film faults affecting the radiographic image
DESCRIPTION
and FactorsTRANSCRIPT
Factors affecting the Factors affecting the radiographicradiographic
image and film faults image and film faults
..
Image qualityImage quality
I. ContrastI. Contrast
II. Image geometryII. Image geometry
III. Characteristics of the X-ray beamIII. Characteristics of the X-ray beam
I. ContrastI. Contrast
Subject contrastSubject contrast
Film contrastFilm contrast
Fog and scatterFog and scatter
Subject contrastSubject contrast
Differences in tissue thicknessDifferences in tissue thickness
Differences in tissue densityDifferences in tissue density
kV or penetrating power of the kV or penetrating power of the
radiation beam radiation beam
Film contrastFilm contrast
The characteristic curve of the filmThe characteristic curve of the film
Optical density Optical density
Type of film- direct or indirect actionType of film- direct or indirect action
ProcessingProcessing
Fog and scatterFog and scatter
Fogged filmFogged film
Scatter radiation from within the Scatter radiation from within the patient’spatient’s
tissues tissues
Perception of the radiographic Perception of the radiographic imageimage
Partial images-we all Partial images-we all seesee the same the same partial images but we don’t partial images but we don’t necessarily necessarily perceive perceive the same objectthe same object
ContrastContrast
ContextContext
Effect of partial imageEffect of partial image
The effect of contrastThe effect of contrast
The effect of contextThe effect of context
Image geometryImage geometry
Positioning of the film, object and x-ray Positioning of the film, object and x-ray beambeam
Focal spot size and principle of line focusFocal spot size and principle of line focus
Focal spot-object distance (FSOD), Focal spot-object distance (FSOD), object-object-
to film-distance (OFD)to film-distance (OFD)
Ideal image geometry Ideal image geometry requirementsrequirements
Focal spot size, heat Focal spot size, heat distribution and image distribution and image
sharpnesssharpness Focal spot 1mmFocal spot 1mm
Heat needs to be distributed over as Heat needs to be distributed over as largelarge
as possible areaas possible area
Principle of line focus Principle of line focus
Focal spot-to film-Focal spot-to film-distance(FSFD)distance(FSFD)
FSFDFSFD
Increasing the distance between the Increasing the distance between the focalfocal
spot and the object results in an spot and the object results in an imageimage
with increased sharpness and less with increased sharpness and less
magnification of the objectmagnification of the object
Object-to film- distance Object-to film- distance (OFD)(OFD)
Decreasing the distance between theDecreasing the distance between the
object and the film increases theobject and the film increases the
sharpness and result in less sharpness and result in less magnificationmagnification
of the objectof the object
Image shape distortionImage shape distortion
Cont’dCont’d
Practical factors Practical factors influencing image qualityinfluencing image quality
The X-ray equipmentThe X-ray equipment The image receptor/screen The image receptor/screen
combinationcombination ProcessingProcessing The patientThe patient The operator and radiographic The operator and radiographic
techniquetechnique
Typical film faultsTypical film faults
I.I. Film too darkFilm too dark OverexposureOverexposure
OverdevelopmentOverdevelopment
FoggingFogging
Thin patients tissuesThin patients tissues
Films with inadequate Films with inadequate contrastcontrast
Processing errorsProcessing errors
Exposure errorsExposure errors
Image unsharp and Image unsharp and blurredblurred
Movement of the patient during Movement of the patient during the exposurethe exposure
Excessive bending of the film Excessive bending of the film during the exposureduring the exposure
Poor film/screen contact within Poor film/screen contact within the cassettethe cassette
Film markedFilm marked
Film packet bent by the operatorFilm packet bent by the operator Careless handling of the film in the Careless handling of the film in the
darkroom :darkroom :- Finger printsFinger prints- Finger nailsFinger nails- BendingBending- Static electricityStatic electricity
Operator positioning faultsOperator positioning faults
1.Incorrect placement of the film packet1.Incorrect placement of the film packet Back to front, image of the lead foil Back to front, image of the lead foil
evidentevident ( film also too pale)( film also too pale) Inadvertently used twice, double Inadvertently used twice, double
exposureexposure (films also too dark)(films also too dark) Not covering the area of interestNot covering the area of interest