The Wonders of Digital Radiography

Digital radiography is one of the most important technological advancements in medical imaging over the last ten years. Using the radiographic films of the past in x-ray imaging is likely to become outmoded within a few years. Similar to the replacement of standard film cameras with digital cameras, digital radiography images can be immediately obtained, revised, if necessary and then sent to a network of computers.

The benefits of digital radiography are vast. To begin with, radiological facilities or departments can become filmless and the technician or physician can view the requested image on a desktop or a personal computer and often report a diagnosis within just a few minutes after the examination was performed. The images are no longer stored in a single location, but can be seen at the same time by physicians who are miles away from each other.

Another major advantage of digital radiography is that radiographic images can be viewed immediately, rather than having to wait for film to be developed. Many physicians and dentist feel that this benefit, alone, is enough to cause a medical facility to switch to using only digital radiography equipment.

Just as important and beneficial, is the ability to enhance images using digital radiography. Digital radiography lets the technician make the image lighter or darker, increase contrast, increase images, and make other changes to the original image to assist in easier diagnosis of any irregularities.

In addition, the patient can be given the x-ray images on a CD to take to another physician or hospital, thanks to digital radiography. Radiographic images can be stored for years and easily retrieved when needed, and from multiple locations. Digital radiography has been very helpful as huge patient files that are difficult to keep track of are no longer necessary.

It is also no longer necessary to weight the risks of x-rays, as it exposes the patient to radiation. Digital radiography has reduced the amount of radiation the patient is exposed to by 70-80%, which is particularly important when multiple images are necessary in dental or medical applications.

A Look at Digital Mammography Systems

Designed to produce radiographic images of the breast, mammography x-ray systems are primarily used for breast cancer screening, staging and grading, and pinpointing specific diagnoses in patients displaying symptoms. Most mammographs show magnified views of the breast, as well as spot images. Special stereotactic attachments facilitate performing stereotactic biopsy procedures. Digital mammography images can be achieved either by a full-field digital detector, or by using CR cassettes and a CR reader. Also, a small-sized digital detector can be integrated into an analogue mammography for image spotting and for of guiding stereotactic biopsies.

The major components of a mammography system are:

• The pedestal support for the tube, the breast platform and the cassette holder or detector
• The X-ray tube assembly, including the collimator and the filters to reduce low energy radiation
• The breast-holding platform and compression paddle
• The detector or cassette holder

There are several benefits of using digital radiography:

• More efficient storage of and access to images
• Fewer retakes
• Better visualization of dense breasts
• Availability of image post-processing and image manipulation

Clinical studies have been reported and generally suggest that digital mammography provides either equal or better imaging performance than film or screen imaging. Digital mammography systems usually have a deeper dynamic range. It is important to note that pixel size is not a good indicator of spatial resolution, as the noise and blurring effects in the detector system can have a significant effect on resolution. In addition, different types of detector technologies have different noise and blurring characteristic.

The user interface should enable full visualization of image data. Standard imaging processing typically includes:

• Magnification, zoom and roam functionalities
• Window and leveling (contrast and brightness)
• Image flip and rotation
• Edge enhancement and noise reduction
• Black/white inversion