X-rays at the Front Lines

Written by Al Staropoli

Since WWII, the portable X-ray machine has progressed
to the smaller, better, lighter systems of today.

“The credo is always more power and lighter weight,” said Gene Mrava, manager of special projects at MinXray, a Northbrook, Ill., developer of portable X-ray systems. But it’s a trade-off between weight and power. The more powerful the unit, the more it weighs.”

Several manufacturers of portable X-rays are in the market today, including Deer Park, N.Y.-based Dynarad; Wauwatosa, Wis.-based GE Heathcare; Rochester, N.Y.-based Kodak; MinXray; San Diego-based Phillips; Bohemia, N.Y.-based Source-Ray; and Malvern, Pa.-based Siemens Healthcare. Each manufactures units with proprietary technology and distinct sizes and levels of ruggedness. They vary in size, weight, processing software and price.

The portable X-ray’s biggest advantage is that one can bring the X-ray to the patient, rather than the other way around. In a situation where time is critical, portable X-rays can move the X-ray room far forward. This is essential to be able to triage troops as quickly as possible.

“The ability to X-ray is moving farther forward to the battlefield front,” said Mavra. “Portable systems are used to determine how badly injured the soldier is and what level treatment is required.”

This helps the technician in the field to determine the person’s injuries, course of treatment and whether or not the person needs immediate medevac.

At a basic level, portable X-ray systems consist of an X-ray generator on a movable arm for greater flexibility and a capture device along with a computer and processing software. Some models can run on locations where electricity is not readily available through batteries or generators. Portables are not only used in the military; they are also seen in other settings such as nursing homes, clinics and correctional facilities.

DIGITAL BATTLE

Much has happened since the days when X-ray film and chemical processing was the only option to record images. Today, two main alternative systems exist: computed radiography (CR) and digital radiography (DR). The advantages of CR and DR over film are that neither needs chemicals, dark rooms or film storage. They also don’t use silver (a limited resource) as film does. In both systems, the image can be transmitted or electronically stored, unlike film.

CR and DR both have their pros and cons. The biggest distinction between CR and DR is how the image is captured. In CR, the image is captured and needs further processing to be digitized. DR, in contrast, converts X-ray energy into a finished image, much like digital cameras do today. In both cases, the image can be adjusted through software.

Of the two systems, CR has been around longer. It was introduced in the 1980s but became more widely used in the early ’90s. CR uses X-rays emanating from conventional radiography, but unlike film, it uses a plate to create an image.

“CR typically uses a phosphor plate that is radiation-sensitive,” said Mrava. “When the plate is irradiated, there is a latent image captured. In order to visualize the image, you need to place the cassette in a scanner, which reads the image with a laser and then erases the image to prepare the plate for the next shot. It’s like reusable film.”

The phosphor plate is mechanically removed from the cassette and bent over a drum to be read, Mrava noted. It takes about a minute to get the image back to the computer. With DR there are no moving parts.

The reliability factor is higher since there are no mechanical parts, but the cost is also higher.

CR can be used with standard X-ray equipment, although a workstation (to read the plate) and a computer (to display and manipulate the image) need to be added to the existing system. In contrast, DR usually means buying and installing a whole new system, which is generally costly. CR’s reduced cost for adoption has made it a more attractive technology. A quality CR system can cost around $50,000, compared to hundreds of thousands of dollars for an equivalent DR system. However, as it happens with most technologies, the cost of DR is likely to decrease over time.

DR’s popularity rose in the late ’90s. Instead of a plate, DR uses a digital detector to produce an X-ray image. It is considerably faster (one can obtain images in seconds compared with minutes), allowing for a greater throughput of patients, and is believed to have better image quality. Acquisition of a nearly instantaneous image allows the technician to quickly determine if a retake is needed, reducing the need for calling back patients. Mrava believes DR will likely be the next wave for the military.

CR has been around for nearly two decades, making it more entrenched in the market, but this may change in the long run as DR’s popularity grows. DR systems in portable X-ray machines are relatively new, with the first portable DR system being introduced in 2001.

CR has been traditionally seen as more flexible, as the thin, wireless cassette can easily slide under a patient who is wounded or who for other reasons can’t be moved. But in 2009, Rochester, N.Y.-based Carestream Health unveiled the DRX-1 system, the world’s first DR wireless, cassette-sized detector. The detector fits in standard machines without the need for retrofitting and transmits the image wirelessly to the console for display. The system is not yet available, but the company expects to receive FDA approval in 2009.

BEYOND DIGITAL

Useful portable systems need to go beyond hardware and be closely integrated with communication and visualization systems, according to Dr. Anthony Pacifico, the portfolio manager for medical imaging technologies at DoD’s Telemedicine and Advanced Technology Research Center (TATRC)at Fort Detrick, Md., which is developing a new filmless, portable X-ray system.

Pacifico said the center is working with GE on a next-generation portable X-ray system that is intended as a rugged, lightweight DR system. Wireless communications between the user in the field and a remote radiologist should allow X-ray images taken in the field to be communicated remotely for analysis.

“The resulting information can help medical personnel in combat support hospitals make decisions between available care or medical evacuation. It’ll be a completely integrated system, from data acquisition to image transmission, and will be ready to support the next generation of the electronic medical record,” he added.

The trend in X-ray technology today is moving from film toward electronics, but developers say they want to make sure the new systems are compatible with existing military electronics.

“We need to make sure that our technologies are compatible with the electronic world, that we are not just developing great hardware solutions, but ensuring that they integrate into the military’s current needs and future vision of medical care for our soldiers,” Pacifico said.

TATRC’s new system will be able to transmit images from the field via available communication channels and then to a radiologist away from theater. Currently, the center is testing prototypes and working on refining technical requirements for the project, and expects to complete the project in three years or less.

“The combat support hospitals often rely on experts in the U.S. or Germany for help,” Pacifico said. “Getting them information quickly and in a format that they can use readily is of paramount importance to make sure our injured servicepersons receive the very best care we can offer.”

Pacifico acknowledges that the challenge goes beyond developing new hardware.

Work still needs to be done in the research community to develop standards that will allow effortless transmission and visualization of images while bridging different technologies, he said.

Despite the need for universal standards, there is no doubt that the portable X-ray system has come a long way from the early days of clunky systems hauled in cars to the battlefield. Size, weight, reliability and image quality have greatly improved over the years. The addition of filmless has also cut down significantly on the time needed to reveal and transmit images. Over the next decade, portable X-ray systems will likely keep improving.

“We’re always striving to make it lighter, smaller and more powerful,” said MinXray’s Mrava. ♦

Back to Top 

When William Roentgen discovered X-rays in 1895, he named them “X” because of their unknown nature. This first “roentgenogram” came about when he placed his wife’s hand over a photographic plate and exposed it to the rays. It revealed his wife’s bones. Roentgen excitedly sent the plate to other scientists and published his results. A few years later, in 1901, he became the first person to receive the Nobel Prize in physics.

Roentgen was seminal in the development of the X-ray, but it would take another Nobelist to take this invention from a small German lab into the battlefield. Marie Curie, who won not one but two Nobels (physics and chemistry), greatly influenced the use of the technology by the military. Soon after Germany declared war on France in 1914, Curie realized that the X-ray could be used in wounded soldiers to identify broken bones and detect bullets or shrapnel inside the body.

She persuaded the French government to set up France’s first military centers for radiology. With help from the Red Cross, she created 20 petite Curies—a series of cars fitted with mobile X-ray equipment that could be transported to the front. Curie went to great lengths to introduce the use of the portable X-ray system in the battlefield. This was reflected in the fact that she eventually learned how to drive and operate vehicles herself and personally drove to the front in them.

Portable X-ray machines have been used by the U.S. Army since WWI. These units were sturdy but relatively large. Following the postwar period, portable X-ray machines were reduced in size and weight to make them increasingly mobile and able to move farther forward. One of their biggest disadvantages of these early systems, however, was the need for film processing.

A steel tank with chemical solutions was required, along with a “field dryer,” a machine the size of a small refrigerator, where wet film could be fan-dried. Unfortunately, extreme hot or cold temperatures affected the processing solutions and also the outcome of the exposure. A rapid processing and drying of radiographic film was needed. The Land-Polaroid process of quick film development was tried in Korea, but the detail on the resulting film was not always satisfactory. Eventually, this technical problem was overcome, and film became widely used. ♦

Back to Top