DIGITAL DIGITAL RADIOGRAPHYRADIOGRAPHY

ModeratorModeratorMr. Ram Singh (Lecturer)Mr. Ram Singh (Lecturer)

Deptt. Of Radio-Diagnosis & ImagingDeptt. Of Radio-Diagnosis & Imaging

P.G.I.M.E.RP.G.I.M.E.R

Presented BySUNIL KUMAR SEKSANAB. Sc. MT ( Final Year Student )Deptt. Of Radio-Diagnosis & ImagingP.G.I.M.E.R

DIGITAL RADIOGRAPHY (DR) is a DIGITAL RADIOGRAPHY (DR) is a representation of continuous analog representation of continuous analog information into digital form by the use of information into digital form by the use of computer which processes the digital data to computer which processes the digital data to form an image.form an image.

Conventional radiography has dominated the Conventional radiography has dominated the filed of radiography for many years. But it has filed of radiography for many years. But it has always been recognized that Film / Screen always been recognized that Film / Screen system has certain limitations.system has certain limitations.

INTRODUCTION

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LIMITATIONS OF FILM / SCREEN LIMITATIONS OF FILM / SCREEN SYSTEMSYSTEM

Exposure error permanent on image.Exposure error permanent on image.

Faults in the film can lead to repeat the Faults in the film can lead to repeat the examination.examination.

Delay in viewing image.Delay in viewing image.

Dynamic range of the x-ray film is limited.Dynamic range of the x-ray film is limited.

Difficult to visualize widely varying tissue.Difficult to visualize widely varying tissue.

Storage and retrieval cost.Storage and retrieval cost.

Copied radiographs are of inferior quality than Copied radiographs are of inferior quality than the original one.the original one.

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These limitations can be These limitations can be overcome by the incorporation of overcome by the incorporation of Computer Technology into the Computer Technology into the diagnostic X-ray imaging.diagnostic X-ray imaging.

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MILESTONE IN DIGITAL RADIOGRAPHYMILESTONE IN DIGITAL RADIOGRAPHY

YearYear DevelopmentDevelopment

19771977 Digital subtraction angiography.Digital subtraction angiography.

19801980 Scan projection Radiography.Scan projection Radiography. 19831983 Computed radiography (CR) storage phosphors.Computed radiography (CR) storage phosphors. 19901990 Charge-coupled device (CCD) slot-scan direct Charge-coupled device (CCD) slot-scan direct

radiography (DR).radiography (DR). 19941994 Selenium drum DR.Selenium drum DR. 19951995 Selenium-based flat-panel detector.Selenium-based flat-panel detector. 19951995 Amorphous silicon–cesium iodide ( scintillator ) Amorphous silicon–cesium iodide ( scintillator )

flat-panel detector. flat-panel detector. 19971997 Gadolinium-based ( scintillator ) flat-panel detector.Gadolinium-based ( scintillator ) flat-panel detector.

20012001 Dynamic flat-panel detector fluoroscopy.Dynamic flat-panel detector fluoroscopy.

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PIXEL:-PIXEL:- An abbreviation of the term 'picture element.' A An abbreviation of the term 'picture element.' A pixel is the smallest picture element of a digital image. pixel is the smallest picture element of a digital image. A monochrome pixel can have two values, black or A monochrome pixel can have two values, black or white/1 or 0.white/1 or 0.

VOXEL:–VOXEL:– An abbreviation of the term ‘volume element.’ An abbreviation of the term ‘volume element.’ The smallest distinguishable box-shaped part of a 3D The smallest distinguishable box-shaped part of a 3D space.space.

SOME IMPORTANT DEFFINITION

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Collection of pixels laid out Collection of pixels laid out in a specific order with width in a specific order with width (x) and height (y) in pixels .(x) and height (y) in pixels .

• • Each pixel has a numerical Each pixel has a numerical value which correspond to value which correspond to gray scale value.gray scale value.

WHAT IS A DIGITAL IMAGE?

PIXEL

NUMERICAL VALUE

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Matrix size – Number of pixels along the length and width of an image.

PIXEL SIZEPIXEL SIZE

Image size – Dimension of the field of view ( FOV ) within the patient’s body, not the size of a displayed image.

IMAGE SIZE

(mm)

MATRIX SIZE

(pixels)

Image size

Matrix sizePixel size =

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It is the method of obtaining high resolution digital X-ray It is the method of obtaining high resolution digital X-ray images which requires the motion or scanning of an X-images which requires the motion or scanning of an X-ray beam during the image acquisition. ray beam during the image acquisition. It is the process of generating an It is the process of generating an X-rayX-ray projectionprojection radiograph by scanning with a fan beam of 2 – 10 mm radiograph by scanning with a fan beam of 2 – 10 mm thick and arced with 30* - 40*. Earlier thick and arced with 30* - 40*. Earlier ScanScan projectionprojection radiography (SPR) was performed on a computer radiography (SPR) was performed on a computer tomography CT system by translating the patient through tomography CT system by translating the patient through the the CTCT gantry aperture. gantry aperture.

SCAN PROJECTION RADIOGRAPHY

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COMPONENTS OF S.P.R. SYSTEMCOMPONENTS OF S.P.R. SYSTEMX-Ray Tube.X-Ray Tube.

- - of high heat loading capacity (usually above 1 MHu ) is required of high heat loading capacity (usually above 1 MHu ) is required

because of long imaging time & detector efficiency. Usually 20 – 50 cm because of long imaging time & detector efficiency. Usually 20 – 50 cm

body part of patient is imaged at a translation speed of 1 – 20 cm/s.body part of patient is imaged at a translation speed of 1 – 20 cm/s.

Pre-Patient Collimator.Pre-Patient Collimator.

Post-Patient Collimator.Post-Patient Collimator.

Detector Array.Detector Array.

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ADVANTAGEADVANTAGE

1.1. High radiographic contrast.High radiographic contrast.

2.2. Low contrast detectibility.Low contrast detectibility.

3.3. Image manipulation.Image manipulation.

DISADVANTAGEDISADVANTAGE

1.1. Poor spatial resolution.Poor spatial resolution.

2.2. Scanning time is more.Scanning time is more.

3.3. More radiation dose to the patient.More radiation dose to the patient.

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Conventional Cassette is replaced by a Conventional Cassette is replaced by a cassette containing imaging plate ( IP ).cassette containing imaging plate ( IP ).Cassette is exposed in the same manner Cassette is exposed in the same manner as conventional cassette.as conventional cassette.Latent image is formed in imaging plate.Latent image is formed in imaging plate.Latent image is made visible by processing Latent image is made visible by processing the imaging plate into the reader.the imaging plate into the reader.

COMPUTED RADIOGRAPHY - CR

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CR Cassette with CR Cassette with Imaging platesImaging plates

ID TabletID Tablet

Image readerImage reader

Image ProcessorImage Processor

Image recorderImage recorder

COMPONENTS OF CR SYSTEMCOMPONENTS OF CR SYSTEM

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MaterialMaterial• • Body: ABS ( Acrylonitryl butadiene Body: ABS ( Acrylonitryl butadiene

styrene)styrene)• • Corners: PUR (Polyurethane rubber)Corners: PUR (Polyurethane rubber)• • Hinges: PP (Polypropylene)Hinges: PP (Polypropylene)• • Inner lining: feltInner lining: felt

SizesSizes Same as that of conventional Same as that of conventional

cassette.cassette. Identification• Embedded memory chip• Contactless RF identificationBackscatter protection• 150 μ leadWeight• 35 x 43 cm typical 1.6 kg

CR CASSETTE WITH IMAGING PLATE

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Imaging PlateImaging Plate PROTECTIVE LAYER

PHOSPHOR LAYER

ANTI-HALO & REFLECTIVE LAYER

BASE

BACKING LAYER

Protective layerProtective layer Fluorinated polymer materialFluorinated polymer materialPhosphor Layer Ba FX: Eu +2Ba FX: Eu +2

Anti-halo Layer + Reflecting Anti-halo Layer + Reflecting LayerLayer

- prevent laser from passing - prevent laser from passing through. through. Base:- PET- Polyethylene teraphtalate

Backing LayerBacking Layer

protects the base from protects the base from damage.damage.

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After exposure the cassette is After exposure the cassette is transferred to reader systemtransferred to reader systemCassette is opened Cassette is opened automatically and the imaging automatically and the imaging plate is transported for plate is transported for scanning by laser beam (He.Ne)scanning by laser beam (He.Ne)It stimulate luminescence It stimulate luminescence proportional to the X-Ray proportional to the X-Ray energy absorbedenergy absorbedLuminescence signals are Luminescence signals are converted into electrical signals converted into electrical signals by photomultiplier tubes.by photomultiplier tubes.Electrical signals are sampled Electrical signals are sampled and converted into digital signal and converted into digital signal by an ADCby an ADCThe digital data is processed to The digital data is processed to form an image which is form an image which is displayed on the monitordisplayed on the monitor

IMAGE READERIMAGE READER

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What Happens to the Plate in the Reader?What Happens to the Plate in the Reader?

1. Cassette and image plate enter the reader

4. Image plate is erased with high intensity light

2. Image plate is removed from cassette

3. Latent image is scanned by laser

5. Image plate is returned to cassette and ejected

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2020

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ADVANTAGE OF CR SYSTEM

- No special equipment is required.- Because of wider exposure latitude more information from the x-ray beam will be extracted.- Repeat becomes a matter of positioning rather than exposure factors.- All types of radiography is possible with CR system.- The image on the CRT can be manipulated in a variety of ways i.e. contrast enhancement, edge enhancement, black / white reversal (post processing).- Elimination of lost radiographs.- Simplification in filing the images.- Increased capability for consultation made possible by electronic transmission of digital images (networking system).

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CCD Slot Scan Direct RadiographyCCD Slot Scan Direct Radiography

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Rotating selenium-dotted drum, which has a positive electrical surface charge, is exposed to x-rays. During exposure, a charge pattern proportional to that of the incident x-rays is generated on the drum surface

Selenium Drum DR SystemSelenium Drum DR System

and is recorded during rotation by an analog-to-digital converter .

Advantage:- provide good image quality that is superior to that provided by screen-film or CR systems.

Disadvantage:-because of their mechanical design, selenium drum detectors are dedicated thorax stand systems with no mobility at all.

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Direct radiography – DR (sometimes termed direct digital Direct radiography – DR (sometimes termed direct digital radiography or even digital radiography)radiography or even digital radiography)

1. 1. flat panel detectors - FPDflat panel detectors - FPD a. direct conversiona. direct conversion - converts x-ray energy directly into an - converts x-ray energy directly into an

electrical signal.electrical signal. b. indirect conversionb. indirect conversion - converts x-ray energy into light - converts x-ray energy into light

signal then into electrical signal.signal then into electrical signal.2. 2. charge coupled device - CCDcharge coupled device - CCD - x rays interact with phosphor which emits light.- x rays interact with phosphor which emits light. - CCD captures emitted light and stores energy as - CCD captures emitted light and stores energy as

‘trapped” electrons.‘trapped” electrons. - stored electrons are ‘read out” and converted to digital - stored electrons are ‘read out” and converted to digital

signal.signal.

DIRECT RADIOGRAPHY

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PRINCIPLES OF DIGITAL RADIOGRAPHYPRINCIPLES OF DIGITAL RADIOGRAPHY

As screen-film radiography serves detector As screen-film radiography serves detector and storage medium both, digital detectors and storage medium both, digital detectors are used only to generate the digital image. are used only to generate the digital image. The digital image then stored on a digital The digital image then stored on a digital medium. Digital imaging comprises four medium. Digital imaging comprises four separate steps:separate steps:

generation.generation.

processing.processing.

archiving.archiving.

presentation of the image.presentation of the image.

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Components required for Components required for direct digital image direct digital image production are production are

- X-ray source.X-ray source.- An electronic sensor.An electronic sensor.- Computer Computer - Analog to Digital converter Analog to Digital converter

(ADC).(ADC).- Screen monitor.Screen monitor.- Printer.Printer.

DIRECT DIGITAL IMAGING

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INDIRECT DIGITAL CONVERSION

-Indirect conversion of x-rays to electric signal.

-Phosphor converts X-rays to light and photodiode converts emitted light into electrical signals.

-Commonly used phosphors are thallium doped Cesium Iodide or Gadolinium Oxy- Sulphide.

-Less sensitive to ambient temperature variations.

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COMPONENTCOMPONENTCOMPONENTCOMPONENT

1. Cesium Iodide (Scintillator)- needle structure provides high

resolution and absorption

- outgoing light spectrum ideally matches aSi sensitivity

- high DQE (Detective Quantum Efficiency)

2. Amorphous Silicon Matrix- industry standard for large area electronics

- high stability with respect to X-ray

- the only effective way to obtain images for radiography a n d fluoroscopy

3. Optimized Electronics- high signal to noise ratio

- fast and efficient reading of line discstogether with readout ICs

Benefit

high spatial resolution, excellentimage quality within a wide kV range

capability for lower dose

high resolution over a large area

high reliability and cost effectiveness

the quality and availability of imagesis equal or superior to film

fast image acquisition

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Important part of overall digital systemImportant part of overall digital systemPrimary viewing station should have high Primary viewing station should have high quality monitorquality monitorConsiderationsConsiderations

1. LCD vs. CRT1. LCD vs. CRT 2. luminance or brightness2. luminance or brightness 3. contrast ratio3. contrast ratio 4. resolution4. resolution

MONITOR

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Digital Image & Communication in MedicineIs the digital imaging standard that allows images to be shared or moved between different pieces of equipment from different manufacturers securely.Essential for teleradiology and communication between other DICOM systems.

Picture Archival and Communication System• Used for storage and distribution of digital images.• Allows one to have all others previous exams available for comparison.• Allows multiple simultaneous viewing.

PACS DICOM

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ADVANTAGES OF DDRADVANTAGES OF DDR- Increased workflow efficiency, saving time and Increased workflow efficiency, saving time and

labour.labour.- Very short exposure time, eliminating motion blur Very short exposure time, eliminating motion blur

( as high powered integrated x-ray system).( as high powered integrated x-ray system).- Auto selection of filter and focal spot size.Auto selection of filter and focal spot size.- Automatic tracking for easy positioning.Automatic tracking for easy positioning.- Automatic exposure control facility reduce the Automatic exposure control facility reduce the

chance of repeat.chance of repeat.- Immediate availability of image for quality check Immediate availability of image for quality check

and diagnosis.and diagnosis.- virtually no missing images due to digital storage

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- High initial cost.High initial cost.

- Some radiographic views are difficult as Some radiographic views are difficult as detectors are not free to be placed in any detectors are not free to be placed in any position.position.

LIMITATIONS OF DDR

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CR –CR – - more flexible.- more flexible. - lower cost.- lower cost. - Portable (still have to use CR reader to - Portable (still have to use CR reader to

process cassette, image available in 90 sec)process cassette, image available in 90 sec)DR –DR – - higher throughput (images within few - higher throughput (images within few

seconds).seconds). - more expensive.- more expensive. - Portable – generally thought to have best - Portable – generally thought to have best

quality image. quality image.

CR vs. DR

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Dynamic detector: Dynamic detector: Integris AlluraIntegris Allura

Dynamic flat-panel detector fluoroscopyDynamic flat-panel detector fluoroscopy

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Scintillator: CsI:Tl needle crystalsScintillator: CsI:Tl needle crystals

Thickness 550µmThickness 550µm good X-ray good X-ray

absorptionabsorption

Needles act as Needles act as light-guideslight-guides

sharp MTFsharp MTF

CsI:Tl emits CsI:Tl emits green lightgreen light

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Photodiode array: a-Si technologyPhotodiode array: a-Si technology

Same technology Same technology as used in active as used in active matrix LCDs matrix LCDs (TFT displays)(TFT displays)

a-Si photodiodes: a-Si photodiodes:

high sensitivityhigh sensitivityfor green lightfor green light

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Integris Integris AlluraAllura

Flat Dynamic Flat Dynamic DetectorDetector

for Cardiofor Cardio

Scintillator Photodiode array Refresh light

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Technical DataTechnical Data

Digital Diagnost Integris Allura FD

Detection static static + dynamic(up to 30 frames/s)

Field of view 43 cm x 43 cm 18 cm x 18 cm

Number of pixels 3k x 3k 1k x 1k

Pixel size 143 µm x 143 µm 184 µm x 184 µm

DQE(0) 60 % 75 %

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Feature Feature ConverterConverter ReadoutReadout Detector Detector sizesize

Pixel SizePixel Size MatrixMatrix

Screen FilmScreen Film Gd2O2S FilmFilm 14x1714x17 Grain Grain size- 2size- 2

………………....

Storage Storage PhosphorPhosphor

BaFBr:EuBaFBr:Eu LASERLASER 14x1714x17 200200 1760x21401760x2140

Slot scan Slot scan CCDCCD

CsI:TlCsI:Tl CCDCCD 17x1717x17 162162 2736x27362736x2736

Direct FPDDirect FPD SeSe Active Se Active Se MatrixMatrix

14x1714x17 139139 2560x30722560x3072

Indirect FPDIndirect FPD

Gd2O2S Active Si Active Si MatrixMatrix

17x1717x17 160160 2688x26882688x2688

CsI:TlCsI:Tl Active Si Active Si MatrixMatrix

17x1717x17 143143 3121x31213121x3121

Technical features of Various Digital radiography System

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IMAGE RECEPTOR COMPARISIONIMAGE RECEPTOR COMPARISIONFEATUREFEATURE FILMFILM PSPPSP DDRDDR

RADIATION DOSERADIATION DOSE HigherHigher LowerLower LowerLower

GENERATION OF GENERATION OF VISIBLE IMAGEVISIBLE IMAGE

Chemical Chemical Laser scanner, Laser scanner, ComputerComputer

ComputerComputer

IMAGE VIEWINGIMAGE VIEWING Delayed, View Delayed, View box box transilluminationtransillumination

Delayed, Computer Delayed, Computer monitormonitor

In few seconds, In few seconds, Computer monitorComputer monitor

RESOLUTIONRESOLUTION 16-20lp/mm16-20lp/mm 6-8lp/mm6-8lp/mm 8-10lp/mm8-10lp/mm

CONSTRUCTIONCONSTRUCTION Thin, flexibleThin, flexible Thin, flexibleThin, flexible Thick, rigid, wireThick, rigid, wire

LIFE SPANLIFE SPAN Single useSingle use Reusable after erasureReusable after erasure ReusableReusable

IMAGE IMAGE ENHANCEMENTENHANCEMENT

Fixed Fixed unchangeable unchangeable imageimage

Multiple operations- Multiple operations- Contrast, Density, Contrast, Density, Magnification, Magnification, positive/Negative, positive/Negative, measurementmeasurement

Multiple operations- Multiple operations- Contrast, Density, Contrast, Density, Magnification, Magnification, positive/Negative, positive/Negative, measurementmeasurement

STORAGESTORAGE Patient recordPatient record Variety of archiving Variety of archiving method Server, Zip, CD method Server, Zip, CD

Variety of archiving Variety of archiving method Server, Zip, CD method Server, Zip, CD

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Image Quality ParametersImage Quality Parameters

Dynamic Range & Contrast

Limiting Spatial Resolution

(LSR)

Signal to Noise Ratio (SNR)

Modulation Transfer Function

(MTF)

Detective Quantum Efficiency

(DQE)

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Contrast / Dynamic Range

Film-Screen

Detector

Low Contrast

High Contrast

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Wide Dynamic Range

Ima

ge

Bri

gh

tne

ss

X-ray Detected

Narrow Dynamic Range

Ima

ge

Bri

gh

tne

ss

X-ray

Toe part

shoulderstraight shoulder

straight

Dynamic Range

Contrast levels or film densities generated over a range of x-ray exposure levels

Toe part

Detected

Dynamic range is a measure of the signal response of a detector that is exposed to x-rays

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Limiting Spatial Resolution (LSR)Limiting Spatial Resolution (LSR)

ResolutionResolution

Spatial resolution refers to the minimum resolvable separation between high-contrast objects. In digital detectors, spatial resolution is defined and limited by the minimum pixel size.

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Decreasing Noise

Incr

easi

ng

Co

ntr

ast

High High SNRSNR

Low SNRLow SNR

NoisNoisee

SignSignalal

Contrast Contrast RatioRatio

Quantum mottle Quantum mottle is an appearance is an appearance of noise in the radiographic image of noise in the radiographic image due to low SNR of the information due to low SNR of the information reaching the image recording reaching the image recording system.system.

Signal to Noise Ratio (SNR)

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Quantum and electronic noise are unavoidable in a digital imaging Quantum and electronic noise are unavoidable in a digital imaging chain. The effect, often expressed as signal-to-noise ratio (SNR), chain. The effect, often expressed as signal-to-noise ratio (SNR), can vary widely from system to system.can vary widely from system to system.

SignalSignal                    Useful Image FormationUseful Image Formation----------   =   ------------------------------------------------   =   --------------------------------------Noise      Noise               Erratic InformationErratic Information

Quantum and electronic noise are unavoidable in a digital imaging chain. The effect, often expressed as signal-to-noise ratio (SNR), can vary widely from system to system.

Signal          Useful image formation

----------   =   -----------------------

Noise           Erratic Information

Quantum and electronic noise are unavoidable in a digital imaging chain. The effect, often expressed as signal-to-noise ratio (SNR), can vary widely from system to system.

Signal          Useful image formation

----------   =   -----------------------

Noise           Erratic Information

  1:1 SNR            2:1 SNR            5:1 SNR

1:1 SNR            2:1 SNR            5:1 SNR

Signal-to-noise ratio.

As noise decreases in a digital x-ray system, object detectability increases very rapidly.

1:1 SNR        2:1 SNR     5:1 SNR

Impact of NoiseImpact of Noise

04/08/2304/08/23 SEMINAR - " DIGITAL RADIOGRAPSEMINAR - " DIGITAL RADIOGRAPHY "HY "

X_Ray Photons

Light Photons

LANEX

High Scattering

Low MTF

CsI

Low Scattering

Good MTF

Electrons

Selenium

No Scattering

“Perfect” MTF

MTF MTF :- :- Modulation transfer function (MTF) is the capacity of the detector to transfer the modulation of the input signal at a given spatial frequency to its output.

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Detective Quantum Efficiency ( DQE )

Detective quantum efficiency (DQE) is one of thefundamental physical variables related to imagequality in radiography and refers to the efficiencyof a detector in converting incident x-ray energyinto an image signal.

It dependent on

- Radiation exposure, - Spatial frequency, - MTF,- Detector material.- Quality of the radiation applied (voltage and current).

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1. image plate artifacts ( In 1. image plate artifacts ( In CR ).CR ).

Artifacts in Digital Radiography

Due to cracking Imaging Plate

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2. Plate Reading Artifact ( in CR )

Line caused from dirt collected Line caused from dirt collected in a CR Reader.in a CR Reader.

Damaged Laser beam head in CR reader. Appears as multiple linear white lines.

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3. 3. Image processing artifactsImage processing artifacts

Missing lines or pixels ( indicating digitization problems ).

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4.operator errors4.operator errors

Digital detector is MORE sensitive Digital detector is MORE sensitive

towel used to help in towel used to help in positioning a child.positioning a child.

Double exposure: Radiographs of both feet and pelvis (arrowheads) on a single film.

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Dust and dirt build up on CR Dust and dirt build up on CR phosphor plates, leading to image phosphor plates, leading to image artifacts. To avoid this, plates need artifacts. To avoid this, plates need cleaning at regular intervals.cleaning at regular intervals.

SolventSolvent• • Ethanol 99.7%Ethanol 99.7%AdditivesAdditives• • Catanac SN (Cyastat SN 50) 0.3%Catanac SN (Cyastat SN 50) 0.3%SafetySafety• • Highly flammableHighly flammable• • Keep container closedKeep container closed• • Keep away from sources of ignitionKeep away from sources of ignition

CR PHOSPHOR PLATE CLEANER

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For Conventional Projection or DR For Conventional Projection or DR RadiographyRadiography: : The same rules, theories, and The same rules, theories, and

laws still apply and can not be overlookedlaws still apply and can not be overlooked - FFD/OFD (SID/SOD). - FFD/OFD (SID/SOD). - Inverse Square Law.- Inverse Square Law. - Beam Alignment.- Beam Alignment. - Tube-Part-Film Alignment.- Tube-Part-Film Alignment. - Collimation.- Collimation.

- Grids. - Grids. - Exposure Factors: KVP, mAs.- Exposure Factors: KVP, mAs.

Quality AssuranceQuality Assurance

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Daily (technologist)Daily (technologist)– – General inspection.General inspection.

– – Film processor / Laser Film processor / Laser printer.printer.

– – Erase imaging plates.Erase imaging plates.

– – Verify digital interfaces Verify digital interfaces and network and network transmission.transmission.

Weekly (technologist)Weekly (technologist)

– – Test phantom images.Test phantom images.

– – System cleanliness.System cleanliness.

PERIODIC QUALITY CONTROLPERIODIC QUALITY CONTROL

Monthly (Technologist)Monthly (Technologist)– – Film processor maintenance (if Film processor maintenance (if any).any).– – Inspect and clean image Inspect and clean image receptors.receptors.– – Review film retake rate.Review film retake rate.Semi-Annually / Annually (Physicist)Semi-Annually / Annually (Physicist)– – Evaluate image quality.Evaluate image quality.– – Acceptance tests to re-establish Acceptance tests to re-establish baseline values.baseline values.– – Review.Review.

QC records.QC records.Service history.Service history.

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By their tremendous impact on the image quality, radiation dose and workflow, digital radiography systems have become practicable alternatives.

CR is a simple and cost effective technology that permits use of existing radiographic equipment. It has been suggested that for moderate work load ( up to 50-60 films per day), a CR system is adequate.

High cost of a DR system is justified only when the workload is much beyond this level.

CONCLUSION

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