Digital radiography is a form of X-ray imaging, where digital X-ray sensors are used instead of traditional photographic film. TechNation reached out to the medical imaging industry to gain insights into digital radiography, including the advantages of using this format and how facilities with a limited budget can best afford this technology.
Industry experts participating in the TechNation roundtable on digital radiography are InterMed Vice President Dave Bauerle; RSTI President/COO Dale D. Cover Jr.; Technical Prospects Director of Engineering Kenneth Hable; and AMX Solutions Strategic Account Manager Mike Helms.
Q: What are some advantages digital radiography offers compared to film-based radiography?
Bauerle: The advantages that digital radiography offers over film based are less retakes, more accuracy, lower dose in most cases, no repeats and much less expensive processing and storage, instant access to images via the computer and huge cost savings and transport of the images electronically rather then snail mail.
Cover: There are numerous differences between film (analog) and digital imaging. Most of them prove digital to be superior. Film, being a physical object, can only be in one place at a time. For consultation with another physician you would either have to copy the film, which reduces resolution, and send it out or bring the doctor in. Digital images, because they are virtual, can be sent nearly instantly anywhere on the planet where there is an Internet connection. Additionally, because it is digital, there is no loss of resolution because the files are identical. One of the best arguments for digital is the ability to apply software enhancements and tools to the raw image. Most systems have several preset algorithms to achieve specific image outcomes even if the technique isn’t quite perfect. Once the initial processing is complete, the image is presented on a monitor. If the reading physician wishes, areas of interest can be enhanced by further manipulation of the numbers through brightness and contrast adjustment. Among the tools available with digital imaging are magnify, area measurements and quantification, computer-aided diagnosis (CAD), inversions and side-by-side comparison. Film, sadly, is static. If the resultant image doesn’t demonstrate the anatomy adequately, the only corrective action is to retake the image using another technique. This is one of the ways digital imaging reduces dose. The primary characteristic where film excels is resolution. The pixels in a digital image are larger than the very fine granules in film. This limits digital’s ability to resolve very small objects such as micro-calcifications. However, the slight loss in resolution is far outweighed by the other benefits of digital imaging.
Hable: This can be a loaded question if addressed without a qualifier; that being, what type of digital radiography are we discussing? The three primary considerations are CR (Computer Radiography) and DR (Digital Radiography) which is split into two categories; Direct and Indirect. The most obvious benefits apply uniformly and are no need for darkroom space and processing chemicals (environmentally friendly), lower overall cost of ownership versus film, more flexible image storage (on/off-site PACS) versus film archive/library, image retention and reproducibility, and image distribution (ease of transfer; CD/DVD, flash drive, file transfer or email). Additionally, depending on the qualifiers mentioned above, you may also see these advantages with the Direct DR option: improved workflow – case management (no more carrying and changing cassettes); and improved workflow – patient management (immediate image review).
Helms: The first and most significant advantage is self-explanatory – no film. Second, and really important, is dose to patient. Third, is the time necessary to get film developed and the obvious cost associated with film and screens developer/processor space and chemicals. Space and storage of film is expensive – digital storage not so much. Technicians are able to see images, check for position, content and patient coverage of diagnosis success without having to wait for film to develop. Images are available instantly on the monitor and, once processed, can be sent to the radiologist for interpretation.
Q: Is it affordable to upgrade to a digital radiography system? How can a facility with a limited budget meet the digital radiography needs of today?
Bauerle: Affordability is on a case-by-case basis however in most cases saving time saves money. Saving space by not having to store film and buy chemicals and pay for the X-ray film itself provides, in many cases, cost savings.
Cover: The easy answer is: It depends. There are several ways to upgrade to digital. The most extreme upgrade would be to replace the entire room with a system that was designed from the ground up to be digital. This is a radical step and, to be honest, not very affordable given a limited budget. Then, there are the upgrades that mount and interface physically into the existing system. These would be less expensive than a new room, but still a bit pricey. The price is compounded by the fact that the image receptor has only one room it can service, if you have a department to convert you would need to buy multiple systems. CR plates and DR panels, that mimic film base cassettes in terms of shape and form, give a facility the opportunity to convert one room or the entire department. The portability of these cassette-style detectors allow them to be used on systems such as an AMX portable to produce digital images. There is one caveat to the DR though; if the panel requires interfacing to the system for exposure window signals then you are back to the one panel, one system scenario. The latest version of the DR cassettes incorporate what is referred to as automatic exposure detection (AED) which eliminates the need for interfacing to the X-ray system so the panel may be used with every system independently. Speaking of upgrades, the new DR panels with AED will, in my opinion, do to CR what CR did to film. Look into this technology when it is time to replace your current CR system.
Hable: It is difficult to say that it is “affordable” but it has become essential to have some digital capabilities within the MI department. Smaller institutions and those with limited budgets can ease into digital radiography through a transitional pathway; where they can continue to maintain their existing exam equipment by replacing film with CR and/or Indirect DR options. Once this transition has occurred, or when new capital equipment purchases are available, making the jump to Direct DR is the logical progression. Lastly, additional costs such as film archive scanning will need to be considered along with justifying the overall expense in terms of realistic workloads, exam throughput and system serviceability requirements. Without these you will most likely not realize a decent return on investment.
Helms: Well, the answer is yes and maybe – not no! While it seems that the cost of going digital looks large at the purchase point, analyzing the overall workflow of the process, you find that the actual cost to own and use very quickly shows workflow savings, processing savings, film delivery to the radiologist and other time and physical cost savings are significant, not to mention the value to our customer’s patients in improved overall service and quality. Finding a way to stretch tight budgets is always a challenge. There are several ways to look at this: up-front costs can be scary; time and savings of personnel and, possibly, fewer people; traditional financing; non-traditional financing. There are leasing and other alternative options in the market now that even larger institutions are leveraging.
Q: What are the advantages and disadvantages of wireless detectors?
Bauerle: Today’s modern wireless detectors offer almost all of the advantages of fixed or tethered with very little downside of the possible security issues involving theft and/or a possible greater propensity to drop the cassette.
Cover: The main advantage of wireless panels is the fact that they are the same size and shape as a large format film cassette. Being the same size eliminates the need to adapt the bucky (film holder) to fit. Portability is another advantage. There are two basic functional types of wireless detectors: those that require interfacing to the X-ray system (pre-AED) and those that don’t (with AED). Pre-AED wireless DR panels still required something to inform the digital imaging system when the exposure begins telling the panel to start accumulating the X-ray signal. It is also needed to inform the imaging system when the exposure ended to initiate a read cycle of the panel. With this type of system, if you wanted to work with one panel and one reader, every system that needed to be converted would need to have an interface to the image computer. With AED you just shoot and read with no interface, similar to CR. Some disadvantages would be battery life and charge cycle issues, image storage capacity when you are out of range of the reading computer or a WiFi access point, drop survivability and being lost or left behind when used with portables.
Hable: Advantages include ease of use (such as) – no cable, lighter weight (depending on model/manufacturer), greater mobility within exam space, and interchangeability (depending on model/manufacturer and other available systems). Disadvantages are cost (initial purchase), maintenance costs (battery replacement), battery life/charge level effects availability, and transmission range.
Helms: Advantages include: wireless detectors offer freedom; no cable to deal with; versatility with respect to where the panel can be used; and patient comfort. Disadvantages include: if the detector is dropped this is costly and the industry has developed insurance for this inevitability. It is not a matter of “if” but “when” a detector will get dropped. It might not be damaged, however, it needs to be planned for. As for the safety of data, these platforms are stable and very safe to use.
Q: What are the most important things to look for in a reputable third-party digital radiography service provider?
Bauerle: The most important thing, since this is a very large investment, is trust and experience once you have made this large investment. Having the ability to fix this important technology rapidly is also of great importance in a provider as well as offering options for drop coverage that would be affordable.
Cover: I would look for the same things that I expect from any service company: trained engineers, enough staffing to meet their customer load, direct access to support services either from the OEM or other reputable sources, a track record of success and customers that are happy to recommend them. Plus, and this is important, a very strong background in IT and computers to include PACS/DICOM.
Hable: Their market presence (time in the industry). Depth of knowledge on the specific product line. Reputation and overall quality. Support capabilities.
Helms: Stability – are they going to be there for you when you need them? Efficient and timely installation and applications training. Response time – do they call back quickly?
Q: What are some of the newer technologies available?
Bauerle: DR technology is going toward lighter, faster, and more durable, due to changes in reimbursements this is a major factor when choosing the right systems and/or equipment.
Cover: There are several notable new and emerging technologies. First, as I mentioned before, the introduction of AED will have revolutionary effects on the radiographic image capture world. With AED, DR is now as adaptable as CR in that without any other modification DR can be used with any system. Another technology that will be gaining will be imaging techniques such as tomo-synthesis where the X-ray tube sweeps across the patient and makes a series of exposures during the pass and the imaging computer compiles a 3D image from the “views” acquired. Currently tomo-synthesis is used in mammography but it would have application in many imaging scenarios. Dual-energy imaging is becoming more popular as well. Thanks to advances in image processing, two images can be taken of the same anatomy at different energies. For example, from a chest X-ray, there would be three possible images produced by subtractive software: just the bones or just the soft tissues and internal organs and both together.
Hable: Improvements in digital image acquisition speeds and panel construction are enabling advanced acquisition capabilities such as dual-energy radiography and digital tomosynthesis. These advanced methods are used to overcome the superimposition limitations of conventional projection radiography while advances in image processing software will increase post-processing and 3D rendering capabilities.
Helms: Digital panels have been around for awhile, the newest and most popular technology available today is the AED (Automatic Exposure Detection). Excess dose is a real hot subject that has been virtually eliminated now by panels that react and acquire at blistering speeds. Less than a 5-millisecond response time is very common. We are now seeing dynamic panels with very fast reaction and reconstruction time so that positioning and techniques can be verified. Even during flouro studies, these panels can be utilized. Panels are now storing and maintaining up to 100 images. The weight of the detectors is coming down and cost is coming down with the competition in the marketplace and strong competition among OEMs.
Q: How can HTM departments make sure they receive the necessary literature and training tools for their digital radiography?
Bauerle: Partnering up with the right company who can align you with the resources and training is a must.
Cover: HTM departments always have the most negotiating power during the bid and purchase process. If documentation, training and special tools are not included in the purchase agreement then it may be very expensive later if you can get it at all. CR and DR systems are ancillary to the X-ray system and do not generate radiation so there is no regulatory requirement to provide documentation, much less training.
Hable: Communication with the departments involved in the evaluation and purchasing of the system is key and is often overlooked as the focus is usually placed on the acquisition of the system and not its maintenance. It is possible to build into the initial purchase support staff training and education when making a significant system purchase from a major OEM. If going with a smaller third-party provider, be upfront and request the necessary literature and discuss any additional support tools and training that may/will be necessary to maintain the product.
Helms: HTMs should be diligent to be involved with the purchase process. However, the serviceability of these products is currently very limited in scope. They should be available for the applications and installation process. Be interested and involved as the companies that sell this product are open to help and share the information. Ask!
Q: What else do TechNation readers need to know about purchasing and servicing digital radiography?
Bauerle: Sometimes the least expensive, even though it’s a wireless panel, is not necessarily the best choice. Image quality has many different components and the necessity for certain levels of image quality, such as pediatrics or mammography, have a much higher image quality need then say chiropractic or general radiography. Orthopedics require higher quality as well so it’s important to not just look at price.
Cover: With so many variations of X-ray systems and almost countless digital imaging possibilities, it is important to understand how these systems interrelate. Budgets are often the driving force for one decision over another but as a service professional with the proper education and experience you may be able to provide insight that can save money in the long run by spending a few more dollars now on a digital imaging system that will be applicable to future systems or scalable enough to handle the entire enterprise.
Hable: Digital radiography detectors (CR and DR detector systems) now make up the majority of the imaging receptor market, especially CR and Indirect DR formats. Knowledge of the different digital-based system characteristics, advantages, disadvantages and operational details will prove most significant in establishing the confidence to make informed decisions regarding purchase and support.
Helms: Be involved in the purchase process and learn all you can about the product. Service for now is going to be “black box.” There really is nothing to amount to in servicing the detectors. Have QC testing available. If the detector fails, it will most likely go back to the factory for repairs due to the design. This will not change for the product. It is a sealed item that has needs for climate control and clean room processes to rewire the internal parts.
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