Sonographic detection of magnetic nanoparticles for Magnetic Drug Targeting in weak echogenic tissue

The research in biomedical nanotechnology led already to a variety of applications of nanoparticles in diagnosis as well as in therapy. One of these medical applications is Magnetic Drug Targeting (MDT), a promising cancer treatment technique. The aim of this medical attendance is a local chemotherapeutic treatment of the cancerous tissue. For this purpose, chemotherapeutic drugs are bound to magnetic nanoparticles and are accumulated in the tumor area by means of an external static magnetic field. It has already been shown that magnetic nanoparticles can be used as ultrasound contrast agents, so sonographic technologies can serve as visualization technique for MDT. However, the nanoparticles are not visible directly using ultrasound imaging techniques because of their weak backscattering. Therefore, the sonographic detection of nanoparticles in biological tissue has to be attributet to sonographic detection of tissue movements, due to magnetically evoked nanoparticles. The feasibility of sonographic detection of tissue movements in turn depends on the echogenicity of the appropriate tissue considerably. Biological tissue can suffer from weak echogenicity, which handicaps the detection of nanoparticle loaded tissue. In this contribution we present a special approach for sonographic detection of magnetic nanoparticles in tissue that suffers from weak echogenicity, which is necessary for the clinical applicability.