Roland W. Clements X-Ray Tube Collection Exhibit

This virtual exhibit is based on an exhibit that was on display on the main floor of Hawaii Medical Library in November 2002.

Roland W. Clements, retired Radiologic Technology Program Director at Kapiolani Community College, donated his collection of x-ray tubes to the Mamiya Medical Heritage Center of the Hawaii Medical Library in August 2002. Clements's extensive collection includes tubes dating back to as early as ca. 1902. In November 2002 some of the most interesting-looking tubes were curated into an exhibit on the main floor of the Hawaii Medical Library.

History

X-rays were accidentally discovered in 1895, during experiments conducted by Wilhelm Röntgen. He referred to this new energy as "x-ray," because the nature of the rays was unknown. Experimenting over the next several weeks, he realized the rays did not penetrate lead or the bones in his hand and that the images could be captured on photographic plates. Röntgen presented "Ueber eine nue Art von Strahlen (On a New Kind of Ray)" to the Wurzburg Physico-Medical Society on December 28, 1895. It wasn't long before the rest of the medical community and others knew and understood the impact of his discovery. Röntgen received the first Nobel Prize in physics for his discovery of x-rays.

Uses

The possible diagnostic uses of the x-ray were astounding. Six months following Röntgen's discovery, physicians were using x-rays to locate dislocations, bullets, and other foreign bodies in patients. What was not known at the time was that the unseen x-rays were causing permanent damage and often led to drastic consequences for early experimenters. Eventually, the dangers were acknowledged and protective devices, etc. developed.

Exhibit

Original Müller Röntgenröhre No. 72203. Made in Germany, ca. 1902. Hand blown in the shop of C.H.F. [Carl Heinrich Florenz] Müller, a glass blower whose first shop dates back to 1865 in Hamburg. Müller's shop produced incandescent light bulbs, fluorescent tubes, and, when asked, the tube you see here and many others that became known worldwide. Müller's firm was purchased by the Dutch company, Philips.

Platinum Anode Gas Tube, ca. 1905. "The essential components of an early x-ray tube are an airtight vessel, usually of glass, and two electrodes sealed into it. In the early tubes the vessel is evacuated to a low pressure, but some gas molecules remain (for which reason these are known as `Gas-Tubes')…The electric discharge when a high voltage is applied between the electrodes causes ionization of the gas atoms, and the positive ions are driven towards the cathode (negative electrode) by the electric potential across the tube. This bombardment of the cathode by the positive ions causes the emission of electrons which, on striking the target, generate X-rays. The target…may be the wall of the vessel, the anode electrode or a separate metal insert connected to the anode." The History of X-rays

GE Coolidge Tube 4R3034 - Hooded Anode x-ray tube ca. 1925. The hooded anode increases heat capacity and provides protection by restricting the amount of x-ray through the small opening. William D. Coolidge's design was another watershed in the evolution of x-ray tubes. Gas tubes could be unstable and unreliable with any change in electrical current. The cathode in Coolidge's tube was an electron-emitting tungsten filament; the filament-cathode bombarded the target, directly producing the x-rays.

Machlett rectifying valve tube ML - 1- E F75263 140 Kv. Ernst Machlett and his son Robert began as glassblowers and became early producers of commercial x-ray tubes in the United States. E. Machlett & Son was founded in 1897 in New York City.

"rectifying tube - n: a thermionic tube having two electrodes; used as a rectifier [syn: diode, rectifying valve]; thermionic tube - n: a system of electrodes arranged in an evacuated glass or metal envelope [syn: tube, vacuum tube, thermionic vacuum tube, electron tube, thermionic valve]." WordNet ® 1.6, © 1997 Princeton University.

SRT X5294 Coolidge hooded anode 1-Ray tube 250Kv. The large radiator fins help to dissipate heat since this tube is also a Coolidge tube, similar to the GE tube in the first large display case.

Machlett ML-41 Serial No. M43427 140KV x-ray valve tube.

Within the first few years of unprotected use of x-rays, the deleterious effects of the rays became apparent. Protective measures for operators/therapists were developed, essentially minimizing time of exposure, maximizing distance from the source and the use of shielding. Unknowingly and unfortunately, some of the early pioneers became "radiation martyrs," suffering "burns" to the point of amputated limbs, malignancies and death.

Photo courtesy of R. Clements

X rays are used in industry as a means of testing objects without destroying them, and can reveal the presence of flaws, thereby eliminating defective products at the point of production. X-rays are used to determine the authenticity of works of art and museum artifacts and for art restoration. Detection of fake gems, smuggled goods at customs, and routine baggage inspection are other industrial applications. An early use of x-rays was in fitting shoes; the practice continued for approximately 60 years until the danger of exposure was recognized as unacceptable.

Photo courtesy of L. Gerwitz

Machlett G68030 Industrial hooded anode tube 140 Kv

Machlett G66103 Pearl Harbor industrial x-ray tube 250 Kv

The biological effects of x-rays, the physical and chemical changes in cells, were obvious early on. John Daniel at Vanderbilt described scalp epilation of a colleague during a diagnostic exposure in 1896. The next year in Vienna, Leopold Freund used the rays to treat a benign hairy nevus. Dermatological conditions, both benign and malignant, responded to radiation therapy; although deep tumors remained problematic until technological advances were made.

GE X334 Maximar therapy tube 100 Kv ca. 1935

Theratron 60 Teletherapy Unit. Model of Cobalt60 radiation therapy machine.

Gilbert H. Fletcher, M. D., physicist Leonard G. Grimmett, and engineer Bailey Moore designed and tested the first Cobalt60 radiotherapy unit in the U.S., which was installed in 1953 at University of Texas M. D. Anderson Cancer Center. This therapy, megavoltage or high-energy radiation delivered by Cobalt60 helped patients because the beams concentrated their maximum energy below the skin surface, closer to many tumor targets and made skin reactions less of a limiting factor.

GE valve tube KR-7 14568

William David Coolidge launched his career with General Electric in 1905. It was at GE that Coolidge developed tungsten filaments in light bulbs and recognized that tungsten filaments, along with some other modifications, would make a vast improvement in x-ray tubes, which GE also manufactured. Since then, the basic design of x-ray tubes has not changed. The patent for the "Coolidge tube" was granted in 1913. When Coolidge died in 1975 at the age of 101, he held a total of 83 patents.

GE mammography tube with beryllium window, ca. 1979. Beryllium windows are inserted into mammography x-ray tubes for clear transmission of x-rays.

Breast radiography was virtually unknown until 1913 when Albert Salomon, a German surgeon, reported his findings correlating radiographic pictures of mastectomy specimens with breast tumors. Most importantly, he recognized that it was possible to obtain a true picture of breast tumors on x-ray film, particularly the invasive characteristics of tumors and patterns of spread. Salomon identified calcifications in some specimens, but it would be several years before the importance of this was realized. For the most part, breast radiography was recognized as having great diagnostic potential, but it remained technically difficult to achieve quality radiographs for many years. In France in the mid-1960's, Charles M. Gros introduced molybdenum targets and advocated forceful compression of the breast during exposures, which improved image quality. It was not until 1965 that the first dedicated mammography unit was mass-produced.

Dental X-Ray Tubes

Within two weeks of Röntgen's discovery, Otto Walkhoff, a German dentist, made the first dental radiograph in Braunschweig. The exposure time was twenty-five minutes and the images were of such poor quality that they had no diagnostic value. Fortunately, it was only three months later that Wilhelm Köning of Frankfurt reduced the exposure time to nine minutes and produced radiographs which were diagnostically more useful.

Coolidge tube 56338, General Electric dental x-ray tube 70 Kv, ca. 1960.

Coolidge tube 21897, General Electric hooded anode dental x-ray tube, ca. 1920.

Coolidge tube, oil immersed type, General Electric dental x-ray tube CDX-2, 63 Kv, 10 Ma, ca. 1930. "Most of the X-ray tubes in present-day use are modified Coolidge tubes. The larger and more powerful tubes have water-cooled anticathodes to prevent melting under the impact of the electron bombardment. The widely used shockproof tube is a modification of the Coolidge tube with improved insulation of the envelope (by oil) and grounded power cables."

Photo courtesy of L. Gerwitz

Credit: All photographs are courtesy of Jason Kimura, except where noted as otherwise.