST Microwave Studio untuk mendapatkan dimensi yang cocok di frekuensi kerja 2,45 GHz. Area ablasi juga dipertimbangkan dalam rancangan dimana radiasi elektromagnetik dapat terjadi di sekitar ujung aplikator secara lokal. Aplikator yang diusulkan dimasukkan ke model phantom sederhana yang merepresentasikan tubuh manusia sel normal dan sel kanker. Baik hasil s...
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