With the click of a button, the bones disappear from the X-ray, leaving the dark outlines of lungs and white impression of muscle and flesh.

Another click of a button, and the organs, muscles and other soft tissue disappear and the X-ray shows the bones.

Digital radiography is to radiology what digital cameras are to photography. It provides access to X-rays and other radiology services almost instantaneously.

The technology makes it possible for the multiple images Wayne Muth, director of radiology, showed on the screen in the digital radiology room at Medcenter One.

Patients only need one X-ray taken for the shot that gives the radiology department three images. It's like a double exposure, with one taken at a high kilovolt and the second at a low kilovolt, which are taken seconds apart. A computer program that operates the digital X-ray machine gives radiologists the option of viewing it as a traditional X-ray or as a soft tissue or bone X-ray.

In addition to the three-in-one imaging, digital imaging in radiology gives radiologists the ability to control quality of the image. The biggest factor controlling quality is the elimination of processing film. With the digital radiography machine, the radiologist gets an image within 10 seconds, compared to 90 seconds it used to take to process. This reduces the amount of time it takes for the technician to decide if another image needs to be taken, Muth said.

A digital image also gives a more accurate image, and one that can manipulate factors like brightness, said Amy Hofmann, director of radiology at St. Alexius Medical Center. St. Alexius also uses digital imaging in its radiology department.

"It's immense in terms of keeping files clean and ready to access," Hofmann said.

In the past, there could be problems with processing film that would not give physicians the clarity, contrast or brightness desired on the X-ray. With a film X-ray, there is no latitude to change the contrast or brightness, as there is with digital.

Digital images give physicians the ability to access the X-rays through a digital database, and for more than one physician to view it at the same time. It also cuts down on the cost of copies for patients because they burn a CD instead of making copies of the films.

"In the past, you would make a copy of the film, and that was costly," Hofmann said. "It could cost the patient $50 to $70 (for copies); now, it is 30 cents."

A CT scan, for instance, could consist of 10 films, and it cost them $7 per film to copy, she said. It also takes much less time to make a CD of the digital images, she said.

The digital technology is showing up in more hospitals and clinics as radiology departments are replacing equipment, Muth and Hofmann said. It is a costly but necessary technology. As it becomes more common, it is dropping in price and is coming into more rural areas.

"If they had money in their accounts (for the technology), they would be buying it today," Hofmann said. "It is an advantage to be in that playing field."

At St. Alexius, for instance, the digital archiving of the radiology images, instead of storing film, has dropped from $5 million five years ago to $1 million, Hofmann said. Medcenter One is moving to the digital archive system, known as Picture Archive and Communication System or PACS, this year. Currently, it archives images on film and stores images digitally for 12 to 18 months, Muth said.

Facilities that don't have it are likely considering it in the future, Hofmann said. It helps with recruiting and retaining radiologists, she said.

In the meantime, facilities are meeting a radiologist shortage through teleradiology. St. Alexius has an agreement with a radiology service in St. Paul, Minn., to read its images after hours, in the evenings and on weekends.

Digital imaging can be used for conventional X-rays, CT scans, MRI and nuclear medicine.

(Reach reporter Sara Kincaid at 250-8251 or sara.kincaid@;bismarcktribune.com.)