Chapter 1 Hardware Anatomy and Physiology of a Personal...

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Section IV: Chapter 8 1

RADT 3463 - COMPUTERIZED IMAGING RADT 3463 - COMPUTERIZED IMAGING

RADT 3463 Computerized Imaging 1

Section IV: Chapter 8 2

SECTION IV - CHAPTER 8

PICTURE ARCHIVING AND

COMMUNICATION SYSTEMS

(PACS)

RADT 3463 COMPUTERIZED IMAGING

2 RADT 3463 Computerized Imaging

ACKNOWLEDGEMENTS This presentation is a professional collaboration of

development time prepared by:

Rex Christensen

Terri Jurkiewicz

and

Diane Kawamura

References and images are gathered from many sources including

those copyrighted by Elsevier / Mosby Publishing as they appear in:

Bushong, S. C. (2008). Radiologic science for

technologists: Physics, biology, and protection, 9th ed.

Chapter 27, St. Louis, MO: Elsevier Mosby.

Seeram, E. Digital Radiography: An Introduction, Delmar

Cengage Learning.

Section IV: Chapter 8 RADT 3463 Computerized Imaging 3

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SECTION III – CHAPTER 8 - OUTLINE

PICTURE ARCHIVING AND COMMUNICATION

SYSTEMS (PACS) 1. Introduction

2. PACS: A Definition

3. Historical Development

4. PACS: Major Components and Core Technologies

5. PACS and Information Systems: Integration and

Overview

6. DICOM: The Bare Essentials

7. Integrating the Healthcare Enterprise

8. Enterprise – Wide Image Distribution

9. PACS in an Educational Institution

10. PACS and Regulatory Approval

11. The Radiologic Technologist as Informaticist


INTRODUCTION

PACS is a software medium used for the viewing, interpretation, storage, and retrieval of digital images.

PACS has surpassed radiology imaging. It has moved into cardiology, pathology, surgery, and dental, just to name a few.

PACS has slowly evolved into what it is today. What do you foresee in the future for PACS?


PACS: A DEFINITION

• “PACS is a network-based, central server used for interfacing, image storage, and data acquisition of images produced by a myriad of radiology modalities that exist in hospitals today.”

Biomedical Instrumentation and Technology, McGeary (2009)

• The key components to a PACS system are:

– Monitors and work stations for displaying and postprocessing images

– Archive for storing images (servers)

– Network for transmitting images to other internal and external locations


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HISTORICAL DEVELOPMENT


• 1970 – Dr. Paul Capp introduces the term “digital radiology”

• 1980 – Heinz Lemke introduces the notion of digital image communications

• 1982-2002 – Several conferences deal with the subject of digital communication feasibility and technical elements

• 2004 – Dr. Huang categorized PACS into 5 models


HISTORICAL DEVELOPMENT

Five Implementation Models (Dr. Huang)

1. Home-Grown model – PACS built by the radiology department. It grows along with the needs of the department.

2. Two-Team Effort model – Collaboration of individuals inside and outside the hospital to meet PACS needs

3. Turnkey model – PACS is developed by an outside vendor. The vendor takes care of everything (implementation, service, etc).


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Five Implementation Models (Dr. Huang) cont.

4. Partnership model – Vendor and hospital work together to ensure an “optimal fit” based on the needs of the hospital and the PACS vendor’s software and hardware.

5. Application Service Provider (ASP) model - Provides all the PACS-related service to the customer including IT requirements.


Major Components and Core Technologies


Modalities

These machines (equipment) are also called acquisition stations (acquire the images).

• CT

• MRI

• Ultrasound

• Nuclear Medicine

• CR/DR

• Dexa


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Modalities

Most modalities are digital in nature (MRI, CT, US) but if they aren’t then they need to upgraded to transfer or convert the image into a digital image.

A DICOM conformity statement should accompany all machines to ensure they will connect to the PACS.

A “frame grabber” digitizes an image by converting it from an analog to digital image


Communication PACS uses communication protocols to share

information with other parts of the PACS.

Two Communication standards:

• DICOM (Digital Imaging and Communication in Medicine) This is the standard used for images.

• HL-7 (Health Level-7) This is the standard used for reports (textual data).


Communication Think of these two communication standards

like a .jpg (image) or a .pdf (article) but instead it is .DICOM (image) and .HL-7 (report)


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Network

A network is a “highway” for information (data) to travel from point to point.

Types of networks:

• LAN (Local Area Network) – A smaller network (distance) that is usually confined to a building.

• WAN (Wide Area Network) – A larger network (distance) that covers a larger area (cities, states, countries). The Internet is an example of a WAN


Network • Network speed is measured in Bandwidth.

The unit of measurement for the bandwidth is Mbps (Megabits per second).

– Bits NOT bytes

• Connectivity is through optical wire, Ethernet cables, microwave transmission, satellites, coaxial cable, copper (T1), and wireless.

• Data is split up and sent in smaller packets along the network.


Network

Why split up into smaller packets?


Big Package Network Congestion

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Network

Why split up into smaller packets?


Smaller Package Smaller lanes = Faster progress

Network

How do we get the packets back together?

• Network (communication) Protocols

– TCP/IP – Transmission Control Protocol/Internet Protocol (two protocols)


Network - Terminology • Node – an individual device or a point on the

network (printer, computer, CT, server, etc).

• Bridge – connects network nodes together.

• Router – Tells the packets where to go.

• Port – access to the server for a specific application. PACS port number is 104

• Socket – Port number + IP address

• Repeater – receives a signal, cleans it and amplifies the outgoing signal


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Network - Security

It is imperative that sensitive patient information be safeguarded against outside malicious attacks.

• Routers

• Firewalls

• Authentication

• Social Engineering


Main Computer • PACS server – also called the PACS controller,

database server, or image server.

• Equipped with several CPUs, increased RAM, and storage.

• It is a more robust computer that processes more data and runs more applications.


Storage

• Magnetic Disk

• Magnetic Tapes

• Optical Disk


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RADT 3463 Computerized Imaging 25

DIGITAL FILE SIZE

MEDICAL IMAGE IMAGE SIZE EXAMINATION SIZE

Nuclear Medicine 0.25 MB 5 MB

Diagnostic Sonography 0.25 MB 8 MB

Magnetic Resonance Imaging 0.25 MB 12 MB

Computed tomography 0.5 MB 20 MB

Digital Radiography 5 MB 20 MB

Digital Mammography 10 MB 60 MB

Storage - capacity

Section III: Chapter 8 Section IV: Chapter 8

Storage - RAID Redundant Array of Independent Discs

Types of storage:

• Online storage – cannot be removed

• Nearline storage – is removable (RAID)

• Offline storage – Must be retrieved and loaded by an individual


Image Compression Compression goals:

• Speed up transmission

• Reduce storage

Compression types:

• Lossless

• Lossy

• JPEG 2000 (wavelet)

– Combines lossless

and lossy techniques


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Compression Ratios

Compression ratios are inversely proportional with the image size and quality.

• Small Ratio (2:1, 3:1, 5:1)

– Higher quality

– Larger file (more storage needs)

• High Ratio (10:1, 50:1, 100:1)

– Lower quality

– Small file (less storage needs)


Image Display and Analysis Workstations

Hardware and software is used to help display images.

Types of displays:


CRT – Cathode Ray Tube LCD – Liquid Crystal Display

Display Orientation


Landscape Portrait

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Display Resolution

Resolution is determined by the number of pixels by row and column (2048×1536).

If we multiply these numbers together we get a higher number = 3,145,728. This number is expressed in Megapixels (or Million pixels) as 3.1 Megapixels


Workstation Functions

• Windowing/Leveling

• Post processing

• Annotations

• Zoom

• Scroll

• Measurement

• Invert

• And MANY more functions………… Section IV: Chapter 8 RADT 3463 Computerized Imaging 32

Web Server

• Allows users to access images remotely

• Uses an Internet browser software as an application interface.

• Uses a “thin-client” model. This means that there is minimal software loaded onto the viewing PC (or viewing device). Most of the software resides on the web server.


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Workflow in PACS Environment

• PACS reduces the number of steps in the Admission > Image collection > Interpretation > Distribution and management.

• Goals for improved workflow are:

– Improve patient care (continuity of care)

– Improve Technologist and Radiologist efficiency.

– Reduce costs

Where are the bottlenecks?


Workflow in PACS Environment


Integration

When you have two or more systems that use different communication standards they need to be integrated so they work together. The software or hardware that accomplishes this is called a Interface.

• Integration – Combining different systems so they work together.

• Interface – The equipment or software used to make the connection between different systems (broker).


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Information Systems

• HIS – Hospital Information System

• RIS – Radiology Information System

• PACS – Picture Archive and Communication System

• EMR – Electronic Medical Record

• VR – Voice Recognition System


HIS

• Medical information about the patient

• Hospital Administration

– Billing

– Accounting

– Statistics

– Budgets

– Material management


RIS • Patient information

• Exam scheduling

• Patient tracking

• Film archiving

• Administration and billing

• Documentation

• Inventory control

• Department statistics

• Communication standards


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Integration

• HIS – Hospital Information System (HL-7)

• RIS – Radiology Information System (HL-7)

Interface

DICOM <-> HL-7

• PACS – Picture Archive and Communication System (DICOM)


RIS/PACS Broker


Translates or verifies the

data (interface) between

the RIS and the PACS.

It confirms that the order

(from the referring

physician) matches the

images obtained.

Broker or Brokerless Integration


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Integration Elements

• Clinical Data Repository

• Data Dictionary

• Mapping

• Master Patient Index

• Uniform Language Efforts

• Data Exchange Standards


Data Exchange Standards (Communication Standards)

• HL-7 The standard for textual information

• DICOM The standard for image information

• IHE – Integrating the Healthcare Enterprise

– An initiative to facilitate communications among various healthcare systems.


DICOM

Digital Imaging and Communications in Medicine

• Developed jointly by the ACR (American College of Radiology) and NEMA (National Electrical Manufacturer’s Association

• It is made up of 15 parts that deal with a specific process.


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Summary of DICOM Features

• DICOM OBJECTS

• DICOM ELEMENTS

• DICOM CLASSES

Section IV: Chapter 8 46 RADT 3463 Computerized Imaging

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).

• DICOM uses Information Objects Definitions (IODs) to identify information objects, such as the images, reports, or transfer syntaxes.


DICOM Elements

• Complex services are built using service elements, called DICOM message service elements, or DIMSEs.

• Two categories of DIMSEs:

– operations (such as "store")

– notifications (such as "event report”)


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DICOM Classes (Service) • Composite

● Verification

● Storage

● Query/Retrieve

● Study Content Notification

• Normalized

● Patient Management

● Study Management

● Results Management

● Basic Print Management Section IV: Chapter 8 49 RADT 3463 Computerized Imaging

Service Class User (SCU) Service Class Provider (SCP)


Service Class User – Someone or Something that uses a service

Service Class Provider – Someone or Something that provides a

service.

DICOM Service-Object Pair (SOP)

• The service classes and information objects are combined to form SOP.

• The SOP class is the elemental unit of DICOM.

• Everything that DICOM does is based on the use of SOP classes.


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DICOM Service-Object Pair (SOP)

SOP

Data Dictionary

Information Object DIMSE Service Element


DICOM Conformance Statements

• A DICOM conformance statement is used when a user or manufacturer is trying to determine if two DICOM devices will communicate to suit a particular application or system. Example: CR connected to a PACS. Are they compatible?


DICOM Conformance Statements

The contents of the conformance statement include:

(a) the implementation model of the application

(b) the presentation contexts to be used

(c) the manner in which associations are to be handled

(d) the SOP classes to be supported

(e) the communication profiles to be used

(f) any extension, specialization, or privatization to be used.


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Integrating the Healthcare Enterprise (IHE)

• A standards-based initiative of the RSNA (Radiological Society of North America) and HIMSS (Healthcare Information and Management System Society)

• Facilitating communications between various healthcare communication systems (lab, medical record, cardiology, etc)


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Who is IHE? Participants:

Professional Societies Healthcare Information and Management Systems Society (HIMSS)

Radiological Society of North America (RSNA)

Other societies

Vendors (over 30 companies)

Standards Group Committee Members

Laboratory Healthcare Partnership

RSNA and HIMSS sponsor IHE to provide a neutral forum for working on the Big Picture

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IHE Technical Framework

• Data Model define how several actors must communicate using existing standards (HL7 or DICOM) e.g. Procedure scheduled

• Actors represent a role performed by the system e.g. Order Placers, Order Fillers

• Integration Profiles are collections of real world functionality that may span several systems e.g. Scheduled Workflow, patient Reconciliation

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Enterprise-wide Image Distribution

• Remote access to the PACS and distribution of images outside the radiology department and the facility.


Enterprise-wide Image Distribution • Approaches:

– Extending traditional approach. Sending images to all areas of the hospital. Requires a dedicated workstation.

– Thin client (web-based). Compresses images and made available through the internet using an internet browser.


Enterprise-wide Image Distribution • Approaches:

– Thin Client (Just-In-Time). Same as the web based, but images are only delivered when the user requires them.

– Compact Disk Read-Only Memory (CD-ROM). Distributed without the need of computer networks.


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PACS in Education

• Students send images acquired from the sim lab to PACS for analysis

• Instructors can access image quality based on positioning, technique, etc.

• Teaching files

• Assignments and analysis on the PACS can be accessed from home

• Images from other institutions can be imported to the PACS for educational learning


Federal Agencies and Regulations

• FDA – Food and Drug Administration (agency)

• HIPAA – Health Insurance Portability and Accountability Act (regulation administered by the Department of Health and Human Services)


FDA

• Medical devices are regulated by the FDA

• PACS is considered a medical device

• PACS vendors have to subject their product to the FDA for pre-market approval (510k)


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HIPAA

• Became law in 1996

• Protection of the patient’s health information

• Security of electronic data and information

• Audit access of patient information


Informaticist

• A person who works in IT (Information Technology). IT is defined as:

“the acquisition, processing, storage, and transmission of vocal, pictorial, textual, and numeric information by microelectronic, computers, and telecommunications.”

Library of Congress (2002)


PACS Administrator

• Usually a Radiologic Technologist

• Background or interest in IT

• Can be a person from the IT department


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PACS Administrator Duties

• PACS is working according to the needs of the department. Understands workflow.

• Operability of PACS workstations

• Assigns and updates usernames and passwords

• Establishes standards, policy, and protocols for using the system (downtime policies)

• Communicates with other departments using PACS


PACS Administrator Duties (Cont.)

• Communicates with the facilities IT department

• Provides ongoing training AND training for system users (THIS IS BIG!)

• Communicates (and may negotiate) with PACS vendor regarding upgrades, updates, and service.

• Maps workflow processes and makes improvements

• Performs quality control of the system Section IV: Chapter 8 RADT 3463 Computerized Imaging 68

PACS Certification

• PARCA – PACS Administrators Registry and Certification Association

– CPIA – Certified PACS Interface Analyst

– CPSA – Certified PACS System Analyst

– CPSM – Certified PACS System Manager

• CIIP – Certified Imaging Informatics Professional. Administered by the ABII (combination of SIIM and ARRT)


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Questions?


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