Transcript Standard Clinical Desktop - Clinical Engineering Society

Basic Principles of
PACS Networking
Emily Seto
Medical Engineering/SIMS
Center for Global eHealth Innovation
April 29, 2004
Overview
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PACS Introduction
PACS Network Related Concepts
Network Lingo and Relevance to PACS
Example of PACS Network
Take Home Message
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What is PACS?
PACS = Picture Archiving &
Communications System
System facilitating viewing &
storage of digital medical images
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Medical Digital Images
X-RAY BASED
MRI
Ultrasound
CT
Mammography
Nuclear Med (PET)
Light
CR
Fluoroscopy
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PACS
Acquisition
Processing
HIS
Storage
Viewing
RIS
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PACS Network Related
Concepts
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Reliability/Security
• Mirrored systems separated by physical
distance
• Archived data
• Redundant paths (consider direct path from
acquisition device to particular PACS PC)
• 24/7 Support (access network remotely)
• Secure lines outside of hospital to view
images
– eg via Virtual Private Network from
physicians’ homes
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Speed
• Online, Near-line & Disaster Recovery
Back-ups
• Prefetching & autorouting (pushing
images)
• Local copy vs streaming data
• Bandwidth (dedicated LAN)
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Compression
• Lossy vs non-lossy (up to 3:1)
• Acceptable compression different for each
type of image
• Different types (eg wavelet, jpeg)
318 kB
10:1 (30 kB)
100:1 (4 kB)
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Network Lingo and
Relevance to PACS
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Local Area Network (LAN)
• Computer network that spans relatively
small area
• Can be desirable to have dedicated
PACS LAN for all PACS devices
(acquisition devices, display
workstations, storage, and servers)
• Advantages:
– Helps ensure adequate bandwidth
– Can aide in device management
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Redundant Array of Independent (or
Inexpensive) Disks (RAID)
• Combination of multiple disks drives to
improve:
– Performance
• Data striping (spread out blocks of each file
across multiple disks)
– Fault tolerance
• Disk mirroring
• Dedicated disk for error correction
• 50% of hardware device failures are
due to disk failures
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Network Attached Storage (NAS)
• Storage device taken away from server
and directly connected to network
• Devices assigned IP addresses and
accessed by clients via a server
(gateway to data) or accessed directly
by clients
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NAS Advantages
• Centralized storage, security,
management, and data back-up
• Servers running different operating
systems can all access data
• Expandability (add new device without
shutting down servers)
• Fault tolerance (server fails can still
access data)
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Storage Area Network (SAN)
• High-speed sub-network of shared
storage devices
• Access data via server systems
connected to both the LAN and SAN
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SAN Advantages
• Centralized storage, modular scalability,
high availability, and increased fault
tolerance
• Removes bandwidth bottlenecks with
LAN based server storage
• Serverless backup (high speed data
backup without using LAN bandwidth)
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Example of NAS/SAN
Image Acquisition Devices
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Tier 1
Storage
-redundant paths out
-connected by
fiber optic cables
-most recent studies
-non-lossy
compression
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Load-Weighted
Servers
Non-compressed
Deep Archive
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Tier 2
Storage
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(2 months later)
Image Display
*NB Entire system should be mirrored offsite
-compressed
(lossy)
-older studies
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Networking Budget
• Mirrored servers & storage (several
Terabytes)
• Archiving (magneto-optical tapes, DVDROMs, CD-ROMs, etc.)
– Petabyte (1024 Terabytes)
• Proper facilities to house servers &
storage
• Network infrastructure (network drops,
cable, etc)
• Support
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Take Home Message
• Each institution will have their own
PACS networking needs depending on
size, type and volume of images,
existing network, and budget available
• Main concepts to keep in mind:
– Reliability/Security
– Speed
– Compression
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Contact Info: Emily Seto
[email protected]
(416)340-4800 x6409
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