Thermal Electrical Property Effects of Bone Structure on the Magnetic-Nanoparticle Enhanced Hyperthermia Targeting Tumor Underneath the Ribs

Bone has very different thermal and electrical properties with the surrounding tissues. Misjustification of the heating dosage during an electromagnetic (EM) hyperthermia may lead to the failure of the treatment. Here aiming to disclose such clinically important issue, the present study presented a theoretical evaluation on the heating effects of magnetic-nanoparticles (MNPs) enhanced hyperthermia on the liver tumor underneath the ribs with bone features particularly addressed. The results revealed the following factors: (1) The existence of bone structure, i.e., ribs has an inevitable effect on the distribution of EM field; specifically, due to its lower dielectric property, the bone structure served as a barrier to attenuate the transport of EM energy and conversion of heat into the tissues, especially the tumor in the deep body. (2) Applying higher dosage or larger size MNPs would significantly enhance the temperature elevation at the target tumor tissues and thereby guarantee the performance of the hyperthermia. (3) Further parametric studies indicated that a higher frequency EM field would result in a worse heating effect; while stronger EM field will evidently enhance the heating effects of the hyperthermia process. This study promoted the better understanding of the EM heating on the bone structured tissues, and the findings are expected to provide valuable reference for planning an accurate surgery in future clinical liver tumor EM ablation.