Optimization of E-slot Applicator for Non-Invasive Hyperthermia Breast Cancer Treatment.
| dc.contributor.author | BIBI SARPINAH BINTI SHEIKH NAIMULLAH | |
| dc.date.accessioned | 2026-07-02T08:20:37Z | |
| dc.date.issued | 2026 | |
| dc.description | Breast cancer remains one of the leading causes of cancer mortality among women worldwide. Cancer tumors often contain hypoxic cells that are less sensitive to radiotherapy and chemotherapy. Because of this resistance, hyperthermia is used as alternative option to enhance the effectiveness of cancer treatment. Non-invasive hyperthermia breast cancer treatment involves raising the temperature from 40ºC to 45ºC to denature proteins and shrink tumors while minimizing damage to surrounding healthy tissue. However, a major limitation of the hyperthermia applicator is the formation of unwanted hotspots in adjacent healthy tissue and poor electromagnetic (EM) focus on the tumor. Although various applicator structures have been studied to improve EM energy focusing, investigation on the slot applicator for breast cancer hyperthermia remains limited, particularly for the U-slot and E-slot applicators. The study aims to develop and optimize the slot applicator and identify the most effective slot design for focused breast cancer hyperthermia in the Industrial, Scientific and Medical (ISM) frequency band across multiple tumor sizes (T1, T2, and T3). This research used electromagnetic (EM) simulation in SEMCAD X to evaluate SAR distribution in a breast phantom. A comparative analysis between the U-slot and E-slot applicators was conducted. The E-slot applicator was selected based on superior performance in directivity,gain, return loss, SAR distribution and SAR (peak). Response Surface Methodology (RSM) was applied to develop second-order polynomial models relating slot design parameters to the localization SAR distribution, defined by surface and inner depths. ANOVA in Design Expert software was used to validate and optimize the E-slot parameters. The RSM-based optimization E-slot applicator was further validated with established optimization methods,namely Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). The findings showed that the optimized E-slot applicator performance significantly enhances directivity (26%: T1, 22.3%: T2, 12%: T3), gain (21%: T1, 8.7%: T2, 24.3%: T3), return loss (36%: T1, 79.8%: T2, 92%: T3) and SAR(peak) (5.6%: T1, 116.5%: T2, 43%: T3) compared to the E-slot applicator. Thus, the optimized E-slot achieved better SAR localization within the tumor and reduced the formation of unwanted hotspots. Unwanted hotspots are areas of excessive heat in surrounding healthy tissue. Less unwanted hotspots indicate reduced excessive heat absorption in healthy tissue. Additionally, it demonstrated a shorter treatment period. | |
| dc.identifier.uri | https://scholarhub.unimas.my/handle/123456789/1060 | |
| dc.language.iso | English | |
| dc.publisher | Universiti Malaysia Sarawak | |
| dc.relation.ispartofseries | Faculty of Engineering | |
| dc.subject | Hyperthermia, E-slot applicator, Inner depth, Surface depth, Specific Absorption Rate (SAR), tumor | |
| dc.title | Optimization of E-slot Applicator for Non-Invasive Hyperthermia Breast Cancer Treatment. | |
| dc.type | PhD |