The concept of ferrofluid preheating in the treatment of cancer by magnetic hyperthermia of tissues.

The frequency dependence of the complex magnetic susceptibility, χ(ω) = χ'(ω) - i χ″(ω), of a water-based magnetic fluid with magnetite particles, over the frequency range 500 kHz to 2 MHz and at three different temperatures of 30 °C, 40 °C and 50 °C are presented. Based on these experimental measurements, the dependence on frequency, f = (ω/2π) Hz, of the heating rate, ΔT/Δt, of the ferrofluid has been evaluated at these stated temperatures and alternating magnetic field of different amplitudes, Ho = 200 A/m, 400 A/m, 600 A/m, 800 A/m and 1 kA/m. The results show that the preheating of the ferrofluid sample at the desired operating temperature has the advantage of using lower levels of H0 during over a shorter time period, as opposed to the case of an unheated sample. This concept of preheating a sample, has major significance for the treatment of cancer by magnetic hyperthermia in that the patient is subjected to lower values of H0 , over the time period of the treatment.