M4 L3 - Image Storage

Medical image storage device and peripherals

What is the archive?

a place where information is preserved

What are the 2 parts of the archives?

• image manager/controller

• image storage/server (archive server)

What does the image manager contain and what does it control?

• contains: master database of everything in the archive

• controls: receipt, retrieval, distribution of images stored, and DICOM processes in the archive

What PACS component interfaces with the RIS and HIS

the image manager

What is the process to query a study?

1. RIS order placed

2. images acquired and sent to archive

3. image manager assigns pointers

4. image manager files away and verifies info

5. when study is queried: pointer locates images and sends them to workstation

Who can change PT demographics at the workstation / using the image manager?

radiologist, technologist, or file room clerk

What is the archive server and what does it store?

the file room of PACS

• stores all historic and current data

What is RAID?

redundant array of independent disks

• large amount of short term storage linked together to perform as a single drive

What is short-term storage (and what other name is it referred to as?)

aka On Line Storage

• provides immediate access to studies

• usually arrays of magnetic disks = RAID

What is long-term storage (and what other name is it referred to as?)

aka Near Line storage

• automated arrays of optical disks/magnetic tape from which studies may be retrieved within 1-5 minutes

• optical disks have shorter access times

What is Off Line storage?

optical disks stored on shelves/racks

• require manual retrieval

What is the size range for RAID?

usually several hundred gigabytes to terabytes

What is the most common form of RAID used in PACS?

Raid 5

What is a Magneto-optical disk (MOD)?

disk housed in plastic cartridge

• read by a laser

What is a Digital versatile disk (DVD)?

plastic disk

• least expensive per GB

What is Ultra density optical (UDO)?

similar to MOD

• uses blue laser for reading and writing to disk

What is a key advantage of tape for long-term storage, and how many tapes can a tape library hold?

• low cost

• libraries can have up to 1448 tapes

  • uses a jukebox

What is Direct attached storage (DAS)?

extension of short form RAID

• connected via cables to the computer

What is Network attached storage (NAS)?

NAS servers are stand alone RAID arrays attached directly to the network

What is a Storage area network (SAN)?

special purpose network that links different devices

• high speed