pacs adoption

PACS Adoption

Janice Honeyman-Buck

THE FIRST QUESTION to ask is why wouldanyone want to go through the trouble and

expense of changing from a perfectly good film-based radiology practice to a filmless or nearlyfilmless picture archiving and communication sys-tem (PACS) environment? Hospital and clinicadministrators make the decision to switch from afilm-based radiology system to a PACS for manyreasons, some with legitimate research literature toback them, some emotional, and some because ofpeer pressure. An administrator considering adopt-ing PACS should consider all the ramifications ofmaking the change, then if a change can bejustified, make the best possible decisions whenselecting methods, vendors, and procedures.

The most frequently mentioned reasons forchanging from a film-based radiology departmentto PACS are to increase productivity, increaseefficiency, save money, improve accessibility ofimages, improve the ability to handle images forinterpretation, and to reduce the time and effort ittakes to handle film. All of these reasons soundgood on paper and are potential benefits of PACS,but more detail is needed. For example, if admin-istrators wish to increase productivity, they need tospecify exactly whose productivity will be in-creased. Are they interested in increasing technol-ogist productivity? If they achieve the expectedresults, will they be willing to reduce the numberof technologists employed at the facility or willthey be able to perform more studies with theexisting technologists? Do they have a patient loadthat will support a goal of performing more stud-ies? Are the administrators interested in improvingthe radiologists’ productivity or that of the otherclinicians treating patients?

If the administrators of the facility wish toincrease efficiency, this is probably closely tied tothe increase in productivity and perhaps this argu-ment should be folded into productivity improve-ment. If the administrators wish to save money,

where is the money currently spent and where dothey expect to see improvement? If film handling isan issue, have they considered the work that will beneeded to manage the PACS?

In many large institutions, the professional com-ponent of a radiology department and a clinicalservice is separate from the technical or nursingcomponent. Frequently, the physician staff is paidunder a different contract from the hospital orclinic staff, and an administrator may be interestedin improving only the component he/she is respon-sible for managing. Probably the best argument forchanging from a film-based system to PACS is toimprove patient care while maximizing the use ofresources.

If the decision is made to adopt PACS, carefulplanning will help make the process go moresmoothly. Planners should be aware of the changemanagement techniques that have been used suc-cessfully in the past. They should also be aware ofthe myriad of things that can go wrong, both duringthe transition and after the change has been made.In the following sections, the literature for help indetermining if PACS can improve productivity orefficiency, if a PACS can be cost-justified, and if aPACS can improve patient care will be examined.This article will look at the change-managementtechniques that can be used and have been used inthe past to improve the chances of a successfultransition.Finally, the problems other institutionshave discovered and ways to avoid those problemsand manage the complexities of PACS will beexamined. The goal is to make a potential PACScustomer more aware of the issues involved inmaking this expensive and complicated conver-sion.

RADIOLOGY WORKFLOW

To start the discussion of how PACS can operatein a radiology department, the workflow of adepartment needs to be examined. A simple de-scription of typical workflow would be as follows:a referring or treating physician orders an exami-nation, the technologist gets the order and performsthe examination, films or images are produced, aradiologist interprets the study, a transcriptionisttypes the report, and the report is communicated tothe ordering physician who treats the patient ororders more examinations. Clerks in a film library

From the Department of Radiology, University of Florida,Gainesville, FL.

Address reprint requests to Janice Honeyman-Buck, PhD,Department of Radiology, 1600 SW Archer Road, PO Box100374, University of Florida, Gainesville, FL 32610.

© 2003 Elsevier Inc. All rights reserved.0037-198X/03/3803-0007$30.00/0doi:10.1016/S0037-198X(03)00045-2

256 Seminars in Roentgenology, Vol 38, No 3 (July), 2003: pp 256-269

place the films in jackets that are filed for futureuse. If a physician needs a film, it is requested fromthe film library and he/she will either get theoriginal film or a copy. In simpler times, before theadvent of sophisticated technology, this workflowserved radiology and medicine well. Now, how-ever, we have complex computed tomography(CT) and magnetic resonance imaging (MRI) ex-aminations with a very large number of images.Add to this the ability to perform interventionalradiology procedures. Because medical and surgi-cal treatments have become more effective, rapidevaluation of diagnostic examinations and integra-tion with the rest of the patient’s medical recordcan make the difference between successful andunsuccessful management of disease processes.Various outside entities influence the practice ofmedicine including the rules imposed on physi-cians and hospitals by third-party payers and stan-dards of care set by regulatory agencies. Patientswho have poor outcomes, whether deserved or not,are suing physicians. A health care institution, tosurvive in the current environment, must maintaina high level of efficiency and must provide the bestpossible patient care.

PACS is only part of a larger informatics struc-ture in a health care system. It must be closelyinterfaced to the hospital information system orradiology information system (HIS/RIS) to beeffective. A physician must see the total picture ofthe patient by integrating all the examination re-sults to use good judgment in selecting the appro-priate treatment. Figure 1 shows how a totalinformation system might look. The functionality

of this system will be elaborated on as the discus-sion of the adoption of PACS progresses.

As in the simpler days of medicine, the referringphysician places an order, usually through a HIS/RIS, but now the order is checked for appropriate-ness. If it passes the first test, the order is thenscheduled with radiology and the technologistperforms the study. In an integrated environment,the information about the order is available at themodality, eliminating duplicate data entry with itspotential for data entry errors. The technologistchooses the appropriate patient and study from aworklist. After the study is completed, it is sent toa PACS archive, to diagnostic workstations for theradiologist’s interpretation, and possibly to a Webserver for access by other physicians. No film isproduced. The radiologist’s report is transcribedautomatically through a voice or speech recogni-tion system and is sent directly to the HIS/RISwhere the referring physician can view the report.The radiologist can view the rest of the patient’srecord if needed for other test results, such aslaboratory results, history and physical informa-tion, or pathology reports. The referring physiciancan view the images while reading the radiologist’sreport. The glue that holds this all together is basedon information transfer standards. Digital Commu-nications in Medicine (DICOM) is the standardthat allows information passing through a PACSfrom the modality to the archive and displaydevices. Health Layer 7 (HL7) is the standard thatallows information to be passed between compo-nents of an HIS/RIS. A translator device allowsHL7 messages to be converted to DICOM somodalities have access to a worklist or schedule ofthe work to be done. This workflow will be used asa reference as the discussion of the adoption ofPACS progresses.

A LOOK AT THE LITERATURE

Technologist Productivity

Increased productivity or efficiency may bedescribed as the ability of a technologist to do theirjob faster, thus allowing him/her to perform moreexaminations in a day or to reduce the waiting timefor a patient in a department. In a conventional filmenvironment, the technologist would perform theradiographic study, transport the cassette to adarkroom or a daylight loader, and process thefilm. The technologist would be responsible foraccurately labeling the film with the correct patient

Fig 1. Data flow in an Integrated PACS/informatics sys-

tem.

257PACS ADOPTION

information. In a PACS environment, the technol-ogist performs the conventional radiographic studyusing computed radiography (CR) or digital radi-ography (DR) equipment and then would check thestudy on a computer monitor for correct position-ing, exposure, and patient information and thensend the images to the PACS. Both CR and DRhave a wider grayscale latitude and may improveproductivity by reducing the number of retakesbecause of exposure problem. With CR, cassettescontain a reusable phosphor plate that must be readand erased and also must be identified with aspecific patient. A DR system does not requiremanual transfer of cassettes and plates to a reader,instead the image is directly produced and sent toa computer for review or to PACS.

At first glance, it would seem that CR would notoffer the potential of improving workflow andefficiency for the technologist. However, in a studycomparing 3 departments, 2 with conventionalfilm-screen, and 1 with CR, the mean examinationtimes for the department using CR was signifi-cantly lower than the ones using film-screen.1 Thestudy reported the average examination time for a2-view chest study as 12.5 minutes with film-screen and 7.4 minutes with CR, whereas theaverage time for a 3- to 5-view spine study as 19.1minutes with film- screen and 8.8 minutes withCR. When DR is used, there is greater potential forimproving productivity because the technologist isnot required to handle cassettes and can concen-trate on positioning and exposure. In 1 studyfilm-screen was compared with both CR and DR.2,3

The authors reported an improvement in through-put for the digital modalities, with DR being themost efficient. Measured in patient throughput perhour for chest examinations, the film-screen roomhandled 8.2 examinations, the CR room handled9.2, and the DR room handled 10.7. The morestriking statistic in this work is the time measureduntil images were available for interpretation. Withthe conventional film-screen system where filmswere hand delivered to the reading room, theaverage time from the start of the examination tothe time when films were available for interpreta-tion was 29.2 minutes; for CR, the average timewas 6.7 minutes; and for DR, the average time was5.7 minutes.

Productivity can also be improved by decreasingthe time and complexity of data entry. In a PACS,patient information must be accurate or studies

cannot be found on an archive. If names andidentifiers are entered carelessly, the images can beas lost as if they are stored in the wrong film jacket.Computers simply do not search and accuratelyfind names of patients, for example, if the namesare not always entered in exactly the same way. IfSally Smith’s study is entered as Smith, Sally 1 dayand SmithˆSally the next, it is possible one or theother will not be found in a search. In a fullyconnected PACS environment with an HIS/RIS, afunction named DICOM modality worklist allowsa technologist to select a patient and study from alist allowing complete and correct data entry witha swipe of a barcode. Many of the modalities thatproduce images were never designed for complexdata entry and do not supply all the fields desirablein an integrated system. They may not provide afield in their interface for a patient’s birth date orsex. They may not have the capacity to enter aprocedure description or a referring physician. Allthe fields can be completed using DICOM modal-ity worklist, even the fields that do not appear onthe modality’s operator’s console, and the patient’sname will always be entered the same each time aprocedure is performed. Two studies comparingthroughput for film-screen with DR with no mo-dality worklist and DR with modality worklistproduced strikingly similar results. In each case,chest examination times were measured and thetotal time in the department was reported. In thefirst study,4 the average time in the department forfilm screen was 307 seconds, for DR with noHIS/RIS was 142 seconds, and for DR with theHIS/RIS interface was 98 seconds. In the secondstudy,5 the average time in the department for filmscreen was 338.9 seconds; for DR with no RIS/HIS, it was 138.8 seconds; and, for DR with theRIS/HIS interface, it was 94.9 seconds.

A technologist working in CT or MRI can alsorealize time savings with PACS. In a film-baseddepartment, the technologist would typically opti-mize images using window and level or someimage processing and then would print the imageson radiographic film. Data entry would be manual.In a PACS environment the CT or MRI technolo-gist would not be required to perform as muchimage manipulation as before because the diagnos-tic workstations can handle these tasks for them. Inaddition, a modality worklist would eliminate theneed for complex data entry. A study was per-formed comparing the length of time required to

258 JANICE HONEYMAN-BUCK

complete a CT study in a “filmless” PACS versusa film-based environment. When technologists nolonger printed images at multiple window andlevel settings, the time required to complete a CTexamination was reduced by 45%.6

Physician Productivity

If an administrator were trying to justify PACSbased on productivity, he/she might be interestedonly in the technical component of improvement.In an integrated hospital or clinic setting, it is alsointeresting to investigate the impact of PACS onphysician productivity and how it might relate topatient care. In this case, the results are not asclear. In 1 study, the time required to read CTstudies from printed film was compared with thetime required to read the studies on a 4-monitorworkstation.7 Films were printed using a 12-on-1format, and comparison studies were printed andplaced in the film jacket for use. Radiologists wereallowed to choose their formats on the PACSworkstations, and window and level presets wereused during the interpretation. A selection of chest,abdomen, and brain studies were chosen for thestudy. There was an overall reduction of 16.2% inthe total time required for CT interpretation withsoft-copy compared with conventional film. Whencomparison studies were used, a significantlygreater productivity gain was realized.

In another study, PACS with interpretation usingspeech recognition did not fair so well.8 Radiolo-gists were asked to describe how the systemeffected their reading times and were given theoptions of less time, the same amount of time, ormore time spent in increments of 25%, 50%,100%, and 200%. Ten radiologists responded with2 reporting an increase of 25% and the restreporting an increase of greater than 100% of theirtime. However, this same study reported a numberof striking positive benefits of the system. Thepercentage of unreported cases at the end of eachmonth dropped from approximately 25% to 0.3%,possibly because of the more accurate trackingmethods associated with a computerized system.Clinicians who responded to a survey reported thatPACS had saved them about 30 minutes a day.After the system was installed, 50% of all exami-nations had reports available within the HIS within60 minutes, 86% available in 12 hours, and 96%available in 24 hours. It would be unusual to see

these results in a film-based system with manualtranscription.

PACS is not just a phenomenon of a largehospital environment. Productivity enhancementscan also be found in a private practice environ-ment. In a study reporting the experiences of aprivate practice group, questionnaires were used togather data on individual’s perceptions of thebenefits of PACS.9 The radiologists respondingreported a nearly 100% improvement in theirproductivity with CT, ultrasound, and MRI modal-ities and 50% with special procedures. Technolo-gist productivity increased by 58% for MRI, 30%for CT, and 42% for ultrasound based on thenumber of examinations performed per full-timeequivalent. Ninety-one percent of the referringproviders reported a productivity benefit fromusing PACS.

Another benefit from a PACS environment forradiologists is the flexibility associated with mov-ing images to where the radiologist is located. In astudy of a large radiology practice, less than 50%of the radiologists needed to be at the site wherethe examination was performed.10 The implicationis that a load sharing can be achieved resulting ingreater productivity overall in a practice or theability for a group of radiologists to serve a widergeographic area.

Cost Justification

It has been shown by several research groupsthat a hospital, clinic, or private practice canachieve productivity enhancements by usingPACS, but does that in and of itself justify theadoption of PACS? Will an institution be able toafford the costs of the technology required to builda PACS?

One PACS vendor has suggested (although hasnot published), that you can estimate the cost ofPACS, not including the modalities, as a factor of9. The rule of thumb works like this. If aninstitution performs 100,000 studies per year, theycan expect to pay about $900,000 for an initialPACS installation. If they perform 200,000 studiesper year, they can expect to pay about $1,800,000for a PACS installation. This is not a scientificstudy or fact, but it may be a starting point for aninstitution looking at adopting PACS. Of course, ifan institution is starting from a strictly nondigitaldepartment or the CT and MRI units have not beenpurchased with the interfaces required for PACS,

259PACS ADOPTION

the costs will be higher. Can an institution make abusiness case for PACS?

The good news is that the cost of PACS iscoming down and with a significant number of newcompanies offering a wide variety of services andoptions, an institution may do very well by shop-ping carefully. The private practice described ear-lier realized a return on investment in 3.5 years andnow saves on order of $500,000 per year based onthe cost of film and processing only.9 Anothergroup reports that they estimate they will spend$2.4 million over 5 years and project that they willbreak even because of the money they expect tosave in that time.11

The administrator should consider the capitalcosts associated with a PACS purchase and bal-ance that against the overall improvement in pro-ductivity and subsequent savings and the savingsrealized by eliminating or significantly reducingfilm usage. An often overlooked cost of managinga film-based radiology service is the time requiredto search for a lost study or the cost associated withrepeating that study, usually without reimburse-ment.

Patient Care

One study from the Mayo Medical Center inRochester, MN, shows the profound effect PACScan have on patient care.12 The study measured theimpact of PACS on image and report turnaroundtimes. The average radiology interpretation timeafter a study was completed decreased from over49 minutes to less than 14 minutes. The averageimage turnaround time to clinicians in an urgentcare center from order to image access decreasedfrom over 4 hours to less than an hour. The averagetime until the referring physician viewed the im-ages or report from the time they became availabledecreased from over 3 hours to just over a half anhour. Diagnostic interpretations were available im-mediately instead of taking over 2 hours before thePACS adoption. With a PACS, images can beavailable everywhere they are needed, and whenspeech recognition is added, diagnostic reports areavailable immediately.

MANAGING THE ADOPTION OF PACS

If the decision is made to go forward with theadoption of PACS, the real work begins. Theprocess is not just a technology installation proce-dure, the environment of the institution will change

and change does not always come easy. Managingchange may be the biggest challenge in a success-ful PACS endeavor. Of course, the process ofanalyzing the needs of the institution and purchas-ing and installing a system to meet the require-ments is also important. The entire process shouldbe a team decision and must include significantinput from all effected parties.

Managing Change

In 1998, Reed Gardner, an informatics pioneer,stated in his Davies Lecture13: “In my opinion, thesuccess of a project is perhaps 80 percent depen-dent on the development of the social and politicalinteraction skills of the developer and 20 percent orless on the implementation of the hardware andsoftware technology!”

As in most informatics projects, the adoption ofPACS will require significant change managementto be successful. The best and most expensivehardware and software will be ineffective if thepeople who are using the system resist it orsabotage its operation. Why do people resistchange? In a review article published by theJournal of the American Medical Informatics As-sociation, the authors assert that whenever there’sa change in an organization, there is a threat, realor perceived, of loss for those involved.14 Anoperational change that affects the way work isperformed usually has the greatest impact on thelower levels of an organization, the workers on theline. In the case of PACS, the line workers are thedirect users, the technologists, film library person-nel, nurses, radiologists, and clinicians. Technolo-gists and film library personnel might believe thatthe automation of some tasks will result in jobelimination, they might be afraid that learning thenew technology is beyond their capability, or theymay not want to give up time for training. Physi-cians may be comfortable in the way they havebeen handling film for years and may not becomfortable with computers. They may have heardhorror stories of PACS failures. All of thesepeople, who are the most valuable asset for anorganization, may feel threatened by a new system.

Change management is the process that leads anorganization to a future state or vision. If success-ful, the individuals who use the system will feel apride and some sort of ownership in the system andwill do what they can to make the system success-ful. Some techniques have been used successfully


and are recommended as an institution starts theprocess of PACS adoption.

First, let’s examine the reasons for informaticsor PACS failures that could be prevented throughsuccessful change management. In the same Jour-nal of the American Medical Informatics Associa-tion article referenced earlier, the authors present acategorized list of some of the reasons for systemfailures. This list has been adapted to our discus-sion of PACS. Table 1 lists the categories ofproblems with some examples. When it comes toPACS adoption, communication, organization, andtraining are key elements. The PACS leadership

must be clearly defined, and the leader must beable to communicate to a wide range of people. Inmany cases, the PACS leader is a physicist orinformation scientist who may have an excellentunderstanding of the systems analysis processesthat are necessary to design and implement a goodPACS but who cannot effectively communicate thetechnology issues with nontechnical users. If this isthe case, then a second partner must be identifiedwho can understand the technology and communi-cate effectively with the people who will be using it.

Once a leader is found, the steps in Table 2 arerecommended to help manage the transition. Of

Table 1. Reasons for System Failures

Category Examples

Communication Ineffective communication to technologists, physicians, file clerksIneffective listeningFailure to prepare staff for the PACS implementation

Culture Hostility toward information technologyNo strategies to get buy-in from end usersFeelings that new technologies are being forced on users

Underestimation of complexity Missed deadlinesUnreasonable expectations

Scope creep Failure to define and maintain success criteriaEnlarging the scope of the project without additional analysis

Organizational No clear vision for changeStaff competencyRoles and responsibilities not clearly defined or understoodFailure to benchmark existing practicesInability to measure success

Technology System too difficult to use, poor user interfacesPoor procurementInadequate testing

Training Inadequate trainingPoor timing of training (too early or too late)

Leadership issues Leader too emotionally committedLeader’s time over-committedFailure to get ownership of the projectLeader’s political skills weak

Table 2. Elements That Lead to a Successful Implementation

State the vision Identify the changes to be made and their benefitsIdentify the critical success factorsSpecify the measurement of success factors

Specify the scope Which systems will be effected/integratedWill you do a step-wise transition or all-at-once

Benchmark current processes Evaluate the processes that will be changedEvaluate the potential for improving processes through automationStudy the current environment and workflow

Communication Form user groupsNews lettersBanners and announcements

Establish PACS team Radiology, IS/IT, administration, facilitiesChoose a knowledgeable technical leader

Training Establish the training methods for all usersIdentify trainers

Proclaim successes As successes and goals are attained, celebrate with all users.If possible, set up a system of reward for users who adapt to the change successfully

Abbreviation: IS/IT, information services/information technology.

261PACS ADOPTION

course, an administrator may choose to add to thislist, but none of these steps should be left out.Although many of the steps in Table 2 seem to besimple common sense, it is surprising how manysystems are introduced without them. Producing avision statement is usually a painful exercise intrying to find exactly the right words to pleaseeveryone and to state what everyone expects toaccomplish. Instead, a simple table or outlinelisting the expected benefits of PACS can beproduced with some measurable goals to achieve.Examples of goals to be included might be to saveoperational expenses, to reduce turnaround time, orto make images accessible wherever they areneeded. In many cases, PACS is introduced in astep-wise manner, starting first perhaps with CTand MRI, then moving into CR, and so on. TotalPACS conversions are now becoming more com-mon as the technology evolves to the point that theconversions become more affordable and feasible.Specify exactly what will be included in the PACSadoption planned for the institution. When bench-marking the current processes, look for processesthat will be improved by the introduction of PACS.For example, the CT technologist will no longerneed to window and level images, print them,collect the films from the laser camera, and assem-ble them to store in a jacket. Document the time ittakes before PACS to perform a task or a processso a benchmark will be available to compareagainst after the PACS is installed.

Communication is a key element of success of aproject. The lines of communication must be keptopen to everyone involved with or concerned aboutthe PACS. One way to achieve good communica-tion and to promote user buy-in to the project is toform groups to manage or oversee the project.Input from a wide range of stake holders willpossibly identify problems before they arise ormay help produce user specifications or expecta-tions that will improve the end product. For exam-ple, a user group of radiologists may be able tospecify the features they want in a diagnosticworkstation.

A good PACS management team is a require-ment for a successful implementation. The teamshould include representatives from radiology(technologists, radiologists, and film room), infor-mation services/information technology, adminis-tration, and facilities.15-17 Other personnel will beneeded from time to time, but the core of the team

should see the project through to the end. A leadershould be identified with the expertise to evaluatetechnology and help translate the often-confusingterms for new users.

Users cannot accept a system they cannot oper-ate. If the users are well trained and familiar withthe system, they will more readily accept it andmay find ways to improve workflow and processesby using the system in unanticipated ways. Train-ing should be considered from the start of theproject by identifying the user population, analyz-ing the skills and competencies available, andestablishing the training needs for each group.18

The PACS management team should identify thetraining equipment and facilities needed; whatmaterials will have to be developed; and, when asystem is chosen, what materials will be availablefrom the vendor, and then develop a PACS imple-mentation and training timetable. Some issues toremember when developing the training are thestaff time constraints and shifts, maintaining anoperating department while training is occurring,and marketing training throughout the institution.Most training will be in fairly small groups andwill need to be repeated during different timeperiods to cover all time schedules. Ongoing train-ing must be organized for new staff and upgradesto the system. It would be advisable to produce acollection of training studies without the originalpatient information to avoid patient privacy prob-lems. Training needs to take place just before thesystem becomes operational so the training is freshin the user’s mind. For the first few weeks a newsystem is operational, have some experts rotatethrough user area during all shifts to observe theuse of the system and address any problems.

With careful attention to communication, plan-ning, process evaluation, and training, change canbe effectively managed and users will accept thesystem and hopefully enjoy using it. If a sense ofpride and accomplishment can be instilled in theusers, the system will be more widely accepted.Finally, after the system is installed and goals areattained, celebrate with the users, reward thosewho have helped the most, and acknowledge theircontributions. Visible positive advances help ev-eryone accept change.

The Technology of PACS

A complete discussion of the technologies thatgo into a PACS is beyond the scope of this article.


However, some attention should be paid to each ofthe main component. Looking back at Figure 1, themain components of the PACS are shown. Essen-tially there must be a way to acquire digital images,send them through a network to an archive, andsend them to display devices. Although this soundssimple, the user needs to be aware of a number ofimportant issues and may want to do more researchon each of these. The issues and their descriptionsare shown in Table 3.

Networks may be available throughout the insti-tution; however, some care should be taken to geta full understanding of the network protocolssupported, the settings required for good operation,administration policies for adding equipment to thenetwork, and security policies. Even when a hos-pital has a modern network infrastructure, misun-derstandings between the network administratorsand the installers of PACS equipment can lead topoor performance. For example, a CR unit can beattempting to automatically determine the speedsupported by the network while the network man-agement components are set up to expect anexplicitly specified speed. When this occurs, theCR vendor may see a successful network attach-ment, but the performance will be so poor that thesystem will be unusable.

All PACS acquisition vendors will claim DI-COM compliance. The question is what do theymean exactly, and what does the customer want? Ina PACS environment, the acquisition device needs

to perform a DICOM modality worklist, DICOMsend, and DICOM print at a minimum. Somevendors may only support DICOM print. Thismeans that when the equipment is installed, it willnot send studies to the archive or displays. Withouta modality worklist, the technologist must enterpatient and examination information on the con-sole manually, which leads to incorrect and incom-plete data in the archive, an extremely undesirablesituation. All modalities must specify exactly whatthey mean by DICOM and the PACS vendor mustvalidate that they can interface with the modality.There are many different interpretations of theDICOM standard resulting in difficulty interfacingequipment.19,20 Even when the interface works,there may be problems. If the interface for theworklist or the send is awkward to use or slow,users will have a problem with the system and willresist using it.

Displays are a very important part of the PACS.They are the physician’s view of PACS and thesubstitute for film.21,22 The basic requirements forphysician’s acceptance are speed, ease of use, andhigh-quality image display. The diagnostic work-station must perform all the functions required forreading, must be reliable with a minimum numberof failures, and must be customizable for eachuser’s preferences. Some of these requirements aremet by software (functionality, easy of use, cus-tomization), and some by hardware (high-quality,well-adjusted displays and fast and reliable com-

Table 3. PACS Components

Networks Do they exist?Can they be installed in the space required?What type/bandwidth is required?Does the system need a wide area network connection, what type and bandwidth?What type of security is provided by the institution and what needs to be installed?Who will administer the network?

Acquisition Are all devices DICOM 3.0 compliant?Do the DICOM compliant devices all communicate with the PACS?What DICOM services are supplied

Display What types of displays are needed?How many?Where should they go?Are the reading rooms adequate?Does the institution want to use a web application to distribute the images?How will you handle the OR, oversized images such as leg-length and scoliosis studies, how will

the physicians do measurements, and how will orthopedic surgeons perform template matching.Storage What type of storage?

How much?Where will it be located, in house, remote?Who will manage?Upgrade/expansion capabilities

Interfaces DICOM modality worklistSpeech recognition

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puter and disk). This is a case in which the usergroups can be a significant help in the selection ofsystems. The physicians should attend trade showsand get a feeling for the available systems and theirunique capabilities and should specify what theyexpect. The PACS management team should besure the expectations of the physicians are reason-able. The number of diagnostic workstations in-stalled and available is important. If an institutionpurchases too few, any efficiencies that may beachieved by PACS can be reduced if radiologistsdo not have access to a workstation and have towait for another person to finish. In a study on theimpact of PACS on resident training, it was shownthat with PACS if too few workstations are avail-able, resident review and dictation decreased sig-nificantly because they simply could not haveaccess to workstations.23

Reading room redesign is an important consid-eration when changing from a film-based depart-ment with viewboxes and alternators to a filmlessenvironment with diagnostic workstations. Factorsthat affect the ability of a radiologist to use aworkstation for reading studies without experienc-ing fatigue include the lighting in the room, theplacement of workstations to avoid glare, andergonomically correct seating.24 It is important thatindirect lighting be used with the ability to adjustthe brightness of the room. Seating should also beadjustable with arm rests, lumbar support, wheels,and the ability to swivel. The keyboard and mouseshould be on adjustable trays with wrist support.

If a Web-based application is used to distributethe images throughout the institution, very carefulselection should be made after reviewing variousoptions. An application service provider (ASP)model is used in many institutions as a way to storeand distribute studies.25 In this model, a vendorwill contract to store and distribute studies, usuallythrough a Web interface, and will charge per study.This charge may be applied to only those studiesthat are viewed or to each study stored. Theyguarantee maximum uptime by keeping a verylarge redundant system in a secure location withconstant supervision and management. This modelmay be appealing to an organization with fewinformatics resources and a light imaging load. Inlarge institutions, this model could prove to be tooexpensive and the institution will opt instead toown the Web server and storage. Whichevermethod is used, the administration of the server

needs to be specified. Who will manage the usersand passwords and who will be available 24 hoursper day, 7 days a week to help users who haveforgotten their passwords? If filming is discontin-ued, this is the only way a referring physician cansee his/her patient’s images.

An image archive must be 100% reliable andmust never lose studies. How can that be achieved?If an ASP model is used, the company must havethe resources to guarantee availability and reliabil-ity. The company must also win the trust of thehealth care institution; after all, they will be re-sponsible for storing medical data for the institu-tion. If the institution has the information technol-ogy resources to manage an archive, the decisionmust be made whether to manage a local archive orto outsource the service to an ASP. If the decisionis to purchase an archive, more decisions will needto be made. First, how much storage is needed?With the cost of storage going down rapidly, thebest strategy may be to calculate approximately 2years of storage initially with plans to expandwhen needed. The storage media should be reli-able, and it is advisable that all data be storedredundantly. It is common to use an automatedjukebox containing tape or disk storage for onlineaccess to images. If an additional tape or disk iscreated, it can be removed from the jukebox andstored remotely for recovery when the originalstorage media is corrupted or destroyed. A disk ortape will nearly always fail at some point, and arecovery method must be in place when it happens.

The PACS must have an interface with theHIS/RIS. Without the interface, inconsistencies inpatient names and identifiers will occur and thePACS database will not be able to accurately findstudies in the archive. This interface, usually calledthe DICOM modality worklist is provided by abroker device that converts HL7 messages fromthe HIS/RIS to DICOM and then allows modalitiesto query for a scheduled order. Modalities musthave the ability to query the worklist and attach theresulting information to a study, and the HIS/RISmust be able to send HL7 messages containingorders to the broker. The PACS vendor should beable to supply the broker functionality as part ofthe purchase. For legacy equipment without theability to provide this functionality, an additionalinterface may be purchased that will perform theworklist operation and attach the information tostudies that are sent from the modality through it to


the PACS. This arrangement is not optimal, but itwill solve the problem for older equipment. Acustomer can expect to pay about $20,000 for thisinterface for each modality that requires it.

If the institution purchases a speech recognitionsystem to replace manual transcription of dictatedreports, it must also be interfaced to the HIS/RIS sothe radiologist can match the PACS study to thereport. To reduce the number of interfaces requiredas well as the number of key boards in a readingroom, the optimal situation would be if the speechrecognition system were integrated with the diag-nostic workstation on 1 computer. It may beadvantageous to have a separate monitor for view-ing and signing reports so the radiologist does nothave to give up image display space for the reporttext. For example, if the diagnostic workstationhad a 2-monitor display, a third monitor could beadded for the text reports.

The PACS management team will have to spec-ify the scope of the project, identifying all modal-ities that will be included in the PACS; will have tospecify the volume of studies that will be stored onthe archive; and will have to choose the displaydevices, both diagnostic workstations for the radi-ologists and the method for disseminating studiesto referring physicians. They will need to study theflow of work and images and design a system thatwill improve productivity while maintaining high-quality diagnostic viewing. They will need to winall the users over to the idea of adopting PACS andprovide training for everyone. They will need toprove to all the users that the new system will befast, reliable, and easy to use.

AFTER THE ADOPTION

Now let’s jump forward in time to when thePACS management team has done their job and thePACS is installed, users are trained, everyone ismore efficient, and the institution is filmless ornearly filmless. All the work has been done, right?Wrong! After the PACS is installed, it needs to bemanaged, upgraded, supported, and watched. Newmodalities will be purchased and will need to beintegrated. Even worse, things can and will gowrong.26

Starting at the beginning of the imaging chain atthe modality and the DICOM modality worklist, anumber of things can go wrong. First, for somereason, the RIS may be in a downtime conditionand not sending orders to PACS. When this hap-

pens, the technologist cannot simply stop perform-ing procedures; manual data entry will have to beused. Of course, when the RIS comes back online,the data in the RIS will not match that in the PACS.Human errors can result in the wrong study beingselected from the worklist, an error that is veryeasy to commit on some systems. If the systemstores study information for a long period of timeand a patient returns for a follow-up study, it maybe confusing to correctly identify which is thecorrect one to select. If, for example, a patient hasa CT scan on Monday and returns on Wednesdayfor a follow-up and the Monday study is selectedincorrectly, it is possible the Wednesday imageswill simply be stored as additional series on theMonday study. From a PACS point of view, thislooks like the Wednesday study is missing or lost.Occasionally, a user may simply forget to start anew study and images from patient B are added toimages from patient A or the user can accidentallyselect the wrong patient from the worklist. All ofthese scenarios result in incorrect data on thePACS that must be corrected.

Moving on along the imaging chain, the modal-ity must send the completed study to the archiveand display devices. If for some reason, the receiv-ing software is not running, perhaps the processcrashed, the communication will not work.Chances are the sending computer will recognizethe error and will inform the user of the failure,triggering a call to PACS service. The processesassociated with the DICOM communication mustall be functioning properly for the study transfer tocontinue. If for some reason the receiving comput-er’s disk is full, corrupted data can result.

For the sake of argument, let’s say all theDICOM communications are working correctlyand everything appears to be going smoothly.Images are going to workstations and are beingdisplayed for diagnostic interpretation or for re-view. A number of errors can occur on the work-stations themselves that may render the imagesunreadable or may introduce artifacts.

Even if the workstations are working properly,images are reproduced correctly, and informationassociated with them is correct, if the physiciantries to access the archive for previous studies andcannot retrieve the images, the perception is thatPACS is down. This can happen if the databaseholding patient and study information is corruptedor unavailable or if the archive is not moving

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selected images for some reason (process failure,hardware failure, disk full, communication failure,and so on).

A new threat to PACS is the possibility ofsabotage by an intruder. There are apparently anumber of clever people who do not have enoughconstructive, productive things to do who findbreaking into other computers an interesting chal-lenge. In 1 case, the hard disk on a MRI machinewas turned into a Napster server, filling the diskand essentially crashing the operating system. Be-cause PACS providers are trying to make sure allthe users who need to get access to patient infor-mation can get it, they are trying to keep the linesof communication open. These outside or insideintruders can insert programs that can make thesystem inoperative, fill a disk, or gain access tosensitive patient information. With the onset ofHealth Insurance Portability and AccountabilityAct security requirements, an institution is legallyas well as ethically required to keep informationsecure. So we have a conundrum, the wish todistribute information to everyone who needs itwhile protecting the systems from unwelcomeintrusion.

Last but not least, the entire system and probablymany other systems in the hospital, will fail if thereis an infrastructure failure. If power, air condition-ing, or networks fail, the PACS will be brought toits knees faster than by any other means.

System Support and Maintenance

Each of the preceding scenarios is a threat to anoperating PACS. The PACS management groupwill need to have a set of tools available to avoidthese threats and to recover from failures of allkinds. There is no way to completely avoid theerrors associated with selecting a study from aworklist, especially because there are times whenthe RIS may not be sending orders to the PACS.Data correction is painful but necessary. The firstline of defense is to be sure there is a soliddowntime procedure and that everyone is aware ofit. A tool or process should be created to editstudies and correct the information. After thecorrections have been made, the study may bestored permanently on the archive and in thedatabase. The tool should be able to change infor-mation on a subset of the complete study in caseimages have been incorrectly added to an existingstudy. In this case, the person making the correc-

tion should work closely with the technologist orphysician to be sure the images are assigned to theright study. If the study has already been stored onthe archive before recognizing the error, it willhave to be retrieved from the archive, imagescorrected, reference to the incorrect study removedfrom the database, and then the study or studiesshould be restored on the archive. It is importantthat any database changes be stored in the databasewith an audit trail so the change can be recreated ifverification of the alterations is needed. The PACSvendor should provide a tool for correcting PACSdata.

Adequate logging capabilities are an importantpart in the identification of computer system prob-lems. The PACS management group and a desig-nated PACS manager should be familiar with thelocations of the logs and the interpretation ofmessages. In a Unix system, logging is common-place for all operating system functions and mostsoftware written for a Unix system will havelogging built into the application. In a Windowssystem, the administrator has access to system,application, and network logs through an eventviewer. At a very minimum, these logs should bechecked on a regular, probably at least daily basis.

Three simple monitor processes can be createdthat check for running processes, quantify diskusage, and interrogate log files. These can run asscripts on a Unix system or batch programs on aWindows-based system and can be automaticallystarted periodically as unix cronjobs or using the“at” command in Microsoft Windows software.These monitor processes should check the localsystem to assure all processes are running that arenecessary for proper PACS operation and to eval-uate the disk space. A metric can be specified for ahigh watermark on disk space beyond which stepsneed to be taken to manually delete files and cleanup the disks. If the disks are filling beyond what isexpected, it could indicate a problem with imagetransfer. These problems can include network er-rors, DICOM processes operating incorrectly, or adestination rejecting images. A monitor processcan be set to send e-mail messages to a systemadministrator unless the situation becomes criticalin which case a page can be sent with a code ormessage indicating the problem and the location ofthe problem. If the monitor process is workingcorrectly, most problems can be identified beforethe users become aware of them. These monitor


processes should be implemented on at least thearchive and database computers in the system.Display workstations and Web servers usuallyhave the capability of setting an automatic delete toavoid full disks, but these processes can fail, so thesame monitors should be in place on these systems.

Because the display workstation is the physi-cian’s window into the PACS, it is important toassure all displays are working correctly. PACSimages must be presented consistently and cor-rectly on all PACS viewing devices. Without astandard, image quality could be affected, render-ing the images nondiagnostic. In addition, allworkstations and especially all monitors on asingle workstation should have consistent gray-scale response to the pixel values in the images.

The calibration of monitors can be a time-consuming job and, in a large PACS installation, adaunting one. Luckily, there are a number ofdevices on the market now that assist in thiscalibration. A photometer is a device that measureslight and sometimes color output from a monitorand is used to quantify the monitor’s response tograyscale values. A known grayscale must beproduced that can be displayed by all monitors ona workstation and throughout the institution. Soft-ware accompanying the photometer includes digi-tal grayscale phantoms for calibration and qualitycontrol of display monitors. The software displaysa finite number of grayscale values generated bythe computer while the photometer attached to thecomputer reads the values. A table of values iscreated and is then used to map to the digitaldriving levels and is stored or loaded into hard-ware. This table can be activated to adjust theoutput of the monitor to standardize the display.The output can then be monitored by repeating thecheck periodically to assure the grayscales con-tinue to conform to the original calibration. Theentire process takes only minutes and results inuniform display characteristics across displaymonitors in a PACS.

Network problems can create havoc in a PACSand in fact in almost any computer system used inmedicine. Network failure can be caused by amyriad of problems including a network line beingcut or broken, electrical failure in the communica-tion closet, the failed component of a networkdevice, or an upgrade to the software on a networkcommunication system. A simple monitor that candetect these problems will periodically send a test

message (a ping or a DICOM echo) to othercomputers on the network it normally expects tocommunicate with. If the test message indicates aproblem, the computer can automatically pageservice for immediate action. With a network ofcomputers sending these small test messages, theentire network can be polled virtually continually.

Physical security of all computer equipment isimportant. This means that the PACS archive anddatabase computers should be on uninterruptiblepower supplies and on emergency power. In addi-tion, the air conditioning units in a computer roomshould be on emergency power. Without air con-ditioning, a computer room will rapidly reach apoint when the heat will affect the performance ofthe computers or shut them down.

From the onset, all PACS must at least beprotected with a username/password authenticationand authorization system. Password administrationshould enforce “good” passwords, those that aredifficult to discover using password cracking tools.Periodic checks of password files using these sametools will help identify passwords that can beeasily compromised. Requiring periodic passwordchanges may help, but human nature being what itis, this practice frequently results in people writingtheir passwords on their computers, keyboards, oron notepads to help them remember. Augmentedsystems include a remote receiver displaying acurrent rapidly changing passcode that must beused in conjunction with the username and pass-word. In this case, the user must have the physicaldevice with the code when using his/her usernameand password.

Many vendors will claim a firewall is the bestway to protect PACS from compromise; however,this may not be desirable or feasible. In the case ofa widely distributed enterprise PACS spanningseveral subnets, a firewall protecting the entirePACS may be too wide and encompass manynon-PACS computers, each of which could be usedto launch an intrusion. This suggests the need formany small firewalls to secure each portion of thePACS and allow access only between the firewalls.Another way to accomplish this is to use staticrouting where access to the system is strictlycontrolled to only authorized subnets or specificnodes. Both of these solutions will help; however,if one trusted computer is compromised, the entiresystem is at risk. In addition, when a modalityvendor performs a software upgrade or service,

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default routing can inadvertently be reinstalled andif not detected, the system can be accessed andcompromised.

When network access is restricted by a firewallor static routing, legitimate access is also re-stricted. In the case of a Web server, it is impos-sible to predict every computer that might accessimages, especially if the computers internet ad-dress is being supplied using dynamic host config-uration protocol from an Internet provider. Avirtual private network (VPN) allows valid usersaccess to computers inside a firewall or those usingsubnet restrictions with static routing. These sys-tems can be either software- or hardware-basedand allow a computer with dynamic host configu-ration protocol to attach to the VPN and beassigned an address on the authorized subnet. Byapplying the VPN and firewall or static routingprotection, the networks and computers will bebetter protected. However, an intruder will almostalways be able to find a “back door” into thenetwork if persistent enough.

Intrusion detection systems can monitor accessto computers and data; report usage; and in somecases, act to stop an intrusion and trace the in-truder. Intrusion detection systems monitor usageand access and respond to unauthorized access andunusual activity using either automated or manualmethods. The lowest level of response might be toalert a system administrator that access is beingattempted. A higher level might be to remove theattacked system from the network and start traceattempts to find the attacker.

One or more PACS or system administratorsmust be identified and hired to manage the system.The PACS administrator will be responsible forassuring that the system runs correctly and thatusers understand the implications of using thesystem. In addition, this person will provide ongo-ing training for new users and retraining when thesystem changes. The administrator will be respon-

sible for correcting errors that are introduced intothe PACS and will check system logs for correctoperation. The required quality assurance must bemanaged by the PACS administrator and may beperformed by him/her. Because it is important forthis administrator to understand the complex oper-ation of a radiology department, a technologistwith a good understanding of computers and theability to analyze situations and come to the correctdecision for correcting errors may be the bestperson for this difficult but rewarding professionalposition.27 A job description must be defined toboth help the administrator understand his/herposition but also to show to the hospital adminis-tration that this person will need compensationcommiserate with their abilities and responsibili-ties.

PACS support must be provided by the PACSvendor or by a third-party PACS support group.Because PACS is a system-critical application, thesupport contract must specify the requirements forresponse times. The institution must have a sched-uled replacement or upgrade path for componentsas well as scheduled preventive maintenance.

SUMMARY

Once the decision has been made to adopt PACSinstead of a film-based radiology practice, there area number of hurdles to jump. Users need to beaware of the impact the change will make on endusers and be prepared to address issues that arisebefore they become problems. Someone who un-derstands the technology of PACS must be identi-fied to help make an informed decision aboutvendor selection, network architecture, worksta-tion functionality, and archives. A PACS adminis-trator should have the tools available to avoidproblems with the system after implementation andshould be able to repair the inevitable mistakes thatwill happen. Hopefully, this article can serve as astarting point for a potential new PACS adoption.

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