Understanding Digital Radiography

What is Digital Radiography?

What is Digital Radiography (DR) Technology?


The easiest way for most people to relate to this advanced technology is to first think of the older film based personal cameras. 

Before the digital age, people had cameras that had to be loaded with bulky rolls of film, that not only were difficult to load; but you were unable to manipulate, delete, or view each image after taking it. You didn't know if the image you had captured really represented what you wanted it to, or if the picture was exposed or lit correctly.


When you finished the roll, because you didn't want to waste the expensive film; the film had to be safely removed so it was not exposed to any excessive light take the roll to be developed using a process that took a long amount of time and involved environmentally harmful chemicals; all before you could see your finished product - the picture. 


Once you had your pictures back to look at it was important for you to make sure the film the pictures were developed from was kept safe and dry in storage for future reference. 


What a process!


 With the introduction of digital technology you now take your picture, view it within seconds, manipulate it, and even have the option of sharing it electronically with friends and family. All without the use of environmentally damaging chemicals, expensive film and the commitment of storing your processed film.

Advances in technology and decreased costs of digital sensors have allowed this digital imaging process to be applied in the medical field in many formats.
 

IDC developed a patented Digital Radiography (DR) technology that provides high resolution X-ray images at a low radiation dose most often encountered with film, Computed Radiography (CR)  and some alternate DR technologies available in the market.


Based in Calgary, Canada, IDC is an emerging leading provider of this high performance DR technology and rapidly capturing a global market share with an install base in over 50 countries.


IDC uses one large CCD (Charge Coupled Device) in its proprietary X-ray technology.

With this innovative design there is no need to align or compensate for multiple cameras focusing on different quadrants of the digital receptor in the acquisition process.   

 

What does this mean?  

The X-ray image captured has no pixel overlap and does not need to have special processing of the overlap areas.


This allows the Radiologist to view a clean, very high resolution image without concern of information being lost in the acquisition process.


Differences between CCD Technologies


A number of DR manufacturers use CCD based technology, developing very complex systems with multiple components instead of a single CCD.


IDC's single CCD system is a more efficient design and allows for a high resolution X-ray image to be captured with less dose required.


The IDC imaging detector design has a superior cooling system. Instead of using water like many other DR manufacturers, which requires hoses, pumps, and cooling which can leak or drip in the sensitive detector; IDC uses a fluid-free chip-based cooling system.

 


 

Digital Radiography (DR) vs. Computed Radiography (CR)


Industry reports pose the decision as choosing between CR as the economical system and DR as the fast system that could triple throughput of patients. 


With IDC’s patented technology and value proposition there is little doubt on the best choice:  IDC offers the best DR on the market for about the same price as CR.


The efficiencies of DR are well documented. It is a truly digital system with no cassettes and therefore none of the time consuming steps needed to process them. Images are ready for viewing in seconds instead of minutes, and DR produces excellent spatial resolution and higher quality images.


The recommended list price for IDC DR technology compares favorably to CR and is lower than Flat Panel technologies and other CCD based DR systems available on the market.

 



DR Technologies: CCD vs. Flat Panel

The two main technology platforms available in Digital Radiography are CCD (Charge Coupled Device) based detectors and Flat Panel (either direct or indirect capture) detectors.


At the core of the IDC proprietary DR technology is a very high density CCD (VHD CCD), lens, and scintillator (filter).


An X-ray beam is focused at the imaging detector. In medical applications the anatomy of the patient that needs to be examined is positioned in front of the detector. As the beam passes through the anatomy and hits the detector it is filtered by a scintillator.


The scintillator comes in different substrate materials and in this application it is most often Cesium Iodide (CsI) or Gadolinium Oxysulphide or Gaddox (GdOS). The scintillator emits light from exposure to the X-ray beam and is deflected by a mirror on to a lens which focuses the light onto the 9 or 16 Megapixels of the CCD dependant of the platform of IDC technology.


The main difference between Flat Panel technology and the IDC’s VHD CCD based detector is that it does not have any electronics in the radiation field which will degregate over time from repeated exposure and have to be replaced.


Flat Panel systems - either direct or indirect - use thin film transistor (TFT) layers that capture the X-ray generated electrons.  Unlike CCD technology, the electronics in Flat Panel systems are in the direct radiation beam which causes degradation to the electronic components and can cause them to fail. To better protect the electronics, and reduce the risk of failure; Flat Panel manufacturers “harden” them, a process which can reduce the efficiency of the image information in the conversion process.


These complex electronic TFT devices have layers of components that are surrounded by protective casings. In order to produce the Flat Panel technology, an array of smaller devices are tiled together which prevents an entirely seamless X-ray image to be produced; allowing for critical information in the X-ray image to potentially be overlooked by the Radiologist.


Another important difference between CCD and Flat Panel technology pertains to fill factor. The higher the fill factor, the higher the resolution of the image and the lower dose required.


IDC has 100% fill factor. This means out of the 9 Million or 16 Million pixels in the two different platforms of the IDC technology, 100% of the pixel area is used. 


The Flat Panel technology has far lower fill factors because of the electronics running through each pixel which reduces the X-ray capture surface area.

If you have a 9 Megapixel camera think of the imaging field full of 9 Million little buckets. Each of these buckets need to be filled with the X-ray beam to create a full, clear image.  In the Flat Panel design there are 'bridges' between the buckets which take up space and don't allow the buckets to fill completely.


In the IDC imaging detector design the single CCD, with no additional components, means that all 9 Million buckets can be filled to the top. This create a very clear image of all anatomy in the imaging field and allows for a more optimal reading by the Radiologist for diagnosis. 


As the 9 Million buckets are easy to fill and have little to no barriers to overcome, this means there is less of a force, in this case X-ray, to be used. Resulting in less dose received by you, the patient.

 

IDC 100% fill factor + low radiation = high resolution X-ray image and maximum efficiency


  

CCD Learning Resources

For information on NASA's use of CCD technology in the space program: click here



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