What most people aren’t aware of is the fact that behind X rays’ power lay a principle of physics that eventually helped researchers see things that were infinitesimally small. According to this principle, a given form of radiation cannot be used to distinguish anything smaller than half its own wavelength; therefore, the shorter the wavelength, the smaller the object that can be imaged.
Beginning in the 1930s, scientific manufacturing efforts to improve the traditional microscopes’ magnifying power, up to 5,000 times for the best optical instruments came to fruition as several researchers across the globe began to use streams of electrons to illuminate surfaces.
Electron microscopes, as they were called, could reveal details many times smaller than visible light could because the wavelengths of the electron beams were up to 100,000 times shorter than the wavelengths of visible light.
With continuing improvements over the years that included the ability to scan across a surface or even probe to reveal subsurface details, electron microscopes ultimately achieved magnifications of up to two million times. This could be compared to the equivalent of enlarging a quarter to the size of a large city.
According to xraytechnicianeducation.com, scientists can see things right down to the level of individual atoms on a specimens surface. A related form of imaging that relied directly on X rays played a role in one of the greatest discoveries of the century. In the 1950s James Watson and Francis Crick benefited from a technique called x-ray crystallography, which records the diffraction patterns created when X rays are beamed through crystallized materials.
The work of many scientists paved the way for the exploration of DNA. Way back in 1868, almost a century before the Nobel Prize was awarded to Watson, Crick and Wilkins, a young Swiss physician named Friedrich Miescher, isolated something no one had ever seen before from the nuclei of cells. He called the compound “nuclein.” This is today called nucleic acid, the “NA” in DNA (deoxyribo-nucleic-acid) and RNA (ribo-nucleic-acid).
Watson, Crick and Wilkins less well known colleague Rosalind Franklin, used x-ray crystallography to take images of DNA, and the diffraction patterns helped them determine that the DNA molecule forms a double helix, an insight that led Watson and Crick to identify DNA as the carrier of the genetic code. But the chief use of X rays continued to be as a diagnostic tool in medicine, where they were soon joined by other exciting new imaging techniques.
A few years after Watson and Crick’s seminal discovery, an American electrical engineer named Hal Anger developed a camera that could record gamma rays, electromagnetic waves of even higher frequency than X rays emitted by radioactive isotopes.
By injecting small amounts of these isotopes into the body, radiologists were able to locate areas in the body where the isotopes were taken up. Known as the scintillation camera, or sometimes simply the Anger camera, the device evolved into use in several of modern medicine’s most valuable imaging tools, including positron emission tomography or PET scanning.
X-ray imaging continued to evolve as well. In the 1970s medical engineers added computers to the equation, developing the technique known as computerized axial tomography or CAT scans, in which multiple cross-sectional x-ray views are combined by a computer to create three-dimensional images of the body’s internal structures.