SIC 3844

Firms in this industry engage primarily in manufacturing irradiation apparatus and tubes for applications such as medical diagnostic, medical therapeutic, industrial, research, and scientific evaluation.

NAICS Code(s)

334517 (Irradiation Apparatus Manufacturing)

Industry Snapshot

After nearly a decade of growth that made X-ray apparatus and tubes one of America's fastest growing industries in the 1990s, the sector has remained stable in the early twenty-first century. The value of shipments in 2001 reached approximately $4.3 billion, roughly the same as 2000. Numerous advances were made in imaging technologies at the beginning of the new millennium. These new technologies stood to benefit an even wider variety of industries, including aerospace and automotive industries. Much of this sector's recent success came from the growing sophistication and portability of X-ray products. The massive machines of hospital X-ray departments still had their place, but now miniaturized versions found everyday use in doctors' and dentists' offices nationwide. In addition, the industry discovered new uses for the nondestructive technology that increased the effciency and quality of manufacturing processes. With the dismantling of the Soviet block and the relaxation of U.S. technology bans, the industry found a number of new and expanding markets in Eastern Europe and portions of the former Soviet Union.

Among medical services, lab tests and X-rays ranked as the fifth category in terms of consumer usage behind physician's services, dental services, eye care services, and service by someone other than a physician. For 1995 (in 1988 dollars), the average expenditure on X-rays for 100.3 million households was $2.7 billion out of a total of $135.1 billion aggregate health care expenditure. On average in 1997, X-ray services were performed in 9.4 percent of all combined visits to physicians (office, outpatient departments, and emergency departments). The largest consumer dollar amount was spent on X-rays for individuals between the ages of 35 and 74. The projected figure for the year 2000 was $2.9 billion based on 105.9 million households with aggregate expenditures of $141.5 billion. The highest consumer expenditure for 2000 was expected to be between the ages of 35 and 74.

Approximately one-half of all sales in this industry went to hospital end-users, with the medical profession in general making up the majority of all shipments. Other demands for X-ray equipment have evolved with the need for increased security measures at airports in the late 1990s and early 2000s. Research facilities provided another avenue for sales of major pieces of often experimental equipment. However, the industry was growing increasingly interested in the nondestructive and non-intrusive nature of the imaging technologies.

Organization and Structure

The 1997 Economic Census reported 154 establishments for the irradiation apparatus industry, an increase of 17 percent from 1992. Total revenues were reported at approximately $3.8 billion. These establishments employed 13,659 people, a decrease of 9.5 percent from 1992.

The medical industry, which also includes dental, electromedical, surgical, and ophthalmic goods, ranked sixth out of 17 major technological manufacturers of various equipment. At the turn of the century, the greatest growth in employees was expected in the Eastern Lakes region of the United States. The Northwest region placed second with a 10 percent projected growth rate and the southwestern United States was third with 7 percent projected growth.

Background and Development

The discovery of the X-ray was an accident. In 1895, Wilhelm Conrad Roentgen, experimenting with electrical discharges in an evacuated tube called a Crookes' tube, discovered that the invisible rays given off from his experiment could penetrate a human hand and project a skeletal image onto a florescent screen. Later, he substituted photographic film to make a permanent record. Since then, scientists have discovered that X-rays are a type of electromagnetic radiation. An X-ray's wavelength of 0.01 to 300 angstroms is shorter than visible light, lying between and partially over the ultraviolet and gamma-ray segments of the electromagnetic spectrum. They are produced by the collision of high-energy particles with other charged particles.

American scientist William D. Coolidge developed the first efficient X-ray tube, called a Coolidge tube, in 1913. Modern tubes fire electrons from a tungsten filament cathode at a target anode, usually made of tungsten, molybdenum, or copper and coated with a thin film of gold.

The speed of passage of the x-radiation through a body depends on density. Relatively dense material, like bone, yielded white images, whereas less-dense material like lungs appeared black. Doctors found the phenomenon invaluable for accurately diagnosing such things as tuberculosis, miners' black lung, and broken bones. However, it only provided a two-dimensional image of the problem area, superimposing layers of body components one on top of another without any indication of depth. One solution to that problem was to use a contrast medium like liquid barium to highlight the esophagus, stomach, and intestine. By using a fluoroscope, which produces real-time images on a video screen, the physician tracked the medium through the digestive system, pinpointing any problem areas.

The late 1960s saw a major advancement in the effective use of X-rays for medical diagnosis. By linking the computer to a moving X-ray emitter inside a doughnut-shaped machine, Geoffrey Hounsfield of EMI produced a three-dimensional image of an entire object. Instead of a few X-ray photographs, the computer-aided-tomograph (CAT) took hundreds of thousands of carefully directed, slice-like images, which the computer reassembled. Tomograph comes from the Greek word for slice. The results, startlingly clear, could be manipulated to highlight specific areas. CAT scans could locate bleeding inside a brain, find and measure tumors, or help to evaluate injuries anywhere in the body.

Concerns over the amount of radiation a patient would be exposed to and the cost and sheer physical immensity of the equipment led to the development of ultrasound tomograph, which did not use X-rays. By the mid-1980s, the ultrasound systems were beginning to gain popularity. Ultrasound systems are classified under SIC 3845: Electromedical Apparatus.

Magnetic Resonance Imaging (MRI) uses a powerful magnet to align the hydrogen atoms in a patient's body. When the magnetic field is released, the atoms return to their original orientation, but different tissues realign at different rates. By using a computer to clock the relative rates of change, physicians can map joints, tumors, and post-surgical changes in the chest, abdomen, pelvis, brain, and spinal cord.

The safety and effectiveness of all medical devices became the responsibility of the Food and Drug Administration in 1938. Radiation emitting devices were specifically targeted in 1968 by the Radiation Control for Health and Safety Act and, in 1976, by the Medical Device Amendments to the Food, Drug, and Cosmetic Act.

In the late 1990s, the continued concern for radiation exposure to patients led to further advances in X-ray equipment development and technological advances. One of the technological advances in 1997, called a "soft" X-ray, was a new technology that used long wavelengths to decrease radiation.

Even though other, safer technologies were displacing X-rays by the 1990s in their traditional medical applications, radiation proved useful in unique ways. The fluoroscope could show movement within the body like the operation of the heart and the intestines. It facilitated angioplasty, providing the physician with a real-time way of guiding a balloon-tipped catheter down a blood vessel to the point where the balloon insert could be expanded with the greatest effect. Radiation oncology used X-rays or gamma-rays to attack cancerous tumors without damaging surrounding tissue. With this technique a linear accelerator, betatron, or cobalt machine is used to direct a beam of radiation from outside the patient's body at the pinpointed tumor.

Initial investigations of the radiation in the research laboratory led to many useful applications for the nonvisible light energy. X-ray crystallography led to X-ray microscopes. Crystal structures direct and control X-rays much as lenses do with normal light energy. Using this principle, researchers were able to delve everdeeper into the structure of crystals. The fact that X-rays are absorbed by material led to absorption spectroscopy, which studies metals in living systems. The industry began using lithography to produce densely packed computer chips. Holography made it possible to glimpse the world within a living cell.

Scientists also used the radiation to look beyond this world. By launching satellites equipped with X-ray detectors, they were able to observe and theorize about the structure of the universe. The first such satellite, UHURU, was launched from a site near Kenya in 1970 and was followed by an international series of successors. Gammaray astronomy extended the reach of X-ray astronomy, making visible the processes of the destruction and creation of chemical elements throughout the universe.

Archeology and paleontology also benefited from the use of X-ray technology. Previously, the study of such ancient artifacts as mummies and fossilized bones required the systematic destruction or at least the disassembly of the scientific treasures. Using a CAT scan, often tied to a supercomputer, researchers could get clear three-dimensional images without reducing the artifact to dust. Such scans often revealed surprising facts about the subject giving a glimpse of what life, society, disease, nutrition, and intrigue was like in historically distant times.

X-rays also proved invaluable in probing modernday intrigues. In the 1980s and 1990s, plane hijackings and bombings brought terror to the skies, and advances in weapons technology threatened to make conventional X-ray scanners ineffective in preventing them. Although metals show up clearly on an X-ray scan, lighter materials like plastics do not. Plastic explosives and the mostly-plastic handgun, the Glock 17, could be smuggled through security inspections undetected. Specially designed innovations like American Science & Engineering Inc.'s Model Z scanner sought ways to tighten security. The Z-scanner concentrates a high intensity beam of X-rays onto the carry-on luggage to compensate for the low absorption rate of softer materials. It then displays both the normal X-ray image, which would pick up metals and the Z-image, which catches plastics. In 1991, France extended that technology for use in its massive cargo inspection facility at Paris's Charles de Gaulle airport. Their building-size X-ray machine examines entire pallet loads of luggage or entire vehicles at once, producing a sophisticated, easily read image.

By increasing the power and size of the X-ray equipment, industry businesses were able to probe through several feet of metal to map interior details. Defense subcontractors used CAT scans to inspect MX missiles and Saturn rockets looking for cracks, poor material bonds, migration of fuel or coolants, integrity of castings, and gaps in insulation. In traditional CAT scans, the object to be probed sits within the doughnut shaped emitter ring, but in the late 1980s industry leaders developed a new innovation on the technology, backscatter imaging tomography (BIT). By capturing only the portion of the beams which are reflected back, BIT machinery allowed operators to probe objects even if they could only access one side.

The process provided an efficient method for checking the quality of manufactured parts and allowed inspectors to certify and document such critical items as pipe welds in nuclear reactors. X-rays have also been used to examine the nation's highways by detecting early signs of failure and allowing preventative maintenance in place of major periodic rebuilding.

Mergers and acquisitions of X-ray apparatus and tubes companies became popular in the mid- to late 1990s to match the trend in hospitals downsizing, physician's offices combining, changes in managed care, and decreases in insurance availability for medical services.

The estimated 1996 U.S. sales volume for conventional fluoroscopy was $369.8 million and $36 million for radiation detection equipment, according to the March 1996, Biomedical Market Newsletter . Bone density scanning tests were became more popular among research centers, hospitals, and physicians. Until the mid-1990s osteoporosis was usually detected by breaking bones. In 1996, normal X-rays were no longer considered acceptable to detect bone loss. The bone density scan tests costs around $220 per patient and the demand for this testing equipment is expected to increase as patients use Fosamax and wish to have their results and condition monitored.

Sales of irradiation equipment were strong in the late 1990s, with the total value of shipments estimated at almost $4 billion in both 1998 and 1999.

Current Conditions

Going into the twenty-first century, shipments of irradiation apparatus peaked in 2000 at $4.3 billion. The number remained virtually unchanged the following year, as well, despite a challenging economic climate. There was increased coverage of X-ray technology in the press, as the events of September 11, 2001 brought increased attention to X-ray use for passenger luggage screening at airports nationwide. InVision Technologies, one of the two companies certified by the Federal Aviation Administration (FAA) to manufacture bomb-screening machines for luggage, received an order for 100 machines from the federal government in response to a new law that all checked baggage be screened for bombs by the end of 2002. The FAA estimated that more than 2,000 of such machines would be needed for such requirements to be met. U.S. Customs inspectors were also using hightech imaging equipment after September 11, with the purchase of the MobileSearch X-ray truck designed to inspect a variety of cargo. The $2 million truck was not yet in widespread use, however, with only 2 percent of U.S. cargo being inspected in such a way.

Shortly after the events of September 11, 2001, attention again turned to this industry when anthrax-tainted letters killed several Americans and infected many others. The U.S. Postal Service immediately purchased several electron beam (e-beam) irradiation systems from the San Diego-based SureBeam Corporation to process its mail. The technology had already been utilized since May 2000 by food companies to kill E. coli bacteria in ground beef, as well as salmonella and related food borne pathogens but the technology truly gained momentum after September 2001. E-beams, which use regular electricity rather than radioactive isotopes as energy, do not change the temperature of the material being irradiated, and thus do not produce a change in the taste or texture of the meat and poultry being irradiated. The technology was the fastest available and used the least energy. Now found in thousands of supermarkets nationwide, e-beam irradiation has gained popularity for its safety and effectiveness on food. SureBeam expected revenues to rise 70 percent in 2002, to reach $60 million.

Mirroring the trend of the popularity of digital photography in the early 2000s, the use of filmless radiology systems, which store images electronically, also was becoming more popular. Benefits of filmless radiology included reducing lost or misplaced conventional X-ray films. They also can be viewed online in a large database, allowing multiple users to have access at the same time, unlike conventional film. There also present potential cost reduction opportunities by negating the need for creating and maintaining conventional film libraries. Filmless radiology is not without its drawbacks, however, including placing technical challenges on hospitals and the initial expense of their costly picture archiving and communication systems.

In 2002, General Electric Co.'s GE Medical Systems announced plans to introduce Excite, a magnetic resonance imaging technology that it claimed would increase the speed of MRIs by as much as four times the speed of current models. Quality and efficiency of the diagnostic procedure would also greatly increase. The technology would also allow MRIs to produce images of lungs breathing and blood flowing, shorten exam times, and be useful in detecting damage from heart attacks and diagnosing stroke victims. The new technology would increase the price of an MRI machine by 10 to 20 percent but test prices would not be affected and efficiency rates would rise. The company also estimated that the number of MRI scans performed each year, numbering 31 million in 2001, would nearly double to 60 million worldwide by 2005. GE's advanced Signa SP/2 MRI systems are used for surgical and interventional procedures requiring virtually real-time imaging during a procedure. Intraoperative imaging has been becoming more practical and useful over the last decade.

Other advancements in the field included a robotic X-ray system called ScanRay. Developed in 2002, it could scan the fuselage and wings of a plane for damage. The system also could be used to inspect ships, roads, bridges, and other concrete structures for damage, as well as to detect explosives in buildings. The technology uses a Reverse Geometry X-ray, which creates an information profile culled from images collected from many different angles. The resulting images are sharp and clearer than conventional X-ray images while also creating a 3-D digital image by the various angles that the X-ray is taken from. Carbon nanotubes (CNTs) were also being explored to create portable medical and industrial X-ray machines with higher imaging resolution. The technology was estimated to be fully developed by 2004 or 2005.

Industry Leaders

Siemens Medical Solutions of Siemens AG with headquarters in Malvern, Pennsylvania, and Erlangen, Germany, is one of the world's largest suppliers to the health care industry. The company produces innovative products, including imaging systems for diagnosis, therapy equipment for treatment, hearing instruments, and critical care and life support systems, as well as a wide array of information technology and data management solutions for hospitals, clinics, and doctors' offices. The company employs about 31,000 people worldwide, with reported sales of $7.6 billion.

With General Electric's purchase of Utah-based OEC came GE OEC Medical Systems, part of General Electric's Medical Systems, that makes computer-based X-ray and fluoroscopic imaging systems for outpatient clinics, hospitals, and surgical centers. Their X-ray imaging systems join radiographic and fluoroscopic imaging with digital image-processing capabilities.

Fischer Imaging Corporation, Colorado, makes general X-ray systems as well as X-ray imaging systems for the detection of breast cancer, including the Mammotest biopsy system and SensoScan digital mammography systems. In 2002, the company had $48.2 million in sales.


Production workers made up over 50 percent of the industry's workforce. The users of X-ray equipment are radiologists. In the United States, they must take four to seven years of specialized training after graduating from medical school.

The number of establishments continued to grow throughout the 1990s with a total of 103 for 1993, up to 154 in 1997. Out of the 103 establishments, 92 of them had over 20 employees. Correspondingly, in 1997, 73 of the 154 establishments had over 20 employees.

Employment decreased from a total of 13,177 in 2000 to 12,952 in 2001 with production workers numbering 4,870 in 2000 and 4,935 in 2001. Average hourly wages for production workers increased during this time period as well, going from $18.12 to $20.51.

America and the World

Foreign imports of X-ray equipment accounted for 42 percent of industry sales in 1992 according to U.S. Industrial Outlook , higher than any other segment of the medical industry group. America's largest competitors were Japan and Germany, contributing 60 percent. By 2000, imports in this sector totaled $1.47 billion, with Germany claiming the largest percentage of that figure with some $490 million, followed by Japan, with $267 million, and The Netherlands, with $196 million.

Exports of X-ray and irradiation apparatus totaled $1.57 billion in 2000. The three largest markets in this segment were Japan, claiming $271 million of that total; Germany, with $223 million; and Canada, with $117 million.

Research and Technology

The uses of X-ray technology and its spin-offs continued to grow throughout the 1990s and into the 2000s. Medical advancements included such procedures as mammograms, which allowed physicians to detect cancerous tumors in women's breasts before they became apparent by traditional methods. Even so, the technology had its limitations. In 1993, a Canadian study revealed that mammograms were ineffective in predicting breast cancer for women younger than 50. The relatively dense tissue in younger women's breasts hides developing tumors resulting in no difference in diagnosis rates for women who received mammograms and those who did not. At the close of the century, there still remained a strong amount of controversy as to when women should be tested for breast cancer and how often they should be checked with a mammogram.

Tomography has also found its way into agriculture to observe harvesting techniques for fruits and vegetables and find out when and why crop damage occurred. The rays showed distribution patterns of pesticides and rates of water absorption by different types of roots and different soil-seed combinations.

Micro-tomography opened the miniature world of ceramics and plastics to the researcher and quality control inspector. By using high-energy sources like synchrotron radiation, industry researchers could analyze the internal structures of rocks and minerals like coal and oil-bearing shales, aiding companies like Exxon in their search for new oil and coal fields. Synchrotron radiation is produced by accelerating particles like electrons to nearly the speed of light within a magnetic field. The result is an intense white light. By channeling that light, researchers can create pencil-thick concentrated beams of x-radiation, ultraviolet, and infrared radiation.

This tunable radiation source could map chemical elements within an object. Exxon has used the technology to map other elements found within copper, nickel, and iron. Biomedical researchers have used the technology to study calcium to gain more knowledge of the makeup of human bones. Intense X-rays could look within the walls of living cells to study their structure and watch the movements of elements like calcium within a body; however, the individual cells targeted by the X-rays would be killed.

A gamma-ray version of the CAT scan—positron-emission-topography (PET)—measured brain activity. Areas of the brain engaged in thought processes absorbed glucose tagged with positron radiation. Decaying positrons gave off gamma-rays that receptors picked up and translated into a light-and-dark image of the brain. Brains that showed higher IQ levels in standard tests showed less activity than those that scored lower. Researchers theorized that the more intelligent brain was "wired" more efficiently and so used less of its capacity to solve a problem. PET was also used for diagnosing cancer and Alzheimer's disease and in evaluating epileptic patients. In the mid- to late 1990s, scientists have also been able to test the areas of the brain for depression, aggression, gender differences, and memory loss using the PET scan.

Another recent advance also used gamma-rays. The single photon emission computed tomograph (SPECT) also tracked radioactive isotopes through the body and used a computer to build an image of a metabolic function. It was particularly useful for monitoring heart functions.

Researchers used the technology to examine the internal structure of the earth and to test the "global warming" hypothesis. Using seismic waves rather than X-rays, they mapped the boundary between the earth's core and its mantle. In 1991, researchers began sending a series of sound waves from Heard Island in Antarctica through the naturally stable environment of deep ocean water. Scientists will need to continue this research for several years to obtain accurate and meaningful information. American Science & Engineering Inc., MA was interested in using its screen equipment technology for airports to screen cargo and mail. Because of the expense of the equipment—ballet scanners cost ranges from $1.2 to $1.5 million—and level of skill needed to operate the machinery, the company president doubts airlines will purchase the equipment anytime soon.

The 60-year-old gamma camera that uses vacuum tube technology was replaced by a gamma camera called Notebook Imager that uses a cadmium-zinc-telluride, solid-state detector array. It was a leading product of Digirad Corporation.

Universal Plastics Corp., and Eastman Kodak Scientific Imaging Division worked cooperatively in 1996 to develop a sequencing device to identify strands of DNA. Kodak also indicated they would replace X-ray film used to capture the images of the strands with a digital imaging capability.

In 1999, Hitachi won the Medical Design Excellence Award for its AIRIS II open magnetic resonance imaging system. The unit features an open air design that is open on four sides, offering greater comfort and access for the patient. Some 650 of these systems are installed in the United States, and 1,700 are installed worldwide. Hitachi has joined with the University of Cincinnati Medical Center to develop and explore other indications for use of this equipment.

Terahertz imaging was being developed in England in the early 2000s as a less harmful imaging alternative to X-rays. The technology would be used to detect abnormalities on the skin, including melanomas, diagnosing blood disorders, and even detecting tooth decay. It would also offer nonmedical applications as well, that would stand to benefit the automotive industry, as it could closely monitor fuel-burning engines, and the food industry, by allowing researchers to study food during processing. Using a much lower frequency than X-rays, scientists claimed terahertz waves are not harmful to the body. Terahertz waves, however, cannot completely replace X-rays in all areas, as they cannot penetrate the body in the same way due to high water content. However, for areas such as teeth, this would not be a problem and could likely replace X-rays. Unlike X-ray, the terahertz rays could even allow experts to image delicate historical books without disturbing them at all, allowing imagers to read words on each individual page.

Another advanced imaging technology being developed in the United Kingdom included a technique known as diffraction enhanced imaging, which would produce a sharper image than conventional X-rays. A crystal between the detector and the object being imaged diffracts rays that have been scattered by the object, discarded by conventional X-ray machines, into the detector. A twodimensional image is then created by scanning the object and the detector through the beam. The technology could allow the detection of spot damage to soft tissue that is unable to be detected by conventional X-rays. The aerospace and automotive industries could also potentially benefit from this new technology as a method of nondestructive testing of new materials.

Further Reading

Elliott, Louise. "Post Office Zaps Anthrax With Electron Beams." Design News , 11 March 2002.

Epstein, Victor. "Anthrax-Killing Machines Move Closer to Major Food-Safety Role." Omaha World-Herald , 28 January 2002.

"Filmless Radiology Brightens its Image." Health Data Management , November 2001.

Hoover's Online , May 2003. Available from .

Lee, Ellen. "Government Orders 100 Bomb-Detecting Machines From Newark, Calif.-Based Firm." Contra Costa Times , 6 March 2002.

"Nanotube X-rays." Electronic Engineering Times UK , 22 July 2002.

"New Ray of Hope for Health Checks." Engineer , 8 March 2002.

Petrak, Lynn. "Sure As Can Be." National Provisioner , February 2002.

Ranalli, Ralph. "Advanced X-ray Technology Scans Shipping Containers at U.S. Border." Boston Globe , 6 September 2002.

"Researchers Develop 'Sharper X-ray'." Engineer , 12 April 2002.

Schirmer, Timo, Yves Geoffroy, Susan J. Koran, and Frank Ulrich. "Signa SP/2—A MRI System for Image Guided Surgery. Medical Laser Application , July 2002.

U.S. Census Bureau. 1997 Economic Census—Manufacturing , 20 March 2000. Available from .

——. Annual Survey of Manufactures , 20 December 2002. Available from .

U.S. International Trade Commission. Export: 334517 X-ray Apparatus , May 2002. Available from .

——. Import: 334517 X-ray Apparatus , May 2002. Available from .

"Varian Signs Supply Deal with Toshiba for X-ray Tubes." Biomedical Market Newsletter , April 1996.

Winslow, Ron. "Health & Technology: GE to Offer New MRI Technology." Wall Street Journal , 20 May 2002.

"X-ray Detects Unseen Hazards." R&D Magazine , September 2002.

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