X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment Summary

  • Last updated on November 10, 2022

Several physicists, including John Douglas Cockcroft, Robert Jemison Van de Graaff, and Theodor Svedberg, produced synchrotron X rays for radiotherapy. X-ray photography would soon become an ubiquitous tool of medical diagnosis.

Summary of Event

Electromagnetic radiation Electromagnetic radiation Radiation, electromagnetic consists of numerous types of energy that exhibit both wavelike and particle (that is, photon) properties and that travel at the speed of light, approximately 300 million meters per second. The electromagnetic spectrum ranges from low frequency (low energy), long wavelength radiations such as radio, television, microwaves, and visible light to high frequency (high energy), short wavelength radiations such as ultraviolet, X, and gamma radiations. The high frequency, short wavelength radiations are called ionizing radiations because such radiations penetrate deep within various materials, especially living tissue, and because such radiations strip electrons from atoms, thereby damaging key life molecules (for example, DNA—deoxyribonucleic acid). [kw]X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment (1949) [kw]Synchrotron Are First Used in Medical Diagnosis and Treatment, X Rays from a (1949) [kw]Medical Diagnosis and Treatment, X Rays from a Synchrotron Are First Used in (1949) [kw]Diagnosis and Treatment, X Rays from a Synchrotron Are First Used in Medical (1949) [kw]Treatment, X Rays from a Synchrotron Are First Used in Medical Diagnosis and (1949) X rays;medical applications Synchrotron Diagnostic technologies Radiotherapy X rays;medical applications Synchrotron Diagnostic technologies Radiotherapy [g]North America;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [g]Europe;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [g]United States;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [g]United Kingdom;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [g]Sweden;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [c]Health and medicine;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [c]Science and technology;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] [c]Physics;1949: X Rays from a Synchrotron Are First Used in Medical Diagnosis and Treatment[02800] Cockcroft, John Douglas Van de Graaff, Robert Jemison Svedberg, Theodor Lawrence, Ernest Orlando Blewett, John Paul Röntgen, Wilhelm Conrad Bragg, Lawrence Cannon, Walter Bradford

X rays were first discovered by the German physicist Wilhelm Conrad Röntgen in 1895. He generated X rays by applying an electric current to the cathode (that is, negative terminal) of a vacuum tube. The cathode became heated such that it discharged a stream of electrons, which were attracted to the positively charged anode of the vacuum tube. When the electrons contacted the tungsten anode, X rays were emitted. For this discovery, Röntgen was awarded the first Nobel Prize in Physics Nobel Prize in Physics;Wilhelm Conrad Röntgen[Röntgen] in 1901. His work was closely followed by another important breakthrough: the discovery of radioactivity in the elements uranium and radium by Antoine-Henri Becquerel, Marie Curie, and Pierre Curie.

Applications of X rays and radioactivity to biology and medicine became readily apparent. Röntgen’s discovery of X rays and their ability to penetrate living tissue meant that a patient’s internal organs could be photographed. W. D. Coolidge developed the first X-ray tube for producing patient X rays in 1913. Walter Bradford Cannon used X rays in fluoroscopy, a process by which the activities of a patient’s internal organs can be observed. Thomas Alva Edison invented the first fluoroscope in 1896. Cannon applied this instrument to patient diagnoses. If a patient swallowed a dense fluid such as barium sulfate while being X-rayed with the X-ray fluoroscope, the dense fluid would fluoresce and appear on the X-ray photographic plate, along with the organs containing the dense fluid. Using X-ray fluoroscopy, Cannon and other physicians could identify abnormalities within internal body organs without operating.

In 1915, Sir Lawrence Bragg and his father Sir William Henry Bragg received the Nobel Prize in Physics Nobel Prize in Physics;Lawrence and William Henry Bragg[Bragg] for their discovery of X-ray diffraction through crystals. X rays beamed through a crystallized material are bent in specific directions when they strike the atoms of the crystal lattice. The Braggs described the properties of X-ray diffraction with a simple mathematical equation called Bragg’s law Bragg’s law[Braggs law] . Their discovery led to a technique for visualizing submicroscopic molecules called X-ray crystallography.

In X-ray crystallography X rays;crystallography Crystallography, X-ray[crystallography, X ray] , a purified molecule such as a protein can be crystallized, followed by the beaming of X rays through the molecule’s crystal lattice. The pattern of images on the resulting X-ray photograph can be measured to determine the molecule’s structure. X-ray crystallography was used from the 1940’s onward in biochemical research to determine the structures of proteins and other important molecules of life. Eventual Nobel Prize-winning work that depended upon X-ray crystallography included the structures of insulin (by Frederick Sanger), the alpha helix of proteins (by Linus Pauling), and DNA (by James D. Watson, Francis Crick, and Maurice H. E. Wilkins).

During the 1930’s and 1940’s, physicists began developing instruments operating at much higher voltages (for example, 1 million to 100 million electronvolts) for generating higher-frequency radiations such as deeper-penetrating X rays and mesons. These devices were called particle accelerators Particle accelerators , or atom smashers. The principle behind an accelerator involves the firing of charged particles (that is, ions) from an ion gun.

The ions are guided through a tunnel surrounded by powerful electromagnets; these electromagnets accelerate and direct the ion beam toward a target material. With high-voltage accelerators, the electromagnets direct the ion beam at speeds approaching that of light (300 million meters per second). The entire process requires much less than one second at such speeds. The ion beam strikes atoms of the target material, splitting the target atoms into subatomic particles and energy, whose pathways are photographed as they rapidly move through a cloud chamber.

Accelerators can be of two types: linear accelerators and circular accelerators. Linear accelerators (for example, the Van de Graaff generator) move charged particles in a straight line to the target material; they must be many kilometers long in order to achieve high velocities. Circular accelerators move charged particles in a circular pathway and have the advantage of repeatedly circling the particles to achieve higher and higher velocities before directing them at the target. Circular accelerators include cyclotrons, synchrocyclotrons, synchrotrons, bevatrons, betatrons, and cosmotrons.

The American physicist Ernest Orlando Lawrence developed the first cyclotron Cyclotrons with his students Niels E. Edlefsen Edlefsen, Niels E. and M. Stanley Livingston Livingston, M. Stanley at the University of California, Berkeley, in 1932. They used this cyclotron to separate isotopes of various elements and to split atoms for the release of subatomic particles and energy. In 1939, Lawrence isolated phosphorus 32, a radioactive isotope of phosphorus containing an extra neutron per atom. He delivered some of this radioisotope to his brother John H. Lawrence Lawrence, John H. , a physician at the Harvard University Medical School in Cambridge, Massachusetts. John Lawrence used phosphorus 32 to treat patients suffering from chronic leukemia and polycythemia. John Lawrence’s radiotherapy experiments were repeated by a colleague, Shields Warren Warren, Shields , also a physician at Harvard.

While these experiments were controversial at the time, they were the beginning of the successful use of radioactive isotopes in treating cancer Cancer;radiation therapy . Following World War II, Ernest Lawrence invented the synchrocyclotron Synchrocyclotron , a very similar instrument that synchronizes the charged particle flow with the acceleration potential of the electromagnets. At this time, the focus had shifted to the peaceful uses of atomic energy. The invention of the synchrocyclotron, synchrotron, betatron, and other closely related particle accelerators led to the generation of radiations useful for subatomic physics research, anticancer radiotherapy, and industry. The breakthroughs in this effort were shared by several scientists and companies that made considerable investments in the construction of bigger and better particle accelerators.

In 1945, the American physicist John Paul Blewett of the Brookhaven National Laboratory predicted the emission of radiation, including X rays, from synchrotrons. This prediction was verified in 1947, when scientists at the General Electric Corporation recorded X-ray emissions from a synchrotron. These results were paralleled in other laboratories.

Robert Jemison Van de Graaff, who invented the Van de Graaff generator at Princeton University in 1929, had worked with John G. Tramp Tramp, John G. at the Massachusetts Institute of Technology to develop a 1 million electronvolt generator for producing X rays. This device was used to treat cancer patients at Huntington Memorial Hospital in Boston in 1937. Using these accelerators, they generated X rays and tested the effects of X rays upon biological molecules. They reported these results in two 1948 articles: “Irradiation of Biological Materials by High Energy Röntgen Rays and Cathode Rays” "Irradiation of Biological Materials by High Energy Röntgen Rays and Cathode Rays" (Van de Graaff and Tramp)[Irradiation of Biological Materials by High Energy Röntgen Rays and Cathode Rays] in volume 19 of the Journal of Applied Physics and “Thick-Target X-Ray Production in the Range from 1250 to 2350 Kilovolts” "Thick-Target X-Ray Production in the Range from 1250 to 2350 Kilovolts" (Van de Graaff and Tramp)[Thick Target X Ray Production in the Range] in volume 74 of the Physical Review.

Sir John Douglas Cockcroft, an English physicist working in the laboratory of the eminent nuclear physicist Ernest Rutherford, began building a cyclotron in the late 1930’s. During World War II, he helped develop radar. Following the war, he supervised the development of several hundred-million-electronvolt synchrotrons. In 1949, his research group produced synchrotron X rays and applied these X rays to the radiotherapeutic treatment of cancer patients. He reported these results in an article entitled “The Development of Linear Accelerators and Synchrotrons for Radiotherapy and for Research in Physics,” "Development of Linear Accelerators and Synchrotrons for Radiotherapy and for Research in Physics, The" (Cockcroft)[“Development of Linear Accelerators and Synchrotrons for Radiotherapy and for Research in Physics] which appeared in Volume 96 of the Proceedings of the Institution of Electrical Engineers. In Sweden, the radiologist Arne Frantzell applied these X rays to the medical imaging of internal organs, bone, and muscle. The eminent Swedish physical chemist Theodor Svedberg supervised the construction of a 700-million-electronvolt synchrocyclotron at the University of Uppsala. This device was applied to radiotherapy beginning in 1951.

Significance

The importance of generating X rays, gamma rays, mesons, and other forms of electromagnetic radiation from cyclotrons and synchrotrons lies in their applications to nuclear physics research, radiotherapy, and industry. Whereas these particle accelerators had been used primarily in the drive to harness atomic energy during World War II, they were redirected toward their original peaceful research objectives following the war. Particle accelerators were constructed rapidly at numerous sites worldwide, including the United States, the Soviet Union, England, France, and Sweden.

In medicine, X rays are useful in radiotherapy (high-frequency “hard” X rays) as well as in photographing internal organs (lower-frequency “soft” X rays). Hard X rays are produced from high-voltage energy sources such as synchrotrons. These X rays can penetrate deep within body tissues, causing severe damage to target cells. High-frequency ionizing radiation (for example, ultraviolet, X, and gamma radiations) damage molecules they intersect. In living tissue, these molecules include proteins, lipids, carbohydrates, and especially DNA.

Irradiation of DNA Deoxyribonucleic acid often produces atomic changes that alter the coding sequence of DNA. Since DNA encodes proteins in living cells, alterations in the DNA coding sequence cause the production of proteins having incorrect amino acid sequences. Such damaged proteins either will not function properly or will not function at all. These changes in DNA and encoded proteins are called mutations. Cellular mutations can be harmless (for example, the appearance of freckles), damaging (sickle-cell anemia), or cancerous. Most cancers are cellular mutations caused by radiation or chemicals.

While radiation can cause cancers, however, it also can be used to kill cancerous cells, because cancer cells are more sensitive to irradiation than are normal cells. Therefore, radiation therapy is very useful in destroying tumors and cancers. The therapy involves the firing of a beam of high-energy X rays at a targeted region of a patient’s body that contains a tumor. The approach produces a shotgun effect, the radiation striking both tumorous and normal tissue. Tumor cells, however, should be killed more easily with some tolerable damage to neighboring normal cells.

With early diagnoses of cancers, radiotherapy can be extremely effective in destroying tumors and curtailing further spread of the disease. The technique is most applicable to internal cancers, especially those that are inoperable. Radiotherapy is performed in conjunction with chemotherapy (anticancer chemicals and drugs) and the ingestion of radioactive isotopes that concentrate in particular tissues where the cancer is located. Researchers have greatly improved radiotherapy instrumentation, producing devices that concentrate high-energy X rays on target cancers with very little damage to normal cells.

The work of a variety of scientists, especially Cockcroft, Van de Graaff, and Svedberg, produced X rays and other radiations from particle accelerators for saving thousands of cancer victims and extending their lives. Their work also demonstrated the tremendous peaceful uses of atomic energy for the improvement of human health and welfare. X rays;medical applications Synchrotron Diagnostic technologies Radiotherapy

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Alberts, Bruce, et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science, 2002. This lengthy introductory molecular biology textbook for undergraduate biology majors is a thorough survey of the science by several leading molecular biologists and seven biochemists. It is clearly written, illustrated, and referenced. Chapter 4, “How Cells are Studied,” provides a strong history of cell biology with the applications of X rays to biological research.
  • citation-type="booksimple"

    xlink:type="simple">Clark, George L. Applied X-Rays. 4th ed. New York: McGraw-Hill, 1955. This extensive, detailed work is a complete presentation of X rays, properties of X rays, X-ray instrumentation, history, and applications. It is well written and diagrammed, although a knowledge of algebra and chemistry is needed for some topics. Chapter 3, “High-Voltage Equipment,” describes synchrotrons and other accelerators. Chapter 12, “The Biological Effects of X-Radiation,” describes medical applications of X rays.
  • citation-type="booksimple"

    xlink:type="simple">Crease, Robert P., and Charles C. Mann. The Second Creation. New York: Macmillan, 1985. This exciting book is a history of physics research during the twentieth century, with special emphasis upon nuclear physics and unification theories. The works of numerous physicists are described, including Albert Einstein and Niels Bohr. Chapter 14, “The Eightfold Way,” describes the cyclotron work of Ernest Lawrence and Cockcroft.
  • citation-type="booksimple"

    xlink:type="simple">Gillispie, Charles Coulston, ed. Dictionary of Scientific Biography. New York: Charles Scribner’s Sons, 1980. This strong reference work is a collection of short, concise biographical essays on major twentieth century scientists, many of whom are Nobel Prize winners. The collection includes biographies of Cockcroft, Van de Graaff, and Svedberg. Each article includes an extensive reference list.
  • citation-type="booksimple"

    xlink:type="simple">Halliday, David, Robert Resnick, and Jearl Walker. Fundamentals of Physics. 7th ed. Hoboken, N.J.: Wiley, 2005. This introductory physics textbook for undergraduate science majors is an outstanding, popular work. It is lengthy, detailed, and requires a strong background in mathematics, particularly calculus. The book includes several chapters on subatomic physics, electromagnetism, and particle accelerator principles. It includes historical sketches of prominent physicists.
  • citation-type="booksimple"

    xlink:type="simple">U.S. Army Medical Service. Radiology in World War H. Washington, D.C.: Government Printing Office, 1966. This reference work is a detailed history and methodology of X-irradiation and its applications prior to and during World War II. It is extremely well documented. The works of Ernest Lawrence with cyclotrons and John Lawrence with radioactive isotope therapy for cancer are discussed.
  • citation-type="booksimple"

    xlink:type="simple">Winick, Herman, and Arthur Bienenstock. “Synchrotron Radiation.” In McGraw-Hill Encyclopedia of Science and Technology. 9th ed. New York: McGraw-Hill, 2002. This article is a concise, detailed summary of particle accelerators and their radiations that is comprehensible for the layperson. Properties of synchrotrons and synchrotron radiation, research applications, and the history of accelerator research are described.

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