Improvement ability of EIT for Thermal monitoring during Thermal Therapy by gold nanoparticles

Introduction: To prevention the healthy tissues from irreversible damages, monitoring the temperature variation of healthy tissues is critical parameter during thermal therapies. Electrical impedance tomography (EIT) is considered as a real time imaging modality for monitoring the temperature but researches show that it suffers from low temperature resolution. In this study using of gold nanoparticles(GNPs) to increase the EIT signal variation due to change in temperature of tissues was studied and improvement of its temperature resolution was surveyed. Materials and Methods: Spherical GNPs with size of 20-25 nm were synthesized with Turkevich method. Size distribution and shape of these NPs was characterized by transmission electron microscopy (TEM). EI of muscle and fat tissues at different temperatures were measured and compared to their EI at presence of GNPs. Results: EI of tissues decrease (electrical conductance increase) as their temperature increase and GNPs cause to intensify this phenomenon. Increase in specific conductance of fat and muscle tissues at   360 C were   3.80´10-3 S m and 8.59´10-2 S m, respectively.  These  values were 15.1% and 13.2% for fat and muscle tissues, respectively. Conclusion: Presence of GNPs could lead to increase the variation of EIT signal intensity due to change of temperature. Therefore, considering the temperature changes followed to use of GNPs in thermal treatment is recommended.