The Biophysical Basis of Ultra-Short Wave Therapy

Abstract

1. Introduction AT the present time three problems are of especial importance In regard to the medical applications of ultrashort waves: (1) dosage measurement; (2) the relation of selective heating effect to wave length; (3) the specific effects of ultra-short waves (athermic, or specific electric effect). This last problem lies mainly in the field of medical biological investigation, while the first two are entirely within the field of biophysical research, and are accordingly the subject of our present considerations. Modern ultra-short wave apparatus is serviceable and reliable and enables us to make more or less exactly reproducible applications of ultra-high frequency energy. There is, however, no reliable dosage procedure which permits, in any given case, the correct determination of the energy transferred. Especially is it difficult to measure the dosage during the actual treatment. The present practice in ultrashort wave therapy is to rely on the subjective reaction of the patient. The resulting dose can, in general, only be determined in an empirical manner. As a result of the difficulties of exact dosage determination, it has not as yet been possible to make any definite observations or to reach any conclusion regarding so-called “specific effect” of ultra-short waves, and in the present state of affairs it will continue to be impossible to do so. The idea of constructing the treatment system, on the basis of physical and physiological-anatomical considerations, in such a manner that conditions can be so predetermined that a favorable transfer of energy may be expected, leads directly to the second of the above-mentioned problems; the wave length dependence of the effects of ultra-short waves. That is, is it possible, by an appropriate selection of the wave length region, to influence the transformations of the high frequency energy in various body tissues in the desired direction? Within recent years considerable research has been done on this problem, which is of the greatest importance, both for the practical application of ultra-short waves and for any investigation into the mechanism of their biological effects. As a result of this research, there is to-day available some definite knowledge regarding the distribution of the high frequency energy, and also the mechanism of its conversion in the irradiated body. On this basis the problem is divided into two parts: on the one hand the investigation of the “external” or geometrical conditions for the supply of the high frequency energy, and on the other, the determination of the actual distribution of the high frequency energy within the body. The first part of the problem is directly concerned with such matters as size, shape, material, and arrangement of the electrodes.