Body Image
A fact of modern warfare is that firepower has increased, but lethality has dropped. Mortality rates among injured U.S. soldiers have decreased from 30 percent during World War II, to 24 percent in Vietnam, to 10 percent in the current conflicts in Iraq and Afghanistan.
By Peter A. Buxbaum
A fact of modern warfare is that firepower has increased, but lethality has dropped. Mortality rates among injured U.S. soldiers have decreased from 30 percent during World War II, to 24 percent in Vietnam, to 10 percent in the current conflicts in Iraq and Afghanistan, according to a report in the New England Journal of Medicine.
Several factors account for this phenomenon, not least of which are advances in medicine and surgery. The deployment of small field X-ray units contributes to these medical advances. The ability to image injuries and trauma closer in space and time to the point of injury allows for better diagnoses and triaging. This has been made possible through the development of smaller and lighter units that have been ruggedized to withstand extreme conditions.
“We went from machines weighing 300 pounds—still considered portable—down to systems that run on 100 volts and weigh 96 pounds,” said Jim Whittaker, president of Mid-Atlantic Telerad Inc., a distributor of imaging equipment in Sterling, Va.
The development of digital radiography technology means that images are available in a matter of seconds, rather than minutes. The application of networking technologies allows remote radiologists to read the images. “In the field the main idea is to stabilize and transport,” said Whittaker. “You don’t have radiologists on the battlefield and there are only a few in Iraq. The ability to transmit the images means that radiologists in Germany or stateside can read the images remotely.”
X-ray systems are continuing to get smaller, lighter and more powerful. “We currently offer a system that is used for dental applications as well as extremities that runs on Dewalt batteries and weighs less than eight pounds,” said Whittaker. “In the next few months we will have a DR system to work with this unit that will run on a PDA.”
X-ray technology has advanced from the era of film, to computer-aided radiography, and now to digital, or direct radiography. The advantage of digital radiography, or DR, is that it displays the X-ray image directly onto a computer screen in a matter of seconds. Film X-ray must be developed and computer-aided radiography, or CR, must be separately processed before it is computer accessible.
“CR is an in-between step between film and DR,” explained Chris Duca, chief operating officer of Virtual Imaging Inc., an integrator and distributor of imaging equipment in Deerfield Beach Fla. “CR still uses cassettes like film. The images are stored on an electric plate and the cassette must be carried to a scanner in order to read patient data.”
Once the CR cassette data is transferred to the scanner, the image can be sent anywhere much as with DR. But CR involves a “huge mechanical process time delay,” according to Duca, when compared to the three to six seconds it takes to transmit a DR image anywhere in the world to be read.
Canon Medical Imaging, which manufactures the DR sensors incorporated in the machines that Virtual Imaging sells, participated in military training exercises over the last two summers which led to improvements in its products. “We made modifications to make the systems work better in adverse conditions,” said Whit Fowler, the company’s assistant manager for government sales. “We made the units much more rugged.”
Canon’s innovations included larger inflatable tires to make the units more maneuverable around tents and the addition of a CD burner so that images could downloaded onto a disk which could accompany a patient’s physical chart. Canon also added a short-range wireless transmission capability with a range of 75 yards, allowing images to be zapped from one end of a field facility to the other.
The field-deployable digital radiography unit marketed by Canon comes packaged in three hardened cases. “A high resolution screen gives people in adverse conditions the same quality image as in a brick and mortar hospital,” said Fowler.
DR technology is making increasing inroads in the U.S. military, according to Duca, although it has not yet been deployed in theater. “Even in the private sector CR is being phased out,” he said. “CR cassettes have a diminishing life from their first day of use.”
The single biggest barrier to the adoption of DR technology is its perceived costs. “The panels are still too expensive at $125,000,” said Whittaker. “CR cassettes cost between $800 and $1,300. If a CR cassette is destroyed, it’s no big deal. If you drop a DR plate or scratch it, it would be an expensive accident.”
But Anne Ji, a Canon marketing supervisor, countered that the reduction in diagnosis time presents a significant advantage. “We’ve reduced the time that it takes to get an image in front of a doctor from 11 minutes down to two minutes,” she said, adding that Canon sensors can be used to upgrade CR equipment to DR without buying an entire system. She also pointed out that facilities typically spend $20,000 to $30,000 each time they order a new supply of cassettes.
Still, she admitted that “in theater they have not started to go digital.” Field DR units have been deployed, Ji added, after last year’s Pakistan earthquake and in the aftermath of the London subway bombing two and a half years ago.
Duca reported that the Department of Defense is testing field imaging equipment to identify improvised explosive devices. “Insurgents in Iraq sometimes hide IEDs in fire extinguishers, dead animals, and Coke cans,” he said. “The contents of these objects can be identified with the use of field X-ray equipment.”
Generating images is one side of the radiology equation. The other side involves the transmission, storage and processing of those images.
Philips Medical Systems provides such an infrastructure in the form of its picture archive and communication (PAC) system which connects various imaging solutions. “The system captures images produced at any location, remotely or locally, and moves them to a storage device for transmission to other computers or other storage devices,” said Eric Mahler, the company’s director for radiology health care informatics.
A Philips platform called iSite incorporates the ability to acquire pictures from any imaging modality and to proactively transmit those together with other patient information to a central or distributed destination. Philips’s iSyntax technology is a wide area network communications protocol that allows delivery of images as needed as opposed to an entire data set. “These technologies minimize manual input and reduce bandwidth requirements,” said Mahler.
Field-deployable dental X-ray equipment is also playing an increasingly important role in the U.S. military. “There are two obvious areas,” said Stefan Gefter, director of international sales for Aseptico International, a manufacturer and marketer of dental equipment in Woodinville, Wash. “First is for diagnostic purposes, the same as in a dental office. You can diagnose what is going on with the patient for problems not visible without an X-ray and without having to transport the patient for the same purpose.” The other use is for forensic identification of casualties through dental records.
“Because dentists in far-forward locations provide more emergent dental care than routine care, a field dental X-ray unit is usually used to produce images for the diagnosis and treatment of trauma-related oral and maxillofacial injuries,” added Dr. David Charlton, senior scientist at the Naval Institute for Dental and Biomedical Research in Great Lakes, Ill., “There are reported cases where dental units, after slight modification, have been used to take medical radiographs when the medical X-ray equipment was overwhelmed by a large number of casualties.”
Field units differ from traditional dental X-ray units in several ways. Traditional units are usually wall mounted with the head, the X-ray generating portion of the machine, at the end of a long folding arm. This arm makes it easy to position to reach all areas of the mouth. Another type of dental X-ray unit is the portable unit. These are similar in design to wall-mounted ones, except that they tend to be smaller and are usually mounted on a stand equipped with casters, allowing them to be moved from room to room throughout a clinic.
True field dental X-ray units are lighter, smaller and take up much less space than traditional and portable units. They tend to be powered by rechargeable batteries and, to enhance ease of use, usually have a smaller number of possible settings available for taking dental X-rays. They are often also provided in hard-shell shipping containers.
Charlton has done extensive investigations of field dental X-ray equipment. “Two important characteristics are the equipment’s size and weight,” he said. “Because the military must be ready to deploy rapidly, the size and weight of dental equipment has to be minimized. True field dental X-ray units are typically powered by rechargeable batteries, which enhances their portability.”
Charlton’s evaluations of field dental X-ray equipment have involved both laboratory testing and clinical-user testing. “Before being delivered to the clinical evaluators, the unit is measured, weighed and tested for electrical safety,” he explained. “It is then subjected to extreme temperature and humidity conditions in our environmental chamber to simulate field conditions. We also subject the unit to a number of tests to determine its radiation safety.”
Users are then asked to use the equipment and provide their opinions of the unit using a detailed questionnaire. “Some of the clinical handling characteristics evaluated include ease of use, ease of set-up, ergonomics, dependability, quality of the manufacturer’s instructions and overall performance of the unit,” Charlton said. “Future evaluations will also include assessing the degree of image resolution produced by the units.”
Charlton’s team has completed tests of one brand of portable dental X-ray unit, Nomad by Aribex, Inc., in conjunction with the Public Health Service in Barrow, Alaska, and with the Air Force at Anchorage Air Force Base, Alaska, and Langley Air Force Base, Va. “Our testing found that it performed very well and was widely accepted by the users,” Charlton said. “Because many of the X-rays taken with the unit where made while the operator held the device, we were able to evaluate the unit’s ergonomics. Although it weighs only eight pounds, some assistants reported that it was too heavy for prolonged use. It is, however, capable of being mounted on an optional movable stand. The images it produced were judged to be very good.”
Future studies will involve a number of field X-ray units from different manufacturers and will compare their features and performance in a field setting under deployment conditions.
“Probably the greatest advance in the past few years has been the ergonomic redesign of field dental X-ray units,” Charlton said. “Instead of having a traditional, rectangular, box-like form, at least one unit has recently been marketed that has a more ergonomic design. It is very similar in appearance to a battery-operated electric drill. As a result, it is easier to hold and can more readily be positioned by the operator. Continued efforts are being made to reduce the size and weight of field dental X-ray units to facilitate their storage and transport.”
For Gefter, the most significant recent innovation in field dental X-ray technology has been in the development of the battery powered systems which were introduced within the last two years. “Before, you had to plug it into a generator or other power source,” he said. “The battery-powered unit enables the same work even more remotely, where you don’t have power immediately available.”
Charlton believes that future field dental units could have a greater number of operator-controlled exposure and time settings, which could further refine the images they produce. It is also possible that units will be made smaller and lighter in the future. “However, there is a limit to the miniaturization process,” he added. “Another innovation may be the introduction of a small viewing screen on the X-ray unit similar to the screen on a digital camera. Operators could instantly evaluate an image and retake it if it was unacceptable. Not having to go to the computer to view the image before retaking it would save time and effort.”
For Duca, the adaptation of general X-ray equipment to extreme conditions has been the most important recent innovation as far as the military is concerned. “Equipment has been adapted to desert conditions and conditions aboard aircraft,” he said. “We are building products with tougher circuit boards, with moisture and debris protection, and with filters to keep out micro-fine particles.”
For the future, Duca sees portable, battery-powered ultrasound units being increasingly accepted by the military. “These units can detect head trauma and internal bleeding not otherwise visible,” he said.
But the key future innovation foreseen by Duca is the enhanced ability to transmit images over the network. “The magic word is bandwidth,” he said. “The idea is to be able to move data and images over limited bandwidth so that they can follow injured soldiers.” ♦