1. What is PACS ? P: Picture, Images & Reports
A: Archive, Online, Near line, Offline
C: Communication, Networking, Transfer Protocols
S: System, Components & Architecture
PACS: for storage and distribution of images and information when necessary

2. PACS: Small or Large
Web Server Distribution

3. Scale of PACS No. of Beds in Hospital/ Exams per year
No. of Modalities
No. of Switches
Considerations:
System connectivity, expandability, reliability and cost-effectiveness
Connection among various hospital information system, open architecture,
Data migration is painful enough if you have money

4. Types of images
1D, 2D, 3D, 4D
Different DICOM Modality type: Cardiac / PET / 4D U/S…..
Image size: Resolution and bit depth
Image quality: Bit Depth and resolution
Color / Monochromatic
Exam. Size: image size x no. of images
Structured Reports
New DICOM IOD:
Endoscopic & Microscopic images / ECGs / Security Profiles…..
IOD=information object definition; Mammo CAD use SR output; DICOM waveform IOD; DICOM visible light IOD; Digital Envelop over Digital Signature

5. 1D, 2D, 3D, 4D, fusion

6. 1D, 2D, 3D, 4D, fusion

7. Image Resolution/ Bit depth
U/S DF CR CR Mammogram
256 x 256
8 bit
65 KBytes
1k x 1k
10 bit
1.25 MByte
2k x 2.5k
12 bit
7.5 MByte
4k x 5k
12 bit
30 MByte

8. Properties of image Bit depth Grayscale or color Resolution in pixel
Example image size of mammogram = 4k x 5k x 12 bit = 30 MB
Microcalcification need 130 µm resolution

9. PACS Architecture

10. PACS – Central Architecture
DICOM
Modality
Diagnostic
Workstations (DICOM)
Clinical
Workstations (DICOM)
Image
Server
(RAID)
Gateway or
Frame Grabber
Diagnostic
Workstation
Non-DICOM
Modality
Film
Digitizer
Web Server
Data Base
Server
CR/ DR QA
Workstation
Archive
Computed
Radiography
or DR
RIS

11. Central Architecture Image Server and Database Manager is the HEART
Any image, any where, any time
Unique central copy
Easy update of data
Requires high performance servers
Potential single point of failure at server
Bandwidth demanding

12. PACS – Distributed Architecture
DICOM
Modality
Gateway or
Frame Grabber
Diagnostic
Workstations
(DICOM)
Clinical
Workstations
(DICOM)
Web Server
Non-DICOM
Modality
CR QA
Workstation
Diagnostic
Workstation
Film
Digitizer
Data Base
Server
Archive
Computed
Radiography
RIS

13. Distributed Architecture
Exams are routed from modality to selected workstations
Complex routing algorithms based on department / user preference
Difficult to support concurrent review of images
Less destructive for failure at database server

14. Components of PACS HIS/ RIS Broker ePR gateway Database Server
Image Server (RAID)
Long Term/ Near line Archive
Networks
Digitizer

15. Components of PACS Acquisition Gateways Non-DICOM modality gateway
DICOM Print Server
Media Server
Reporting Server
Monitor QC Server
Web Server
Workstations

16. PACS layout 1

17. PACS layout 2
All in blue must mention

18. PACS layout 3

19. PACS Components Image Server (RAID) ePR gateway Enterprise Archive
DICOM
Modality
Diagnostic
Workstations (DICOM)
Through Acq. gateway
W/S QA Server
Clinical
Workstations (DICOM)
Image
Server
(RAID)
Gateway or
Frame Grabber
Diagnostic
Workstation
Non-DICOM
Modality
Film
Digitizer
Web Server
Data Base
Server
CR/ DR QA
Workstation
LTS Archive
SAN/NAS
Computed
Radiography
or DR
Media Server
Broker for
RIS/HIS

20. Acquisition (DICOM) Gateway
HIS/RIS
Interface
(Broker) DG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

21. Role of Acquisition gateway
Compression/ decompression and security
Check the images for integrity
Convert to PACS format (header, byte-order, matrix size)
Queue for images (priority) to database server (background)
Share the workload and no point of failure for multiple Acquisition gateway

22. Database Server and Image Server
RAID
Database
Server
HIS/RIS
Interface
(Broker) DG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

23. Database Server (PACS controller)
The Heart of the system
Integration cross point between HIS/RIS and PACS (status update)
Create and manages patient folders
Manage reading worklists and user profiles
Manage data transfer within the system
Support data mining and teaching folders

24. Image Server (RAID)
Online (rapid access) exam storage and distribution device
Support simultaneous exam input and output transfer operations
Up to Three months of storage capacity
Scalable capacity

25. What is RAID Redundant Array of Independent Disks
Bandwidth equal to sum of disk transfer rates
Highest speed disk storage available
Hot Swap
2 MB/s 1 2 3 4 5 6
16 MB/s 7 8
Image
Parity
Disk Array

26. RAID 5 configuration
If disk fails, disk can be rebuilt- fault tolerant
High data transfer rate for read, write slower
Min. 3 disks to start
Array capacity is N-1

27. Bandwidth
Bandwidth is a measure of the information (data) carrying capacity of a network
10/100/1000 MB/sec
Information Flow
Data Pipe (Network)

28. Network Bottleneck
The bandwidth of an information delivery system is limited to the bandwidth of the slowest component in the system
Network Bottleneck

29. Data Compression Data compression reduces the information rate
a network must support
Uncompressed Data
Compressed Data

30. Lossless Image Compression
I - D = 0 I D
Decompressed image is identical to original image
JPEG lossless compression
Average compression of 2:1 for x-ray images

31. JPEG 2000 Compression
Selected parts of the image can be defined as Regions of Interest, they can then be delivered before other parts of the image, or losslessly, whilst other parts of the image that are less critical use normal lossy compression
JPEG 2000 codestream can be ordered to deliver images of lower resolution before the full image can be transmitted
Motion JPEG 2000 does not have any form of extrapolation (and hence potential distortion) in the time domain.  Each frame is a separate JPEG 2000 coded image

32. JPEG 2000 images

33. Storage Device (Long Term)
RAID
Database
Server
MOD
DLT
HIS/RIS
Interface
(Broker) DG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

34. Types of storage media Media DVD MOD DLT 9840 AIT2 GB Cost
WORM
DLT
9840
AIT2 GB
3.8
5.2 35 20 50
Cost
Less Expen.
Expen.
Cheap
Most Expen.
Load + Assess
Very fast
113 sec
15 sec
45 sec
Max. T rate MB/s 5
5.1 10 6

35. Long Term Archive
Used to store digital data for longer periods of time
Storage ranges from 100 MB to 10 TB
Optical disk most common media
- 5 1/4” MOD
- 2.6 GB and 5.2 GB Capacity
DLT used for longer term storage and redundancy
ISP module

36. Storage Device (Near line)
RAID
Database
Server
SAN/NAS
MOD
DLT
HIS/RIS
Interface
(Broker) DG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

37. Storage Area Network
SAN is a high-speed sub-network of shared storage devices
Contains storage device (disk) for storing data
SAN's architecture works in a way that makes all storage devices available to all servers
Use of Fiber Channel
High scalability for additional storage and redundant networks
PCs
Storage devices

38. Network Area Storage
NAS is a class of dedicated hard disk-based storage devices which provide LAN users with additional disk storage through a standard network connection
In most cases, a NAS device (or NAS server) receives an IP address, connects to the LAN through an Ethernet cable, and resides on the LAN as an independent network device
Users are not demanding the server's processing time for mundane storage tasks -- often improving the performance of local application servers
NAS systems also include some onboard memory (RAM) to cache network data to or from the disks

39. SAN Vs NAS Difference between NAS and SAN is subtle
NAS devices are big, single purpose storage appliances that you plug into network
NAS sits between your application server and your file system
As perform only 1 task, can serve files very fast
NAS is network-centric
SAN is a defined architecture that sits between your file system and your underlying physical storage
SAN is data-centric

40. Display MOD DLT SAN/NAS DG RIS W/S PCs CR QA CT MR R&F NM CR XRAY US
RAID
HIS/RIS
Interface
(Broker)
Database
Server
MOD
DLT
Diagnostic W/S
Dedicate W/S
SAN/NAS DG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

41. Workstations Four Primary Categories
- Advanced Analysis: Used by specialists for advanced diagnosis - 3D, volume rendering
Diagnostic: For primary diagnosis; located in reading rooms; high-end 2K monitors
Clinical: Used by clinicians and staff to consult; ICU / ER applications; less costly than diagnostic; 1K monitors
At Home Review: low-end; PC based; cost-effective; review application; lossy compressed for faster transmit

42. Standalone Vs direct PACS w/s
Standalone Workstation
Direct PACS Client Workstation
Hard Disk Storage
Yes, varies
Minimal
Query PACS number
All PACS system (CT, ACC, Angio.)
Single PACS system (ACC PACS)
Retrieval mechanism
DICOM Q/R and association made with different vendors
Direct attached, same vendor
Retrieval time
Slower
Faster
Diagnostic value
Depends on Monitor Grade and Modules like MPR, 3D etc
Suggested usage
for meeting/museum purpose
for single modality image reviewing and reporting like Radworks in U/S Rm
Direct PACS workstation for reporting

43. Web distribution High availability, low cost
Reports / select images to referring physician desktop
Point of integration with electronic patient record
Lossy compression for performance
Potential for TeleRadiology
Security issues to be resolved

44. RIS, HIS, ePR and PACS integration

45. Broker HIS/RIS and PACS interfaceDG
RIS
W/S
PCs
CR QA
Film
Digitizer
Frame
Grabber CT MR
R&F NM CR
XRAY US

46. Hospital Information System
Support clinical and medical patient care activities in the hospital
Administer the hospital’s daily business transactions like finance, payroll etc
Evaluate hospital performances and costs and make long-term forecast

47. Clinical System in HA, HK
Patient Administration
In-Patient and Out-Patient Administration System
Accident & Emergency Information System
Medical Record Abstract System
Medical Record Tracking System
Clinical Support
Laboratory Information System
Radiology Information System
Pharmacy Management System
Dietetics Catering Management System
Clinical Management
Clinical Management System (In-Patient) Discharge Summary
Clinical Management System (Out-Patient)
Electronic Patient Records
Clinical Data Analysis and Reporting System

48. Non-Clinical System in HA
Human Resources and Payroll Systems
Hospital Based Financial System
Materials Management System
Patient Billing and Revenue Collection System
Executive Information System
Code 9 and view codes

49. Radiology Information Systems
Similar to HIS but of smaller scale
Interfaces to PACS based on HL7
Department administrative management
- Scheduling and Film tracking
- Resource management and reporting
- Monitor patient status
Link to Hospital Information System (HIS)
- Billing and Master Record
Link to Clinical Management System (CMS)
- Prefetch for Clinical visit
- ePR integration

50. RIS workflow Exam Order Exam Scheduled Web distribution to referring
physicians
RIS
Modality Worklist
Demographics
Downloaded
Patient Exam
Is Performed
Images
copied on
web-server
Order
Event
Images
transferred
in STS
Database
server
/Archive
Prefetch Exams
From Storage
PACS Worklist
Updated
Images /
Prior Reports
Exam
Read
Dictated
status
Image migration STS to LTA
Final report
available
Report
Verified
Preliminary status
Exam
Transcribed

51. Broker service Database server DR HA HIS CR HA RIS HA CMS US DF Mitra
ADT CR
Mitra
PACS
Broker
interface HA
RIS
Appt.,
X-ray request
HA CMS
Clinical visit US DF
Database server
Modalities: Get WORKLIST
Get REPORT, Get INFO

52. Broker service
A restricted access account will be created at Sybase that gives limited authority for the DICOM Broker solely for the purpose of the interfaces
In general, for data flow from RIS to the Broker, the RIS write the supported events to the table, and the Broker polls against the events table and calls the associated stored procedures for the conversion to DICOM messages

53. Broker service Broker main function: - Worklist generation
- Reports storage
Registration + Post exam data capture (RIS)
Acc # generation + call broker for update
Need SOME time!!
Modalities query Broker for worklist update
Broker poll RIS event table and convert to DICOM info

54. ePR Architecture
Selected images from individual hospital’s PACS are sent
make use of the ePR record indexing and browsing capabilities to read the radiology images through CMS workstations

55. Data Flow Diagram RIS ePR HA system Appointment Attendance
Exam records
Reports (15mins)
CMS
RIS operational data
ePR
Web Server
PACS
Attendance
Exam & workload units (daily)
RIS statistical data
Data warehouse
Non clinical system

56. Characteristics of ePR
Near instant image review
Web distribution can be within hospital, to other hospitals or even private clinics
TeleRadiography possible
Update of patient information
Lossy Vs lossless
Broken pathway
15 minutes time lag

57. Guidelines for HIS, RIS, PACS interface
Each system remain unchanged in its configuration and function, only data are shared
Identify the subset data to be shared and set up access rights/ authorization
Convert the subset data to HL7 standard
Define transfer protocol (TCP/IP or DICOM)

58. Typical patient and data flow
Admission: Patient registration, notify HIS (HL7)
Order entry/Arrival: Schedule exam and notify RIS
Broker notified and PACS database server updated (prefetch)
DICOM worklist to modality
Exam completed: data to DICOM gateway (MPPS)
Information/images to database/image server through gateway (DICOM store)
Images stored in PACS archive
Images to workstations from PACS archive
Dictation, transcription etc: workstation to RIS/PACS
RIS reporting and PACS updated for reports
Transfer: HIS/RIS to PACS, images to other PACS
Discharge: HIS/RIS to PACS, images rub out

59. Mobile PACS

60. What is DICOM?
The standard for Digital Imaging and Communications in Medicine.
Developed by the National Electrical Manufacturers Association (NEMA) in conjunction with the American College of Radiology (ACR).
Covers most image formats for all of medicine.
Specification for messaging and communication between imaging machines.

61. A little history The first version was ACR-NEMA, released in 1985.
Its goal in developing a standard was
To enable users to retrieve images and associated information from digital imaging equipment in a standard format using point-to-point connection.
To hide differences same across multiple image equipment manufacturers.
To handle developing network and image standarts, a new standard, DICOM, was proposed in 1981.

62. DICOM Application Domain
MAGN
ETOM
Information Management System
Storage, Query/Retrieve,
Study Component
Query/Retrieve
Results Management
Print Management
Media Exchange
LiteBox

63. Summary of DICOM Features
NETWORK PROTOCOL
DICOM incorporates negotiation to permit peers to agree on the functions to be performed
MESSAGE ENCODING
DICOM defines 24 data types (V2.0 had 4)
DICOM message encoding includes JPEG compression (17 varients)
DICOM supports multiple character repertoires

64. Summary of DICOM Features
OBJECT DATA MODEL
DICOM is based on a completely specified data model
DICOM includes a robust UID mechanism
DATA DICTIONARY
DICOM includes a large number of new data elements
SERVICE CLASSES
DICOM defines classes of service for specific applications (e.g. image management, printing) and conformance levels

65. DICOM Objects
Things such as images, reports, and patients are all objects and are called information objects.
Two kinds of objects in DICOM:
Composite objects (Old objects inherited from NEMA).
Normalized objects (New objects defined in DICOM).
All objects and their format constitutes Data Dictionary.
DICOM uses UIDs to identify information objects, such as the images, reports, or transfer syntaxes.
The form of the UID conforms to an international standard.
is the root and the same for every DICOM UID.
Example: UID for the DICOM explicit VR little endian transfer syntax is

66. DICOM Service Classes Composite Verification Storage Query/Retrieve
Study Content Notification
Normalized
Patient Management
Study Management
Results Management
Basic Print Management

67. Hardcopy Image Reading + Dictation/Transcription (Use Case 1)
Hardcopy Reading
Hardcopy DICOM Print as Seen at Modality
Reporting:
RIS-Based Transcription / Validation of Narrative Report
RIS-Based Report Storage and Management
Send Reports
Query Prior Reports

68. Hardcopy Image Reading + Dictation/Transcription (Use Case 1)
Report Storage / Mgmt.
Report
Repository
RIS
Electronic Report
Paper print/
Mail/
Fax/
send
Narrative Info Only
Electronic Report
query
Acquisition
Transcription
& Correction
print
Validation
Filming
Film Archive
Hardcopy
Interpretation
& Dictation
manual
network
DICOM
HL7/other
optional

69. Hardcopy and Softcopy Image Reading + Dictation/Transcription (Use Case 2)
Hardcopy Reading
Hardcopy DICOM Print as Seen at Modality
Softcopy Reading
Hardcopy DICOM Print as Seen During Softcopy Reading
Reporting:
RIS-Based Transcription / Validation of Narrative Report
RIS-Based Report Storage and Management
Send Reports
Query Prior Reports

70. Hardcopy and Softcopy Image Reading + Dictation/Transcription (Use Case 2)
store
Selected
Images
Softcopy
Interpretation
& Dictation
Report Storage / Mgmt.
Report
Repository
RIS
Electronic Report
Paper print/
Mail/
Fax/
send
Electronic Report
Narrative Info Only
query
Acquisition
Transcription
& Correction
print
Validation
Filming
Film Archive
Hardcopy
Interpretation
& Dictation
manual
network
DICOM
HL7/other
optional

71. Acquisition Workflow Support + Burn CD/DVD (Use Case 3)
Image Acquisition:
RIS-based Acquisition Workflow Support (Modality Worklist)
Image Reading:
Hardcopy Reading
Hardcopy DICOM Print as Seen at Modality
Softcopy Reading
Hardcopy DICOM Print as Seen During Softcopy Reading
DICOM Store Images -> Burn CD/DVD
Reporting:
RIS-Based Transcription / Validation of Narrative Report
RIS-Based Report Storage and Management
Send Reports
Query Prior Reports
Optional DICOM Store Reports -> Burn CD/DVD

72. Hardcopy and Softcopy Image Reading + Dictation/Transcription (Use Case 3)
Modality Worklist
store
Selected
Images
Softcopy
Interpretation
& Dictation
Report Storage / Mgmt.
Electronic Report
Report
Repository
RIS
Paper print/
Mail/
Fax/
send
Electronic Report
Narrative Info Only
query
Acquisition
Transcription
& Correction
print
Burn CD/DVD
Off-Line Archive
Validation
store
Filming
Film Archive
manual
network
DICOM
HL7/other
optional
Hardcopy
Interpretation
& Dictation

73. PACS for Management of DICOM Persistent Objects (Use Case 4)
Image Acquisition:
RIS-based Acquisition Workflow Support (Modality Worklist)
Image Reading:
Hardcopy Reading
Hardcopy DICOM Print as Seen at Modality
Softcopy Reading
Hardcopy DICOM Print as Seen During Softcopy Reading
DICOM Store Images for Burning CD/DVD
PACS-based Storage and Management of DICOM Persistent Objects
Archive Imaging Studies
Query Prior Imaging Studies
Reporting:
RIS-Based Transcription / Validation of Narrative Report
RIS-Based Report Storage and Management
Send Reports
Query Prior Reports
Optional DICOM Store Reports for Burning CD/DVD

74. PACS for Management of DICOM Persistent Objects (Use Case 4)
Modality Worklist
store
Object Storage / Mgmt.
Electronic Report
Electronic
Report
Selected
Images
Report
Repository
RIS
Paper print/
Mail/
Fax/
send
Softcopy
Interpretation
& Dictation
query
Narrative Info Only
Transcription
& Correction
Image
Repository
PACS
Acquisition
store
Validation
print
store
q/r
store
Off-Line Archive
Filming
Burn CD/DVD
Film Archive
Hardcopy
Interpretation
& Dictation
manual
network
DICOM
HL7/other
optional