Solution exposure to air and light with the manual processing technique can be avoided by using a:

Citation, DOI & article data

Citation:

Shetty, A., Knipe, H. X-ray artifacts. Reference article, Radiopaedia.org. (accessed on 13 Nov 2022) https://doi.org/10.53347/rID-27307

X-ray artifacts can present in a variety of ways including abnormal shadows noted on a radiograph or degraded image quality, and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts. 

There are common and distinct artifacts for film, computed (CR) and digital radiography (DR). 

On this page:

• improper handling of the films
• errors while processing the films
• patient movement while taking the image

• motion artifact
  • due to patient movement resulting in a distorted image
• image compositing (or twin/double exposure)
  • superimposition of two structures from different locations due to double exposure of same film/plate
• grid cut-off
• radiopaque objects on/external to the patient (e.g. jewelry (e.g. necklaces, piercings), clothing (e.g. buttons), hair (e.g. ponytail, hair braids etc.)
• debris in the housing 
  • debris in the housing caused by the collimator tube can cause small trapezoidal regions, indicative of lead shavings

• finger marks
  • improper handling with hands
• clear film
  • malfunction of the machine or placing the film in the fixer before developer solution
• static electricity
  • black “lightning” marks resulting from films forcibly unwrapped or excessive flexing of the film
• crescent-shaped black lines
  • due to fingernail pressure on the film
• crescent-shaped white lines
  • due to cracked intensifying screen
• black film
  • complete exposure to light.
• clear spots
  • air bubbles sticking to film during processing
  • fixer splashed on film prior to developing
  • dirt on the intensifying screen

• detector image lag or ghosting
  • latent image from previous exposure present on current exposure
• incorrect detector orientation i.e. upside-down cassette
  • spoke like radiopaque lines (case 6)
• backscatter
  • electronics are visible on the exposed image
  • increased radiation exposure required for portable DR (digital radiography) examinations
• stitching artifacts
  • occur when two separate DR/CR (digital/computed radiography) images are merged into a single image (see case 3)
• over exposure
• dead pixel artifact
• signal dropout 4
  • large areas of signal loss, due to detector drop
• speckled radiopaque spots 4
  • due to detector drop
• detector calibration limitation 4
  • faint radiopaque striping (often vertical) in the background of an image, yet not evident on the anatomy 
  • this artifact should be carefully examined, if it does not interfere with the anatomy, it is not a detector failure/grid cut off, rather a limitation of the detector calibration
  • often seen as lower exposure
• failure of detector offset correction 4
  • similar to ghosting, however, the digital detector not being calibrated when promoted is the cause 
• electronic shutter failure 4
  • the digital image often will have obscurely shaped, tight collimation that defies logic
  • often a computer error often fixed with recollimation post exam (this should be explored before re-examination)
• values of interest misread 4
  • image appears washed out and underexposed
  • this is often due to a largely collimated area of smaller anatomy i.e. a patella protection 
  • tighter digital collimation in conjunction with reprocessing will correctly assign the correct values of interest
• mid grey clipping 4
  • loss of contrast in areas of different pixel density yet not change in density can be seen i.e. the metal on a knee replacement 
  • due to poor contrast enhancement
• grid-line suppression failure 4​​
  • faint grid lines present on an image, with no grid cut off

References

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   Film is not equally sensitive to all wavelengths (colors) of light. The spectral sensitivity is a characteristic of film that must be taken into account in selecting film for use with specific intensifying screens and cameras. In general, the film should be most sensitive to the color of the light that is emitted by the intensifying screens, intensifier tubes, cathode ray tubes (CRTs), or lasers.

Blue Sensitivity

   A basic silver bromide emulsion has its maximum sensitivity in the ultraviolet and blue regions of the light spectrum. For many years most intensifying screens contained calcium tungstate, which emits a blue light and is a good match for blue sensitive film. Although calcium tungstate is no longer widely used as a screen material, several contemporary screen materials emit blue light.

Green Sensitivity

   Several image light sources, including image intensifier tubes, CRTs, and some intensifying screens, emit most of their light in the green portion of the spectrum. Film used with these devices must, therefore, be sensitive to green light.

   Silver bromide can be made sensitive to green light by adding sensitizing dyes to the emulsion. Users must be careful not to use the wrong type of film with intensifying screens. If a blue-sensitive film is used with a green-emitting intensifying screen, the combination will have a drastically reduced sensitivity.

Red Sensitivity

   Many lasers produce red light. Devices that transfer images to film by means of a laser beam must, therefore, be supplied with a film that is sensitive to red light. 

Safelighting

   Darkrooms in which film is loaded into cassettes and transferred to processors are usually illuminated with a safelight. A safelight emits a color of light the eye can see but that will not expose film. Although film has a relatively low sensitivity to the light emitted by safelights, film fog can be produced with safelight illumination under certain conditions. The safelight should provide sufficient illumination for darkroom operations but not produce significant exposure to the film being handled. This can usually be accomplished if certain factors are controlled. These include safelight color, brightness, location, and duration of film exposure.

   The color of the safelight is controlled by the filter. The filter must be selected in relationship to the spectral sensitivity of the film being used. An amber-brown safelight provides a relatively high level of working illumination and adequate protection for blue-sensitive film; type 6B filters are used for this application. However, this type of safelight produces some light that falls within the sensitive range of green-sensitive film.

   A red safelight is required when working with green-sensitive films. Type GBX filters are used for this purpose.

   Selecting the appropriate safelight filter does not absolutely protect film because film has some sensitivity to the light emitted by most safelights. Therefore, the brightness of the safelight (bulb size) and the distance between the light and film work surfaces must be selected so as to minimize film exposure.

   Since exposure is an accumulative effect, handling the film as short a time as possible minimizes exposure. The potential for safelight exposure can be evaluated in a darkroom by placing a piece of film on the work surface, covering most of its area with an opaque object, and then moving the object in successive steps to expose more of the film surface. The time intervals should be selected to produce exposures ranging from a few seconds to several minutes. After the film is processed, the effect of the safelight exposure can be observed. Film is most sensitive to safelight fogging after the latent image is produced but before it is processed.

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What exposure factor controls contrast?

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How many minutes should you manually develop a radiograph and at what temperature?