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

The frequency dependence of the complex magnetic susceptibility, chi(omega) = chi'(omega) - i chi ''(omega), 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 degrees C, 40 degrees C and 50 degrees C are presented. Based on these experimental measurements, the dependence on frequency, f = (omega/2 pi) Hz, of the heating rate, Delta T/Delta t, of the ferrofluid has been evaluated at these stated temperatures and alternating magnetic field of different amplitudes, H-0 = 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 H-0 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 H-0, over the time period of the treatment.