03 xray film etc

X-ray EquipmentX-ray EquipmentThe X-ray machineThe X-ray machine

GridsGridsFilm and cassettesFilm and cassettes

ProcessingProcessing

X-ray FilmX-ray Film

Types of filmTypes of film

Handling of filmHandling of film

Choosing filmChoosing film Depends on size, subject, machineDepends on size, subject, machine


Purpose: Purpose: provides permanent record of x-ray imageprovides permanent record of x-ray image

Fluoroscopy/ultrasound traditionally transientFluoroscopy/ultrasound traditionally transient

Newer technology allows video captureNewer technology allows video capture


Composed of silver halide crystals on Composed of silver halide crystals on plastic sheetplastic sheetCrystals interact with:Crystals interact with: Ionizing radiation (including x-rays)Ionizing radiation (including x-rays) Visible lightVisible light PressurePressure BendingBending MoistureMoisture


CompositionComposition Similar to photographic filmSimilar to photographic film Silver halide emulsion on both sides of Silver halide emulsion on both sides of

polyester basepolyester base Most film bases are blue tinted Most film bases are blue tinted

Pleasing to the eyePleasing to the eye


Latent imageLatent image Formed by absorption of light photon by Formed by absorption of light photon by

silver halide crystalsilver halide crystal Energy of photon dislodges an electronEnergy of photon dislodges an electron The electron causes positively charges The electron causes positively charges

silver ions to join into a silver atomsilver ions to join into a silver atom


Latent image formationLatent image formation Br > Br+ e-Br > Br+ e- e- attracts Ag +e- attracts Ag + Ag+ Ag+ > Ag atoms Ag+ Ag+ > Ag atoms

X-ray Film CharacteristicsX-ray Film Characteristics

Film densityFilm density Measure of film blackeningMeasure of film blackening Equals log of incident light intensity Equals log of incident light intensity

divided by transmitted light intensitydivided by transmitted light intensity


Film contrastFilm contrast Difference between two densities on a Difference between two densities on a

radiographradiograph


FilmFilm contrastcontrast Dependant upon:Dependant upon:

Characteristic curve of the filmCharacteristic curve of the film Film gamma refers to steepest part of Film gamma refers to steepest part of

curvecurve


Film gamma refers Film gamma refers to steepest part of to steepest part of curvecurve


FilmFilm contrastcontrast Dependant upon:Dependant upon:

Film densityFilm density


Film contrastFilm contrast Dependant upon:Dependant upon:

X-ray exposureX-ray exposure Higher kVp = greater gamma = Higher kVp = greater gamma =

lower contrast (more visible shades lower contrast (more visible shades of gray, smaller steps between of gray, smaller steps between grays)grays)


Higher kVp = Higher kVp = greater gamma = greater gamma = low contrast low contrast (more visible (more visible shades of gray, shades of gray, smaller steps)smaller steps)

High kVp


Film contrastFilm contrast Dependant upon:Dependant upon:

Film processingFilm processing Longer developing times = lower Longer developing times = lower

gamma = less contrastgamma = less contrast


Film latitudeFilm latitude Exposure range that produces Exposure range that produces

acceptable densities (0.25-2.0)acceptable densities (0.25-2.0)


Film speedFilm speed Fast filmsFast films

Larger crystalsLarger crystals

Require less exposureRequire less exposure

Produces a grainier imageProduces a grainier image

Less latitudeLess latitude


Film speedFilm speed Slow filmsSlow films

Smaller crystalsSmaller crystals

Require greater exposureRequire greater exposure

Higher definition image/less grainyHigher definition image/less grainy

Greater latitudeGreater latitude


Film speedFilm speed Based upon size of Based upon size of

silver halide silver halide crystalscrystals

X-ray Film TypesX-ray Film Types

Two general types Two general types Non-screen filmNon-screen film Screen filmScreen film


Non-screen filmNon-screen film More sensitive to ionizing radiationMore sensitive to ionizing radiation

Allows for finer detailAllows for finer detail

Requires more exposureRequires more exposure

Requires thicker emulsion and thus manual Requires thicker emulsion and thus manual processingprocessing

Ex.: dental filmsEx.: dental films


Screen filmScreen film Crystals also sensitive to fluorescent light Crystals also sensitive to fluorescent light

from intensifying screensfrom intensifying screens Less sensitive to direct ionizing radiationLess sensitive to direct ionizing radiation BenefitsBenefits

Less exposureLess exposure DrawbacksDrawbacks

Loss of image definitionLoss of image definition


Screen filmScreen film Blue sensitive filmBlue sensitive film

Film responds to ultra-violet, violet and blue light Film responds to ultra-violet, violet and blue light emitted from screenemitted from screen

Green sensitive filmGreen sensitive filmRespond to screens that emit 60% green and 25% Respond to screens that emit 60% green and 25% bluesblues

Relatively newer technology using rare earth Relatively newer technology using rare earth phosphorsphosphors


Blue and green screen can be used with Blue and green screen can be used with either blue or green sensitive filmeither blue or green sensitive film

But most efficient if film is sensitive to light But most efficient if film is sensitive to light emitted by screenemitted by screen


Screen filmScreen film Standard silver halide crystals absorb violet to Standard silver halide crystals absorb violet to

blue lightblue light ““Ortho” filmOrtho” film

Thin layer of green absorbing dye transfers energy Thin layer of green absorbing dye transfers energy to silver halide crystalsto silver halide crystalsTherefore extends sensitivity of film into green Therefore extends sensitivity of film into green wavelengthswavelengths

““Pan” filmPan” filmRed absorbing dye Red absorbing dye


Screen filmScreen film Crossover or punch-Crossover or punch-

through effectthrough effectDecreased detail of Decreased detail of radiograph due to radiograph due to additional exposure to additional exposure to light from screen on light from screen on opposite sideopposite side


Common sizesCommon sizes 14 x1414 x14 14 x1714 x17 7 x177 x17 8 x 108 x 10 10 x 1210 x 12 11 x 1411 x 14

Intensifying screensIntensifying screens

Thin cleanable sheet of phosphor crystals Thin cleanable sheet of phosphor crystals which lies adjacent to the film within the which lies adjacent to the film within the cassettecassette

Purpose:Purpose: To decrease amount of radiation required for To decrease amount of radiation required for

a diagnostic radiographa diagnostic radiographAble to use lower mAs (faster exposure)Able to use lower mAs (faster exposure)


4 layers of a screen4 layers of a screen BaseBase

Substrate for phosphor crystalsSubstrate for phosphor crystals Reflecting layerReflecting layer

To reflect light back toward filmTo reflect light back toward film Phosphor layerPhosphor layer

Must be uniform and flexible (to avoid cracking)Must be uniform and flexible (to avoid cracking) Protective coatingProtective coating



Intensification factor Intensification factor Direct film requires roughly 34 times more Direct film requires roughly 34 times more exposure than screen filmexposure than screen film

A 0.1 second exposure on screen film A 0.1 second exposure on screen film would require 3.4 seconds on non-screen would require 3.4 seconds on non-screen filmfilm


Screen speedScreen speedLarger crystal = faster screen = more grainyLarger crystal = faster screen = more grainy

Thicker phosphor layer = faster screen = Thicker phosphor layer = faster screen = decreased detaildecreased detail


Phosphor layerPhosphor layerCalcium tungstate and barium lead sulfate Calcium tungstate and barium lead sulfate emit blue lightemit blue light

Rare earth screens more green light Rare earth screens more green light emittedemitted

Extremely important to keep screens Extremely important to keep screens clean and undamagedclean and undamaged

Film holdersFilm holders

CassettesCassettes Must be rigid, durable, light-proof and Must be rigid, durable, light-proof and

transparent to x-rays on at least one facetransparent to x-rays on at least one face Provide housing for intensifying screens and Provide housing for intensifying screens and

filmfilm Must be maintained wellMust be maintained well

CassettesCassettes

Film holdersFilm holders

Cardboard or light-proof paperCardboard or light-proof paper Use for non screen filmsUse for non screen films Light-weightLight-weight Low/no maintenanceLow/no maintenance

Manual Film ProcessingManual Film Processing

Dark roomDark room Must be light-proofMust be light-proof

Tight seal of doorTight seal of door

Stray light may fog filmStray light may fog film Must be not be exposed to radiationMust be not be exposed to radiation

Adjacent x-ray machine may cause fogging of filmAdjacent x-ray machine may cause fogging of film


Dry areaDry areaFilm storageFilm storage

Use lightproof cabinetUse lightproof cabinet

Cassette loadingCassette loading

SafelightSafelight Must be of visible spectrum that will not fog filmMust be of visible spectrum that will not fog film Red part of spectrumRed part of spectrum


Wet areaWet areaSolution tanksSolution tanks

SinkSink

ViewerViewer

HangersHangers



DevelopingDeveloping Developer solution reduces silver bromide Developer solution reduces silver bromide

crystals to black metallic silvercrystals to black metallic silver


DevelopingDeveloping Chemical process dependant upon time and Chemical process dependant upon time and

temperaturetemperatureIdeally 5 minutes in developer tank at 68 degrees Ideally 5 minutes in developer tank at 68 degrees Fahrenheit Fahrenheit

High temperature causes reticulationHigh temperature causes reticulation Artifact caused by slipping of emulsion layerArtifact caused by slipping of emulsion layer


Rinse bathRinse bath WaterWater About 30 secondsAbout 30 seconds


FixerFixer Converts undeveloped silver bromide crystals Converts undeveloped silver bromide crystals

into a solution that is washed awayinto a solution that is washed awayBlack metallic silver left on filmBlack metallic silver left on film

Also hardens filmAlso hardens film


Minimum fixing timeMinimum fixing time Determined by change in film appearance Determined by change in film appearance

from cloudy to clear (clearing time)from cloudy to clear (clearing time)


After clearing, film should be left in for After clearing, film should be left in for twice that amount of timetwice that amount of time Ex. 2 minutes to clear = keep film in 4 Ex. 2 minutes to clear = keep film in 4

additional minutesadditional minutesClearing time should not exceed 2-3 minutesClearing time should not exceed 2-3 minutes


WashingWashing Removes residual silver and fixerRemoves residual silver and fixer 20 minutes if water changes 10 times per hour20 minutes if water changes 10 times per hour


DryingDrying Perform in clean cabinetPerform in clean cabinet

Avoid dust artifacts, water spotsAvoid dust artifacts, water spots

Automatic Film ProcessingAutomatic Film Processing

BenefitsBenefits Compact sizeCompact size FasterFaster More consistentMore consistent Time and temperature controlledTime and temperature controlled Produces dry radiograph immediatelyProduces dry radiograph immediately

Film ProcessingFilm Processing

Solutions need to be specially disposed Solutions need to be specially disposed due to contentsdue to contents Treated as hazardous waste in many Treated as hazardous waste in many

including Californiaincluding California

03 xray film etc

Entertainment & Humor

film film gamma

sensitivity of film

film bases

filmchoosing film

film holderscardboard

machinegrids film

film holderscassettes

xray film types blue