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Development Of PACS At Georgetown University Radiology Department Seong K. Mun Peter Choyke Andre Duerinckx Paul Wang Fred Fahey Harold Benson Larry P. Elliott

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DEVELOPMENT PACS AT DEVELOPMENT OF OF PACS AT GEORGETOWN GEORGETOWN UNIVERSITY UNIVERSITY RADIOLOGY RADIOLOGY DEPARTMENT DEPARTMENT

Seong r Andre Seong K. K. Mun, Mun, Peter Peter Choyke Choyke, Andre Duerinckx, Duerinckx, Paul Paul Wang, Wang, Fred Fred Fahey, Fahey, Harold Harold Benson Benson P. Elliott Elliott and Larry P. Georgetown University Hospital, Hospital, Department Department of of Radiology, Radiology, 3800 3800 Reservoir Reservoir Road, Road, N.W. N.W. D.C. 20007, (202) (202) 625 625-2141 Washington, D.C. -2141

INTRODUCTION

Computer is becoming becoming more more common common in in the the practice practice of of modern modern radiology. radiology. Computer based information is Patient Patient information, information, radiological radiological reports reports and and many many radiological radiological images images are are already already in in electronic format. There is is also an increased increased application application of of computer computer technologies electronic digital format. technologies throughout hospital. Use (HIS) and throughout the hospital. Use of of hospital hospital information information system system (HIS) and radiological radiological inforinformation system (RIS)is (RlS)is receiving mation system receiving wider wider acceptance acceptance in in the the medical medical community, community, in in an an attempt attempt to to provide timely and efficient patient patient care. care. As provide and computer computer based based As more more computer technologies and management management tools tools are are utilized utilized in in the the operation operation of of the the Radiology Radiology Department, Department, full full realization realization of communication system system (PACS) (PACS) encompassing of integrated integrated digital digital picture archiving and communication encompassing all all the the subsystems devices, report report generating generating system, system, archiving archiving system, subsystems such such as as digital digital imaging devices, system, system, information information distribution distribution system system and and administrative administrative management picture viewing system, management comcomis becoming within the ponent is the reach reach of of currently currently available available technologies technologies (1,2). (1,2). Only when all reports, images images and and administrative administrative data data can can be be simultanesimultaneall the the patient patient data, data, radiological reports, ously computer technology technology be be realized realized in in the the practice practice of ously managed, managed, will will the the full benefit of computer of radiology. Hospital (GUH) (GUH) started started several several years (3) to plan plan for for the We at Georgetown University Hospital years ago (3) the eventual of PACS into the operation operation of of the the Department Department of of Radiology. Radiology. We are are eventual implementation implementation of in and there there is is already already aa hospital hospital wide wide in the the process process of of major major expansion of the department and hospital information system system (HIS) (HIS) that that contains contains radiology radiology information information system system (RIS) (RIS) as as aa subsubhospital component. Our Our project project is is driven driven by by the the clinical clinical needs needs in in the the radiology radiology department department rather rather than hardware or software oriented oriented technical than technical feasibility. feasibility. We at GUH, GUH, aa team team of of physicists, physicists, radiologists, functional specifications specifications based based on on the radiologists, and and department manager, manager, first developed functional the current rapidly expanding expanding department. department. This paper discusses current needs needs and and projected projected needs of the rapidly discusses not only the functional specifications specifications of of PACS PACS but but also also our our overall overall objective, objective, methodology not methodology of system evaluation evaluation criteria criteria from from the the clinical clinical of establishing establishing aa system configuration and system operational operational point of view. Various reviews reviews of of the current practice of Radiology in terms and adminVarious practice of Radiology in terms of of technical technical and administrative in the the literature literature (1). (1). Here, istrative functions functions for for PACS are readily available in however, we Here, however, focus in which PACS PACS ultimately focus our our attention attention on on the the daily clinical environment in ultimately has has to to survive. While the the practice of of radiology is is becoming specialized, requiring requiring more becoming highly highly specialized, more complicated care, better care care can can be be delivered delivered if if the the existing existing large large complicated logistics logistics in in patient care, amount data can be systemically presented amount presented to to radiologists. radiologists. One of the the fact fact One has has to be aware of that the that the ultimate ultimate objective objective of of PACS PACS is is to to facilitate facilitate aa new new system system of of data data management management to to provide provide better patient care care at at aa lower lower cost. cost. In In order objective, the the system system order to achieve the objective, has well-targeted professionals involved involved in in has to provide various well -targeted services services and and benefits to many professionals the of patient care, care, always always keeping keeping in in mind the delivery of mind the the critical critical cost cost issue. issue. This means the to serve many groups groups of of people people in the PACS PACS has has to in medicine. medicine. It is aa system that will interinterIt is relate relate vast vast amounts amounts of of radiological radiological images, images, and and patient patient data, data, with with many many medical medical professprofessionals. It It should should be be designed designed in in such such aa way way the the following following groups groups of of professionals professionals can can better of radiology radiology related related patient patient care. care. better function in the delivery of 1. Radiologists 2. Referring Physicians 3. Administration 1.

Radiologists; PACS PACS should provide the the following following services services to to radiologists: radiologists: a) Greater efficiency in in accessing accessing radiological radiological information information and and patient patient data. data. b) Efficient of generating generating radiological radiological reports reports at at the the time time of of review. Efficient and accurate means of review. c) Convenient in which Convenient method method in which the the radiological radiological reports reports and and the the images images can can be be presented presented to referring physicians. physicians. d) Timely involvement of of radiological radiological consultation consultation in in patient patient care. care. e) Easy means radiological images images and and data. data. means to access multimodality radiological f) Greater in the the use use of of radiologist's radiologist's time. time. Greater efficiency in g) Efficient communication with Efficient means means of of communication with the the subspecialties subspecialties within within the the radiological radiological service.

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2

2.

referring PACS should should provide provide the the following following services services to to referring Referring Physicians: PACS physicians. images. necessary images. and necessary reports and consultation reports a) Timely availability of consultation b) Convenient Convenient ways ways that that the the radiological radiological consultation consultation can can be be obtained obtained overcoming overcoming the the radiologists. and radiologists. reports, and images, reports, of images, locations of of locations geographical decentralization of geographical sites. remote sites. at remote images at radiological images Instant availability of radiological c) Instant

3. 3

requires the following of medical component of Administration: Administrative Administrative component medical practice practice requires PACS. of PACS. benefits of staff. and staff. space, and floor space, equipment, floor of equipment, utilization of and utilization in the efficiency and Increase in a) Increase activities. of activities. accounting of b) Accurate accounting services. radiological services. of radiological cost of Overall reduction of cost c) Overall SYSTEM PERFORMANCE REQUIREMENT

The general purpose purpose of of PACS PACS is is to to facilitate facilitate the the archiving, archiving, communication, communication, management management The general and and integration integration of of all all the the radiological radiological data, data, texts, texts, and and images, images, so so that that efficient efficient patient patient we specifications we functional specifications In developing detailed functional cost. In reduced cost. at reduced be provided at can be care care can aroups: four croups: into four. project into the project separated the Base Management Data Base 1. Data 2. Workstation Configuration 3. System 3. System Interfacing Interfacing and Configuration 4. System System Management Management and and Evaluation DATA BASE MANAGEMENT MANAGEMENT SYSTEM

storage Hierachy of data storage Since image data information. Since patient information. and patient reports, and text reports, images, text includes the images, data includes The data The are much much larger larger than than the the text text data, data, for for the the purpose purpose of of bulk bulk estimation estimation of of storage storage requirerequireare counted. are counted. image data are ment, only the image ment,

local levels of Three levels Three of data data storage storage are are proposed proposed in in this this PACS; PACS; archival, archival, intermediate, intermediate, and and local low long-term -term storage storage of of aa large large volume volume of of data data at at aa low provides long storage provides storage. Archival storage be storage may be critical. Intermediate storage less critical. is less In archival archival storage, storage, retrieval time is cost. In as as large large as as 11 Gegabyte Gegabyte of of magnetic magnetic storage storage that that contains, contains, down down loaded loaded archival archival data data of of patients. cases ofof inin-house active cases or active re-examined arerethat are patients that of patients studies of previous studies examined or -house patients. The purpose purpose of of an an intermediate intermediate storage storage device device is is to to reduce reduce the the time time required required for for down down loadloadThe ing from the the permanent permanent archive archive and and to to provide provide aa high high degree degree of of system system reliability reliability by by adding adding ing from imagers, they will be initially in the completed in are completed studies are the imagers, some redundancy. After the studies sent to sent to the the intermediate intermediate storage storage devices devices before before being being sent sent to to aa local local storage storage at at aa workworkof is aa memory within an image processor of storage is local storage The local device. The or an archival device. station station or It may may hold hold image image data data in in the the range range of of 100 100 Mb Mb for for rapid rapid display, display, and and prevent prevent aa workstation. It communication. overloading the network communication. Flow Flow of of images images across across the network It is is important important to to know know the the transactions transactions in in and and out out of of the the different different levels levels of of storage storage to to It in transactions in of transactions levels of system. There the system. of the loads of estimate the the average average and and peak loads There are two levels estimate data the data to the access to requires access transaction requires scheduled. The demand transaction and scheduled. latency; demand and of latency; terms terms of time. longer time. in aa longer completed in be completed can be transactions can seconds. The scheduled transactions few seconds. within aa few

generunidirectional. The image generis unidirectional. flow is data flow storage, data intermediate storage, imagers to the intermediate From imagers the to the data to the data send the to send requested to be requested will be source will image source an image ating equipment which which functions as an ating equipment storage. intermediate storage. biare bitransactions are these transactions storage, these Between the the archival archival storage and the intermediate storage, Between data archived data the archived These include include retrieving all the scheduled. These can be scheduled. of them can Most directional. Most of examined. is scheduled to be examined. a patient of patient who who is of a bidirectis bidirecttransaction is data transaction the data workstations, the Between the the intermediate intermediate storage and the workstations, Between The transactions transactions of of text text data data is is also also bidirectional bidirectional because because the the radiologist radiologist needs needs ional. The reports. previous reports. any previous review any to review also to but also not to generate generate reports at the workstation, but not only to unidirectional only unidirectional stations, only viewing stations, remote viewing the remote intermediate storage and the the intermediate Between Between the place. transactions take place.

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Requirements load transaction Requirements of of storage storage and and peak peak load transaction of data storage storage and the functions functions of of each level of storage, storage, the Knowing the hierarchy of requirements based on on the the current current workload workload statistics statistics (4). (4). requirements of of storage storage can be projected based No data compression was assumed assumed in in this this calculation. calculation. Generally, to estimate the size size of of Generally, to compressed simple compression compression factor. factor. The question of of the the acceptable acceptable compressed data data we we only need a simple of compression is is outside outside the the scope scope of of this this paper. paper. The size requirements requirements degree of The matrix size for imaging modalities are are different. different. For simplicity, simplicity, aa uniformed uniformed 1024 1024 xx 1024 for different different imaging 1024 pixel x x 8 8 bits is used used to pixel bits resolution resolution is all the the film equivalent images to digital to convert convert for for all digital For digital images, the matrix size remains format. remains the the same same size as on the current For digital images, Shown 1 is is the the final final summary summary of imagers. Shown in in Table Table 1 of our our department's department's annual annual workload statistics. It 20,000 procedures It includes includes 20,000 procedures of of chest chest studies, studies, 10,000 10,000 extremities, extremities, 20,000 20,000 portables, 7,600 7,600 CT studies, 6,000 6,000 ultrasound exams, exams, and 7,000 nuclear medicine cases. cases. portables, CT studies, and 7,000 1. Table 1.

Data Base Storage Requirements Data Base

SYSTEM SOFTWARE I.D. PATIENT I.D. TEXTUAL DATA a. Diagnostic Message b. Adm. Adm. Report c. c. Documents IMAGE IMAGE DATA

TOTAL OR

MB/yr 800 MB /yr 8 8 200

1,300 1,300 744,400

748,000 MB/yr 748,000 MB /yr 7,615,000 bits/y. 7,615,000 MM bits /y.

Peak load load requirement somewhat reduced reduced in in our of three three level data storage storage Peak requirement can can be be somewhat our approach of configuration, storage at configuration, because, because, aa large large amount amount of of image image data data can can be be sent sent to to the the local local storage at each basis. each workstation, workstation, on on a scheduled basis. Data structure structure

The manner are organized organized can can be The manner in in which which the the data data are be chronological, chronological, by patient name or by by procedures. The image by by patient's patient's name, name, type type of of procedure, procedure, body body part, part, The ability to access image date date of of procedure, procedure, radiologist, radiologist, referring referring physicians, physicians, or or any any combination combination of of these, these, is an is an of PACS. PACS. The important advantage of structure must requirements The data data structure must be be designed designed to to meet meet the requirements of factors. of the the response response time, time, and economic factors. Workstation Workstation of the the most critical components components of of the PACS, PACS, because it is Workstation design design is is one one of most critical is interaction with with the the system system will will take take place. place. In where the most human interaction institutIn aa teaching institution see the the need need for for three three types types of of workstations: workstations: Radiology workion such such as as Georgetown we see station, hospital display display terminal. station, review review terminal, terminal, and hospital terminal. These distinctions are are made made based based on and cost. cost. on the the complexity, complexity, utility utility,, and A.

"Radiology Workstation" The "Radiology

This should support support simultaneous simultaneous viewing of of up to 44 screens. This comprehensive comprehensive workstation workstation should screens. The shall be 1024 x 1024 1024 monochrome video video displays. displays. The time to load load aa film film The displays displays shall be 1024 equivalent equivalent data data set set from from local local disk disk storage storage to to the the display display screen screen should should be be less less than than 5 5 seconds. The of multiple displays displays is is intended intended to to provide provide aa view view-box The use use of -box function function in in the the workstation. The images to another screen shall be less less than 66 seconds. The time time to move move images seconds. The station station is is expected expected to to have have at at least least one one highly highly interactive interactive display display where where sophisticated sophisticated image can be carried out. out. Once Once the the necessary processing is finished image processing processing can finished the the entire entire set set of of images images display display on on the the screen screen can can be be transferred transferred to to one one of of the the designated 4 4 screens screens less interactive. interactive. The interactive screen should be able to perform all that are less all the the processing capabilities listed listed in in the the next next section. section. The an inteinteThe system should also have an grated capability. This This enables enables reports reports to be quickly entered grated report report generating capability. entered into into the the network distribution. network for for review and distribution. B.

The Review Terminal

This This terminal terminal will will be be placed within the the Department Department of of Radiology, Radiology, including the the radioloradiologist's office. It large matrix screen that It will will have have only only one one large matrix screen that can display multiformated multiformated images of film equivalent. equivalent. It It should should also images of single film data also be be able able to to display and edit text data such as such as radiological reports. reports. It as It is is also also capable capable of of limited limited image image processing such as and zoom. zoom. The speed speed of of image image loading windowing and loading is is not not critical. critical. These terminals are are expected comexpected to to be be used used for for preliminary preliminary readings readings and and cases cases not not involving involving extensive and comprehensive review. review.

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C.

The "Hospital Display Terminal" The "Hospital

"Hospital Display to be The "Hospital Display Terminal" Terminal" will will be be an an inexpensive inexpensive image image display display system to be placed placed in multiple locations in the hospital on the the clinical clinical floors, floors, in in the the operating operating rooms, rooms, and and in multiple locations clinics. Also, Also, it it is is expected expected to to be be aa noninteractive noninteractive terminal. terminal. It be able able in the clinics. It should be to images, patient data, data, and and radiological radiological reports. reports. to display processed processed images, Image Image processing workstations there should be image processing and and presentation capabilities for the At workstations images the network. network. The need not The image image processing processing capabilities capabilities to be provided need not images received from the include reconstruction routine. routine. include an an image reconstruction These include; These capabilities capabilities should include; a) Image Image Presentation i) Display and viewing of of multiple images, images, including including moving moving aa frame frame within within aa multi multi-i) format zoom in 0.1 0.1 increments increments up to a magnification of of 2X. 2X. iii) format screen. ii) Continuous zoom iv) Reformatting (i.e., (i.e., changing the selection and order of images displayed) displayed) of Flip. images study. v) Reformatting studies of of the the same same images from from the the same study. Reformatting different different multimodality multimodality studies patient. vi) Pan. b) Image b) Image Processing i) Masking. ii) Windowing. c) Image Image Analysis i) Statistical analysis, analysis, including including histograms histograms on on presented presented-scale values. ii) Mea-scale values. surements images. surements on images. Report Report generation capability requirements of The major requirements of aa Report Report Generating Generating System System are are that that it it be be accurate, accurate, accessible accessible and fast with a good human interfacing. interfacing. In In this this section we will review review briefly briefly current current and fast methods of of report report generation, generation, what what data data is is necessary for a a complete report, report, and methods methods of of report transmission. A detailed review of this this subject subject is is presented presented as as aa separate separate paper paper in in this this conference. conference. a) Methods; of a rereMethods: Radiology reports are most commonly generated by the transcription of corded "dictation" "dictation" by by the the radiologist. radiologist. A requisition slip accompanies the tape tape recording corded and and the the transcriptionist transcriptionist enters enters the the patient's patient's name name and and computer computer assigned assigned order order number number exam was was performed. performed. All All other patient data that has been previously specifying which exam Once the the report report is is transcribed transcribed on on the system, entered terminal. Once system, it it entered will will appear on the CRT terminal. can or from from aa CRT CRT terminal terminal elsewhere elsewhere in in the the department. department. In can be be reviewed reviewed either as hardcopy or the latter the former former case, case, the the signature signature serves serves as as legal legal evidence evidence of of review review whereas whereas in in the the latter case, purpose. Following the Following signature, signature, real real or or electronic, electronic, the case, aa code code number number serves this purpose. report report can can be be sent sent through through the the hospital hospital information information system system to to the the appropriate appropriate ward, ward, office office or clinic. In In aa university hospital setting reports reports not staff radiologist radiologist hospital setting not yet yet reviewed by a staff but "preliminary" or "not but dictated dictated by by aa radiology radiology resident resident can can be be assigned assigned aa status status as as "preliminary" or "not reviewed". After review by by aa staff staff radiologist radiologist the the status status can can be bechanged changedtoto"final "final". reviewed ". ". Other, less less commonly include computer assisted assisted Other, commonly employed employed methods methods of of report report generation generation include techniques in techniques in which which stock stock phrases phrases can can be be selected selected from from memory memory and and pieced pieced together together to to create create to this this system. system. Voice reports. Awkward Awkward or or repetitive repetitive wording wording is is an an occasional occasional drawback drawback to recognition technology holds great great promise as as an an accurate accurate and and fast fast transcription transcription method. method. At recognition the present satisfactory method method remains remains the the dictated dictated report. report. the present time, time, however, however, the most satisfactory b) Data format: format; Reports should should include include data data such such as as patient patient name name and and medical medical record record number, number, date date of of birth birth or or age, age, computer computer assigned assigned order order number number which which specifies specifies the the type type and and time time of of exam. The The patient's status, room number number or physician are axe patient's admission status, or address address and attending physician phone number number and and/or can be be included included as as well. well. The /or paging paging number can included. The physician's phone following following dates dates are are also also included; included; birth birth date, date, admission admission date, date, date date of of exam, exam, date date and and time time of of transcription, transcription, date date and and time time of of review review and and signature signature and and if if aa hard hard copy copy is is generated generated the the date it is is printed. printed. In of delays delays can can be be In this this manner, manner, accurate monitoring of date and and time time that that it accomplished and this this will will hopefully hopefully lead lead to to corrective corrective measures. measures. accomplished by by the the system manager and The dictation (commonly one single space space typed typed page The dictation itself itself is is of of variable variable length length (commonly one single page although although long as 3 pages) pages) and includes includes several several paragraphs. paragraphs. The last paragraph or occasionally as as long as 3 "Impression" includes their meaning meaning and and are are generally generally in in "Impression" includes aa summary of of the findings and their numerical sequence sequence in order of importance. importance. The the transcriptionist's transcriptionist's numerical The report report must include the initials. Although system, aa reliable Although much much sophisticated sophisticated hardware hardware is is employed employed in in such such aa system, reliable and and the pivotal role role in in assuring assuring aa reliable reliable and and accurate accurate system. system. accurate transcriptionist plays the

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c) can be Hospital c) Distribution: Transmission Transmission of of reports reports can be accomplished accomplished directly directly through the Hospital Information System or (electronic or or postal). postal). In it is is logical Information or by mail (electronic In aa PAC PAC system it logical that that the "tagged" to the image image although although it it must must clearly clearly be be separable. separable. Access to the the report report be be "tagged" system system should should be be limited to authorized personnel. A referring physician should should be able to retrieve record number number or, or, by retrieve cases cases by by patient name or medical record by his his own own name. name. Given the the relatively relatively modest modest additional additional memory memory requirements requirements it it would would be be of of benefit benefit to to store store all all reports reports of Archive. Reports could be of examinations in the Archive. cases Reports could be coded coded by by diagnosis diagnosis and appropriate cases designated separate Teaching Teaching File. File. designated for for duplication into a separate System Interface Recently, imaging system system interface interface standard standard has has been been proposed proposedbybyACR ACR-NEMA Recently, an imaging -NEMA task task group. group. Our supports the the ACR ACR-NEMA Our approach fully supports -NEMA interface interface standard and interface interface design design is is consist consist-ant ant with with the standard. standard. It It is, is, however, at once once however, difficult difficult to to implement implement the the entire entire standard at of limitations limitations imposed imposed by by the the existing because of existing imaging imaging equipment. equipment. The implementation The full implementation of of the the standard will take take time. time. Meanwhile, lower level level interface interface may may have have to to be be adopted. adopted. Meanwhile, lower The is summarized summarized here. here. (5) (5) The standard is Performance Performance Specifications a) Error Rate: Rate: Successful operation is defined such that sum of the error error rate rate on on 17 17 lines is is no no more more than than 17 17 xx 10 10~-9 9 prior corrections. b) Rate of Data Transparallel lines prior to any corrections. Transfer: The target data transfer transfer rate rate should should be be 88 Mbyte Mbyte/sec /sec given given cable cable length length of of up to 15 15 meters. Classification of devices

All All the the interfaced interfaced devices devices are are divided divided into into two two separate separate categories categories depending on their their role role in the network. Classification of of devices devices as as SINK SINK and and/or /or SOURCE is shown shown in in Table Table 2. 2. Table 22

Classification of Devices SOURCE

SINK

Digital Equipment Digital Image Producing Equipment Computed Tomography Computed Digital Subtraction Angio Digital Digital Roentgenography Digital Digital Ultrasound Imager Imager Digital Imager Magnetic Resonance Imager Digital Nuclear Med. Med. System Digital Film Digitizer

X X X X X X X

Hospital/Radiology Hospital /Radiology Information Information System

X

X

Data Data Storage Devices Archive Device Intermediate Intermediate Storage Local Storage at Workstation

X X X

X X X

Workstation Radiology Workstation Viewing Station Display Terminal

X X

X X X

Interpretive Interpretive Report Report Generation Generation System System

X

X

Telecommunication System

X

X

Command Structures

of primitive commands is defined in this section. A minimum set of section. Four command Four types of command defined. i) Requests: SEND, SEND, GET, primitives are defined. GET, MOVE, MOVE, and and FIND. FIND. ii) Acknowledge Requests: RESPONSE, MOVE MOVE RESPONSE, RESPONSE, FIND SEND RESPONSE, RESPONSE, GET RESPONSE, FIND RESPONSE. RESPONSE. iii) Exceptions: iv) Verification: ECHO. ABORT. Commands subsystem, i.e. i.e. imaging imaging equipment, Commands are are initiated initiated by by aa subsystem, equipment, workstation, workstation, a terminal. terminal. The The command command response response is is always always initiated initiated by by the the receiver receiver if if the the original original request request is sent is sent back to the initiator of the the initial initial request. request. Imaging is aa source source of of data data Imaging equipment that is is and receive receive SEND SEND RESPONSE RESPONSE commands. is required required to to initiate initiate SEND commands and commands. Imaging equipequipment is aa sink sink is receive SEND ment that that is is required required to to receive and initiate SEND RESPONSE commands. SEND commands commands and commands.

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SEND REQUEST (the device The data data source source (the device that that has has the the data) data) initiates initiates the the SEND REQUEST and and a) SEND The messerror messan error or an success) or (status == success) transfer (status receives an an indication of the successful data transfer successful data receives and source and data source the data is the initiator is RESPONSE. The (status == failure) age The request initiator age (status failure) via the SEND RESPONSE. is primitive is this primitive destination. b) FIND The is the data destination. the request request receiver receiver is The function of this the is. There data is. the data where the so, where if so, and if There may be exists and if the request data exists (query) if to to find find out out (query) etc. c) GET This primitive and etc. SUCCESS, and PENDING SUCCESS, request, PENDING FIND request, multiple responses to a FIND request image. The request an image. back an send back system send command requests requests that that another imaging equipment system command initiator. request initiator. the request to the back to initiator is is requesting the request receiver to image back an image SEND an to SEND initiator send to send command to SEND command the SEND uses the command uses GET command the GET of the If the the image image is is available available then the receiver of If another that another requests that d) MOVE This command requests command. d) of the GET command. the the image image to to the the initiator of requestis requestinitiator is system. The third system. imaging equipment equipment system send an image to aa third The request initiator imaging image to the data destination. ing that that the the request request receiver sends an an image ing Hardware Hardware interfacing protocols

a) Simple features: a) following features: the following ACR-NEMA the ACR adopted the We have adopted -NEMA standard standard that that calls for the circuits for c) Differential circuits 16-bit retrofitted. b) Carry 16 -bit data data with parity. enough to be retrofitted. f) AsynchMb/sec. of 88 Mb flow of /sec. f) meters. e) Data flow 15 meters. noise. d) Cable length upto 15 ground and noise. ronous handshake. for data and 17 for circuits including 17 32 differential have 32 hardware will The hardware will be be chosen to have differential circuits the in the micro-type pin micro 64 pin grounds. A common 64 for control and grounds. 7 for -type connector connector as as specified in parity, parity, 7 adopted. standard standard will will be adopted. HIS/RIS with HIS Interface with /RIS functions its functions and its HIS and of HIS subsystem of HIS/RIS have aa HIS already have we already GUH, we At GUH, /RIS network. RIS is a subsystem include patient patient registration, registration, scheduling scheduling file file room room management, management, reporting, reporting, management management reportreportinclude programs. The The RIS RIS currently does does not not have have aa long long ing, ing, patient patient tracking, tracking, filling and utility programs. should be term archiving archiving of of selected selected data data including including radiology radiology reports reports that that should be performed performed within within replaced by the DBMS file room room management management operation operation will will be be eventually replaced DBMS of of The file PACS. The the PACS. should image data The relatively relatively small small amount amount of of data data involved involved in in RIS RIS compared compared with with image data should The PACS. should be not require require technical technical difficulties difficulties in in interfacing interfacing except except that that the the network network should be able able not between shared command between of shared information. A high degree of required information. the required issue, get to issue, to get and request the desirable. be desirable. RIS RIS and PACS would be System Configuration The detailed detailed engineering PACS. The Georgetown PACS. of Georgetown diagram of block diagram the block is the Fig. 11 is Shown in Fig. represent However, the the building blocks blocks in the diagram represent finalized. However, yet finalized. not yet specifications are not the the basic configuration.

ACR-NEMA the ACR adopting the by adopting directly by interfaced directly be interfaced will be equipment will imaging equipment Various Various digital imaging -NEMA film standard and standard and the the film film based based image image data data will will be be entered entered into into the the network network using using aa film stand-alone be aa stand there may be future there digitizer. It It is is possible possible that in the future -alone reporting reporting system system network. the network. interfaced to the local. The and local. The diagram shown; archival, storage devices types of Three types Three of storage devices are are shown; archival, intermediate intermediate and archive. It the archive. for the configuration for hardware configuration exact hardware does not not necessarily specify exact It can be any does tapes. or tapes. disc or laser disc cards, laser disk, cards, type of of storage storage such as advanced disk, type system will the system shown. Eventually, workstation/viewing of workstation Three types of Eventually, the /viewing terminals terminals are are shown. have have to to support support up up to to 10 10 comprehensive comprehensive workstations, workstations, at at least least 12 12 review review stations, stations, and and 25 25 is part The interface part report generating system which is the radiology report interface with the remote terminals. The of RIS RIS is is especially especially noted noted to to emphasize emphasize the the high high degree degree of of interaction interaction required required at at the the workworkof station. functions. This RIS functions. of RIS part of is aa part system is generating system report generating the report HIS includes RIS and the Our HIS PACS assumes PACS assumes that that aa RIS RIS is is interfaced interfaced to to the the network network to to handle handle all all the the administrative administrative and and center currently. The center constructed currently. is being constructed center is imaging center scheduling tasks. An outpatient imaging link telecommunication link imagers. There will have have MRI, MRI, CT and and other radiological imagers. There will be a telecommunication will data. and data. images and to the network to to transmit the images the network

III) for Medical Applications (1985) (PACS Ill) Systems(PACS CommunicationSystems andCommunication Archivingand PictureArchiving 536Picture Vol.536 SPIEVol 234 //SPIE 11985)


Figure 11

SYSTEM SYSTEM CONFIGURATION

radiology radiology report generation generation system system

comprehensive workstations workstations Film Digitizer

o

oninteractive display Other Digital Imager

30\115 HIS

1

'

RIS

Digital Imaging Systems

Interactive display

local storage

image processor Netwo k

C Computer

LWA Archival Storage

interactive Station Intermediate Magnetic Storage

r-

Hard Copy Center

Simple Display Usual Computer Prephirals Terminals Printers

System Management and Evaluation System Reliability

meeting. It this meeting. in this paper in separate paper as aa separate presented as Detailed discussion will be It is be presented week. days aa week. day, 77 days hours aa day, 24 hours operate 24 whole, must operate The system as a whole, summarized here. 1) The network. the network. in the components in different components for different varies for required varies degree of of reliability required The degree 2) The sufficient amount The system should have have sufficient amount of of backup backup capacity capacity to to allow graceful graceful degradation degradation system should 3) The of levels of 4) Three levels shutdown. 4) complete shutdown. than complete rather than of performance performance in in case of difficulties rather of storage devices, devices, archival, archival, intermediate, intermediate, and and local local workstation workstation and and additional additional stages stages at at each each storage reliability. and reliability. security and of security layer of sufficient layer image generating generating station station will will provide sufficient image Security

limit the There to be be aa security system to to limit the has to There has be secure enough to to inhibit inhibit unauthorized unauthorized changes, changes, secure enough be Dissemination of of information information should should be be restricted restricted Dissemination of to know. It should also be able to keep track of activities.

should network. It should to the network. accessibility to data. of the data. additions, additions, or or deletions deletions of to to organizational organizational personnel personnel with aa need need their system and their individuals accessing the system individuals

System Evaluation

project. In of the project. is also a vitally important part of Proper of the system is Proper evaluation of studies, line studies, order to to have have aa comprehensive comprehensive evaluation evaluation one one has has to to establish establish initial initial base base line order that, with The objective objective of of the the Georgetown Georgetown PACS PACS program program is is to to develop develop aa prototype prototype system that, with The extensive minimal costs costs and and schedule schedule impacts, impacts, provides provides maximum maximum flexibility to to support an extensive minimal effectiveness. clinical effectiveness. system's clinical the system's and the features and evaluation of design features evaluation of evalscope of sufficient scope The prototype prototype will will have have aa sufficient of capabilities capabilities to to allow allow the the following evalThe uation.

Clinical Clinical Features three of medical care in three the practice PACS" on "Digital PACS" The effect effect of of aa "Digital on the practice and and provision of 1. 1. The different clinical environments. Department The "Imaging Department" environment; environment; e.g., e.g., within within the the GUH Radiology Department "Imaging Department" a) The Therapy); Radiation Therapy); to Radiation expandable to including Nuclear Nuclear Medicine and expandable including SPIE Vol. Vol.536 536 Picture PictureArchiving Archiving and and Communication Communication Systems Systems (PACS (PACSIII) III)for forMedical MedicalApplications Applications(1985) (1985)// 235 SPIE


b) The "Hospital/Referring flow of of pictorial pictorial The "Hospital /Referring Physician" Physician" environment, environment, e.g., e.g., the flow b) information between Department and and the the Medicine Medicine and and Surgical Surgical Floors, information between the GUH Radiology Department Floors, the the intensive care care unit, the emergency room, intensive unit, the room, etc. etc. c) The "Teleradiology" environment, The "Teleradiology" environment, e.g. e.g. between between GUH GUH and and an an independent independent Outpatient Outpatient c) Center. Imaging Center. 2. Differences in in workstation configurations and Differences workstation configurations and differences differences in "radiology "radiology studies" studies" 2. display techniques. techniques. 3. The Base consisting consisting of of earmarked earmarked images images (selected 3. The potential potential need need for a separate Data Base (selected by the the radiologist) radiologist) available for almost instantaneous instantaneous viewing viewing by by all all referring referring physicians physicians time. in the hospital at any time. 4. Archiving strategies strategies and and "image "image compression compression schemes ". schemes". 5. Radiology policies policies/regulations "image access" access" with with aa "Digital "DigitalPACS PACS". 5. /regulations about "image ". Technical Technical features 1. Methods 1. for direct images from from several several modalities and access Methods for direct access access of of images modalities and access of of images images from reference to to the the NEMA NEMA-ACR and Communication Communication from digitized film with reference -ACR Digital Digital Imaging and Standards. 2. Interfacing with with existing existing RIS 2. /HIS at GUH. RIS/HIS GUH. 3. Local Local Area (LAN) configurations configurations for for data a workstation Area Network Network (LAN) data communications communications between a workstation and and several modalities. 4. 4. Effectiveness of data storage storage and and data data base base management's management's capabilities. capabilities. Effectiveness of 5. Hardcopy generating 5. generating methods. methods. Economical/social Economical /social features 1. The potential cost cost effectiveness effectiveness of of aa PACS PACS system, system, both bothinintime time-convenience 1. -convenience and and amount (film savings, savings, decreased interruptions, interruptions, etc.) etc.) amount of of dollars dollars (film 2. The The impact impact of of PACS PACS on on the the practice practice of of radiology, radiology, specifically, specifically, the the potential potential for for new new ways of of displaying clinical relevant relevant radiology radiology information. information. 3. "Digital PACS" PACS" for for each each environment environment (i.e. (i.e. Radiology Radiology Dept.; Dept.; 3. The relative cost of "Digital Hospital links). Hospital referring referring physician, physician, Teleradiology links). Summary The The implementation implementation of of PACS PACS will will strongly strongly affect affect all all aspects aspects of of radiology, radiology, because because it it inter-relates people. Based on on the the inter -relatesvarious various hardware hardware components, components, information information systems, systems, and people. clinical clinical need need of of our our department, department, we we have have developed developed comprehensive comprehensive functional functional requirements requirements for for PACS with both clinical utility and PACS and cost cost effectiveness effectiveness in in mind. mind. The requirements include include data base data base management management system system workstation workstation configuration, configuration, system system interfacing interfacing and and system system management and evaluation. evaluation. Detailed is under under development. Detailed engineering specification is development. Careful planning followed followed by is expected expected to to produce produce aa clinically clinically acceptable acceptable PACS. a stepwise implementation is PACS. Acknowledgments The The authors authors are are grateful grateful to to Carolyn Carolyn Brafford Brafford for for her her enthusiastic enthusiastic support support in in preparing preparing the the manuscript. The authors wish to thank Frank Frank Hartel, Hartel, Ph.D. Ph.D. of of MITRE Corp. Corp. for valuable valuable discussions. References 1. Templeton, 1. et al., al., One One-line Term Digital Digital Management Management Systems, Templeton, A.W., et -line and Long Term Systems, Radio RadioGraphics, Vol. Vol. 5, 5, p. p. 121. 121. 1985. Graphics, 2. Dwyer, S.J., ed. ed. PACS III for Medical Applications, SPIE, SPIE, Vol. 2. Dwyer, S.J., PACS III Vol. 418. 418. 1983. 3. Mun, S.K., Elliott, L.P., and and Benson Benson H., H., Design Design Criteria 3. Criteria for for PACS, PACS, AAPM AAPM Meeting, Meeting, Mun, S.K., Elliott, L.P., NYC 1983. 4. 4. Dwyer S.J., S.J., et et al. al. Cost of of Managing Digital Diagnostic Diagnostic Images Images for for aa 614 614 Bed Bed Hospital. Hospital. SPIE, 318, p 3. 3. 1984. SPIE, Vol. Vol. 318, 5. National 5. National Electrical Manufactures Association, Washington, Washington, D.C. D.C.

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