Techniques for heating brain tumors with implanted microwave antennas

A technique is described in which microwave antennas are inserted into an array of nylon catheters implanted in brain tumors and a localized heat treatment is applied to raise the tumor to 43 degrees C. Flexible antennas of various designs have been used, such as dipole, choke dipole, modified dipole, and helical designs. Phase shifting and phase rotation techniques have been incorporated into the treatment system to steer power in the tumor, as predicted by computer modeling. Choke antennas counter the sensitivity of dipole antennas to insertion length. Clinical results with the different antenna designs are discussed.<>