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Artifact analysis . Artifact analysis. One of the causes of rejected images listed in the repeat analysis worksheet is the presence of image artifacts.
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Artifact analysis • One of the causes of rejected images listed in the repeat analysis worksheet is the presence of image artifacts. • An artifact can contribute significantly to the total repeat rate; therefore a thorough knowledge of artifacts and their possible causes is necessary so that corrective action can be taken.
What Is An Artifact? • Any optical density that is not anatomy • An unwanted density on the radiograph • Interferes with diagnosis
There Are Three Time Periods In Which Artifacts Can Occur • During exposure • During processing • During film handling, prior to processing, loading cassette, or storing
Exposure Artifacts • They are caused by the patient, the technologist, or the equipment during a diagnostic procedure • Poor screen-film contact • Improper use/positioning of a grid • Double exposure • Patient motion • Poor patient preparation • Clothing, jewelery, glasses, belts, etc.
Processing Artifacts • They are caused by or occur during the processing of diagnostic images • Dirty Rollers • Will leave deposits on film • Areas of increased or reduced density • Occasionally some sludge may not be washed off and dried onto the film • Chemical Fog • Improper or inadequate chemistry • Leaves a uniform dull gray haze on the film • May also be seen in two different colors • Referred to as dichroic stain
Guide Shoe and Roller Marks • Guide shoes are sprung or improperly positioned • The ridges in the guide shoe press against the film leaving an artifact • Pi-lines • Dirt or stain on a roller • 3.14 inches apart • Pressure marks • Irregular or dirty rollers • Small, circular patterns are produced
Hypo Retention • Yellowish stain that appears on finished radiograph • Due to inadequate washing • Remaining thiosulfate from fixer solution
Handling And Storage Artifacts • They occur during darkroom handling or during storage before use. • Light or Radiation Fog • White light streaks • Safelight too close or wrong wattage • Film left in x-ray room during exposure
Kink Marks • Improper handling or storage • Appears as a fingernail mark
Static • Caused by buildup of electrons in the emulsion • Three types of static artifacts • Crown • Tree • Smudge
MOIRE EFFECT Are artifacts also called zebra pattern Artifact It is a double set of grid lines caused by the placement of a grid cassette in a Bucky tray.
