HOSPITAL, RADIOLOGY, AND PICTURE ARCHIVING AND
IAN D. ROBERTSON, TRAVIS SAVERAID
Images generated during the course of patient evaluation and management are an integral part of the medical
record and must be retained according to local regulations. Digital Imaging and Communications in Medicine
(DICOM) makes it possible for images from many different imaging modalities to be distributed via a standard
internet network to distant viewing workstations and a central archive in an almost seamless fashion. The
DICOM standard is a truly universal standard for the dissemination of medical images. Picture Archive and
Communication System (PACS) refers to the infrastructure that links modalities, workstations, the image
archive, and the medical record information system into an integrated system, allowing for efﬁcient electronic
distribution and storage of medical images and access to medical record data. This paper discusses the important elements to a successful PACS implementation in a practice, including how it interacts with other
practice computing systems. Veterinary Radiology & Ultrasound, Vol. 49, No. 1, Supp. 1, 2008, pp S19–S28.
Key words: Digital Imaging and Communications in Medicine, hospital information systems, information
storage and retrieval, medical image distribution, Picture Archive and Communication System, radiology
IMAGINE THIS WORKFLOW. While in dialogue with a client
in an exam room, a clinician orders a radiographic exam using the Hospital Information System (HIS). Within minutes, the order subsequently appears at the modality in a list of patients requiring radiographs that day. The radiology technicians select the appropriate patient from the list and conducts the study. Once the images are generated, they are sent to a central local server and the exam is
automatically completed and charged in the HIS. By simply clicking the ‘‘view images’’ button under the images tab in the HIS the images appear in an easy to use browserbased medical image viewer, or on a Digital Imaging andCommunications in Medicine (DICOM) workstation program on the local computer. Either viewing scenario allows real-time adjustment of contrast and brightness, magniﬁcation, the ability to perform measurements and manyother image viewing features. That is the basic functionality of a Picture Archive and Communication System(PACS). There are no data entry errors, the images do not
end up in cyberspace and the images are indelibly linked to
the medical record and report. In addition, the images and
reports are accessible from anywhere inside the local area network (LAN) and also potentially available outside the clinic network via the world wide web. Additionally, people do not have to navigate out of one application, open another, and then spend many minutes searching for the imaging exam within a different application.
For all sorts of reasons, that scenario, seemingly a reasonable workﬂow requirement in this age of computer
technology is not commonly seen in veterinary practice.
Despite all that, medical image dissemination and archiving is much easier than it was in the early 1990s. The
introduction of the DICOM standard and the transition
from analog ﬁlm to digital radiographic images has revolutionized the dissemination and archiving of medical
images, allowing major improvements in imaging suite
efﬁciency and productivity. For more information about
the basics of DICOM see the article in this supplement.
What is PACS?
PACS refers to the host of technologies that contribute to the creation, distribution, and archiving of digital images.
2Typical PACS components include a digital imagingmodality or device, a network with reasonable bandwidth,an archive device, diagnostic workstations, archive/routingsoftware, and usually some interplay with the hospital orradiology information system. Bandwidth, deﬁned as therate at which information can be transmitted in a speciﬁctime interval, is important because medical image ﬁles areText extracts reprinted from Robertson, I., Image dissemination andarchiving. Clin Tech in Small Anim Prac, 2007;22:138–144., with permission from Elsevier.
Address correspondence and reprint requests to Ian Robertson, at the
above address. E-mail: firstname.lastname@example.org
From the Department of Molecular Biomedical Sciences, North
Carolina State University, Raleigh, NC 27606 (Robertson) and the Department of Veterinary Clinical Sciences, University of Minnesota, Minneapolis, MN.
S19large, averaging on the order of 10–50 Megabytes (Mb) per
study. For comparison, a digital photograph made with a
digital camera may create a ﬁle of 250–500 kilobytes
(roughly 50–100 times smaller). All modern PAC systems
use the DICOM standard. The standard utilizes a network
protocol that runs on top of the existing internet standard
Potential Beneﬁts of PACS
Managing and displaying images to clinicians in a timely
manner are some of the biggest challenges in maintaining a
modern clinical imaging suite. An integrated PACS can
assist in the endeavor, offering many potential beneﬁts,
Direct cost savings associated with decreased consumption of radiographic ﬁlm and chemistry, decreased
processor workload/maintenance, less requirement for
hard copy storage space, and decreased labor cost associated with ﬁlm handling and distribution.
Increased connectivity and integration between facilities and departments.
Productivity improvements (less time spent looking
for misplaced radiographs or ultrasound images, less
time spent hanging/removing ﬁlms, less time distributing ﬁlms).
Simultaneous viewing of the same images in multiple
Increased revenues through eliminating lost examinations and increasing effective capacity.
Better image quality than analog ﬁlm or thermal
Decreased time to interpret and communicate diagnoses.
Provides an avenue for rapid consultation with
Basic PACS Conﬁguration
In its most simplistic form, a PACS is comprised of one
or more imaging modalities, an archive server and at least
one viewing station connected on an isolated LAN (Fig. 1).
Using DICOM as the image format and transmission protocol means that the server and viewing stations should
communicate image data seamlessly regardless of vendor
Network and DICOM Connectivity
To establish communication between an imaging modality and server or server and workstation, the name, and
network address of each component must be shared.
Fig. 1. A schematic of basic image distribution. The modalities send images to a central archive. Clinicians query the server and retrieve a copy of the study
to the local workstation for viewing.
S20 ROBERTSON and SAVERAID 2008DICOM interconnectivity requires three simple address
speciﬁcations. These include the Internet Protocol (IP) address of the computer or full registered hostname, the Application Entity Title (AE title), and an assigned
communication port (Fig. 2). The IP address identiﬁes
the computer on the network and is unique to the computer. The AE title relates to the application or program onthe computer, and again must be unique. The assigned
communication port identiﬁes the speciﬁc computer entry
and exit port through which image information is allowed
to travel when making a connection or receiving information from the network. This connection protocol is oftentermed a ‘‘DICOM Association.’’ A computer might run
more than one DICOM server program at any one time
and in that case both the port and AE title for each application would be unique, even though the IP address forthe application would be the same. For more information
about networking, see the article in this supplement.
Essentially, devices have initial communication, called a
handshake, to ensure appropriate connectivity and compatibility before data transfer is attempted. Each DICOM
device has a remote device table that allows the operator to
load the IP address, AE title, and port of destinations to
which the operator wishes to connect. Some devices require
the DICOM address of the sender (SCU), while other devices can be conﬁgured to receive images from an unknown
device, provided connectivity and compatibility parameters
are correct. The latter conﬁguration is often referred to as a
DICOM workstation software usually continuously runs image management services
behind the scenes so that image distribution and cataloguing can occur in the background and not interrupt the
clinician using the viewing features of the program.
An important aspect of connectivity is ensuring the entire image study gets to the desired destination. If only part
of the study actually arrived at the server or workstation,
an incomplete data set would result in delays and potential
misdiagnosis. Correctly designed software generates an error message and usually has a user adjustable, automatic
retry function if there is a connection failure. This becomes
extremely important when images are being sent beyond
the LAN, where there is more chance of a transmission
Most modern LANs transfer data at 100Mb/s or faster.
New or upgraded systems transfer at speeds up to 1 Gb/s.
Having a robust, fast network, and modern switches results
in minimal delays in image transmission and minimal data
One or many imaging modalities can be connected on
the network. Typical veterinary modalities include computed radiography (CR), digital radiography (DX), computed tomography (CT), nuclear medicine (NM),
ultrasound (US), or magnetic resonance imaging (MRI).
All these modalities should generate images in DICOM
format and be able to send images to a remote server using
the standard DICOM association (DICOM STORE
SCU). Each should have a unique AE title, IP address,
and port assignment. As has been stated elsewhere, not all
so called DICOM-compliant systems are equal and it
behooves the PACS administrator to ensure connectivity
using a live test before purchasing and connecting a new
modality to the network.
Fig. 2. Screen capture of part of a device table in image management software. Courtesy of integrated PACS provider, Amicas Inc., Boston, MA,
www.amicas.com. PACS, Picture Archive and Communication System.
Vol. 49, No. 1, Supplement 1 HIS, RIS, and PACS S21Image Archive and Server
The basic function of the image server is to receive images from the modalities, store the image ﬁles, and catalogue the studies in a database. There are many levels of
image server software sophistication. In the most simplistic
conﬁguration, the clinician can query the server by a variety of search criteria (patient name, patient ID, study
date, modality, etc.) Once the study is identiﬁed, the images
can be retrieved from the server (an association using
DICOM query/retrieve protocol). Copies of the images are
transferred to the workstation for soft copy review. Ideally
the clinician would like to view images without having to
wait for image download that may be a minute or so
depending on the size of the study and network bandwidth.
This can be achieved by setting up autorouting rules in
the server software, such that, as each study or image is
received at the server, it is immediately sent to selected
In addition to providing query/retrieve functionality,
many image servers can make studies available to the
internet. This allows image viewing using a standard webbrowser (most commonly, Windows Internet Explorer
from any computer with a high-speed internet connection
(see browser based viewers later in this article). As with
DICOM viewers, there is considerable variability in functionality between vendors, particularly with respect to
compression algorithms, transmission speed, viewer speciﬁcations, and reliability. The advantage of making the
images web accessible is most apparent when images are
viewed outside the LAN. The images are usually transmitted via http or https (standard internet browser, port 80,
and secure internet browser, port 443) so there is usually
less difﬁculty negotiating ﬁrewalls, unlike DICOM associations. Many vendors use a proprietary image transfer
protocol and the images viewed on the web may not be in
DICOM format. Provided the server software can respond
to a DICOM query/retrieve command and distribute
images in DICOM format on demand, how a vendor
provides viewing via a web browser is, in the authors’
opinion, less important than how well it actually works.
Server software should provide the ability to edit certain
tags in the DICOM header. Even in the most controlled
environments, mistakes in patient registration are made.
Editing certain DICOM tags (e.g., patient number, patient
name, exam description, date of birth) should be reserved
for those with system administrator privileges. DICOM
protocol requires that ﬁeld editing be recorded by the application so that potentially malicious editing is documented. Usually there are various user proﬁles and the interface
with the server is via http or https.
The server should be able to compress images using
industry standard and preferably FDA-approved compression algorithms. Compression settings are usually modality
speciﬁc and can be either lossless (no loss of digital data) or
lossy (loss of digital data, but ideally no loss of clinical
data). There are many potential options with respect to
how the server software compresses and stores image ﬁles.
Some vendors do not store the images long term in
DICOM format but in other formats (e.g., jpeg2000). Provided the server can respond to a DICOM query/retrieve
command, how the images are stored is not important.
Methods of image storage do, however, become important
with respect to redundancy and backups and if you decide
to change PACS vendor. It is imperative that if you decide
to change PACS vendor, that the images can be exported
out of the old server in a format that can be received and
imported by the new vendor’s software. Realistically, one
should maintain a copy of the original native DICOM.
There are three basic methods by which one can view
images remote from the modality.
Dedicated Medical Image Viewing Workstations
These are speciﬁc programs that are designed to allow
the clinician to open and view medical images in DICOM
format. Historically, image viewing workstations were
expensive proprietary computer systems loaded with
proprietary software. The DICOM standard has led to a
proliferation of relatively inexpensive DICOM image viewing software packages that can be used both in the PC and
MAC environments. DICOM viewing software of various
quality is available as freeware from the internet or can be
purchased, costing anywhere from approximately $500 to
over 10 times that. These programs are designed primarily
operating systems but Mac OSX
-compatible programs are available. One of the most widely used
-based programs is eFilm Workstation,
popular freeware, Mac OSX
program is Osirix.w
The basic requirements of a DICOM workstation are as
the ability to query and send image ﬁles to multiple
DICOM devices, including other workstations;
the capability to manipulate images (window/level,
magniﬁcation, measurements, annotation, stack scroll,
invert, rotate, etc.);
a HIS/Radiology Information System (RIS) interface
to link reports to the images;
the ability to import other image types, such as jpeg
and tiff, and convert them to DICOM;
the ability to export single images or a complete series
of images in jpeg, tiff, or movie ﬁle format;
the functionality to allow dual monitor viewing;
eFilm Workstation, Merge Healthcare, Milwaukee, WI.
wOsiriX - http://www.osirix-viewer.com/index2.html
S22 ROBERTSON and SAVERAID 2008 the ability to print to either a windows printer, or
preferably a DICOM printer;
the ability to create a CD containing DICOM ﬁles
and an embedded DICOM viewer with basic image
This conﬁguration uses a web browser, usually Microsoft Internet Explorer
, to access images from a server that
has this functionality. Usually the user is required to download a simple plug-in, a program that extends the functionality of the browser to enable manipulation of medical
images. Historically, browser based viewers have had less
functionality than dedicated DICOM workstations but
medical image browsers are becoming increasingly sophisticated, including RAM-demanding multiplanar and 3D
reconstructions for CT studies. This technology commonly
employs Active X, Java, or Dot NET technology to distribute and display images. Often the images are not actually downloaded onto the computer but loaded into
cache and deleted when that browser session is terminated.
Dual Function Workstations
The standard DICOM association, while robust and secure, poses problems with respect to ﬁrewalls and blocked
ports. Some DICOM workstations have standard DICOM
association capability and can access images via the web,
either through the standard browser port (80) or via alternative ports. A common veterinary example of this is Image Channel, a web accessible portal available with Merge
eFilm Workstation and Merge Fusion Server.z
Alternatively, some DICOM workstations use http or
https to retrieve DICOM ﬁles to the local computer and
then seamlessly import the images into the same workstation software loaded on the local computer. The advantage
of this conﬁguration is that the images can be retrieved
through ﬁrewalls that might have speciﬁc DICOM ports
blocked (e.g., hotel room). The clinician receives the actual
DICOM images (usually compressed, but compression settings can be changed) and the clinician has all the advantages of a dedicated DICOM workstation without the
connectivity issues often associated with common DICOM
A full discussion of viewer software and monitor selection is beyond this paper. There has been a number of
studies comparing the diagnostic accuracy of commercial
grade color monitors with medical grade monochrome
monitors. Results have been variable. A recent study
showed there was no difference in accuracy of observer
performance for detection of wrist fractures with a PC
(color monitor 1024 768) compared with a PACS workstation monitor.
A similarly designed study showed a
nonstatistically signiﬁcant (at 95%) trend toward higher
diagnostic accuracy using a dedicated medical grade monitor vs. 2 megapixel (MP) 20 in. LCD monitor when evaluating thoracic radiographs for pneumothorax and wrist
In the authors’ opinion, there are many factors that
inﬂuence the accuracy of softcopy viewing, including
ambient lighting, extraneous distractions, functionality of
viewing software, quality of graphics card, cathode ray
tube vs. liquid crystal display, monitor viewing dimensions,
monitor calibration, resolution, bit depth, and refresh rate.
These are rarely optimized in the clinical setting and were
optimized for both of the studies referenced above. Conducting the ﬁnal interpretation of CR and DX images on
small 1MP color monitors that are not conﬁgured and
positioned for optimal digital image viewing is not advised.
For more information about image display, see the article
in this supplement.
The basic PACS shown in Fig. 1 can be expanded. More
modalities can be added and more viewing workstations
deployed. A DICOM printer can be added. Potentially an
inﬁnite number of devices may be added, however, in reality, at some point server processing speed, transmission
bandwidth, and other technical limitations arise. Importantly, images can be transferred using a DICOM association to a destination outside the LAN, if the LAN is
connected to the internet. Transmission beyond the LAN
often requires adjustments to the institutional ﬁrewall con-
Figure 3 shows a more complex infrastructure. In this
diagram, the veterinary practice has a LAN behind a ﬁrewall and is also connected to the internet. The practice is
able to send images to a colleague for consultation using a
DICOM association. The image server is able to distribute
images to the internet for easy access via a browser. Also
shown is another common conﬁguration; the local server
sends images to a remote archive for long-term storage and
backup. Some remote archives can also distribute images
via the web. There are many conﬁguration options and this
diagram is not a typical conﬁguration but a composite of
the most common conﬁgurations.
Essential components of DICOM functionality as they
apply to veterinary medicine include storage, query/retrieve
and image display. Some DICOM services are not essential
for basic functionality but can be important in larger practices. These include DICOM modality worklist and
DICOM print. A worklist allows the HIS or RIS to comzMerge Fusion Server, Merge Healthcare, Milwaukee, WI. municate with the modality and automates the entry of
Vol. 49, No. 1, Supplement 1 HIS, RIS, and PACS S23patient demographic information for each exam. Additionally, the need may arise to generate hard copy images,
and the DICOM print service class provides a method of
accurately printing images on translucent ﬁlm.
The DICOM requirements of a practice will vary with
the needs of the practice and the type of imaging devices
Unfortunately, many DICOM services are not yet
supported by some vendors of veterinary digital imaging
devices and PAC systems. Determining what DICOM
functionality is needed is an essential part of purchasing
DICOM Compliance and Conformance
The term DICOM compliant is an all-encompassing
term used by many vendors and is of little value. It is more
important and accurate to identify which service classes (as
deﬁned above) are supported by a given imaging modality.
This critical information should be available in the
DICOM conformance statement associated with each
piece of imaging equipment.
Storage and compression of ultrasound cine loops (multiframes), can be challenging for two major reasons. First,
compression of cine loops can be problematic. Many ultrasound machines send compressed images, either lossless
or lossy, by default because uncompressed studies (especially cine loops) can be extremely large and take a considerable amount of time to transfer to the archive or
download from the archive to a DICOM workstation.
Many PACS archives store ﬁles in a compressed format
and sometimes cannot import ﬁles that are already compressed, particularly images compressed using nonstandard
algorithms. Usually, some adjustment of compression settings on both sides (server and modality) can resolve this
problem. Additionally, some PACS vendors have difﬁculty
compressing cine loops from other vendors because the
individual images within a cine loop may be presented to
the PACS as though they were one image (rather than 250)
and this causes problems for the compression engine. A
second problem involves color palate selection. Ultrasound
machine vendors have many options with respect to how
the color ﬂow overlay on the monochrome image is
achieved and these issues can sometimes result in archive
import failure. Currently, there is no well-deﬁned standard
for DICOM cine loops and this may be contributing to
connectivity problems between vendors.
In addition to the general questions relating to functionality, one should ask prospective PACS vendors how
their system handles cine loops, even if initially you do not
envision using ultrasound in the immediate short term. The
Fig. 3. A basic PACS. A printer has been added to the local area network and the HIS/RIS generates DICOM modality worklist that is distributed to the
modalities. Reports from the HIS/RIS are accessible from the workstations. The LAN is connected to the internet via commercial broadband connection but
protected from the internet by a hardware ﬁrewall. The studies can be viewed outside the clinic network, either via a browser or via a DICOM association. The
images are also sent to a remote archive for long term storage. PACS, Picture Archive and Communication System; DICOM, digital imaging and communications in medicine; LAN, local area network; HIS, Hospital Information System; RIS, Radiology Information System.
S24 ROBERTSON and SAVERAID 2008importance of ensuring connectivity and adequate functionality before ﬁnancial commitment cannot be overstated.
Integration of Medical Record Data and Images
To achieve optimal functionality, a PAC system does
exist as a stand-alone technology. Ideally, workstations
should have quick, direct access to patient demographics,
histories, and reports. Additionally, images need to be
readily accessible from the medical record in the HIS.
Currently, most veterinary HISs do not have the functionality required to successfully integrate with a digital image
environment. Larger veterinary practices that have recently
invested in digital imaging systems are rapidly discovering
the need for such functionality. Entering patient data multiple times via a keyboard or touch screen at a modality
in a busy practice can result in a large number of errors.
Many wasted hours can be spent locating and correcting
misidentiﬁed imaging studies. A RIS or RIS module integrated with the HIS is the link for creating a fully functional digital environment. Ultimately, a RIS may be the
most important component of a clinic’s digital imaging
infrastructure, particularly for outside consultation.
In the human medical environment, the HIS and RIS
are usually independent software programs from different
vendors, though this is not necessary from a functionality
perspective. In human hospital systems, to negate the need
for multiple entries of patient demographics when there are
two independent systems (e.g., client registration with
medical records and re-registration with radiology), patient
registration data and exam order data are transferred from
the HIS to the RIS automatically. This is done using HL7,
an acronym for Health Language 7 or Health Link 7,
standard for text communication between various systems
used in the medical community. HL7 is considered to be
the text standard equivalent of the DICOM standard
for images. HL7 is commonly used to interface clinical
laboratory software and the HIS in human hospitals.
While this may be a viable option in large veterinary hospitals and university veterinary teaching hospitals, having a
separate RIS and HIS in smaller veterinary practices adds
an unnecessary level of complexity and expense. However,
a module that generates a DICOM Modality Worklist
from the HIS order and links images to the electronic
medical record either via the accession number (automatically generated sequential number) or the Study Unique
can dramatically improve efﬁciency
and data accuracy. Currently, a very small number of veterinary HIS vendors provide a DICOM modality worklist
or have any integration between patient images and the
HIS. In the authors’ opinion, DICOM worklist signiﬁ-
cantly enhances workﬂow and essentially eliminates misidentiﬁed and lost studies. Some HIS vendors allow
DICOM graphic ﬁles from the digital modality to be loaded into the HIS application database. Provided a customized viewer is engaged that allows adequate image
manipulation as is done in a dedicated DICOM viewer,
this is probably a satisfactory simplistic solution for small
practices. In the authors’ opinion, in larger practices, images should be maintained on an image server independent
of the HIS application. In either conﬁguration, it is important that the software allows easy transmission of studies via DICOM association to a destination remote from
the hospital so as to allow external consultation.
The potential advantages of an integrated RIS and
PACS are best realized when the RIS is web based. This
takes full advantage of the networking and connectivity
afforded by the internet. For example, a radiologist can
access patient information, view images, ﬁle a report, and
verify a report all from a remote location.
A RIS module allows generation of a worklist for all
requested, current, and completed imaging studies for that
day (Table 1). This allows easy access to scheduling data
and enables one to tell at a glance the status of a patient in
the radiology suite (Fig. 4).
Accessing the exam history enables access to reports and
images on all studies done on that patient (Fig. 5). From
the report, links to the image server allow immediate
browser based (or DICOM workstation) viewing of the
images pertaining to that study (Image icon).
More than Just Radiographic Images
The infrastructure described above can be used to catalog and distribute any images and motion clips, pertaining
to the medical record. The common graphic ﬁles (jpeg, tiff,
bitmap) can be readily converted to a DICOM ﬁle, identiﬁed via DICOM modality worklist and sent to the archive
for distribution and review in the same way as normal
radiographic studies. Thus dermatologic, ophthalmologic,
surgical, endoscopic, cytologic, or gross necropsy images
could be readily linked to the patient ﬁle. The ideal RIS or
RIS module should also be able to catalog and store non
DICOM images including lameness movies, movies of
neurologic examinations, endoscopic and laproscopic examinations, ECG tracings or even sound ﬁles of cardiac
Accessing Studies Beyond the LAN
Many teleradiology services are available to the veterinary profession, providing a variety of services at differing
costs. Hardware vendors often provide teleradiology options to augment CR, DX, and US hardware sales. One
does not normally need to make an upfront ﬁnancial comVol. 49, No. 1, Supplement 1 HIS, RIS, and PACS S25mitment for additional hardware and software, but if
investment is necessary, it is important to ensure investment in an open architecture DICOM compliant system.
This ensures the clinician the ability to send imaging
studies to any colleague or specialist, using a standard
DICOM association. Using open architecture DICOM
systems prevents the user from being locked to a particular
Security, Backup, and Disaster Recovery
Unlike standard graphic ﬁles, DICOM ﬁles have been
intentionally designed to not be easily modiﬁed. These images are a component of the legal medical record and should
only be modiﬁed by authorized personnel. Legal requirements with respect to the archiving of veterinary images
differ between regulatory bodies and it is important
Table 1. Basic Digital Imaging Suite Workﬂow
Workﬂow in a digital environment showing the most basic integration between HIS/RIS and PACS
Order for radiographic exam logged in HIS or RIS
Exam scheduled in the appropriate room on appropriate imaging device (Resource)
RIS updates DICOM Modality Worklist with exam information, Patient ID, Patient Name, Gender, Age, Exam Description, Accession Number or Study UID
Operator queries DICOM Modality Worklist at the modality and selects the appropriate patient from a list of today’s exams
The modality loads the DICOM header of the study with the patient-speciﬁc and exam-speciﬁc data generated from DICOM Modality Worklist. Image
acquisition date and time and other header information are added by the modality
Images are generated and send to PACS Image Server for archiving and distribution
Images are autorouted to DICOM workstations based on preset autorouting-speciﬁc rules. Images distributed to the web and/or sent to remote archive
Images can be reviewed via the HIS/RIS—Using a hyperlink from patient ﬁle. Conversely, a hyperlink from any DICOM viewing software to the RIS allows
the report to be viewed in a separate window while viewing the images both on the web and at a DICOM workstation
Systems using the study UID instead of accession number work very similarly. There are many more sophisticated variations of this basic infrastructure, including the Image Archive sending a message to the RIS that the study has been successfully received and automated charging of the study
in the HIS once the exam is completed. In addition, various methods of automated study receipt veriﬁcation are used in more sophisticated
systems.DICOM, Digital Imaging and Communications in Medicine; HIS, Hospital Information System; PACS, Picture Archive and Communication
System; RIS, Radiology Information System.
S26 ROBERTSON and SAVERAID 2008to adhere to local regulations. Data security is important,
not only from a data corruption and data loss perspective,
but also from an unauthorized access perspective. The veterinary profession is not currently under the same pressure
as the medical profession to maintain client conﬁdentiality
Health Insurance Portability and Accountability Act (HIPAA) but it is likely this will change in the future.
A modern server with hardware redundancy (primarily
redundancy of array controllers, hard drives and power
supply) should be used. Image ﬁles and databases (just like
medical record data), should be backed up to a second offsite device with hardware redundancy or burned to data
DVD/CD or tape and those stored at a remote location.
Consideration should be given to engaging a commercial
entity to archive data and there are a growing number of
vendors who supply offsite archiving services to veterinarians. Many modality hardware vendors also provide on-site
and off-site archiving services. Some research of these
Fig. 4. Partial screen capture of a daily Worklist page. Courtesy of web-based RIS/PACS provider, Empiric Systems, LLC, Raleigh, NC, 866-367-4742,
www.empiricsystems.com. RIS, Radiology Information System; PACS, Picture Archive and Communication System.
Fig. 5. Screenshot of an Exam History page. Courtesy of web-based RIS/PACS provider, Empiric Systems, LLC, Raleigh, NC, 866-367-4742, www.empiricsystems.com. RIS, Radiology Information System; PACS, Picture Archive and Communication System.
Vol. 49, No. 1, Supplement 1 HIS, RIS, and PACS S27systems is recommended as there are major differences in
functionality and cost between vendors. For more information about data storage, see the article in this supplement.
Internet security is important to prevent hackers from
gaining access to your system. A hardware ﬁrewall is mandatory for establishing a secure clinic network as is ensuring all current operating system security patches are
loaded. When images are distributed outside the LAN,
consideration should be given to ﬁle encoding or transmission via a virtual private network (VPN).
The DICOM standard is the universal medical image
ﬁle format and should be considered over all other
image ﬁle formats.
A PAC system is a host of technologies that contribute to the creation, distribution, and archiving of
clinical digital images.
Image distribution can be limited to a local area network or extended to a remote destination via the internet, either public or via a VPN.
Electronic linking and seamless integration between
images and patient data requires either the acquisition
of an independent RIS or creation of a RIS module
within the HIS. Currently few veterinary practice
software vendors have responded to these challenges.
Ultrasound generates some speciﬁc challenges with respect to archiving as many studies are cine loops and it
is important that compatibility with equipment from
other vendors is conﬁrmed before equipment purchase.
Industry standard practice with respect to data security, archiving, backup, and disaster recovery is mandatory and should not be overlooked. Seek advice
and consider off-site services.
Deﬁnitions at a Glance
LAN—Local Area Network – A local area network
(LAN) is a group of computers and associated devices
that share a common communications line or wireless
link and typically share the resources of a single processor
or server within a small geographic area (e.g., within an
DICOM—Digital Imaging and Communication in Medicine - The standard that deﬁnes the protocols for storing,
querying, retrieving, and printing digital clinical images
and allows for the exchange and viewing of these images
PACS—Picture Archival and Communication Systems—
The combination of technologies that contribute to the creation, distribution and archiving of digital clinical images.
The component technologies typically consist of the digital
imaging devices, the computer network, an archive device,
diagnostic workstations and archive/routing software
RIS—Radiology Information System—The stand-alone
software or a component of HIS software that provides
for entry, access and storage of patient demographics,
signalment, histories and previous radiology reports and
which links the patient ﬁle to associated images, usually
stored on another server
HIS—Hospital Information System—Various types of
commercially available software which form the backbone
of a hospital’s patient medical record system and often
include numerous additional components including
pharmacy management, billing, hospital patient census, etc
HL7—Health Level 7—A standard for communication
between various data systems employed in the medical community that deﬁnes protocols for text information exchange.
DICOM Modality Worklist—A list of exams generatedby the RIS that is queried and displayed on each imaging device. The list contains information on patient exams tobe performed (usually that day) on that device as assigned directly by the RIS. Each list contains patient demographics, patient ID, accessionnumber, study description and date and time information at a minimum.Disclosure of Conﬂicts of Interest: The authors have declared no conﬂicts of interest.
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