Abstract
Thermal ablation has been widely explored and may become a promising treatment against cancer. Especially, electromagnetic-based thermotherapy has been extensively investigated for a variety of medical applications in recent years. Briefly, it applies a high-frequency alternating electromagnetic field to heat up nano-particles, seeds, or needles made of magnetic materials which are injected or inserted into the target organs to locally ablate tissues. In this work, two promising applications including internal medicine and surgery for an electromagnetic thermotherapy system have been demonstrated. In internal medicine, a prototype synchronized electromagnetic thermotherapy system equipped with a new coil design and a two-section needle was reported in this study. It could generate an effective alternating electromagnetic field with a deep penetration depth to heat up the needle placed up to 40 cm away from the coils such that a minimally invasive surgery becomes feasible. Several important parameters of the synchronized electromagnetic thermotherapy system, including the heating effect of the needle at different positions, the intensity of the electromagnetic field and the temperature distributions on the tissue around the needle, were first explored. An in-vitro animal experiment was also performed. It showed that the porcine liver could be successfully ablated by the needles array under the long-distance alternating electromagnetic field which effectively penetrated 40 cm deep and the ablation area was measured about 3 cm X 3 cm. Then in-vivo experiments on New Zealand white rabbits and Lan-Yu pigs were also conducted in the study. Experimental results showed that the two-section needle arrays combined with the electromagnetic thermotherapy system could be promising for minimally invasive surgery. In surgery, a new configuration of two-row needle arrays under an electromagnetic thermotherapy system with a temperature feedback control system was demonstrated. With this approach, tissue and tumor could be bloodlessly resected in large animals and humans. The survival rate in the clinical trials achieved 100%, and the blood loss was lower than 20 ml. The developed system may be promising for cancer therapy in the near future.