RAD370 - CH 9 PACS

Electronic version of the radiologist’s reading room and file room

PACS

Universally accepted standard

DICOM

Fundamental parts of PACS

• Image acquisition

• display workstations

• archive servers

First modality to use PACS

Ultrasound

soft-copy

digital

Led to need for PACS in CT and also MRI

Image sets increased in number

Most interactive part of a PACS

display workstation

• any computer used to view a digital image

• receives images from archive or various modalities

Houses all of the historic and current data

PACS - Archive Server

• file room of PACS

PACS - based workflow

• order entry

• exam

• image process

• image interpreted

• transcribed report

Technologist gets order via an electronic worklist, the order is then

input into the RIS

• RIS sends a message to PACS

• PACS finds/archives historical images

When a radiologist dictates a report, it may be

transcribed with voice recognition software

hardware and software infrastructure of a computer system

system architecture

Exams sent to PACS can be viewed anywhere, but

only one person can view at a time

• message sent to others who attempt to open at same time

disadvantages of PACS

• archive server is seen as a single point of failure

• system is network dependent

When an archive server hands many requests at once

it can become bottlenecked

distributed or standalone models

• all images are locally stored

• images remain on local hard drive until deleted by user or system rules

• images are sent from modality to archive server

• server distributed images to designated workstation

Advantages of a distributed system

• if archive server goes down can still access local reading at workstation

• system is less dependent on network for speed

Disadvantages of a distributed system

• personnel rely heavily on system to perform image distribution correctly

  • prefetching of historic exam will be wrong

• Each workstation has different worklist; only one person at a time can work on that list

Web Based Systems

• images and application software are held centrally and load to client display

• Only the images are held at archive

4 - 6 monitors needed

Early PACS

Most popular monitor type

LCD

Radiologist

• highest quality hardware / monitor

Primary reading station

Physicians

• ability to view current and previous reports with images

Review Stations

• step down model

Technologist

• used to review images after acquisition but before sending to radiologist

Technologist Quality Control (QC)

• 1k monitor

File room personnel

image management station

• Navigation functions

• image manipulation + enhancement functions

• image management functions

• Advanced workstation functions

Common functions of a PACS workstation

Used to move through images, series, studies, and patients

Navigation Functions

Not to be used to label left or right to indicate the patient’s side

Annotation

• used to indicate prone or supine, 30 minutes, upright or flat

used to orient image in correct anatomic hanging position

Flip and Rotate

Extension of PACS, distributes digital images for off-site interpretation

Teleradiology

• predates large PACS applications