What's new in Diagnostic Radiography

If you're like me, you might have learned the practice of radiography on plain film with chemical processors and that oh-so-familiar darkroom smell. Manual techniques actually used to appear differently when you doubled your mAs or altered your kVp to adjust scale of contrast. You may currently miss the ability to create a soft-tissue technique for an extremity without post-processing manipulation or to use extremity film at 50 kVp and obtain the best recorded detail imaginable. You may feel that the skill that you were once good at has become obsolete. Well, let's face it, a lot of that knowledge gained only from experience is becoming unneeded.

I remember my earlier days of radiography in the late 1990's when our facility received the first CR system in the local area. All of the hospital administrators from competing hospitals toured our facility in amazement when they saw how you could manipulate the image in PACS. I remember the technical conversion from our regular 400 speed film to CR... we were told to begin by trippling our mAs on every exposure. Of course, this seemed like an outstanding increase in radiation to the patient, but we were told that it made up for the amount of repeats required on conventional film due to improper technical factor formation. All you had to do was perform post-process manipulation and you could turn it in. We were the test site... there was no S number or exposure index. We were to create technique charts and give them to the engineers from the company that provided us the equipment.

Well, some time has gone by, and the amount of radiation required for a CR image has gone down quite a bit. We have more accurate ways of optimizing our exposure factors and we're more strict with quality control. But DR equipment has been making some incredible changes lately. Sure, DR technology has been around for some time, but for many facilities, it has not yet been cost-effective to switch the whole department over to DR. The advantage of CR is the hospital may utilize old x-ray equipment (tables and tubes) without paying for a room overhaul. Most administrators are probably holding out for the benefits of the new technology are great enough... or until the competing hospitals make the switch.

In the former scenario, I don't think it will be long before those benefits will be top priority. Some of the new software applications that are being utilized are amazingly successful at performing tasks previously unseen on CR or plain film. Take for instance a typical lateral c-spine projection: You only see C-6 on your film and you have to shoot a swimmer's. As displayed on GE healthcare's website, there is a new feature called "tissue equalization" that provides the same radiographic density throughout the entire image regardless of differences in anatomical thickness.



There is also another feature called "dual energy subtraction" which allows different anatomy to be better visualized all with the same exposure. As GE states, "Dual energy imaging is a subtraction technique based on the different attenuation characteristics of soft tissue and bone. The two images during the PA chest exam use different energy spectra. Information from the low-energy image (60-80kVp) is combined with information from the high-energy image (110-150kVp; the same image as a standard PA exam) to generate bone and soft-tissue images. The dual energy algorithm has been optimized for thorough removal of bone from the soft-tissue image, while minimizing image noise."







Expect to see more integration of different modalities into the general diagnostic realm in the near future as well. The "Arcadis Orbic 3D" from Siemens Medical is a newer c-arm that can perform 3D images, or basic axial CT slices on extremities in the OR.



Here is an image from their website:



You can view an entire study here (it may take about 30 seconds to load with a cable connection).

In a way, I'm saddened by the inevitable loss of a skillset learned in plain-film imaging. I will miss being able to take a really nice sternum image at 55 kVp or some ribs at 60 kVp and see a noticable difference. However, one of the exciting aspects about this field is the constant lunge of technology into the previously unheard of. It is a great time in our field and we are on the brink of new imaging capabilities every year. We have to keep changing with the technology, and continue to strive for imaging excellence.