AJR 2005; 184:1021-1023
© American Roentgen Ray Society
The Electronic Viewbox
Charles T. Lau1 and
Warren B. Gefter1
1 Both authors: Division of Thoracic Imaging, Department of Radiology, Hospital
of the University of Pennsylvania, 3400 Spruce St., 1 Silverstein,
Philadelphia, PA 19104.
Received January 28, 2004;
accepted after revision June 30, 2004.
Address correspondence to W. B. Gefter
(Warren.Gefter{at}uphs.upenn.edu).
Abstract
OBJECTIVE. We describe an effective, resource-free method for
facilitating the comparison of film-based and PACS-based radiographic
studies.
CONCLUSION. Side-by-side comparison of film-based and PACS-based
radiographic studies is often inconvenient because of the absence of an
ergonomically satisfactory viewbox near the workstation. With a simple
maneuver, any PACS display monitor can be used as a rudimentary viewbox,
providing a convenient and ergonomically effective alternative.
Introduction
Although the survival of radiographic film has become increasingly
endangered in radiology departments using PACS, it is still impossible to
escape film in everyday practice
[1]. Commonly, a radiologist is
forced to move back and forth between a PACS workstation and a traditional
viewbox when a comparison study is available only on film. We describe a
simple method to permit side-by-side comparison of PACS and film-based studies
at the PACS workstation that requires no viewbox, no additional hardware, and
no financial investment.
Materials and Methods
In our radiology department, situated in a major university hospital in a
large city, PACS has been in widespread use for more than 7 years. Despite the
large archive of potential comparison studies available on PACS, film-based
studies are still routinely encountered. This frequently occurs when a
comparison study arrives from an outside institution on film.
In some reading areas, a traditional viewbox may not be in close proximity
to the PACS workstation. In other areas, a traditional viewbox is nearby, but
placed in an ergonomically unsatisfactory location that prevents easy
side-by-side comparison, leading to disruptions in normal workflow
[2]. The task of comparing
studies can often become frustrating or cumbersome, even if only a cursory
review of a film-based study is required.
The presence of multiple display monitors at PACS workstations and the
inherent flexibility of most PACS software packages permit a simple solution
to this problem. By simply zooming a random bright pixel or region in any
radiographic image to the full size of the screen on which it is displayed, a
radiologist can create a large homogenously illuminated field against which to
transilluminate a film (Fig.
1A). On PACS workstations where the magnitude of maximum zoom is
limited, adjusting the window and level values to "burn-out" any
radiographic image can create a similar effect
(Fig. 1B). With very little
effort, any PACS display monitor can be converted into a rudimentary
viewbox.
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Fig. 1A. —Two methods of creating an electronic viewbox. Four consecutive
screen-captures from PACS display reveal that zooming a bright pixel within an
enhanced vessel to the full size of a display window creates a large,
homogeneously illuminated field.
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Fig. 1B. —Two methods of creating an electronic viewbox. Four consecutive
screen-captures from PACS display reveal that adjusting window and level
values to "burn out" a radiographic image can also create a large,
homogeneously illuminated field.
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Discussion
A number of different solutions exist to facilitate comparison of PACS- and
film-based radiographic studies. Three methods are in common use at our
department and sister institution.
One alternative used in our radiology department involves the digitization
of entire sheets of radiographic film into PACS as single images. Although
this method permits in-house archival of films from outside institutions,
interpretation of CT and MRI studies prepared in this manner has proven to be
time consuming and difficult. When a digitized sheet of film containing
multiple image slices is displayed in its entirety on a PACS monitor, in
exactly the same way a sheet of radiographic film would be presented, the
resolution of each individual image slice appearing on the display screen
becomes markedly compromised. As a result, the radiologist cannot simply look
at the digitized sheet like a radiographic film, but must roam over the entire
sheet with a digital magnifying glass to inspect each individual image slice.
Alternatively, the radiologist may choose to zoom the entire film to provide
an acceptable amount of resolution. However, the entire sheet no longer
remains visible on the display and the radiologist must pan throughout the
entire sheet, an equally wearisome task. Both alternatives require an
excessive amount of manipulation and are much less ergonomically satisfactory
than looking at a true film.
A second alternative, used at our sister institution, relies on the use of
specially constructed desks at each reading station. A row of viewboxes is
mounted on a special frame immediately above the row of PACS display monitors
sitting at each station (Fig.
2). Although viewboxes mounted in this arrangement are readily
accessible, comparison performed in an up-and-down manner remains awkward,
particularly if multiple separate comparisons must be made. Mounting viewboxes
to the side of each PACS display monitor would make the comparison process
more facile, but such an arrangement is frequently impractical.
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Fig. 2. —Photograph of a specially constructed desk (TechniCenter with
Illuminators, AFC Industries) shows one alternative to facilitate comparison
of PACS and film-based studies. A row of viewboxes is mounted on a special
frame immediately above a row of PACS display monitors.
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The third alternative, which we describe, provides a convenient, effective,
and ergonomically satisfactory alternative that requires no additional
hardware, no financial investment, and very little physical movement from the
workstation itself (Fig. 3). In
fact, it is possible that other frustrated radiologists may have also
discovered this maneuver out of necessity. Using a PACS display monitor as an
electronic viewbox effectively minimizes disruptions to normal workflow when
film-based studies must be reviewed at the PACS workstation. With the latest,
brighter PACS display monitors (and flat panel displays, in particular), this
method will only become more effective. In our department, we have found that
the electronic viewbox not only has encouraged more careful comparison of
PACS- and film-based studies but also may have limited oversights arising
during repetitive comparison tasks (e.g., lung nodules or lymph nodes).
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Fig. 3. —Photograph of the electronic viewbox in practice. Using a PACS
display monitor as an electronic viewbox requires little physical movement
from the workstation and provides an ergonomically satisfactory alternative
for comparison of PACS- and film-based studies.
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We are aware that limitations to this method exist and that it is sometimes
more clinically appropriate to use a true viewbox. For example, traditional
viewboxes meet rigorous standards for brightness and illumination
[3], whereas the electronic
viewbox may not. Because the field of illumination provided by this method may
be less intense than a traditional viewbox, very small or subtle lesions that
are similar in attenuation to their background may be difficult to discern. In
addition, the size of a PACS display and its orientation (portrait vs
landscape) may also limit the size and shape of the field of illumination. On
occasion, the radiologist may be better served by a bank of conventional
viewboxes in situations that call for simultaneous comparison to multiple
films (e.g., triphasic liver CT studies). However, in a great number of
day-to-day situations, the potential benefits of this resource-free maneuver
most likely outweigh the limitations we have considered. Although other
limitations to this methodology may yet await exploration, we do expect that
the electronic viewbox will offer distinct benefits in the clinical
setting.
Acknowledgments
We wish to thank Steven C. Horii for his helpful suggestions during the
preparation of this manuscript.
References
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Computer-aided design and modeling of workstations and radiology reading rooms
for the new millennium. RadioGraphics2000; 20:1807
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- Abdullah B, Ng K. In the eyes of the beholder: what we see is not
what we get. Br J Radiol2001; 74:675
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Abstract
Introduction
