CR/DR M1 (copy)

FILM-SCREEN RADIOGRAPHY

Workhorse of radiology since 1895

1. Eliminate film-based imaging systems
2. Introduce new technologies for the purpose of improving diagnostic interpretation & digital image management
3. Reduce the radiation dose to patients

Goal of Radiology Department:

1. CR | Computed Radiography
2. DR | Digital Radiography
3. Digital Mammography
4. Digital Fluoroscopy for routine GI
Fluoroscopy & vascular imaging
5. CT | Computed Tomography
6. MRI | Magnetic Resonance Imaging
7. Nuclear Medicine
8. Diagnostic Medical Sonography

Digital Image Acquisition Modalities

Computed Radiography

A digital way of doing general radiography with the use of CONVENTIONAL X-RAY MACHINES

Digital Radiography

An advanced form of x-ray inspection which produces a digital radiographic image instantly on a computer.

Uses x-ray sensitive plates to capture data during object examination, which is immediately transferred to a computer without the use of an intermediate cassette.

Digital Mammography

uses low-energy x-rays

Digital Fluoroscopy

\-real time

Computed Tomography

\-series of x-ray images at different angles

Magnetic Resonance Imaging

\-strong magnetic fields

Nuclear Medicine

\-small amounts of radioactive materials

Diagnostic Medical Sonography

\-sound waves

DIGITAL RADIOGRAPHY

\- Computer process data collected from patients using special electronic detectors that have replaced the X-ray film cassette.

\-Includes image and information management systems, image storage, and image & data communications

FILM-BASED RADIOGRAPHY

1. X-rays pass through
the patient & fall upon
the film to form a
latent image
2. Rendered visible
using chemical
processing
3. Displayed on a view
box for viewing &
interpretation by a
radiologist

varying degrees of blackening

The film image appears with __*___ ___ of ___*__ as a result of the amount of exposure transmitted by different parts of the anatomy.

More exposure

produces more blackening

Less exposure

produces less blackening

FILM DENSITY

Blackening in the image

FILM CONTRAST

Differences in densities in the image

film contrast

The film, therefore, converts the radiation transmitted by the various types of tissues (tissue contrast) into ___ ___

1. Data Acquisition
2. Computer Data Processing
3. Image Display & Post-processing
4. Image Storage
5. Image & Data Communications
6. Image & Information Management

DR Imaging System: Major Components

DATA ACQUISITION

\-Refers to the collection of X-rays transmitted through the patient

\-First step in the production of the image

CCD/TFT

These detectors are of several types & utilize various technologies to convert X-rays to electrical (analog) signals.

INDIRECT

Converts X-rays into light, followed immediately by the conversion of light into electrical signals

DIRECT

Avoids the light-electricity conversion process & convert X-rays directly into electrical signals.

ANALOG TO DIGITAL CONVERTER (ADC )

 An electronic integrated circuit used to convert the analog signals such as voltages to digital or binary form consisting of 1s and 0s.

COMPUTER DATA PROCESSING

 The ADC sends digital data for processing by a computer.  The computer uses special software to create or build up digital images using the binary number system

HUMANS – DECIMAL SYSTEM

Base 10 (10 different numbers) 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9

COMPUTERS – BINARY SYSTEM

Base 2 (2 different numbers) 0 or 1 (digits or bits)

BITS

\- Smallest unit of data in a computer

\- are not continuous, they are discrete units

\- Computers operate with binary numbers, 0 s and 1 s, discrete units that are processed and transformed into other discrete units

IMAGE DISPLAY & POST PROCESSING

 The digital image, must first be converted into an analog signal before it can be displayed on a monitor for viewing by the observer.

 Reduce image noise

 Enhance image sharpness

 Improve contrast

 Stitch several images

IMAGE STORAGE

The vast amount of images generated for the wide range of digital radiology examinations must be stored not only for retrospective analysis but also for medico-legal purposes

1. Magnetic tapes
2. Disks
3. Laser optical disks (long-term storage)
4. RAID (Redundant Array of Independent
Disks

Types of Image storage

IMAGE & DATA COMMUNICATIONS

 Use of computer communication networks to transmit images from the acquisition phase to the display/viewing & storage phase.

LANs

Image transmission within hospital (Intranet)=

WANs

 Outside hospital/Remote locations (Internet)=

PACS

Used for storing/archiving & communicating images in the digital radiology department.

INFORMATION SYSTEMS

RIS/HIS is integrated with the PACS via computer networks, using communications standards such as DICOM & HL7, for effective managements of patient information.

* Lossless or Reversible Compression
* Lossy or Irreversible Compression

Popular Compression Methods For DIGITAL RADIOGRAPHY

Lossless or Reversible Compression

 all the data from the original file is preserved

Lossy or Irreversible Compression

 removes some data from the original file and saves the image with a reduced file size

 method which eliminate unnoticeable data

IMAGE & INFORMATION MANAGEMENT

 Refers to the use of PACS & RIS and HIS to manage the vast number of images & text data produced in a digital radiology department with databases & file management software.

RIS/HIS

 Handle essential textual information

PACS

 Handle images generated by the various digital imaging modalities

1998

Concept of IHE originated in

Radiological Society of North America (RSNA) & the Healthcare Information and Management Systems Society (HIMSS)

developed what they refer to as Technical Framework that is based on 3 essential elements

1 Data model
2 An Actor
3 An integration Profile

Technical Framework that is based on 3 essential elements

COMPUTED RADIOGRAPHY

 Makes use of photostimulable or storage phosphors to produce digital images using existing X-ray imaging equipment.

 A computer is used to process data collected by radiographic means to produce digital images of the patient.

1983

Fuji Medical Systems introduced CR Imaging System

1. The IP is exposed to X-rays, which causes electrons in the phosphors to move
to another energy level, where they remain trapped, creating a latent image.
2. The plate is then taken to the CR reader/processor (digital image processor)
where it is scanned by a laser beam, which causes the trapped electrons to
return to their original orbit, and in the process, light is emitted.
3. This light is collected by a light guide & sent to a photomultiplier tube (PMT).
The electrical signal output from the PMT is subsequently converted into digital
data.
4. A digital processor processes the digital data to produce a CR image that can
be viewed on a monitor.
5. The IP exposed to a bright light to erase it (the residual latent image is
removed).
6. The IP can now be used again.

Basic steps in the production of a CR image

CR Systems

• Limited ability to image detail (spatial resolution)

• 3-5 lp/mm

• Contrast resolution can be manipulated

• Better DQE (converts X-ray into useful image)

FLAT-PANEL DIGITAL RADIOGRAPHY

 Developed to overcome the shortcomings of CR systems

 Designed as a flat-panel, totally different in design structure & function

PACS (PICTURE ARCHIVING & COMMUNICATIONS IN MEDICINE)

* A comprehensive computer system that is responsible for the electronic storage & distribution of medical images in the medical enterprise.
* The system is highly integrated with digital acquisition and display devices and is often related closely to other medical information systems, such as the RIS or HIS

1. Image acquisition devices
2. PACS computer
3. Device called interfaces
4. Display workstations

* Major PACS components
* All of which are connected & linked to the HIS and RIS through digital communication networks.

* DICOM
* HL7

2 standards used in a PACS environment

DICOM

– concerned primarily with images from the digital image acquisition modalities

HL7

– concerned mainly with textual information from the HIS and RIS

Quality Assurance & Quality Control

Procedures are effective strategies to ensure continuous quality improvement of a product.

i. Ensure that patients are exposed to minimum radiation using the ALARA philosophy

ii. Produce optimum image quality for diagnosis

iii. Reduce the costs of radiology operations

In Radiology, QA/QC policies & procedures and related activities are all intended to: