Radiology: A Historical Perspective PDF

Radiology: A Historical Perspective Dr. Chona DL. Cabatay  Learning Objectives: Upon completion of this lecture, students will be able to: 1. List the pioneers in radiology and describe their contributions to the field. 2. Describe the events leading to the discovery of x-...

Radiology: A Historical Perspective Dr. Chona DL. Cabatay  Learning Objectives: Upon completion of this lecture, students will be able to: 1. List the pioneers in radiology and describe their contributions to the field. 2. Describe the events leading to the discovery of x-rays. 3. Give a short history of Wilhelm Conrad Roentgen. 4. Describe the works of Marie and Pierre Curie in radioactivity. 5. List the events leading to the development of nuclear medicine. 6. Describe the modern radiology department, including equipment, specialized tasks, and staff development through continuing education.  The Pioneers of Radiology The work of the early scientists and craftworkers made possible the production of x-rays. More, recently, three specific aspects of science helped paved the way to the discovery of x-rays: Electricity Vacuums Image recording material  Evangelista Torricelli – produced the first recognized vacuum when he invented a barometer in 1643. Otto van Guericke – invented an air pump that was capable of removing air from a vessel or tube. Robert Boyle – repeated the experiment of Otto van Guericke in 1659 and Herman Sprengel in 1865. Their techniques considerably improved the amount of evacuation, thus making better vacuum tubes available for further experimentation bu other scientists. William Gilbert of England was one of the first men to extensively study electricity and magnetism. He was also noted for inventing a primitive electroscope.  From the 17th century on, the main interest of scientists seemed to be experimentation with electricity. Robert Boyle’s experiments with electricity merit him a place among the serious investigators. Most investigators had to build their own equipment. Isaac Newton built and improved the static generators. Charles DuFay, working with glass, silk, and paper, distinguished two different kinds of electricity. Abbe Jean Nollet made a significant improvement in the electroscope, a vessel for discharging electricity under vacuum conditions. The electroscope was a forerunner of the x-ray tube itself.  William Watson demonstrated a current of electricity by transmitting electricity from a Leyden jar through wires and a vacuum tube with electrical discharges, William Morgan noticed the coloration and the difference in color of partially evacuated tubes. He noted that, when a tube cracked and some air leaked in, the amount of air in the tube determined the coloration. In 1831, Michael Faraday induced an electric current by moving a magnet in and out of a coil. From this experiment evolved the concept of electromagnetic induction, which lead to the production of better generators and transformers and higher voltages for use of evacuated tubes. John Wilhelm Hittorf conducted several experiments with cathode rays, streams of electrons emitted from the  William Crookes furthered the study of cathode rays and demonstrated that matter was emitted from the cathode with enough energy to rotate a wheel placed within the tube. Hittorf’ss work were repeated and further developed by Crookes. Philipp Lenard furthered the investigation of the cathode rays. He found that cathode rays could penetrate thin metals and would project a few centimeters onto the air. Lenard did a tremendous amount of research with cathode rays and determined their energies by measuring he amount of penetration. He also studied deflection of rays due to magnetic fields. William Goodspeed produced a radiograph in 1890. His achievement was recognized only in retrospect after the discovery of x-ray by Roentgen and Goodspeed was not  The image-recording materials, or photographic recording techniques, were very important to the investigators of the cathode rays. The first photographic copy of written materials was produced by J.H. Scholtz in 1727. The technique was tested further and greatly improved in later years. In 1871, R.L. Maddox produced a film with a geleatin silver bromide emulsion that has remained the basic component for film. In 1884, George Eastman produced and patented roll paper film. With this significant improvement of image- recording material and the cathode rays experiments, the basis for modern day radiography was established. Wilhelm Conrad Roentgen  Was born on March 27, 1845 in Lennep, Germany, a small town near the Rhine River. He was the only child of Friedrich Conrad Roentgen, a textile merchant whose ancestors had lived in or near Lennep for several generations. In 1872, Wilhelm Roentgen married Bertha Ludwig. In 1888, Roentgen received an offer from the University of Wurzburg, which he readily accepted, knowing if its new physics institute with very good facilities. Roentgen was elected rector at the university, although he continued to work in the physics department as well as on his personal research projects. Roentgen became interested in the cathode rays experiments with the Crookes tube, which he worked with until he discovered x- rays.  Discovery of x-rays On November 8, 1895, Roentgen discovered x-rays while working in his modest laboratory at the university. While operating a Crookes tube at high voltage in a darkened room, Roentgen noticed a piece of barium platinocyanide paper on a bench several feet from the Crookes tube. He noticed a glowing or fluorescence of the barium platinocyanide after he passed a current through the tube for only a short period. Knowing the parameters of this particular experiment, Roentgen realized that the fluorescence was some kind of ray, rather than light or electricity, escaping the Crookes tube.  Roentgen proved that by continuously producing the fluorescent effect of the barium platinocyanide he had produced some type of x-ray (x being a mathematical symbol for an unknown quantity). By performing several more tests of the mysterious rays, Roentgen determined that the x-rays had a degree of penetrative power dependent on the density of material. On 28 December 1895, Roentgen submitted a report entitled On a New Kind of Rays to the Wurzburg Physico-Medical Society.  Roentgen realized there could be potential medical use for this new kind of rays. Putting this thought to action, Roentgen discovered that by placing his hand between the tube and a piece of cardboard coated with barium platinocyanide he could actually visualize the bones of his hand, thus demonstrating the primitive fluoroscopic screen.  Roentgen realized there could be potential medical use for this new kind of rays. Putting this thought to action, Roentgen discovered that by placing his hand between the tube and a piece of cardboard coated with barium platinocyanide he could actually visualize the bones of his hand, thus demonstrating the primitive fluoroscopic screen. Roentgen knew he had discovered something that could revolutionize the world of science, but he did not know whether his observations were correct.  This prompted him to further test the cathode rays so that he could prove the validity of his previous experiments. After several work was, in fact , valid. He tried another experiment in which he convinced his wife to place her hand on a cassette loaded with photographic plate upon which he directed the x-rays from the tube for approximately 15 minutes. Development of the plate proved again that Roentgen’s experiments were successful. The bones in his wife’s hand, as well as the two rings on her finger, were clearly visible. Roentgen continued studying the effects of x-rays and presented his notes to the different societies.  In addition to many other awards and honors, Roentgen received the First Nobel prize in Physics in 1901 in Stockholm. In 1902, Roentgen received an invitation from Carnegie Institute in Washington, D.C., to use its laboratory for special experiments, but he did not accept the invitation. On 10 February 1923, Roentgen died in Munich. Marie and Pierre Curie in radioactivity  Marie Curie is remembered for her discovery of radium and polonium, and her huge contribution to finding treatments for cancer. One hundred years ago, Marie Skłodowska-Curie was using her scientific knowhow to organize fleets of radiology cars to carry portable X-ray equipment to wounded soldiers on the front line during World War I. She was a double Nobel Prize winner and one of only 48 women ever to win a Nobel Prize. She opened new fields in medicine, engineering and science. But her legacy was amplified by her activities as a humanitarian, an ambassador for science, and, not  Skłodowska-Curie and her husband, Pierre Curie, were fascinated by uranium salts which had been shown by their contemporary, Henri Becquerel, to naturally emit X- rays. Pierre had invented instruments that could measure radiation and with these the Curies demonstrated that, no matter what form the uranium was in, it continued to radiate with an intensity proportional to the amount of uranium in the sample. This convinced them that the radiation was coming not from any peripheral chemistry arising from molecular interactions but from deep within the atom – a startling idea because the atom was supposed to be the basic, indestructible building block of any element.  The Curies shared the 1903 Nobel Prize in Physics with Becquerel. And Skłodowska- Curie won the Nobel Prize in Chemistry in 1911 for the discovery of radium and polonium and the isolation of radium, which provided science with a method for isolating and purifying radioactive isotopes.  Nuclear Radiology Continuous improvements of x-ray equipment brought about severalin 1942. other studies in radiology. In 1932, Ernest Lawrence invented the cyclotron, a chamber that made possible to accelerate particles to high speeds for use as projectiles. The cyclotron forst made radioisotopes available in large quantities. Enrico Fermi made a significant breakthrough when he induced a successful chain reaction in a uranium pile at University of Chicago  The results of this breakthrough were first demonstrated when atomic devices were detonated experimentally in 1945 at White Sands, New Mexico. Shortly, thereafter, these devices were introduced as weapons whrn atomic bombs were dropped on the cities of Hiroshima and Nagasaki. Ironically, from the same basic research that ushered in the age of nuclear arms emerged the highly beneficial medical applications of radiosiotopes.  Modern Radiology The technical advances in radiology since Roentgen’s discovery of x-rays in 1895 have been overwhelming. Today’s imaging department consists of an impressive array of diagnostic and therapeutic devices. Many specialties have emerged, including CT scanning, nuclear medicine, radiation therapy, ultrasound, neurovascular radiology, digital vascular imaging for intravenous angiography, and of course, routine diagnostic radiography.  The equipment advances in contemporary radiology departments is made with extreme precision. The tubes are capable of producing accurate multiple exposures. Continuing education has played an important role in the development of radiology and is essential to keeping abreast of the rapid changes and innovations in the field. Radiology, in its short history, has proven its capabilities and wil continue to serve the patient in the years to come. Reference: Introduction to Radiologic Technology by Laverne Tolley Gurley and William Callaway