Midterm 2 Artifacts (Film Screen Image Acquisition) PDF

Film screen image acquisitio n, processing and image analysis MIDTERM Radiographic Film Analysis ARTIFACTS An artifact is any appearance/opacity on a radiograph which doesn't represents an actual anatomic structure within the patient being radiographed.   Undesirable optical...

Film screen image acquisitio n, processing and image analysis MIDTERM Radiographic Film Analysis ARTIFACTS An artifact is any appearance/opacity on a radiograph which doesn't represents an actual anatomic structure within the patient being radiographed.   Undesirable optical densities or blemishes ARTIFACTSon a radiograph or any other medical image. ARTIFACTS  Degrades the quality of radiograph and effect interpretation. - Cause visual distractions for the radiologist leading to misinterpretations of an actual anatomic structure. - Can mimic pathology Exposure Artifacts Processing Artifacts Handling & Storage artifacts EXPOSURE ARTIFACTS I. Exposure artifacts  Foreign object artifact  Motion  Double Exposure  Improper patient positioning and instruction  Poor screen-film contact  Improper grid position a. Foreign object artifacts Radiopaque materials that superimposed the patient anatomy. RADIOLUCENT RADIOPAQUE – Appears – Appears black on white on the radiograph' the radiograph; Structures that absorbs X- Structures that transmits X- rays. (Bone, contrast media rays. (Air, tissue) or foreign bodies) a. Foreign object artifacts e.g. Patient jewelries, hearing aid, facial or body piercing, zippers, buttons, etc. Foreign Body Localization b. Double exposure Two separate image in one radiograph Reuse of cassette that is already exposed c. Motion  Blurred image/Poor quality  e.g. breathing, involuntary movements  Prevention:  Restrain - pediatrics  Sedation  Proper and clear Instruction d. Poor screen-film contact Poor quality (blurring of image) and obscures the detail of the image Due to warped cassette e. Positioning errors i. Patient rotation ii. Distortion iii.Upside-down cassette er patient rotatio n Distortion Misrepresentatio n of either size and shape of the anatomic part. Distortion  Elongation – refers to the image of objects that appear longer than the true object  Foreshortening - refers to the image of objects that appear shorter than the true object Upside-down cassette Image appears underexposed. II. PROCESSING ARTIFACTS  Guide shoe marks  Dichroic stain  Chemical fog  Pi Lines q Gelatin build up q Emulsion pickoff  Wet pressure sensitization a. Guide shoe marks Guide shoe marks occur when the guide shoes in the turnaround assembly of the processor are sprung or improperly positioned b. Pi lines  Pi lines occur at 3.1416- inch (π) intervals because of dirt or a chemical stain on a roller, which sensitizes the emulsion.  Because the rollers are 1 inch in diameter, 3.1416 inches represents c. Dichroic Stain or "Curtain Effect" Improper squeezing of processing chemicals from film Dichroic stain is a term that is generally applied to all chemical stains (chemical fog) Dichroic means two colors. The dichroic stain d. Wet Pressure sensitization  common artifact that is produced in the developer tank.  Irregular or dirty rollers cause pressure during development and produce small circular patterns of increased OD. e. Emulsion Pick off Dirty or warped rollers which result in sludge deposits on the film.  artifact caused by little pieces of emulsion that stick to the rollers and is picked off by a passing III. Handling & Storage artifacts  Light leak  Radiation fog  Storage Fog  Static artifacts  Kink Marks  Hyporentention Stain  Scratches a. Light Leak A form of fog  Cassette is not closed properly. Film bin/box left open. Safelight cracks. b. Radiation fog The film bin is inadequately shielded from radiation. The film has been left in the x-ray room during other exposures. c. Storage fog Outdated film Darkroom/storage room is too high. Prevention: q FIFO – First in, first out d. Pressure or Kink Marks The film is improperly or roughly handled. The film is stacked too high in storage (the weight causes marks). Kink Mark It is caused by the kinking or abrupt bending of film. Both events usually appear as increased OD. e. Scratches  White lines appear on the film due to careless handling of film. f. Static Artifacts It is caused by the buildup of electrons in the emulsion and is most noticeable during the winter and during periods of extremely low humidity. 3 Distinct patters: a. Crown b. Tree c. Smudge Static Artifacts g. Hypo retention Stain The yellow-brown stain that slowly appears on a radiograph after a long storage time indicates a problem with hypo retention from the fixer. h. Finger marks Black: Developer on fingertips  Prevent: Keep fingers dry and clean. Touch only film edges