One of the biggest questions chiropractors are facing in X-ray today is what is the best way to "go digital".
The answer is, it depends on a lot of variables. However, proper up-front understanding of the technologies and alternatives can make for a better decision and can create a positive long term effect on your practice.
With respect to the different technologies, there are basically two approaches for going digital—CR (Computed Radiography) and DR (Direct Digital Radiography). Both technologies produce digital images, but in different manners, with their own set of pro’s and con’s.
CR (Computed Radiography)
A CR system includes CR cassettes and a CR scanner. The CR cassettes contain a special screen that captures the X-ray image. The cassettes are inserted into a bucky or grid cabinet, just like film cassettes, and all of the imaging is performed in the traditional manner. After the X-ray is taken, the cassette is removed from the bucky or grid cabinet and inserted into the scanner. The scanner can sit in the X-ray room, so no dark room is needed. The scanner will scan the image screen and display a digital image on the monitor. This process usually takes less than sixty seconds.
One of the biggest benefits of CR is that, in most instances, you can use your existing X-ray system, as long as it is reasonably current technology. It should be at least a 300mA/125kV system, preferably high frequency. Very old systems with limited power will have the same challenges making high quality CR images as they do making high quality film issues.
Things to look for in a CR System:
Image Quality: There is a variance in image quality of the different CR systems on the market. Much of that is due to image processing. This is a computer program within the CR system that takes the raw digital image data and converts it to an image which is displayed on the monitor. The top performing systems provide images that show excellent skeletal detail and soft tissue detail in a single image. The operator always has the capability to "window and level" the image further to enhance the visualization of specific pathology.
System Speed: This refers to the dose sensitivity of the system. Most chiropractors are using 400 speed film/screen systems with their current film imaging. CR systems also have a relative speed, although the measurement varies slightly from film. This relative speed may range from 200 to 400, based on the specific brand of CR. The higher the speed, the lower the dose and the shorter the exposure times. This is especially important on large patients where motion and overall system penetrating power can be a challenge.
Ease of use: All CR systems have a computer with monitor, keyboard, and mouse which are used for reviewing the images and managing the commucation/storage of the images. The software should be intutive and easy to use. Advanced systems will typically include a medical grade touch screen monitor.
DR (Direct Digital Radiography)
DR uses a digital capture device that takes the place of the bucky or grid cabinet in a wall stand or an X-ray table. With DR, the image is captured directly with the digital image receptor, so there are no cassettes to handle or feed into a scanner.
One of the benefits of DR is that the image displays on a monitor within a few seconds after the image is taken, and there is no handling of cassettes. However, DR is substantially more expensive than CR. Also, upgrading to DR usually entails buying an entire new X-ray system as opposed to upgrading an existing one.
Things to look for in a DR system:
Image Quality and System Speed: There is also a variance in image quality of the different DR systems on the market. Much of that is due to the imaging system, itself. Most DR systems for chiropractic imaging use a CCD based digital camera system. The X-ray photons strike a scintillator plate and are then focused through a lens and on to a CCD chip. The material the scintillator plate is composed of plays a large role in the image quality and dose sensitivity. The two most common materials for the scintillator are Gadolinium Oxysulfide (Gad-OX) and Cesium Iodide. These materials affect both the image quality and system speed.
Cesium has substantially higher dose sensitivity and, therefore, requires less dose and the images typically have lower noise. However, a system with a Cesium Iodide scintillator is usually more expensive. Gad-OX has a lower dose sensitivity and, therefore, requires higher dose, but is typically less expensive. Image processing also plays the same role as mentioned with CR systems above.
Ease of use: All DR systems also have a computer with monitor, keyboard, and mouse which are used to review the images and manage the communication/storage of the images. As with CR, the software should be intuitive and easy to use.
Which is best for you?
It depends on a number of factors, including your current X-ray system, exam volume, type of practice, and budget. The most important thing is to do your homework up front and make sure the system will provide the following:
• Excellent image quality at reasonable dose levels
• Ease of use
• Will perform well with your current X-ray system
• Fits within your budget
• Is supported by a dependable and knowledgeable local dealer who has exten sive experience with installing and servicing digital X-ray systems. This is crucial when making the decision as to from whom you will purchase the equipment.
Additional important issue when you go digital
The equipment discussion above dealt with the technologies used for acquiring the X-ray image digitally. Also important is the viewing, storage, and transferring of the images. The key is to establish a plan up front of where and how you want to be able to review, recall and store the images. A PACS system is the proper way to complete the system and accomplish these functions (Picture Archive and Communication System)
Viewing images: Most doctors will want to send the images from the digital imaging system, either CR or DR, to a computer in their own office where they can review the images, mark angles, and add annotation. In addition, some may want to be able to display the images in an exam room for patient consultation. This will require computers with the appropriate viewing software and licenses. Web-based access to the images is also available for reviewing images remotely.
Image Storage: This is an important area to focus so images are always safe and secure. There are a number of alternatives based on your volume and budget. In addition, you may want the ability to burn images on a CD for patients to take with them. This can be a good way to market the modern digital imaging technology that you are providing through your practice.
Terry Yochum, DC, DACBR, Fellow, ACCR is director of the Rocky Mountain Chiropractic Radiology Center in Arvada, Colorado. He can be reached with questions pertaining to this article at 1-800-742-4476 or at