The Evolution of Radiography

Medical imaging is the eye of medicine. There has been many developments ever since the father of radiography who was a German physicist Wilhelm Roentgen discovered x-rays while experimenting with beams of electrons inside a vacuum tube In November 1895.

Fluoroscopy is a technique for obtaining real-time moving images of an object's inside using X-rays. The fluoroscope was invented by Thomas Alva Edison in 1896, just one year after Wilhelm Conrad Rontgen discovered X rays. The fluoroscope's main purpose is to produce images of the human body's internal structures and fluids. The radiologist doing the procedure sees a continuous image of the interior structures' movements during fluoroscopy. A fluoroscope's principal application in medical imaging is to let a physician to see a patient's internal structure and function, such as the heart's pumping movement or swallowing motion, for example. This is used in general radiology, interventional radiology, and image-guided surgery for both diagnosis and therapy. A fluoroscope is made up of an X-ray source and a fluorescent screen, between which a patient is positioned. Most fluoroscopes, however, have integrated X-ray image intensifiers and cameras since the 1950s to improve image visibility and make it available on a remote display screen. For many decades, fluoroscopy tended to produce live, unrecorded images, but since the 1960s, this has changed.

Not long after Wilhelm Roentgen discovery of x-rays, Marie Curie also discovery of radioactivity with her husband Pierre Curie and Henri Becquerel. Though Becquerel was the one who discovered radioactivity, it was Marie Curie who coined the word. When she won the Nobel Prize for the discovery of Polonium and Radium in 1911, she became the first woman to win the prize and the first person to earn two Nobel Prizes.

In 1971, electrical engineers Hounsfield and Cormack co-invented the X-ray computed tomography (CT) scan. The CT scan, which employs a combination of X-rays and computer software to make images of specific parts of the body, is significant in radiology history. The brain, lungs, heart, and other internal organs can be imaged in detail using a CT scan.

In the 1930’s, a physics phenomenon was discovered, called nuclear magnetic resonance or NMR. Felix Bloch, working at Stanford University, and Edward Purcell, from Harvard University, discovered NMR. In NMR nuclei were placed in a magnetic field, they absorbed energy in the radiofrequency range of the electromagnetic spectrum, and re-emitted this energy when the nuclei transferred to their original state. This phenomenon was termed NMR as follows: "Nuclear" as only the nuclei of certain atoms reacted in that way;” Magnetic" as a magnetic field was required "Resonance" because of the direct frequency dependence of the magnetic and radiofrequency fields.

For their discovery of NMR Bloch and Purcell were awarded the Nobel Prize for Physics in 1952.Use of NMR to investigate the chemical composition and physical structure of matter. Relaxation times, T1 and T2.

T1:Time taken by nuclei in test samples to return to their natural alignment T2: Duration of the magnetic signal from the sample. In 1970s Raymond Damadian, proposed that each tissue in the body has a different relaxation time, but cancerous tissue has an abnormally long relaxation time. He believed that the NMR could be used as an “external probe for the internal detection of cancer” Damadian presented first commercial NMR scanner at the annual meeting of the American Roentgen Ray Society in 1980. Paul C. Lauterbur determined the origin of the radio waves by analysis of their characteristics. Discovered the possibility to create a two-dimensional picture by introducing gradients in the magnetic field. In 1972, obtained the first MRI. Pater Mansfield further developed the utilization of gradients in the magnetic field. Signals could be mathematically analyzed. Showed how extremely fast imaging could be achievable. In 1976, he and his colleagues created the first MRI of a human body part, a finger.

References

1. http://www.edubilla.com/invention/fluoroscopy.
2. https://www.thoughtco.com/magnetic-resonance-imaging-mri-1992133.
3. https://uk.mysearchexperts.com/web?o=1470367.
4. https://www.sciencefocus.com/science/who-really-invented-the-mri-machine/

By Emmanuel Ampofo

Intern Radiographer at 37 Military Hospital

Telephone 0240054881

Email: [email protected]