The use of heat to treat cancer has been applied to the
whole body and to parts of the body using a variety of modalities, including
microwave arrays, focused ultrasound, and radio frequency ablation wires with varying degrees of success. However, whether using ablative treatments at temperatures
higher than about 50 °C for a few minutes or hyperthermic treatments in the
temperature range of 39 to 45 °C for longer periods,
thermal therapy of tumors is limited by toxicity towards healthy tissues. Heat is a rather nonspecific mechanism
for cell killing, with potential toxicity concerns similar to other treatment
modalities, and thus can similarly benefit by targeting its effects to tumors.
The challenge is to more precisely pinpoint
temperature rise to tumors and tumor-associated structures, e.g. tumor
vasculature, tumor cells, and sub-cellular structures such as membranes and the
nuclear matrix. We pinpoint temperature rise to diseased tissues using nanoscopic heating elements. Unusually high heating rates can be achieved by using high
amplitude fields to power proprietary magnetic nanoparticles. These nanoparticles can be energized remotely through
externally applied energy: when placed in an alternating magnetic field (AMF)
the nanoparticles are capable of generating heat in the tumor. AMF heating of tissues containing
nanoparticles is attractive in part because magnetic fields in useful frequency
ranges can penetrate the body deeply and are not attenuated by tissue nor are
they reflected by boundaries between tissues. The nanoparticles that Aspen MediSys is developing act as cellular ablation
devices that operate at a size scale typical for drug delivery vehicles.
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