By illustration with magnetic particles, the blood flow of a living organism has been represented in three dimensions and in real time. Researchers at the Royal Philips in Hamburg injected iron oxide nanoparticles into the blood of 18 mice and used a technique similar to magnetic resonance imaging. Magnetic resonance imaging is not suitable for observation of soft and fluid tissues, but iron oxide particles look great in the body. Adapting the new technology to use in the human body can help diagnose heart disease and cancer, as well as monitor body response to treatments.