title: Optimization of dual slot antenna using floating metallic sleeve for microwave ablation.
abstract: Backward heating reduction is vital in power distribution optimization in microwave thermal ablation. In this study, we optimized dual slot antenna to yield reduction in backward heating pattern along the antenna shaft with the application of floating metallic sleeve. Finite element methods were used to generate the electromagnetic (EM) field and thermal distribution in liver tissue. The position of the sleeve from the tip of the probe (z = 0 mm) was varied within the range 14 ≤ z ≤ 22 mm while sleeve length was varied within 16 ≤ z ≤ 48 mm at 2 mm interval using operating frequency of 2.45 GHz. The best optimized design has reflection coefficient of -20.87 dB and axial ratio of 0.41 when the sleeve position was at 17 mm and sleeve length was 18 mm. Experimental validation shows that inclusion of a floating metallic sleeve on dual slot antenna for hepatic microwave ablation averagely increased ablation diameter and aspect ratio by 17.8% and 33.9% respectively and decreased ablation length by 11.2%. Reduction in backward heating and increase in power deposition into liver tissue could be achieved by using this antenna to provide greater efficiency and localization of specific absorption rate in delivering microwave energy for hepatic ablation.
authors: Department of Radiation Biology and Radiotherapy, College of Medicine of the University of Lagos, Lagos, Nigeria. Electronic address: azibitoye@cmul.edu.ng.
authors: Z A
authors: ZA
authors: Ibitoye
authors: Department of Biomedical Engineering, Faculty of Basic Sciences, College of Medicine of the University of Lagos, Lagos, Nigeria.
authors: E O
authors: EO
authors: Nwoye
authors: Department of Radiation Biology and Radiotherapy, College of Medicine of the University of Lagos, Lagos, Nigeria.
authors: M A
authors: MA
authors: Aweda
authors: Department of Anatomy, Faculty of Basic Sciences, College of Medicine of the University of Lagos, Lagos, Nigeria.
authors: A A
authors: AA
authors: Oremosu
authors: Department of Morbid Anatomy, Faculty of Basic Sciences, College of Medicine of the University of Lagos, Lagos, Nigeria.
authors: C C
authors: CC
authors: Annunobi
authors: Department of Anesthesia, Faculty of Clinical Sciences, College of Medicine of the University of Lagos, Lagos, Nigeria.
authors: O N
authors: ON
authors: Akanmu
mesh_terms: D055011:Ablation Techniques / Q000295:instrumentation* / Q000379:methods*; D000818:Animals; D003198:Computer Simulation; D004574:Electromagnetic Fields; D004867:Equipment Design; D020342:Finite Element Analysis; D006358:Hot Temperature; D008099:Liver / Q000528:radiation effects; D008670:Metals; D008872:Microwaves; D008962:Models, Theoretical; D055618:Radiation Equipment and Supplies
chemical_list: D008670:Metals
keywords: Axial ratio; Cancer; Dual slot; Finite element method; Metallic sleeve; Microwave ablation; Reflection coefficient