Cancer therapy using magnetic beads. Sentinel lymph node mapping and MRI contrast enhancement

Using magnetic beads we are developing novel technique for mapping sentinel lymph nodes (SLN's, the first lymph nodes that filter the fluid draining away from the tumor) by the so-called 'sonic-wave emission by magnetically-stimulated particles (SEMP)' which we discovered recently. The SLN's are resected for pathological testing to determine the stage of metastasis of the cancer (especially of breast). If no metastasis is found then resection of the downstream lymph nodes is avoided. We successfully performed mapping false SLN's (containing ferrite beads and embedded in a gel phantom at. 10 mm depth) by SEMP. Applying an ac magnetic field of 900 kHz, second harmonic sonic waves (1800 Hz) were detected by a microphone. We are also developing highly efficient MRI contrast agent of ferrite beads (4 nm) to identify small cancer tumors by T1 weighted positive imaging. (author)