Coax-Fed Dipole-Type Applicator for Hepatic Cancer RF Ablation

Authors

Basari Basari, Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, IndonesiaFollow
Aditya Rakhmadi, Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba, Japan 263-8522
Kazuyuki Saito, Center for Frontier Medical Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba, Japan 263-8522

Abstract

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.

Bahasa Abstract

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 simulasi dan pengukuran menunjukkan bahwa aplikator yang diusulkan dapat beroperasi di frekuensi tengah 2,45 GHz dengan zona ablasi berbentuk tetes darah. Suhu di sekitar sel kanker dapat mencapai lebih dari 60 derajat Celsius berdasarkan hasil simulasi. Selain itu, untuk memperluas zona ablasi terhadap sel tumor target, sebuah aplikator empat-susun bentuk bujur sangkar diusulkan untuk dianalisis. Hasil-hasil simulasi menunjukkan luas zona ablasi yang lebih lebar.

References

M. Cavagnaro, C. Amabile, P. Bernardi, S. Pisa, N. Tosoratti, “A Minimally Invasive Antenna for Microwave Ablation Therapies: Design, Performances, and Experimental Assessment,” IEEE Transactions on Biomedical Engineering, vol. 58, no. 4, pp. 949-959, Apr. 2011.

L. Hamada, K. Saito, H. Yoshimura, and K. Ito, “Dielectric-loaded coaxial-slot antenna for interstitial microwave hyperthermia: longitudinal control of heating patterns,” Int. J. Hyperthermia, vol. 16, no. 3, pp. 219- 229, 2000.

H. Luyen, F. Gao, S.C. Hagness, and N. Behdad,, “Microwave Ablation at 10.0 GHz Achieves Comparable Ablation Zones to 1.9 GHz in Ex Vivo Bovine Liver. IEEE Trans. on Biomedical Engineering, pp. 1702-1710, June 2014.

B.T., McWilliams, E.E. Schnel, S. Curto, T.M., Fahrbach, and P. Prakash, ”A Directional Interstitial Antenna for Microwave Tissue Ablation: Theoretical and Experimental Investigation,” IEEE Trans. on Biomedical Engineering, vol. 62, no. 9, pp. 2144-2150, Sep. 2015 .

J.G. Webster, J.M. Bertram, D. Yang, M.C. Converse, and D.M. Mahvi, “Antenna Design for Microwave Hepatic Ablation Using an Axisymmetric Electromagnetic Model,” BioMedical Engineering On Line, 2006.

C.L. Brace, P.F. Laeseke, and D.W. van derWeide. Microwave Ablation with a Triaxial Antenna: Results in Ex Vivo Bovine Liver. IEEE Trans. Microwave Theory and Technique, vol. 53, no. 1, pp. 215-220, Jan. 2005.

G. Longo, B. Gentili, M. Cerretelli, and N. Tosoratti, “A Coaxial Antenna with Miniaturized Choke for Minimally Invasive Interstitial Heating,” IEEE Trans. on Biomedical Engineering, vol. 50, no. 1, pp. 82-88, Jan. 2003.

J.C. Lin and Y. Wang, “The Cap-Choke Catheter Antenna for Microwave Ablation Treatment,” IEEE Trans. on Biomedical Engineering, vol. 48, no. 6, pp. 657-660, Jun. 1996.

A.P. Rourke, M. Lazebnik, and J.M. Bertram, “Dielectric properties of human normal, malignant and cirrhotic liver tissue: in vivo and ex vivo measurements from 0.5 to 20 GHz using a precision open-ended coaxial probe,” Physics in Medicine and Biology, pp. 4707-4719, 2007.

International Commission on Non-Ionizing Radiation Protection (ICNIRP), “Guidelines For Limiting Exposure to the Time-Varying Electric, Magnetic and Electromagnetic Fields (up to 300 GHz),” 1998.

Recommended Citation

Basari, Basari; Rakhmadi, Aditya; and Saito, Kazuyuki (2018) "Coax-Fed Dipole-Type Applicator for Hepatic Cancer RF Ablation," Makara Journal of Technology: Vol. 22: Iss. 1, Article 7.
DOI: 10.7454/mst.v22i1.3382
Available at: https://scholarhub.ui.ac.id/mjt/vol22/iss1/7