Development and Evaluation of a Laparoscopic Induction Heater for Adjuvant Treatment of Peritoneal Cancers
Induction heating (IH) systems are widely used in domestic, industrial, and medical applications due to the advantageous characteristics they possess. These systems heat electrically conducting materials, such as those of ferromagnetic nature, by exposing them to a high-frequency alternating magnetic field (AMF). Magnetic fluid hyperthermia is an interesting application of this technology and refers to the temperature elevation of a tumor with the aid of magnetic nanoparticles (MNP) and an alternating magnetic field. MFH has the spatial resolution to limit the damage to only the cancer cells. To this day, there is no evidence of a laparoscopic induction heater used for MFH purposes in the clinical setting. Therefore, the main goal of this work was to design, develop, and characterize an induction-heating instrument for laparoscopic magnetic fluid hyperthermia applications. First, A 20-turn miniature magnetic field generator (?outer=11 mm), was built. This coil was inserted in a 34-cm long polycarbonate tube (?outer=15.9 mm), which was sealed and prepared for cold water to circulate through it to remove the heat dissipated by resistive losses. A metallic disk sample was placed in different media (air, water, gelatin), at different axial distances from the instrument, and exposed to magnetic field intensities that ranged from 3.3 to 15 kA/m at 290 kHz. Uncoated iron oxide nanoparticles at different concentrations, synthesized by an optimized co-precipitation method, were exposed to an AMF of 28.5 kA/m at 290 kHz. The disk reached temperatures as high as 430°C (in air). Temperatures recorded were higher for air than for gelatin or water, as expected. The temperatures decreased as the distance from the magnetic field generator to the sample increased. As for the nanoparticles, the highest temperature recorded was 96°C. The temperatures reached were lower as the concentration decreased. Lower concentrations still exhibited a perceptible temperature rise. The heat dissipation of the MNPs was confirmed by the negligible temperature rise of a water sample. The LIH can generate magnetic fields that are strong enough (28.5 kA/m) for IH applications. Its design and dimensions are comparable to other instruments used in laparoscopic procedures. In the realm of magnetic fluid hyperthermia (MFH), this design has the potential to treat deep-seated tumors that are unreachable by other designs.