The Tale of the Tape:
If CR (computed radiography) and DR (direct radiography) were two championship prize fighters they would very likely be combating one another in the medical imaging ring. DR would be the new challenger with fresh appeal and a faster tempo but carrying a heavier weight price. CR would be the current champion whose range and abilities show flexibility but whose style is decidedly old-school, not next-generation.
Unlikely to be decided in just 12 three minute rounds, the CR versus DR competition is more likely to play out for some time to come and will, in the end, be judged by performance and price. The competition between the two modalities is as tough as that among the best fighters in the ring. From a technology perspective, CR and DR are fairly well matched. Both are digital modalities and offer relative advantages including the same post-image processing.
Medical Imaging magazine’s Renee Diiulio talked to vendors, technologists, and managers about the tale of the tape of these two modalities:
“The advantage of having a digital image, whether CR or DR, is that you have a wider dynamic range and can take advantage of advanced processing tools that can enhance the image,” says Penny Maier, director of marketing for imaging systems at FUJIFILM Medical Systems USA Inc, Stamford, Conn.
Fredrick Walker, radiology technologist at Sharp Rees-Stealy in San Diego, added: “If an image is too dark, we can now window it or shadow it or make it lighter without having to reshoot, he says. Patients are exposed to less radiation and exams can be faster than what was achieved with traditional x-ray film technology.”
Depending on the vendor, the workstation and interface may be the same for both CR and DR. “Techs have the convenience of using the same tools, and radiologists see images with the same look and feel regardless of where the image was acquired.” Maier said.
But the process of image acquisition between CR and DR is quite different. Cassettes, standard to CR, are eliminated in the DR workflow allowing for fewer repetitive motion injuries and faster acquisition times.
Alan Hill, lead technologist at Kaiser Fair Oaks in Fairfax, Va, experienced degenerative changes in the bases of his thumbs using CR, which prompted a switch to a DR system. “Every time I took one image with CR, I handled the cassette six times. Since switching to DR, the problem has disappeared,” Hill said.
Workflow has also been streamlined. “The fastest time we clocked using CR was 35 seconds per image. For DR, the same process was 3 seconds,” Hill said.
Tim Martin, radiology director at Cabell Huntington Hospital in Huntington, WV, has made similar comparisons. “DR acquires images in about 6 seconds versus 45 seconds for CR. DR really streamlines workflow, so the time frame from patient setup to image acquisition is less,” Martin said.
Faster acquisition results in shorter patient visits and therefore greater patient satisfaction. “Once the patient is in radiology, an exam that used to take about 25 to 30 minutes now takes about 10 to 12 minutes using DR,” Walker said. Not only is a quick visit more convenient, but it may also be less stressful, particularly when results are reported more rapidly.
Where CR still holds a clear advantage is in its flexibility and portability. “The big advantage CR can provide to a technologist in a clinical application is the flexibility the cassette brings in a trauma environment or the OR, where you need to position a cassette to record an anatomical area in an unusual place or as a lateral,” Maier said.
The differences are narrowing however as DR manufacturers bring new systems online. Canon offers portable DR that extend applications to neonatal and trauma. Fujifilm also offers a portable system, the FCR Go, as well as the new Unity SpeedSuite system that features a u-arm that can rotate around the patient to accommodate lateral views.
“DR is definitely the way of the future. I think we are going to see CR become an obsolete modality within the next 3 or 4 years,” Hill said. Though many don’t agree it will occur that quickly, DR does have its proponents who believe that the biggest obstacle to its domination is its expense.
Those who have compared the long-term cost of the two systems believe they are comparable and that perhaps DR offers a better deal in the long run. The ability to handle a greater volume of patients means more revenue generation and greater efficiency. DR devices often require less space than CR units, and the extra room can be used to install more units or fulfill other needs, such as physician and staff offices.
Some DR installations may also be able to reduce personnel costs. “If you can utilize an imaging assistant to take the place of a technologist, you can cut the salary budget in half,” says April Hammarsten, central region radiology supervisor at Sharp Rees-Stealy.
DR’s elimination of cassettes not only deletes the consumables costs at $2,000 to $5,000 per cassette but also results in less related expense for workers’ compensation and less time off for technologists suffering from repetitive motion injuries.
“DR costs more up front, but the maintenance of CR ends up costing more,” Hammarsten said.
You can expect DR and CR to share the ring for more than just 12 rounds. Technologists can make themselves more marketable by learning both methods. Generally, the basic radiographic principles are the same. There is a learning curve as systems move from conventional film to digital and from CR to DR, but it need not be intensive or complicated. “The training is so simple that you can take techs coming directly from film and train them in a DR environment and they will be successful. Even older techs who are computer illiterate will eventually catch up,” Hammarsten said.
As the price of DR continues to come down it will become more attractive. Some DR systems are already at the price of CR, however there are applications where CR is clearly the only choice. Some day soon there will be a DR and CR product in every price category.
So, just like in the championship ring, the question is: Can the fighter perform in a higher weight class as he or she did in the lower one? Clearly the real winners are the facilities who embrace these evolving technologies and the patients they serve.