RAD370 Intro to DR and PACS PowerPoint

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TFT

thin-film transistor

CCD

charge-coupled device

PACS

picture archiving and communication system

DICOM

digital imaging and communications in medicine

FPD

flat panel detector

PSP

photostimulable phosphor

CR

computed radiography

DR

digital radiography

Conventional Film/Screen Radiography (F/S)

• film is processed chemically

• manifest image on film is viewed in a lightbox

Digital Imaging

defined as any image acquisition process that produces an electronic image that can be viewed and manipulated on a computer

When was the term “digital imaging” first used?

1970s with development of computed tomography (CT)

What panel technology does CR use?

PSP (uses cassettes)

What panel technology does DR use?

FPD (non-cassette)

Developed first CT scanner (bringing imaging devices and computers together)

Godfrey Hounsfield

Early CT scanners would

• require hours to produce a single slice

• reconstruction of images took several days to produce

• first commercial use imaged head only

One of the greatest medical milestones in history

Godfrey Hounsfield’s development of the first CT scanner in 1971

Teleradiology

moving images via telephone lines to and from remote locations

PSP (previously referred to as CR) was

• first introduced in US by Fuji Medical Systems of Japan in 1983

• 1996 law reduces Medicare reimbursements starting in 2018 (drive towards to DR)

PSP storage plate

where acquisition of image takes place

When x-ray strikes psp plate,

some is absorbed and some is released to create image

PSP reader

reads by laser light

FPDs uses

x-ray absorber material coupled to a TFT to form the image

Two types of FPD

• indirect capture

• direct capture

Direct Conversion (FPD)

• 2 step process (XE)

  1. X-rays interact with IR

  2. X-rays converted to electrons

Indirect Conversion (FPD)

• 3 step process (XLE)

  1. X-rays interact with IR

  2. X-rays are converted to Light using a Scintillator

  3. Light is converted to electrons

FPD Direct Conversion uses what material?

Amorphous Selenium

FPD Indirect Conversion uses what material?

Amorphous Silicon

FPD 3rd layer

TFT layer

• comprised of an array (matrix) of very small detector elements

DEL

detector elements

Most devices produce images as an analog picture that must be

converted to a digital image

ADC

an image acquisition component of the digital process is responsible for converting analog information produced by a

a base unit into digital binary coded numbers

Efficiency ratings of conventional F/S and PSP are about the same but

FPD is much more efficient, images are available immediately

Latent Image Formation

In F/S the x-rays strike an intensifying screen but in PSP

strikes phosphor plate and energy is deposited in the phosphor

F/S is processed by

requiring chemicals

PSP is processed by

light

FPD is processed by

image detected

F/S exposure response is

nonlinear; narrow exposure latitude

PSP and FPD exposure response is

linear; wide exposure latitude

F/S image contrast determined by

• kVp

• film response curve

PSP and FPD image contrast determined by

• kVp

• LUTs

in F/S density (brightness) determined by

mAs

In PSP and FPD density (brightness) determined by

Image processing - LUTs

PSP and FPD are more sensitive to ______ then F/S

scatter radiation

PACS serves as

file room, reading room, duplicator, and courier

DICOM lets

• RLS, HIS, and PACS communicate with each other

• standard that allows modalities PACS communicate with each other

First full-scale PACS

VA Medical center in Baltimore 1993

PACS uses

• reading stations

• physician review stations

• specialty workstations

• web access

• technologist quality control station

• administrative stations

• archive systems

• multiple interfaces to other hospital and radiology systems

Technologist markers

every effort should be made to mark the side appropriately before exposure. Side marker errors can have catastrophic results for the patient