I sat down with a couple of experts to get the answers to some questions asked by our customers.
My first conversation was with Richard Spaedt, vice president at Medical Imaging Innovations. Richard is a leader in the field and was able to shed some light on key areas.
What you should know about computed radiography (CR), digital radiography (DR) and film
"CR and DR are the two main ways to make digital X-ray. Each has their pros and cons, but the market is clearly moving toward DR for a variety of reasons," said Richard.
According to the Conference of Radiation Control, Computed Radiography, or CR, records radiographic images to a phosphor plate. This process is similar to the workflow associated with film and chemistry, but instead of going to the darkroom to develop the film, the image is recorded on a CR cassette. This cassette is scanned and converted to a digital format so it can be saved and displayed on a computer. The cassette can be cleaned and reused. CR is faster than the film process and can be less expensive than DR.1
"Film takes longer to develop the image than both CR and DR and has an on-going consumable expense of the film and processing. It also exposes the patient to more radiation," Richard added, "but, if you are doing small volumes and looking for the least expensive outlay up front, this may be worth considering. Just be careful to factor in the long-term costs of the consumables and watch regulations that may require connectivity and legal requirements for backup."
Richard also noted, "In most cases if you did an ROI on a lease payment for CR with mini-Picture Archiving and Communications Systems (PACS), you'd end up having lower long-term costs as the consumable costs with film and chemistry will continue long after the lease payment if over."
The US National Library of Medicine states that Digital Radiography, or DR, is a direct digital capture of an image, instead of a capture and convert process like CR. DR provides better image quality and the ability to capture multiple images quickly. It also exposes the patient to the lowest dose of radiation.2
Richard commented, "Industry wide, DR pricing has come down significantly in recent years, and a 17x17 DR detector is now only marginally more expensive than complete CR units. DR provides a better long-term value - savings in time and maintenance. DR upgrades, as well as CR reader installations, can be performed same-day on X-ray units."
Here's a snapshot from Medical Imaging Innovations on the features of CR vs. DR.
| ||CR ||DR |
| Equipment Size (footprint) ||X ||X |
| Faster || ||X |
| No Removable parts || ||X |
| Lower Patient Exposure || ||X |
| Higher Quality Image || ||X |
| Lower Purchase Price ||X || |
Richard explained, "Although CR is faster than film, CR is slower than DR - minutes compared to seconds. With CR, the workflow only changes minimally from traditional analog film and chemistry: it takes time to remove the cassette, read it, clear it, and replace it. With a limited number of cassettes, this impedes patient care, as there are many exams where you could have more images needed than cassettes on hand. There is also no validation of the image quality with CR until after it has been processed."