Application of novel metal nanoparticles as optical/thermal agents in optical mammography and hyperthermic treatment for breast cancer.

Low heat (42-45 degrees C) hyperthermia is an effective cancer therapy with few side effects. Well engineered nanoparticles can effectively guide heat to the tumor without damaging the normal tissue. When nano-sized particles are injected to an organ with a tumor, they tend to accumulate in the tumor due to the unorganized nature of its vasculature. Magnetic nanoparticles, such as Fe3O4, are heated by a well selected alternating electromagnetic frequency. At a frequency of 450 KHz or lower, Fe3O4 nanoparticles at a size of 10-30 nm were heated effectively, without heating tissue main components. Gold nanoparticles are known as strong near infrared (NIR) absorbers. Nanogold particles at a diameter of 150 nm were added at 0.01 wt% to the tumor model, placed at depths of 1-2.5 cm, in an optically equivalent experimental breast model. Then the surface of the breast model was scanned with NIR light at 788 nm. The particles in the tumor model increased the optical contrast of the tumor by 1-3.5 dB. Considering that some of the FDA approved MRI contrast agents are made of Fe3O4, gold-coated Fe3O4 particles have a potential to be used as safe optical and thermal markers, allowing seamless breast cancer detection and cancer-specific hyperthermic treatment.