  This study investigates the treatment of brain cancer by the magnetic
hyperthermia approach and nanoparticles including Fe_3 O_4 core with gold,
silver alloy shell, and MoS_2 coating. Optical properties of these
nanoparticles within the tumor, including the extinction coefficient and
surface plasmon peak (SPR) as a function of size, structure, different
compositions, and thickness are also investigated using the effective medium
theory. Moreover, the impact of temperature distribution was assessed through
the analytical modeling of alternating current (AC) magnetic field. The results
of this study indicated that nanoparticles with a compound of Fe_3 O_4 -
Au_0.25 Ag_0.75@MoS_2 and a thickness of 3 nm of gold-silver alloy and 3 layers
of MoS_2 have the best coefficient of extinction and SPR in the biological
window. The gold-silver alloy improved the extinction coefficient and, at the
same time, prevented the accumulation of magnetic nanoparticles. Since the
gold-silver alloy alone cannot function within the range of biological windows,
MoS_2 was used, which increased the extinction efficiency at higher
wavelengths. Examination of the temperature distribution in the tumor for the
proposed alloy compound indicated that after a short time from the start of
irradiation, the tumor temperature reaches 45 C degree. Also, the temperature
distribution within the tumor tissue reached its maximum value at the center of
the tumor and decreased dramatically as getting away from the center. The use
of magnetic hyperthermia enabled localized delivery of therapeutic dose to
malignant brain tumors; hence, exhibiting superior performance/efficiency over
the photothermal method.
