March 3- Radiographic Errors Finals Flashcards
(45 cards)
What are the characteristics of a perfect radiograph.
- Detail, Definition, Density, Contrast.
- No placement, handling or processing errors
- Area of interest and landmarks visible (with correct size and contour)
What are the two factors affecting detail
- KVP
- Developing
4 Factors affecting definition
- Distance factors
- Focal spot size
- Receptor type
- Motion
4 Factors affecting density
- Kvp
- mAmp
- Exposure time
- Processing
4 Factors affecting contrast
- Kvp
- Receptor type
- Processing
- Subject contrast
When a radiograph isn’t perfect like we want it to be what are some things we need take into account.
- Is the error minor?
- Is the error major necessitating a retake?
- What caused the error?
• How can I ensure that the error will not occur on the retake film?
Give some examples of Patient Preparation Errors?
- Forgetting to:
- Remove glasses
- Remove dentures
- Remove piercings (Tongue and Nose rings
- Thyroid collar/ lead apron placed incorrectly/ BID not taking into account the thyroid collar/lead apron
What are some examples of Patient Errors?
Image is unsharp and blurred due to
• Patient movement
• Receptor movement
• BID movement/drifting
- Patient not biting down on bite block.
- leads to incorrect orientation of XCP holder.

what would cause a blurry image like this?

The patient moving as X-ray is taken
What is caused this image error?

Patient not biting down on bite block

What are some examples of receptor errors?
Improper placement of adhesive bite block on receptor
Putting PSP plate or film in backwards
What happens if the adhesive biteblock isn’t placed properly on the biteblock?

You could miss the apices of the teeth you are looking at OR you could miss the incisal edges

How are adhesive bite blocks properly attached to receptors/plates?

How is an adhesive bite block properly attached to a direct receptor?
For direct sensors the edge of the adhesive biteblock for anterior periapicals should be placed where the dots start-(about 3 mm above the edge of the sensor)- otherwise incisal edge will be missing on image.
If placed too down you’ll miss apices

How can you tell if film has been placed backwards in the mouth?
You will get the trade mark “tire treads” or “cobblestone” markings
OR
You could get an error an Dot Artifact from Dot in the Slot film holder. (you want the dot to be superimposed away from root apices)

How can you tell if a PSP plate has been put in the mouth backwards?
You will see a radiopaque circle on the radiograph.

What happens as a result of holder assembly error.
the most common problem with holder receptor errors is cone cutting.
ALWAYS MAKE SURE THE RECEPTOR IS IN THE MIDDLE OF THE HOLDER OR ITS NOT ASSEMBLED PROPERLY

Receptor placement error can result in missing apices.
How can this be avoided/corrected?

- Position receptor in highest part of palate/deepest part of lingual sulcus
- Use steeper vertical angulation

Incorrect receptor placement can result in you missing the specific area of interest being missed. How can this be avoided/corrected?
- Adhere to performance criteria for a full mouth series. (on moodle )
- If an isolated tooth required: place tooth of interest in center of image.
It is often difficult to position a direct sensor in a person with a small mouth or shallow palate. How can this be fixed?

• Easier with a PSP plate or film as thinner and can be brought more anterior to capture the distal of the canine

If sensor/plate/film is not placed correctly or if the BID isn’t oriented properly it can cause contacts to be overlapping.

Position the BID so that the X-ray beams pass through the contacts. This can be done by orienting the plate PARALLEL to the LINGUAL SURFACE OF THE TEETH and ensuring BID is perpendicular to the plate.

How should horizontal bitewings with tabs be positioned to avoid overlapping contacts?
Like this:

Sometimes if receptor/patient aren’t positioned properly it can result in a tipped occlusal plane. How can this be avoided?

- Solution:
- Ensure patient’s occlusal plane is parallel to floor.
- Ensure the edge of the receptor is placed parallel to the occlusal surface of the teeth.
Receptor placement error can cause foreshortening of the teeth on the radiograph. Why does this happen?

- Paralleling technique-
Receptor not parallel to long axis of tooth.
- BA technique-
Too great a vertical angulation of BID.


















