Film Digitizers

Compared to the sophisticated technologies nestled in radiology departments today, there is much ado about film digitizers.

Simply stated, film digitizers convert hard-copy x-ray, CT, ultrasound, MRI and dose films to digital images that are electronically transmitted, viewed, analyzed and stored. Lightweight and compact, fitting on a desktop or hung on a wall, a film digitizer is about the same size as a fax machine.

In the process of transitioning to an all-digital imaging department, buying a digitizer may become a top priority.

Of the billions of imaging procedures performed worldwide, the majority of them are still printed on film. Few, if any, rural facilities currently are up to par technologically with the larger, more affluent institutions and account for many of the analog-acquired images. Larger hospitals with PACS utilize digitizers to get extraneous film on to the network and support legacy equipment.


Computed radiography (CR) and digital radiography (DR) modalities are shaping the digitizer market, not eliminating it. Both modalities can be costly endeavors; flat-panel DR systems are priced at $400,000 to $650,000, and CR systems run from $70,000 to $300,000. On the other hand, depending on the type purchased, digitizers are priced at $16,000 to $32,000.

"In the beginning, CR and DR came out and it was said that film would dissipate, which is not true. Film digitizers actually complement CR and DR applications," says Tom Nardozzi, president of Array Corp. U.S.A. Array has manufactured and sold its fifth generation 2905 laser digitizer since the early 1990's.

The Medical Center of the University of California-San Francisco (UCSF) utilizes CR and DR units and supports facilities that cannot afford the technology. Exams from hospitals in India, Israel, Holland and England, as well as U.S. county hospitals, deliver images over the network to UCSF using a film digitizer.  "The images are sent to be read wherever the expert is, but not necessarily where the image was taken," says Dr. Katherine Andriole, assistant professor of radiology at UCSF. 

As technology improvements continue, prices will inevitably lower. When this price decline will happen, however, remains uncertain. Some scanner companies are projecting the total market for digitizers to run between 1,000 and 1,200 units annually in the United States over the next several years.

"The real definition of filmless means 80 percent, 85 percent, 90 percent reduction in film usage," says Gary Reed, PACS consultant for Integration Resources Inc., of Lebanon, N.J. Since implementing a PACS works best in a phased approach, room is left for extraneous film to be generated, whether it's produced by legacy equipment or brought in by patients themselves.


Legal issues that concern archiving film influence a hospital's plan to go filmless. Currently, no national standard exists as to how long a radiography study must be saved. "Each state has different standards, however, they are broken down to include protection for minors, which are usually maintained longer than adult exams," says Nardozzi. Good clinical practice requires hospitals to keep patient x-rays on file for at least five to seven years.

The existence of film libraries in almost every imaging department and the legal requirements to archive prior images make certain that film and soft-copy reading will co-exist for many years.

Providence Health System's St. Joseph Medical Center went live with a PACS in March. "We use [scanners to] digitize films produced in surgery, because we are adding PACS to our surgery suites on a phased approach," says PACS administrator Daren Burns. While Burns believes that at least one digitizer is required in every radiology department, he does not see any necessity to archive all of the patient's film-based history digitally.

Administrators, radiologists and technologists must equally evaluate how the medical device will contribute to workflow by identifying its predominant application use: PACS, teleradiology, mammography or computer-aided detection (CAD). Determining the needs and goals will influence the type of digitizer purchased.

"The magnitude of the film archive, the speed and magnitude of the proposed PACS implementation, the speed and the micron size of the scanner, and the mix of modalities being scanned should all factor into the equation," says Reed.

Howtek Devices, a division of the Boca Raton, Fla.-based iCAD, recently launched Fulcrum, made specifically for mammography applications. Eastman Kodak Co. manufactures a line of laser scanners, including the LS75, designed for high-resolution teleradiology applications. Vidar Systems manufactures the DiagnosticPro plus digitizer which is sold by a large roster of original equipment manufacturers.

Unlike Kodak's LS75 and Array's 2905, the DiagnosticPro falls into the second generation of scanners that employs a charged couple device (CCD) to capture images. CCD digitizers have improved significantly in image quality and reliability from early models. Once again, which type to purchase hinges on the exigencies of each hospital. CCD digitizers are generally less expensive than laser scanners, but not as flexible in utilization as the latter.   


No legal precedence has been established for which resolution to use for which application. Film digitizers come with different sets of micron sizes. Switching from one size to another is much easier than deciding on the micron size for different modality types and applications.

 "There are two governing bodies for x-ray scanning," says Stephen Neushul, president of Radiographic Digital Imaging, Torrance Calif. "The FDA checks that manufacturing practices and standards are met and the American College of Radiology has a standard for secondary capture devices and teleradiology (2K at 10 bit). These are the guidelines radiologists should follow," says Neushul.

Radiologists should rest assured that digitizers produce images equivalent to the original. According to Neushul, scanning technology is better than ever. RDI manufactures the slim-design, CCD Cobrascan line, including its flagship model, 2000SL.

Analysts project that the surging popularity of CAD devices will push the digitizer market well into the next decade helping to bridge the gap between conventional radiography and digital imaging.