Application of the principle of reciprocity to impedance tomography and other problems in bioelectromagnetism

Though the principle of reciprocity was invented by Hermann von Helmholtz already over 150 years ago, and though it is a very powerful tool in solving various important problems in bioelectromagnetism, it is not generally used. In impedance tomography the measurement sensitivity distribution has generally been misunderstood. This can be easily demonstrated with the principle of reciprocity. Some other applications of the principle of reciprocity are also discussed.