History of Radiology

Many of of us have ungone some form of X-ray over our life-time. When you enter the Military, a new job physical or just an annual check up with your private physician, you encounter the world of Radiology. Along with the routine blood, urine and EKG exams, you possibly have had a chest X-ray. I bet you even had to endure dental X-rays, to check on the possible abcess or other manifestation with your teeth.

Regardless of the reason for having X-rays, you may not be that familiar with the origin or person who actually discovered X-rays. Radiology officially began in November 1895, by Wilhelm Conrad Roentgen, a German Physist. In fact, experiments prior to Roentgen's discovery, took place as early as 1785 by a Welsh mathematician William Morgan, who actually made the first steps during the 1850's.

Roentgen was credited with his presentations to the scientific community. WIthin a year of Roentgen's work, 1000 scientific papers were published regarding X-rays. Not only did people have interest in diagnostic uses, but using X-ray as a method of therapeutic treament was activily explored. In fact, JAMA carried an article in 1896, discussing the theories of therapeutic x-ray use.

As in any earlier explorations of a new method of treatment, there were unfortunate harmful results and death. The early x-ray tubes (cathode rays), lacked the protection needed and the standards for exposure were had not been established. In the early applications of x-ray use, the operators used their own hands to test the apparatus. Protection measures were gradually introduced after 1903 and professional associations for operators were formed to provide training.

Basic principles of X-rays have not changed significantly since its discovery in 1895. Current is applied to a metal cathode, producing free electrons. X-rays are produced when electrons, that are moving at a high speed, are suddenly stopped as they s trike a metal target of the gas tube. In 1913, William David Coolidge, a GE researcher, developed a new X-ray tube , that could produce x-rays with consistent exposure and quality from the older tubes. Coolidge improved the filament in light bulbs, and his work with tungsten filament was a major player in the development of today's X-ray tubes.

The physics of X-rays may seem complex to you, but perhaps the following will help to de-mystify the process.
X-rays with a wavelength approximately longer than 0.1 nm are called soft X-rays. At wavelengths shorter than this, they are called hard X-rays. Hard X-rays overlap the range of long-wavelength (low energy) gamma rays, however the distinction between the two terms depends on the source of the radiation, not its wavelength: X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei.

PHOTON or light is the QUANTUM or amount of electromagnetic field (composed of two vector fields: the electric and the magnetic field..... imagined encompassing all of space (or local, relative area).
Light, when referenced in this instance, is electromagnet radiation with a wavelength that is visible to the eye, visible light, or technically / scientifically, electronmagnetic radiation of any wavelength.

The photographic plate or film with holder, frequently used method of use. The X-rays blacken the photographic plate or negative, it is black where X-rays go through "SOFT TISSUE" parts of the body, such as skin and organs, and the white areas where the X-rays are stopped are the "HARD or Boney areas". When contrast products such as Iodine are injected into the body the areas picking up the contrast are identified as white.

Atomic Nuclei are composite particles made up of protons and neutrons. These two particles are collectivly known as nuceous.

* I feel this is enough of a description at this time. I do not wish to over extend you on the subject.

In time, I hope to introduce you to the various elements of Radiology that we know today, and how they have been developed.