Medical physics is commonly regarded as a new branch of medicine. The discovery of fundamental physical phenomena, such as the cathode rays, x-rays, radioactive substances, and neutrons, as well as successful applications of earlier discoveries in practical medicine, has fostered the impression that medical physics is an achievement of the twentieth century. That impression is not accurate. The science of physiology, for example, began with Harvey, who was the first to use systematic measurements in biological investigations and the first to attempt to correlate biological phenomena with physical laws. Fundamental knowledge of blood pressure depended on the development of suitable manometers. Many facts about the heart and circulation of blood could not have been learned without the microscope, string galvanometer, stethoscope, and roentgen rays. With the discovery of x-rays electronics entered the service of medicine. This discovery by Röntgen in 1895 and that of radium by the Curies in 1898, together with the subsequent evolution of medical radiology, vividly illustrate the close relationship of physics and medicine. Although recent discoveries and developments have led to an increasing recognition of physics as an essential part of the substructure of medicine, progress in biology and medicine has always been significantly related to advances in physics.1, 2, 3
Medical physics interprets living processes by physical laws; it analyzes the effects of physical agents on living tissues. Medical physics provides information concerning the physical theories and principles that apply to various medical procedures and instruments and a working knowledge of their use. Accordingly, the. . .