Technical errors Flashcards
Processing artifacts are
98% of all film artifacts are produced in the processor or by manual processing
This is a review of the majority of the common problems
3 groups of artifacts on film
Equipment
Processing
Handling
X-ray tube malfunction
Collimator incorrectly positioned
Wrong area of interest
Too tightly collimated causing cut off of area of interest
Table malfunction
Grid cut off due to:
Incorrect distance
Incorrect positioning
Cassette issues
Front old or damaged
Dirt/debris inside the cassette
Warped cassette
Faulty latches
Foreign body on image can within what part of the machine
Within cassette
Within collimator
Between table and grid
Processor artifacts
Transport artifacts
Chemical artifacts
Sight development issues
Vertical streaks of alternating dark and light areas, as if some liquid ran down the film (which it did!)
The person processing the film did not use a time temperature chart and instead pulled the film out of the developer and held it up to the light to see if the film was black enough
The black streaks are where developer chemical was in contact with the film longer
Handling issues can cause
Dust on feed tray
Double exposure
Film fog – from, heat, age etc.
Scatter fog
Static
Sweaty fingerprints
Safelight fog and darkroom integrity
Patient artifacts
Motion
Artifacts on haircoat
Technical errors are caused by
Improper technique
kVp
mAs
Difference b/w conventional and computed/digital
The cassette containing intensifying screens and film is replaced by a reusable imaging plate (IP) or detector
Radiographic images are electronically captured, recorded and viewed at a computer terminal
The “wet” film processor is replaced with a computed imaging reader
After the digital radiographic image is made it is transferred to a computer for “image processing”
The image can then be adjusted as needed by the veterinarian
Computerized radiographic system is and consists of
CR was developed to retrofit existing radiographic machines
The basic CR system consists of:
Operator’s console with monitor or touch screen, barcode reader, keyboard and mouse
Variety of plates/cassettes
Plate reader
Conventional x-ray machine and table
Computed radiography steps
Enter patient information into the CR workstation
Create a study and ensure all necessary information is entered so the radiographs are legal
Perform erasure on plate(s) to be used
Select view and scan barcode of proper Imaging Plate (IP)
IP is placed in the bucky or on the table
Select proper factors
Make exposure
Insert IP into imaging reader
The image is processed onto a computer monitor
The IP is erased (flashed) so that it can be used again
After the digital radiographic image is made the image can be adjusted as needed by the veterinarian
Accept or reject image after evaluation
Complete study
Imaging plate works by
CR uses a PSP (phosphostimulable phosphor) detector screen, called an imaging plate
This type of screen absorbs and stores most of the x-ray energy, which is “read out” later
The PSP screens fit into a cassette that looks very similar to a conventional film-screen cassette; and is used identically to conventional screen-film cassette
Following exposure, the CR cassette is taken to a laser reader unit called an imaging reader
Here the latent image is processed